Dietary polyphenols have been considered as novel prebiotics, and polyphenols could exert their functions through modulating intestinal microbiota. The diverse bioactivities of kudingcha could derive from its phenolic compounds, but the effects of dicaffeoylquinic acids (diCQAs) from Ilex kudingcha on intestinal microbiota have not been investigated. In the present study, high-throughput sequencing and anaerobic fermentation in vitro were utilized to investigate the microecology-modulating function of I. kudingcha diCQAs. As a result, diCQAs raised the diversity and exhibited a more considerable impact than a carbon source on the microbial profile. DiCQAs increased the relative abundances of Alistipes, Bacteroides, Bifidobacterium, Butyricimonas, Clostridium sensu stricto, Escherichia/Shigella, Parasutterella, Romboutsia, Oscillibacter, Veillonella, Phascolarctobacterium, Lachnospiracea incertae sedis, Gemmiger, Streptococcus, and Haemophilus and decreased the relative abundances of Ruminococcus, Anaerostipes, Dialister, Megasphaera, Megamonas, and Prevotella. DiCQAs also affected the generation of short-chain fatty acids through microbiota. The contents of acetic and lactic acids were raised, while the production of propionic and butyric acids was reduced. Conclusively, diCQAs from I. kudingcha had significant modulating effects on intestinal microbiota in vitro, which might be the fundamental of diCQAs exerting their bioactivities.Keywords: dicaffeoylquinic acid; Ilex kudingcha; intestinal microbiota; modulating effect;

•Three polysaccharides (GRPS) were obtained from Gracilaria rubra by hot water.•GRPS-1-1, GRPS-2-1 and GRPS-3-2 were all sulfated polysaccharides.•GRPS-2-1 and GRPS-3-2 had little toxicity to L-02 cells.•GRPS-3-2 exhibited excellent antioxidant and immunostimulating activities in vitro.In this work, crude polysaccharides from Gracilaria rubra (GRPS) and its three purified fractions, GRPS-1-1, GRPS-2-1 and GRPS-3-2, were obtained through hot water extraction and chromatographic purification with DEAE-52 cellulose column and Sephadex G-50 column. The three purified fractions, being homogeneous heteropolysaccharides with average molecular weights of 1310, 691, 923 kD and sulfuric radical contents of 5.96, 8.46 and 12.03%, respectively, were all composed of galactose and fucose. GRPS-2-1 and GRPS-3-2 had little toxicity to L-02 cells. Crude GRPS and its purified fractions exhibited strong scavenging activities against ABTS and superoxide radicals and lipid peroxidation inhibition. At a cellular level, GRPS-3-2 showed the strongest protective effect on H2O2-induced oxidative injury in PC12 cells. Moreover, GRPS-3-2 exhibited a much stronger immunostimulating activity on RAW264.7 cells than GRPS-1-1 and GRPS-2-1. The results suggested that GRPS, especially GRPS-3-2, could be developed as a promising functional food supplement.

Purification, characterization, and antioxidative activity in vitro of shrimp phosphatidylcholines (PCs) were investigated. The molecular structures of shrimp PCs were determined by MALDI-TOF/TOF MS. The MS2 fragments produced from protonated PC precursors and sodiated PC precursors were identified. The specific fragments including [M + Na – trimethylamine]+, [M + Na – 205]+, [M + Na – RCOOH – trimethylamine]+, and [M + H – RCOOH – trimethylamine]+ could distinguish the precursor type to confirm PC molecular structures. The antioxidative activities of purified shrimp PC fractions were evaluated by assay of DPPH free radical scavenging activity, and their effects on the oxidative stability of camellia oil were measured by monitoring changes in the peroxide value assay during oxidation. The PC fractions from Penaeus chinesis and Macrobranchium nipponense showed stronger antioxidative activities than those of other species. All of the shrimp PCs at 0.2% (w/w) improved the oxidative stability of camellia oil significantly (P < 0.05) compared to controls. The experimental findings suggest that shrimp PCs might be a valuable source of natural antioxidants for edible oils or other food dispersions.Keywords: identification; MALDI-TOF/TOF MS; oxidative stability; shrimp PC;

•The main anthocyanin in the fruit of Lycium ruthenicum (compound 1) was prepared.•The structure of compound 1 was identified by MS and NMR.•Compound 1 had little toxicity to PC12 cells.•Compound 1 exhibited excellent antioxidant in vitro.•Compound 1 exhibited excellent cytoprotective effect on PC12 cells.The fruit of Lycium ruthenicum Murray has been widely used as a precious Chinese herbal medicine. In this study, the major anthocyanin in L. ruthenicum fruit was obtained via an AKTA purifier system with YMC-Pack ODS-A column and identified by mass and nuclear magnetic resonance spectroscopy to be petunidin 3-O-[6-O-(4-O-(trans-p-coumaroyl)-α-l-rhamnopyranosyl)-β-d-glucopyranoside]-5-O-[β-d-glucopyranoside] (compound 1). Compound 1 exhibited higher scavenging activities against 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), 1,1-diphenyl-2-picrylhydra-zyl and superoxide radicals than the crude extract of anthocyanins. Moreover, compound 1 was demonstrated to have potential cytoprotective effect on hydrogen peroxide-induced intracellular reactive oxygen damage in neuronlike rat pheochromocytoma line cells by promoting cell proliferation, mitigating lipid peroxidation and regulating endogenous antioxidant enzymes (glutathione peroxidase, superoxide dismutase and catalase).

•CS/GA-CS/GA-g-CS, gelatin, glycerol and Tween20 were utilized to formulate films.•Moisture content and water vapor permeability decreased in GA-CS and GA-g-CS films.•Mechanical property was improved with the increase of GA concentration.•Antioxidant and antimicrobial activities of GA-g-CS films exceeded GA-CS films.Gallic acid-grafted-chitosan (GA-g-CS) was synthesized in the presence of 1-ethyl-3-(3′-dimethylaminopropyl) carbodiimide and hydroxybenzotriazole under room temperature. To develop a kind of newly functional film, CS, gelatin, glycerol and Tween 20 were utilized to prepare CS-based composite films with incorporated GA (GA-CS) or conjugated GA (GA-g-CS), and the films were characterized in aspects of physical and functional properties, as well as microstructures. With the increasing of GA concentration, there was a reduction in transmittance, elongation at break and water vapor permeability (WVP) for GA-CS film. For GA-CS films, the higher tensile strength and lower WVP could be obtained when GA was evenly distributed across the films. Different from the GA-CS films, water solubility, swelling ratio, water vapor permeability and scavenging activities on 2,2-Diphenyl-1-picrylhydrazyl/2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) radicals were enhanced for GA-g-CS films, which could be ascribed to the rough surface morphology. The GA-g-CS films exhibited enhanced water vapor permeability when the substitution degree of GA increased. Also, the antimicrobial activities of GA-g-CS films were superior to those of GA-CS films. Our present work developed a way to prepare GA-g-CS films that owned many desirable properties and could be explored as promising biomaterials in food packaging.

•Chlorogenic acid (CGA) and high deacetylation degree of chitosan was conjugated.•The substitution degree of CGA reached up to 144.8 mg CGA equivalent/g complex.•The solubility of conjugate was greatly enhanced due to conjugation.•The conjugate exhibited higher inhibitory effect on lipid peroxidation than CGA.•The conjugate had higher inhibition on β-carotene-linoleic acid bleaching than CGA.Chlorogenic acid-chitosan conjugate was synthesized by introducing of chlorogenic acid onto chitosan with the aid of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and hydroxybenzotriazole. The data of UV–vis, FT-IR and NMR for chlorogenic acid-chitosan conjugates demonstrated the successful conjugation of chlorogenic acid with chitosan. Compared to chitosan, chlorogenic acid-chitosan conjugates exhibited increased solubility in distilled water, 1% acetic acid solution (v/v) or 50% ethanol solution (v/v) containing 0.5% acetic acid. Moreover, chlorogenic acid-chitosan conjugates showed dramatic enhancements in metal ion chelating activity, total antioxidant capacity, scavenging activities on 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) and superoxide radicals, inhibitory effects on lipid peroxidation and β-carotene-linoleic acid bleaching, and protective effect on H2O2-induced oxidative injury of PC12 cells. Particularly, chlorogenic acid-chitosan conjugate exhibited higher inhibitory effects on lipid peroxidation and β-carotene-linoleic acid bleaching than chlorogenic acid. The results suggested that chlorogenic acid-chitosan conjugates could serve as food supplements to enhance the function of foods in future.

In the present study, digestion under saliva, simulated gastric and small intestinal conditions and fermentation in vitro of polysaccharides from the flowers of Camellia sinensis (TFPS) by human gut microbiota were investigated. The results indicated that human saliva and simulated gastric and intestinal juices had no effect on TFPS, while TFPS could be utilized by human fecal microbiota, which was proved from the decreased molecular weight and lower content of total or reducing sugars after fermentation under anaerobic conditions. It was found that pH in the fermentation system decreased, and the production of short-chain fatty acids was significantly enhanced. Furthermore, in vitro fermentation of TFPS altered the composition of gut microbiota, specifically in elevating the ratio of Bacteroidetes to Firmicutes and enriching Prevotella. The present results suggest that TFPS has the potential to be developed as functional foods to modify gut microbiota.

•Ciceritol could enhance growth of Lactobacillus–Enterococcus and Bifidobacterium spp.•Ciceritol could inhibit growth of Bacteroides–Prevotella and C. histolyticum groups.•Production of SCFAs was improved by addition of ciceritol.•Ciceritol from chickpeas could behave as a potential prebiotics.The aim of this study was to evaluate the effects of ciceritol on human colonic microflora and the production of short chain fatty acids (SCFAs). Ciceritol was extracted from chickpeas by using 50% ethanol-water solvent with a ratio of 1:10, and the extract was purified by chromatography of charcoal-Celite column and gel chromatography of Biogel P-2 column. Bacterial population and the concentration of SCFAs during in vitro anaerobic fermentation were investigated to evaluate the effect of ciceritol on human colonic microflora. The results indicated that the addition of ciceritol could significantly enhance the growth of Lactobacillus–Enterococcus group (8.26 compared to 7.71 log10 cells/mL of control group) and Bifidobacterium spp. (10.43 compared to 9.45 log10 cells/mL of control group), and inhibit the growth of Bacteroides–Prevotella, Clostridium histolyticum and Eubacterium–Clostridium groups. Besides, the production of SCFAs was significantly improved by addition of ciceritol that the content was twice of the control group. Accordingly, we conclude that ciceritol can behave as a potential prebiotics by optimizing the microflora of human colon and promoting the production of SCFAs, which will benefit to human health.

•This review presented naturally occurring polysaccharides from tea materials (TPS).•Main methods for extraction and purification were summarized.•Physicochemical characterization and functional property of TPS were summarized.•Relationship between structure and biological activity of TPS was presented.•Future perspective and challenges of TPS were proposed.Tea has a long history of medicinal and dietary use. Tea polysaccharide (TPS) is regarded as one of the main bioactive constituents of tea and is beneficial for health. Over the last decades, considerable efforts have been devoted to the studies on TPS: extraction, structural feature and bioactivity of TPS. However, it has been received much less attention compared with tea polyphenols. In order to provide new insight for further development of TPS in functional foods, in present review we summarize the recent literature, update the information and put forward future perspectives on TPS covering its extraction, purification, quantitative determination techniques as well as physicochemical characterization and bioactivities.

•The hot water extraction of CHPS was optimized by a Box–Behnken design.•The maximum extraction yield of CHPS was 5.37 ± 0.15%.•Three fractions were purified from CHPS by using the method of chromatography.•Crude CHPS and its purified fractions showed excellent antioxidant activity in vitro and in cellular level.The optimal extraction conditions with a yield of 5.37 ± 0.15% for extraction of polysaccharides from chickpea (Cicer arietinum L.) hull (CHPS) were determined as extraction temperature 99 °C, extraction time 2.8 h and ratio of water to raw material 24 mL/g. Three fractions of CHPS-1, CHPS-2 and CHPS-3, with average molecular weight of 3.1 × 106, 1.5 × 106 and 7.8 × 105 Da, respectively, were obtained from crude CHPS by chromatography of DEAE Fast Flow and Sephadex G-100. CHPS-1 was composed of mannose, rhamnose, galactose, galacturonic acid, glucose and arabinose, CHPS-2 was composed of mannose, rhamnose, galacturonic acid, galactose, xylose and arabinose, CHPS-3 was composed of galacturonic acid, galactose and rhamnose. CHPS-3 showed the strongest reducing power and protective effect on H2O2-induced oxidative injury in PC12 cells and highest scavenging activities against DPPH and ABTS radicals, while CHPS-2 showed the highest scavenging activity against superoxide anion radical.

Monocaffeoylquinic acids (mono-CQAs) can be hydrolyzed or metabolized by pancreatin, intestinal brush border esterase, and microbiota in the colon. Data about the conversion of dicaffeoylquinic acids (diCQAs) in digestion are scarce. The diCQA-rich fraction including 3,4-, 3,5-, and 4,5-diCQAs was prepared from Ilex kudingcha, and the conversion in simulated gastricintestine was investigated. Artificial saliva, gastric and pancreatic fluids, Caco-2 monolayer cells, and anaerobic fermentation model were utilized to mimic digestions of the oral cavity, stomach, small intestine, and colon in vitro. The results revealed that diCQAs remained intact in simulated saliva, gastric, and pancreatic fluids and within Caco-2 cells. In anaerobic fermentation with human fecal slurry, diCQAs were hydrolyzed to mono-CQAs and caffeic acid, which were further metabolized to caffeic acid and dihydrocaffeic acid, respectively. The hydrolysis of diCQAs depended on the chemical structures, carbohydrates in the culture medium, and microbial compositions. Our research demonstrated that hydrolysis of diCQAs happened in the colon by intestinal microbiota.Keywords: dicaffeoylquinic acid; digestion in vitro; intestinal microbiota; kudingcha;

The effects of several parameters on the extraction yield of total polyphenols from grape seeds by pressurized liquid extraction were investigated. The highest recovery of total polyphenols occurred at 80 °C within 5 min, and a single extraction allowed a recovery of more than 97% of total polyphenols. Following the purification with macroporous resin, the effects of grape polyphenols (>94.8%) on human intestinal microbiota were monitored over 36 h incubation by fluorescence in situ hybridization, and short-chain fatty acids (SCFAs) were measured by HPLC. The result showed that the grape polyphenols promoted the changes in the relevant microbial populations and shifted the profiles of SCFAs. Fermentation of grape polyphenols resulted in a significant increase in the numbers of Bifidobacterium spp. and Lactobacillus–Enterococcus group and inhibition in the growth of the Clostridium histolyticum group and the Bacteroides–Prevotella group, with no significant effect on the population of total bacteria. The findings suggest that grape polyphenols have potential prebiotic effects on modulating the gut microbiota composition and generating SCFAs that contribute to the improvements of host health.

The enzymatic acylation of anthocyanin from black rice with aromatic acid methyl esters as acyl donors and Candida antarctica lipase B was carried out under reduced pressure. The highest conversion of 91% was obtained with benzoic acid methyl ester as acyl donor; cyanidin 3-(6″-benzoyl)-glucoside, cyanidin 3-(6″-salicyloyl)-glucoside, and cyanidin 3-(6″-cinnamoyl)-glucoside were successfully synthesized. This is the first report on the enzymatic acylation of anthocyanin from black rice with methyl aromatic esters as acyl donors and lipase as biocatalyst. Furthermore, the acylation with aromatic carboxylic acids enhanced both the thermostability and light resistivity of anthocyanin. In particular, cyanidin 3-(6″-cinnamoyl)-glucoside was the most stable among the three acylated anthocyanins synthesized.

Modification of chitosan (CS) through grafting with caffeic acid (CA, CA-g-CS) and ferulic acid (FA, FA-g-CS) significantly improved its solubility under neutral and alkaline environments. Spherical and physicochemically stable nanocomplexes assembled from the phenolic acid grafting CS and caseinophosphopeptide (CPP) were obtained with particle size <300 nm and zeta potential of <+30 mV. The net polymer nanocomplexes composed with the phenolic acid grafting CS and CPP showed strong antioxidant activity. The encapsulation efficiencies of epigallocatechin-3-gallate (EGCG) in the CA-g-CS–CPP nanocomplexes and FA-g-CS–CPP nanocomplexes were 88.1 ± 6.7 and 90.4 ± 4.2%, respectively. Improved delivery properties of EGCG were achieved after loading with the antioxidant nanocomplexes, including controlling release of EGCG under simulated gastric environments and preventing its degradation under neutral and alkaline environments.

•In vitro fermentation study of pure components of GOS and FOS was carried out.•A relatively high selectivity toward bifidobacteria and higher PI values with GOS.•GOS with β-(1→6) linkages had higher PI values than those of β-(1→4) linkages.•Higher values of lactobacilli were obtained with pure components of FOS.•Structure–prebiotic function relationship of GOS and FOS was obtained.A structure–function study was carried out to expand the knowledge base of the effects of carbohydrate glycosidic linkage, monosaccharide composition and degree of polymerization (DP) on the selectivity of fermentation by mixed culture. Galactooligosaccharides (GOS) with β-(1→4)- and β-(1→6)-linkages were prepared from the transgalactosylation of β-D-galactosidases from Bacillus circulans and Aspergillus oryzae with lactose as substrate, respectively, whereas fructooligosaccharides (FOS) with varied DP from three to five were commercially obtained. Pure single components of GOS and FOS were purified and characterized by mass spectrometry with an electrospray ionization source and nuclear magnetic resonance spectroscopy, and a prebiotic index (PI) was calculated for each oligosaccharide. The results demonstrated that GOS showed a relatively high selective stimulation toward bifidobacteria as well as higher PI value compared with FOS, and GOS with β-(1→6)-linkage exhibited relatively higher PI value than GOS with β-(1→4)-linkage, whereas higher value toward lactobacilli was observed for FOS. Additionally, with the exception of GOS with β-(1→6)-linkages, all investigated oligosaccharides gave similar PI values at 24 h, although significant variations were found for the growth of different genus bacteria in mixed cultures.

•PDP-3 inhibited the proliferation of human breast estrogen-dependent cancer MCF-7 cells.•PDP-3 regulated proteins expression in the proliferation and cell cycle in MCF-7 cells.•PDP-3 regulated expression of ERα and proteins involved in the apoptosis in MCF-7 cells.•P38/MAPK signal transduction pathway was the potential mechanism of PDP-3 in regulating both of proliferation and apoptosis.The antiproliferative and apoptosis-inducing activities of an acidic polysaccharides fraction from Pholiota dinghuensis Bi mycelium (PDP-3) against human breast cancer MCF-7 cells were investigated. As a result, PDP-3 displayed a significant prevention of cell growth towards MCF-7 cells, with an EC50 value of 38.35 µg/mL. Furthermore, PDP-3 induced significant apoptosis towards MCF-7 cells. From Western blot results, up-regulated p21 and down-regulated cyclin D1, CDK4 and PCNA, up-regulated Bax and down-regulated Bcl-2, caspase-9 and caspase-3 were found in the protein expressions of MCF-7 cells. In MCF-7 cells treated with PDP-3, down-regulated TRAF2 and up-regulated ASK1, phosphorylated of p38 and p53 were also found. Notably, PDP-3 treatment represented a significant decrease in both nuclear and cytoplasmic expression of ERα in MCF-7 cells. Therefore, p38/MAPK signal transduction pathway was the potential mechanism of PDP-3 in regulating both cell proliferation and apoptosis in oestrogen-dependent human breast cancer MCF-7 cells.

•The hot water extraction of MLP was optimized by a Box–Behnken design.•The maximum extraction yield of MLP was 10.0 ± 0.5%.•Crude MLP and its purified fractions (MLP-3a and MLP-3b) were acidic polysaccharides.•MLP-3b had a relatively high content of uronic acid.•Crude MLP, MLP-3a and MLP-3b exhibited potent antioxidant activity in vitro.Extraction optimization, characterization and antioxidant activity in vitro of polysaccharides from mulberry leaves (MLP) were investigated in the present study. The optimal extraction conditions with an extraction yield of 10.0 ± 0.5% for MLP were determined as follows: extraction temperature 92 °C, extraction time 3.5 h and ratio (v/w, mL/g) of extraction solvent (water) to raw material 34. Two purified fractions, MLP-3a and MLP-3b with molecular weights of 80.99 and 3.64 kDa, respectively, were obtained from crude MLP by chromatography of DEAE-Cellulose 52 and Sephadex G-100. Fourier transform-infrared spectroscopy revealed that crude MLP, MLP-3a and MLP-3b were acidic polysaccharides. Furthermore, crude MLP and MLP-3a had more complicated monosaccharide compositions, while MLP-3b had a relatively higher content of uronic acid. Crude MLP, MLP-3a and MLP-3b exhibited potent Fe2+ chelating power and scavenging activities on 1,1-diphenyl-2-picrylhydrazyl, hydroxyl, superoxide and 2,2′-azinobis-(3-ethyl-benzothiazolin-6-sulfonic acid) radicals. The results suggested that MLP could be explored as natural antioxidant.

•Structural characterization of CSPS-1 was performed by methylation and GC–MS.•Backbone chains of CSPS-1 were linked by 1 → 4 glycosidic bonds.•Branches were attached to main chain by 1 → 6 glycosidic bonds.•Sulfated modification of CSPS-1 was accomplished by the CSA-Pyr method.•Antitumor activity of CSPS-1 was enhanced after sulfated modification.In the present study, we investigated the preliminary structure, sulfation and antitumor activity of a polysaccharide fraction from Cyclina sinensis (CSPS-1). Results of structural characterization showed that the backbone chain of CSPS-1 was composed of glucose linked by α-(1 → 4) glycosidic bond, and the branch chain was attached to backbone chain by (1 → 6) glycosidic bond. CSPS-1 was sulfated by chlorosulfonic acid-pyridine method under different modification conditions according to the orthogonal test L9(34), affording nine sulfated polysaccharides (CSPS-1-S). The optimal sulfation conditions for CSPS-1 were reaction temperature of 65 °C, reaction time of 2 h and chlorosulfonic acid-pyridine ratio of 1:4. Structural analysis revealed that sulfation had occurred at position of C-6 in CSPS-1. In addition, CSPS-1-S exhibited significantly higher inhibitory activity in vitro against human gastric cancer BGC-823 cells.

•A deconvolution method was used to detect crystal structure changes in starch.•A moisture analysis method was used to detect crystal structure changes in starch.•The two methods could provide mutual corroboration.To detect more credibly the changes in the crystal structure of chickpea starch during processing treatments, two methods, a deconvolution method based on X-ray diffraction (XRD) pattern of starch and a moisture analysis method based on starch moisture content, were applied to determine the relative crystallinity (RC) of A- and B-type polymorphs (RCA and RCB) in the same chickpea starch sample. It was found that the values of RCA for chickpea starch samples determined by these two methods were close and showed similar trend. The results suggested that these two methods could be used to estimate RCA in the same chickpea starch sample and provide mutual corroboration. Based on the deconvolution method, it was observed that the crystalline region of chickpea starch was less susceptible to α-amylase hydrolysis than its amorphous region, and B-type polymorph in chickpea starch was more resistant to α-amylase hydrolysis than A-type polymorph.

Anti-angiogenic activities of crude Hyriopsis cumingii polysaccharides (HCPS) and its purified fractions (HCPS-1, HCPS-2 and HCPS-3) were evaluated in vivo using the chicken embryo chorioallantoic membrane (CAM) assay. The promoting effects of crude HCPS and its purified fractions on the chemotaxis, proliferation and phagocytosis of peritoneal macrophage were tested by cell model in vitro and cyclophosphamide-induced immuno-suppression animal model in vivo. The results showed that HCPS could significantly suppress the neovascularization of chicken embryo CAM and promote peritoneal macrophage migrating to monocyte chemotactic protein-1 (MCP-1), propagating and devouring sheep red blood cell (SRBC) in a dose-dependent manner. In addition, HCPS-3 showed stronger immunostimulatory activities in vitro than crude HCPS, HCPS-1 and HCPS-2. The beneficial effects of HCPS on the immune system might be, at least in part, attributed to the improvement of chemotaxis, proliferation and phagocytosis of peritoneal macrophage. All these results suggest that HCPS is a potential immunoenhancing and anti-tumor agent.

The present study provided a new approach to enhance the stability of protein-emulsified nanoemulsions and to control the lipase digestibility of lipid droplets through spontaneous cross-linking of the interfacial layer with genipin, a functional ingredient isolated from the fruit of Gardenia jasminoides E. Cross-linking casein-emulsified nanoemulsions under different genipin/casein mass ratios (1:20, 1:10, 1:5) significantly (p < 0.05) or very significantly (p < 0.01) enhanced their stability under harsh gastric pH environments and prevented nanoemulsion flocculation. As observed by transmission electron microscope (TEM), under the pH 1.2 condition, the genipin cross-linked nanoemulsion showed more compact microstructure with clear and defined contour as well as “core–shell” structure caused by the swelling of the surface protein film. Interestingly, the intestinal digestibility of lipid droplets was delayed very significantly (p < 0.01) after cross-linking the interfacial casein layer with genipin, which was enhanced by the increase in genipin/casein mass ratio and cross-linking time.

Polyphenols and caffeoylquinic acid (CQA) derivatives (3-CQA, 4-CQA, 5-CQA, 3,4-diCQA, 3,5-diCQA, and 4,5-diCQA) were prepared from Ilex kudingcha C.J. Tseng, and their effects and mechanisms on the activities of α-glucosidase from Saccharomyces cerevisiae were investigated in the present study. As results, the IC50 values for CQA derivatives were 0.16–0.39 mg/mL, and the inhibition mode of CQA derivatives was noncompetitive. On the basis of fluorescence spectroscopy and circular dichroism spectroscopy data, the binding constants and number of binding sites were calculated to be 106–108 M–1 and 1.42–1.87, respectively. CQA derivatives could bind to the enzyme mainly through hydrophobic interaction, altering the microenvironment and molecular conformation of the enzyme, thus decreasing the catalytic activity. To the authors’ knowledge, this is the first report on α-glucosidase inhibitory mechanism by CQA derivatives from I. kudingcha, and the findings suggest a potential use of kudingcha as functional foods for the prevention and treatment of diabetes and related symptoms.

Sinonovacula constricta has been widely used as a health food and medicine in China, Japan, and Korea. In the present study, a water-soluble polysaccharide fraction (SCP-1) was prepared from S. constricta by enzyme-assisted extraction and purification of chromatography with DEAE-52 cellulose anion-exchange column and Sephadex G-100 size exclusion column. On the basis of the analytical results of high-performance liquid chromatography, Fourier transform-infrared spectroscopy, methylation analysis, and NMR spectroscopy, SCP-1 was found to have an average molecular weight of 15.63 kDa and a linear backbone of (1→4)-linked α-d-Glcp residue with one branch, α-d-Glcp, attached to the main chain by a (1→6) glycosidic bond at every five α-d-Glcp units. Furthermore, it was found that SCP-1 could significantly increase the viability of macrophages, enhance the capability of macrophage phagocytosis, increase the activity of acid phosphatase, and promote the production of nitric oxide, mouse tumor necrosis factor (TNF)-α, mouse interferon (IFN)-γ, and mouse interleukin (IL)-1β. The results suggest that SCP-1 possesses potent immunomodulating effect and may be explored as a potential biological response modifier.

The effects of thermosonication on enzymes (polyphenolase, peroxidase, pectinmethylesterase and lipoxygenase), microorganisms (total plate count, yeast and mold), coloring pigments (carotenoids, lutein and lycopene), ascorbic acid, total phenols, flavonoids, tannins, pH, acidity, °Brix and color of carrot juice in comparison with thermal treatment were investigated. Carrot juice was thermosonicated (20 kHz, 70 % amplitude and 48 W cm−2 of ultrasonic intensity) at 20, 40 and 60 °C for 5 and 10 min using 5 s on/off pulse cycle. The thermal treatment was carried out in a water bath at 80 °C for 1 min. The highest inactivation of enzymes and microorganisms was achieved after thermal and thermosonicated (60 °C) treatments. However, maximum improvement in coloring pigments and more retention of ascorbic acid, total phenols, flavonoids and tannins were observed in thermosonicated (60 °C) treatment compared to thermal treatment. °Brix, pH and acidity remained unchanged irrespective of treatments. The results suggest that thermosonication at 60 °C may be a good alternative to thermal treatment and it may successfully be applied to carrot juice production with reduced enzymes and microbial activity and improved bioactive compounds.

•Sonication could enhance the individual polyphenolic compounds of apple juice.•It could improve the sugar contents, some mineral elements and total carotenoids.•Sonication did not affect the total anthocyanins and electrical conductivity.•Sonication showed a potential to enhance the phytonutrients of apple juice.A study was initiated with the objective of evaluating the effects of sonication treatment on quality characteristics of apple juice such as polyphenolic compounds (chlorogenic acid, caffeic acid, catechin, epicatechin and phloridzin), sugars (fructose, glucose and sucrose), mineral elements (Na, K, Ca, P, Mg, Cu and Zn), total carotenoids, total anthocyanins, viscosity and electrical conductivity. The fresh apple juice samples were sonicated for 0, 30 and 60 min at 20 °C (frequency 25 kHz and amplitude 70%), respectively. As results, the contents of polyphenolic compounds and sugars significantly increased (P < 0.05) but the increases were more pronounced in juice samples sonicated for 30 min whereas, total carotenoids, mineral elements (Na, K and Ca) and viscosity significantly increased (P < 0.05) in samples treated for 60 min sonication. Losses of some mineral elements (P, Mg and Cu) also occurred. Total anthocyanins, Zn and electrical conductivity did not undergo any change in the sonicated samples. Findings of the present study suggest that sonication technique may be applied to improve phytonutrients present naturally in apple juice.

•Quality enhancement of apple juice by thermosonication has been investigated.•Thermosonication enabled inactivation of enzymes and microbes of apple juice.•Retention of ascorbic acid and polyphenolic compounds was observed.•The pH, titratable acidity and °Brix remained unaffected.•The technique could be efficiently utilized for apple juice processing.Enzymatic browning and microbial growth lead to quality losses in apple products. In the present study, fresh apple juice was thermosonicated using ultrasound in-bath (25 kHz, 30 min, 0.06 W cm−3) and ultrasound with-probe sonicator (20 kHz, 5 and 10 min, 0.30 W cm−3) at 20, 40 and 60 °C for inactivation of enzymes (polyphenolase, peroxidase and pectinmethylesterase) and microflora (total plate count, yeast and mold). Additionally, ascorbic acid, total phenolics, flavonoids, flavonols, pH, titratable acidity, °Brix and color values influenced by thermosonication were investigated. The highest inactivation of enzymes was obtained in ultrasound with-probe at 60 °C for 10 min, and the microbial population was completely inactivated at 60 °C. The retention of ascorbic acid, total phenolics, flavonoids and flavonols were significantly higher in ultrasound with-probe than ultrasound in-bath at 60 °C. These results indicated the usefulness of thermosonication for apple juice processing at low temperature, for enhanced inactivation of enzymes and microorganisms.

•A FT-IR method is developed to determine the relative crystallinity (RC) of starch.•There is a holocrystalline-peak (HCP) in FT-IR spectra of starch.•The HCP can be divided into amorphous region and crystalline region.•The RC of starch is the ratio of the area of crystalline region to the area of HCP.•The RC of starch determined by FT-IR is in agreement with that determined by XRD.A new method for determining the relative crystallinity (RC) of chickpea starch was developed by using Fourier-transform infrared (FT-IR) spectroscopy, based on hypotheses as described as follows: there is a Gaussian holocrystalline-peak (HCP) in the 800–1300 cm−1 region of FT-IR spectrum of starch which is divided into amorphous region and crystalline region; the crystalline region of HCP is the overlap of the HCP and the FT-IR spectrum of starch; the RC of starch is the ratio of the area of crystalline region to the area of HCP. It was found that there was no significant difference between the RC determined by FT-IR method and that determined by X-ray diffraction (XRD) method. The intra-class correlation coefficient was 0.998 (p = 0.000, n = 9) and the 95% confidence interval was 0.992–1.000 for the RC determined by XRD and FT-IR. Furthermore, the developed method showed good repeatability (coefficient of variation (CV), 1.1–2.9%) and good intermediate precision (CV, 2.8%).

•The medium for production of mycelium biomass and PHEPS was optimized.•The maximum production of mycelium biomass 12.98 ± 0.14 and PHEPS 5.33 ± 0.11 g/L were obtained.•PHEPS showed relative higher antiproliferative activity in vitro against HepG2 cells.•PHEPS could be explored as promising antitumor agents.In the present study, optimal medium for the growth of mycelia and the production of exopolysaccharides from Paecilomyces hepiali HN1 (PHEPS) in submerged culture was investigated. As a result, the maximum production of mycelia (12.98 ± 0.14 g/L) and PHEPS (5.33 ± 0.11 g/L) were achieved under the optimal medium of sucrose 46.08 g/L, yeast extract 4.71 g/L, (NH4)2SO4 5.72 g/L, KH2PO4 1.70 g/L, CaCl2 0.50 g/L, MgSO4 0.50 g/L, potato extract 1% and malt extract 1%. Furthermore, the antitumor activity of PHEPS in vitro was evaluated by using three cell lines of human liver tumor HepG2 cells, breast cancer MCF-7 cells and cervical cancer Hela cells. It was found that PHEPS exhibited relative higher anti-proliferative activity against HepG2 cells than MCF-7 cells and Hela cells. At a concentration of 500 μg/mL and 72 h treatment, the inhibition rate of PHEPS on HepG2 cells reached to 62.58%. All these results suggested that PHEPS could be explored as novel natural antitumor agent with great potential application.

A new, simple, and effective method to graft gallic acid (GA) onto chitosan (CS) in aqueous solution in the presence of carbodiimide and hydroxybenzotriazole was developed. The grafting amount of GA reached as much as 209.9 mg/g of copolymer, which appears as the highest one among the reported literature, and the grafting degree of GA to CS was adjustable with modulation of the mass ratio of GA to CS. The covalent insertion of GA onto the polymeric backbones was confirmed by UV–vis and 1H NMR analyses. Grafting endowed the resulting copolymer GA-grafted-CS (GA-g-CS) with both the advantages of CS and GA. The antioxidant capacity of GA-g-CS was much higher than that of the plain CS examined by assays of DPPH, superoxide, and ABTS radicals scavenging activities, reducing power, chelating power, inhibition of lipid peroxidation, ferric reducing antioxidant potential, and β-carotene-linoleic acid assays. Particularly, GA-g-CS showed significantly higher antioxidant activity than GA in β-carotene-linoleic acid assay. Furthermore, the viscosity of GA-g-CS was significantly higher than that of CS. The present study developed a novel approach to synthesize GA-g-CS that could be a potential biomaterial in food industries.

In order to investigate the inhibitory effects and possible mechanisms of Oolong tea polyphenols, (−)-epigallocatechin gallate (EGCG) and (−)-epigallocatechin 3-O-(3-O-methyl) gallate (EGCG3″Me) on pancreatic α-amylase, the inhibition, enzyme kinetics, ultraviolet (UV) absorption spectrum and fluorescence spectrum of α-amylase were investigated. The results showed that Oolong tea polyphenols, EGCG, and EGCG3″Me all exhibited inhibitory effects against α-amylase, and their half inhibitory concentration (IC50) values were 0.375, 0.350, and 0.572 mg/mL, respectively. The results of Lineweaver–Burk double reciprocal plot indicated that the inhibitory types of Oolong tea polyphenols and EGCG were competitive, whereas EGCG3″Me was in a noncompetitive pattern. Oolong tea polyphenols, EGCG, and EGCG3″Me all induced red-shift of UV absorbance and quenching of fluorescence of α-amylase, suggesting possible changes in the conformation of α-amylase. The differences of inhibitory effects and inhibition types for EGCG and EGCG3″Me might be due to their structural difference (the hydroxyl group at C-3 in D ring of EGCG substituted by methoxy group, forming EGCG3″Me).

In the present study, the immunostimulatory activity of verbascose from mung beans (Phaseolus aureus) was evaluated by using in vitro cell models and in vivo animal models. The results of in vitro experiments showed that verbascose could enhance the ability of devouring neutral red of peritoneal macrophages and promote the release of nitric oxide and immune reactive molecules such as interleukin (IL)-6, IL-1β, interferon (IFN)-α, and IFN-γ. Treatment with verbascose at a dose of 200 μg/mL exhibited the best effects. For assay in vivo, administration of verbascose at a medium dose of 90 mg/kg body weight could significantly increase the index of spleen, activity of lysozyme in spleen and serum, hemolysin level in serum, and swelling rate of earlap in the delayed type of hypersensitivity (DTH) of immunosuppressed mice. All of the results suggested that verbascose had potent immunostimulatory activity and could be explored as a potential natural immunomodulatory agent in functional foods.

Genipin-cross-linked caseinophosphopeptide (CPP)–chitosan (CS) nanoparticles (smaller than 300 nm) showed significantly improved stability and adjustable release profile in the gastrointestinal (GI) tract. Optimal purification of the nanoparticles was established by centrifugation to terminate the cross-linking reaction, which was further confirmed and characterized by FT-IR. Results from transmission electron microscopy (TEM), dynamic light scattering (DLS), and electrophoretic mobility (ζ-potential) measurements revealed that genipin cross-linking significantly prevented the bursting of the CPP–CS nanoparticles in simulated stomach acid and their precipitation under neutral intestinal environment. Pepsin showed little impact on the nanoparticle colloid stability; however, trypsin induced their aggregations. Genipin cross-linking slowed the burst release of (−)-epigallocatechin-3-gallate (EGCG) from the nanoparticles. The EGCG-loaded nanoparticles showed strong cytotoxicity against cancer cells; meanwhile, the net nanoparticles demonstrated high biocompatibility. The findings in the present work provide fundamental information for the rational design of biopolymer nanoparticles as an effective delivery systems for polyphenols.

Fresh apple juice treated with ultrasound (for 0, 30, 60 and 90 min, at 20 °C, 25 kHz frequency) was evaluated for different physico-chemical, Hunter color values, cloud value, antioxidant capacity, scavenging activity on 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical, ascorbic acid, total phenolics, flavonoids, flavonols and microbial characteristics. No significant effect of sonication was observed on pH, total soluble solids (°Brix) and titratable acidity of apple juice. Sonication significantly improved ascorbic acid, cloud value, phenolic compounds, antioxidant capacity, DPPH free radical scavenging activity and differences in Hunter color values. Moreover, significant reduction in microbial population was observed. Findings of the present study suggested that sonication treatment could improve the quality of apple juice. It may successfully be employed for the processing of apple juice with improved quality and safety from consumer’s health point of view.

In the present study, we investigated the preliminary structure, in vitro antioxidant and in vivo hepatoprotective activities of polysaccharides from Cyclina sinensis (CSPS). The analytic results of Fourier transform-infrared spectroscopy indicated the presence of α-type glycosidic linkages in CSPS-1 or CSPS-2, and the average molecular weights for CSPS-1, CSPS-2 and CSPS-3 were 69, 81 and 101 kDa, respectively. For antioxidant activities in vitro, crude CSPS, CSPS-1, CSPS-2 and CSPS-3 showed moderate H2O2 scavenging activity, lipid peroxidation inhibition effect and strong Fe2+ chelating activity. For hepatoprotective activity in vivo, the administration of CSPS significantly decreased serum levels of alanine aminotransferase and aspartate aminotransferase, inhibited the formation of malondialdehyde and enhanced the activities of liver superoxide dismutase and glutathione peroxidase in carbon tetrachloride-induced liver injury mice. These results suggested that CSPS had potent antioxidant and hepatoprotective activities.Highlights► There were α-type glycosidic linkages in CSPS-1 and CSPS-2. ► Average molecular weights of CSPS-1, CSPS-2 and CSPS-3 were 69, 81 and 101 kDa, respectively. ► CSPS exhibited high antioxidant activities in vitro. ► CSPS exhibited a significant protective effect against CCl4-induced acute hepatotoxicity in mice.

•The molecular weights of SPS-3-1 and SPS-3-2 were determined to be 5.87 and 7.25 kDa, respectively.•SPS-3-1 was composed of glucose, mannose and galactose in a molar ratio of 11.18:1.00:0.96.•SPS-3-2 was composed of fucose, xylose, mannose, glucose and galactose in a molar ratio of 2.53:0.61:1.00:0.46:0.92.•SPS-3-2 was composed of (1→4)-linked fucopyranosyl backbone.•Branch chains of SPS-3-2 consisted of (1→3)-linked galactopyranosyl, (1→3)-linked mannopyranosyl, (1→2)-linked xylopyranosyl and (1→6)-linked glucopyranosyl residues.The structural characteristics of two purified fractions of polysaccharides from Sargassum pallidum (SPS) were investigated in the present study. As results, the molecular weights of the two polysaccharide fractions, SPS-3-1 and SPS-3-2, were determined to be 5.87 and 7.25 kDa, respectively. SPS-3-1 was composed of glucose, mannose and galactose in a molar ratio of 11.18:1.00:0.96, while SPS-3-2 was composed of fucose, xylose, mannose, glucose and galactose in a molar ratio of 2.53:0.61:1.00:0.46:0.92. Both SPS-3-1 and SPS-3-2 exhibited the characteristics of polysaccharide in the frequency range of 4000–400 cm−1 based on their Fourier-transform infrared spectra. Furthermore, the results of periodic acid oxidation, Smith degradation, methylation analysis and nuclear magnetic resonance spectroscopic analysis suggested that SPS-3-2 was composed of (1→4)-linked fucopyranosyl backbone and (1→3)-linked galactopyranosyl, (1→3)-linked mannopyranosyl, (1→2)-linked xylopyranosyl and (1→6)-linked glucopyranosyl branch chains.

The peduncles of Hovenia dulcis, containing abundant nutrients and having a taste like a combination of raisin, clove, cinnamon and sugar, have been consumed as fruits and used as traditional herbal medicine for a long time in China. Up to date, little information is available about the polysaccharides from peduncles of H. dulcis (HDPS) and their potential bioactivity. In this study, three purified fractions were prepared by sequential purification of crude HDPS through ion-exchange chromatography and gel-filtration chromatography. The three fractions of HDPS-1, HDPS-2 and HDPS-3 were found to be homogeneous heteropolysaccharides mainly composed of rhamnose, arabinose, galactose and galacturonic acid with an average molecular weight of 235, 70 and 53 kDa, respectively. HDPS-3 was quite different from HDPS-1 and HDPS-2, as it contained much higher content of galacturonic acid (40.5%). In vitro immunostimulatory activity evaluation revealed that all the three fractions could significantly stimulate the proliferation of splenocytes and enhance phagocytosis, nitric oxide production and acid phosphatase activity of peritoneal macrophages, which suggested that HDPS had a potent immunostimulatory activity and could be explored as a potential natural immunomodulatory agent.Highlights► Polysaccharides from peduncles of Hovenia dulcis (HDPS) were prepared and purified. ► The three purified fractions were mainly composed of Rha, Ara, Gal and GalA. ► The three purified fractions had potent immunostimulatory activities in vitro. ► HDPS-1 exhibited relative higher immunostimulatory activity in vitro.

(−)-Epigallocatechin-3-gallate (EGCG), one representative of the well-studied chemopreventive phytochemicals but with low bioavailability, was encapsulated in monodispersed nanoparticles that were assembled from bioactive caseinophosphopeptide (CPP) and chitosan (CS). The encapsulation efficiency of EGCG in CS–CPP nanoparticles ranged from 70.5 to 81.7%; meanwhile, the in vitro release of EGCG from CS–CPP nanoparticles was in a controllable manner. The EGCG-loaded CS–CPP nanoparticles exerted stronger activity of scavenging free radical than the free EGCG (p < 0.01) in the cellular antioxidant activity assay. Furthermore, cellular uptake of the EGCG-loaded CS–CPP nanoparticles was confirmed by the green fluorescence inside the human hepatocellular caricinoma (HepG2) cells, which was considered to play an important role in the improvement of the antioxidant activity of the nanoencapsulated EGCG. The results suggested that encapsulation of EGCG using CS–CPP nanoparticles should be a potential approach to enhance its antioxidant activity in biological systems.

Sesaminol triglucoside (STG), the most abundant lignan glycoside existing in sesame cake/meal, has exhibited various biological activities. However, little information about its in vitro fermentation with intestinal microbiota is available. Therefore, the effect of STG from sesame cake on the fermentation of human fecal microbiota was evaluated. First, high-purity STG was successfully prepared from defatted sesame cake by extraction with 80% ethanol and simple purification procedures of polyamide column chromatography and Toyopearl HW-40S column chromatography. Then the influence of STG on intestinal microbiota was conducted by monitoring bacterial populations and analyzing the concentrations of short-chain fatty acids (SCFA). We found that STG could significantly induce an increase in numbers of Lactobacillus–Enterococcus group and Bifidobacterium in fermentation in vitro with human fecal microbiota, while it did not stimulate the bacterial growth of Eubacterium rectale–Clostridium coccoides group, Clostridium histolyticum group, and Bacteroides–Prevotella group. Furthermore, it was found that concentrations of formic, acetic, propionic, and butyric acids in STG culture increased significantly during the fermentation, and its total SCFA concentration was relatively higher than those of the control and glucose cultures at 6 and 12 h fermentation. Our findings provided further evidence for the importance of human intestinal bacteria in the bioactivity of STG and its metabolites in the maintenance of human health.

Nanochemoprevention by oral consumption was developed by the encapsulation of (−)-epigallocatechin-3-gallate (EGCG) with nanoparticles that were electrostatically assembled from bioactive caseinophosphopeptides and chitosan, which was highly biocompatible and able to enhance the bioavailability of EGCG.

Epigallocatechin gallate (EGCG) was successfully encapsulated in novel nanocomplexes assembled from bioactive peptides, caseinophosphopeptides (CPPs), and chitosan (CS), a natural cationic polymer. Their particle sizes and surface charges were determined to be in the range of 150.0 ± 4.3 nm and 32.2 ± 3.3 mV respectively. Crosslinking between the NH3+ groups of CS with the PO− and COO− groups of CPP, as well as the hydrogen bonding were confirmed from the FTIR results. Atomic force microscopy (AFM) images showed that EGCG loaded CS–CPP nanocomplexes were spherical in shape. Maintaining the surface charge as high as +32.2 mV, crosslinking CS with peptides reduced the cytotoxicity of CS nanoparticles. In addition, cellular internalization of EGCG-loaded CS–CPP nanoparticles was confirmed from green fluorescence inside the Caco-2 cells. The process of nanoparticle uptake was dose and time dependent in the range of time and concentration studied. Furthermore, the intestinal permeability of EGCG using Caco-2 monolayer was enhanced significantly as delivered by nanoparticles, which indicated the promising elevation of EGCG bioavailability.Highlights► Chitosan (CS)–caseinophosphopeptide (CPP) nanoparticles as a delivery system for epigallocatechin gallate (EGCG) have been developed. ► Physical, chemical and biological properties of the nanoparticles were characterized systematically. ► Cross-linking CS with peptides reduced the cytotoxicity of CS nanoparticles. ► Dose and time dependent cellular internalization of EGCG-loaded CS–CPP nanoparticles was confirmed by green fluorescence inside the Caco-2 cells. ► Intestinal permeability of EGCG was significantly enhanced by the CS/CPP nanoparticles.

Optimization of extraction, preliminary characterization and hepatoprotective activity of polysaccharides from Stachys flordana Schuttl. ex Benth. (SFPS) were investigated in the present study. Firstly, the optimal conditions for extraction of SFPS were obtained by a Box-Behnken design as follows: extraction temperature 94 °C, extracting time 4 h and ratio of water to material 19 mg/ml. Then, the analysis of monosaccharide composition by gas chromatography revealed that SFPS was composed of rhamnose, arabinose, glucose and galactose in a molar percent of 2.05, 9.16, 28.66 and 60.14, respectively. Finally, we demonstrated that SFPS had a significant protective effect against acute hepatotoxicity induced by carbon tetrachloride (CCl4) in mice, as evident by lower levels of serum alanine aminotransferase, aspartate aminotransferase and hepatic malondialdehyde, higher activities of superoxide dismutase and catalase, as well as higher reduced glutathione concentration compared to the CCl4-treated group. The results suggested that SFPS could be explored as novel natural supplement.Highlights► Optimal extraction conditions for polysaccharides from Stachys flordana Schuttl. ex Benth (SFPS) were obtained. ► SFPS was composed of Rha, Ara, Glc and Gal in a molar percent of 2.05, 9.16, 28.66 and 60.14, respectively. ► Administration of SFPS had a significant protective effect against CCl4-induced acute hepatotoxicity in mice.

To isolate and characterize novel angiotensin I-converting enzyme (ACE) inhibitory peptide from loach (Misgurnus anguillicaudatus), six proteases, pepsin, α-chymotrypsin, bromelain, papain, alcalase, and Neutrase, were used to hydrolyze loach protein. The hydrolysate (LPH) generated by bromelain [ratio of enzyme to substrate, 3:1000 (w/w)] was found to have the highest ACE inhibitory activity (IC50, 613.2 ± 8.3 μg/mL). Therefore, it was treated by ultrafiltration to afford fraction of LPH-IV (MW < 2.5 kDa) with an IC50 of 231.2 ± 3.8 μg/mL, having higher activity than the other fractions. Then, LPH-IV was isolated and purified by consecutive purification steps of gel filtration chromatography and reverse-phase high-performance liquid chromatography to afford a purified peptide with an IC50 of 18.2 ± 0.9 μg/mL, an increase of 33.7-fold in ACE inhibitory activity as compared with that of LPH. The purified peptide was identified as Ala-His-Leu-Leu (452 Da) by Q-TOF mass spectrometry and amino acid analyzer. An antihypertensive effect in spontaneously hypertensive rats revealed that oral administration of LPH-IV could decrease systolic blood pressure significantly.

The production, preliminary characterization and antitumor activity in vitro of mycelial polysaccharides from Pholiota dinghuensis Bi (PDP) were investigated in the present study. Firstly, crude PDP was prepared from the mycelia of P. dinghuensis Bi by submerged culture. Then, the crude PDP was purified by chromatography of DEAE-52 cellulose and Sephadex G-100, resulting three purified fractions of PDP-1, PDP-2 and PDP-3. We found that the monosaccharide composition of PDP-3 was greatly different from that of PDP-1 or PDP-2. In addition, it contained the highest contents of protein, sulfate and uronic acid among the polysaccharides tested. Furthermore, PDP-3 exhibited higher antiproliferative activity against human gastric cancer BGC-823 cells in vitro than crude PDP, PDP-1 or PDP-2. At a concentration of 400 mg/L and an exposure time of 72 h, the inhibition rates for crude PDP, PDP-2 and PDP-3 were 69.36%, 73.65% and 85.78%, respectively.

In the present study, we investigated the extraction, purification, preliminary characterization, antioxidant and anticancer activities in vitro of polysaccharides from Cyclina sinensis (CSPS). Firstly, the optimal parameters for extraction of CSPS were obtained by using a central composite design as follows: extraction temperature, 90 °C; extraction time, 250 min; ratio of water to raw material, 29; and extraction times, two times. Then, the crude CSPS was sequentially purified by chromatography of DEAE-52 and Sephadex G-100, resulting in three purified fractions of CSPS-1, CSPS-2 and CSPS-3. We found that the composition and property of CSPS-3, having relatively higher contents of protein, uronic acid, sulfate and more complicated monosaccharide composition, were quite different from those of CSPS-1 and CSPS-2. Furthermore, we demonstrated that CSPS-3 had strong scavenging activities in vitro on superoxide radical and hydroxyl radical and strong inhibitory effect in vitro on the growth of human gastric cancer BGC-823 cells.

Kudingcha made from Ilex kudingcha C.J. Tseng is a potent antioxidant in vitro and rich in polyphenolic compounds. For better utilization of the resource, response surface methodology was used to optimize the extraction conditions of polyphenolic antioxidants from kudingcha. In the present study, the total polyphenol content (TPC) and IC50 of scavenging activity on 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical were considered as the response values. Through optimization, the optimal extraction conditions with ethanol as extraction solvent were as follows: ethanol concentration 71%, extraction temperature 74 °C and time 61 min for TPC (235.24 mg chlorogenic acid/g); ethanol concentration 70%, extraction temperature 71 °C and time 60 min for potent scavenging activity on DPPH free radical (IC50 480.87 μg/mL). While for water as a solvent, the optimal conditions were extraction temperature 91 V and time 36 min for TPC (198.45 mg chlorogenic acid/g) and extraction temperature 92 °C and time 36 min for potent DPPH free radical scavenging activity (744.74 μg/mL). Similar parameters were obtained for extraction with higher TPC and lower IC50 of scavenging activity on DPPH free radical when using either ethanol or water as solvent. Our results suggest that the same optimal conditions can be used to get extract of kudingcha with higher TPC and lower IC50 of scavenging activity on DPPH free radical with ethanol or water as solvent.Highlights► Response surface methodology was used to determine the extraction parameters for kudingcha extract with higher total polyphenol content (TPC) and lower IC50 value of scavenging activity on 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical. ► Optimal extraction conditions with ethanol solution as extraction solvent were ethanol concentration 72%, extraction temperature 68 °C and time 59 min. ► Optimal extraction conditions with water as extraction solvent were extraction temperature 91 °C and time 32 min. ► The regression models obtained were accurate and adequate for the extraction of polyphenol antioxidants from kudingcha with ethanol solution or water as extraction solvent.

The assembly of nanocomplexes from bioactive peptides, namely, caseinophosphopeptides (CPPs) and chitosan (CS), at physiological conditions and various CS/CPP mass ratios has been systematically studied using a combination of liquid chromatography–tandem mass spectrometry (LC–MS/MS), turbidimetric titration, dynamic light scattering (DLS), electrophoretic mobility (ζ-potential) measurements, transmission electron microscopy (TEM), and fluorescence spectroscopy. Peptides incorporated with CS forming nanoparticles were prepared and identified using LC–MS/MS. They were characterized by different amounts of clusters of phosphorylated seryl residues. At low salt concentrations, an increase in CS/CPP mass ratio shifted the critical pHφ1 value, which was designated as the formation of CS/CPP nanocomplexes, as well as pHmax, which represents the neutralization of positive and negative charges at higher pH values. The sizes, charges, morphologies, binding mechanisms, and binding constants of the bioactive peptide–chitosan nanocomplexes were analyzed, and our results suggest that three processes are involved in nanocomplex formation: First, negatively charged CPPs absorb to positively charged CS molecular chains to form intrapolymer nanocomplexes saturated with CPPs (CPPNPs). Subsequently, the negatively charged CPPNPs are bridged by the addition of positively charged CS, resulting in the formation of nearly neutral associative biopolymer complexes. Finally, further addition of excess chitosan breaks down the bridges of associative complexes and causes the formation of positively charged isolated spherical nanocomplexes. The binding between the peptides and CS is mainly driven by electrostatic interactions with a binding constant of Kcs = 4.6 × 104 M–1. Phosphorylated groups and other negatively charged amino acids, such as aspartic acid (Asp) and glutamic acid (Glu), in the CPPs might be the dominant sites for interaction with −NH3+ groups on the CS molecular chains.

An effective liquid chromatographic method that involved precolumn derivatisation with o-phthaladehyde combined with solid-phase extraction has been developed for the determination of free amino acids in tea. Firstly, tea infusion was treated by C18 cartridge before derivatisation, resulting in great improvement of separation by Zorbax Eclipse XDB-C18 column. Then, the contents of free amino acids in Chinese green, black, and Oolong teas and the flower of plant Camellia sinensis have been determined. The results showed that theanine was the most abundant amino acid in teas, and green tea contained much higher amounts of free amino acids than fermented ones. While the contents and composition of free amino acids in tea flower were quite different from those of teas. The tea flower contained much higher content of free amino acids. Furthermore, although theanine was the most abundant amino acid in tea flower as tea, histidine became the second one.

The antioxidant activities of exopolysaccharides (EPS) from endophytic bacterium Paenibacillus polymyxa EJS-3 were evaluated by various methods in vitro and in vivo. In antioxidant assays in vitro, both crude EPS and its purified fractions (EPS-1 and EPS-2) were found to have moderate 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, hydrogen peroxide scavenging activity, lipid peroxidation inhibition effect, and strong ferrous ion chelating activity. And the antioxidant activities in vitro of EPS decreased in the order of crude EPS > EPS-2 > EPS-1. In antioxidant assays in vivo, mice were subcutaneously injected with d-galactose (d-Gal) for 6 weeks and administered EPS-1 via gavage simultaneously. As a result, administration of EPS-1 significantly increased the thymus and spleen indices of d-Gal induced aging mice. Moreover, EPS-1 administration significantly enhanced the activities of antioxidant enzymes and total antioxidant capacity and decreased the levels of malondialdehyde in both serums and livers of aging mice. These results suggested that EPS had potent antioxidant activities and could be explored as novel natural antioxidant.

The structural characterization of purified Hyriopsis cumingii polysaccharides (HCPS) were studied by using periodic acid oxidation, Smith degradation, methylation combined with HPLC, GC, GC–MS, FTIR and NMR spectra. Results showed that sugar rings of purified HCPS were pyranose rings. In HCPS-1 and HCPS-2, glycosyl residues were linked mainly by α-configuration glycosidic bond. As to HCPS-3, sugar residues were connected by α- and β-configuration glycosidic bonds. Number of glycosyl residues in one repeat unit was 7, 9 and 10 for HCPS-1, HCPS-2 and HCPS-3 respectively. Backbone chains of purified HCPS were linked by 1 → 4 glycosidic bonds. In HCPS-1 and HCPS-2, there were one backbone chain and two branch chains (one linked by 1 → 3 glycosidic bond, another connected by 1 → 6 glycosidic bond) in one repeat unit. As to HCPS-3, three branch chains (two connected by 1 → 3 glycosidic bond, one linked by 1 → 6 glycosidic bond) were attached to backbone chain in one repeat unit.

Optimization of medium ingredients for the production of mycelial polysaccharides from Phellinus baumii Pilát (PBMP) in submerged culture, preliminary characterization and the evaluation of antioxidant activity in vivo of PBMP were carried out. An optimal medium for PBMP production was obtained through a 2(7−3) fractional factorial design and a central composite design in response surface methodology as follows (g/l): glucose 35.36, yeast extract 2.88, peptone 2.73, MgSO4 1.47, KH2PO4 1, VB1 0.0075 and diammonium oxalate monohydrate 0.3. The resulting PBMP was composed of d-glucose, d-galactose, l-fucose, d-mannose, and l-rhamnose in a molar ratio of 12.74:1.39:1.00:1.92:0.22. It was demonstrated that the administration of PBMP could increase the activities of antioxidant enzymes, decrease the levels of malondialodehyde, and enhance total antioxidant capabilities in livers and serums of d-galactose-induced mice. The results suggested that PBMP had potent antioxidant activity and could be explored as novel natural antioxidant.

In this study, response surface methodology was employed to optimize the medium compositions for the production of exopolysaccharides (EPS) from endophytic bacterium Paenibacillus polymyxa EJS-3. Firstly, fractional factorial design was applied to evaluate the effects of different components in the medium. It was found that sucrose, yeast extract and CaCl2 influenced significantly the production of EPS. Then, steepest ascent method and central composite design were used to optimize the concentrations of the three variables. As results, the optimal medium compositions were determined as following (g/L): sucrose 188.2, yeast extract 25.8, K2HPO4 5 and CaCl2 0.34, with a corresponding yield of 35.26 g/L. In addition, both polysaccharide fractions (EPS-1 and EPS-2) from crude EPS were mainly composed of (2 → 6)-linked β-d-fructofuranosyl residues backbone with (2 → 1)-linked branches based on their structural characterization by FT-IR spectroscopy, methylation analysis and 13C NMR spectroscopy.

The total polyphenol contents (TPC) of leaf extracts from 116 varieties of sweet potato cultivated in China were determined by Folin-Ciocalteu method. In addition, the crude extract (CE) of Pushu 53 leaves, with relatively higher TPC and its fractions of chloroform, ethyl acetate, n-butanol and water, were prepared and subjected to the determination of TPC, evaluation of antioxidant activities in vitro by assays of DPPH, ABTS and FRAP, and analysis of phenolic constituents by high performance liquid chromatography (HPLC) and HPLC–mass spectrometry. Our results show that the extracts demonstrated potential antioxidant activity, and that a satisfactory correlation between TPC and antioxidant activity was observed. In addition, the main bioactive compounds for the antioxidant activity of the extract were polyphenols, especially derivatives of caffeoylquinic acid (CQA), such as 5-CQA, 3,4-diCQA, 3,5-diCQA, and 4,5-diCQA. Their contents (8.95%) were 0.41, 3.41, 4.09, and 1.04%, respectively, accounting for 79.6% of TPC in CE (11.24%).

In the present study, β-d-galactosidase from Bacillus circulans was proved to be a suitable biocatalyst for the production of N-acetyl-oligosaccharides with lactose and N-acetylglucosamine (GlcNAc) as biocatalyst. During the hydrolysis of lactose, apart from no ultraviolet absorption oligosaccharides such as β-d-Galp-(1 → 6)-d-Glcp (6′-allolactose) and β-d-Galp-(1 → 4)-β-d-Galp-(1 → 4)-d-Glcp (4′-galactosyl-lactose), the formation of four N-acetyl-oligosaccharides was followed by high-performance liquid chromatography with a diode-array detector. The four N-acetyl-oligosaccharides were isolated from the reaction mixture and identified to be as β-d-Galp-(1 → 4)-d-GlcpNAc (LacNAc, I), β-d-Galp-(1 → 6)-d-GlcpNAc (allo-LacNAc, II), β-d-Galp-(1 → 4)-β-d-Galp-(1 → 4)-d-GlcpNAc (III), β-d-Galp-(1 → 4)-β-d-Galp-(1 → 4)-β-d-Galp-(1 → 4)-d-GlcpNAc (IV) by authentic standards and the spike technique or high-resolution mass spectrometry with an electrospray ionization source and nuclear magnetic resonance spectroscopy. Furthermore, the effects of synthetic conditions including reaction temperature, concentration of substrate, molar ratio of donor/acceptor and enzyme concentration on the formation of N-acetyl-oligosaccharides were examined. We found that the optimal synthetic conditions were different for production of oligosaccharides with β-(1 → 4) linkages and β-(1 → 6) linkage. The optimal reaction conditions for I, III and IV were 40 °C, 0.50 M lactose and 0.50 M GlcNAc and 1.0 U/mL of enzyme. Under such conditions, the N-acetyl-oligosaccharides formed were composed of 28.75% of I, 2.29% of II, 9.47% of III and 5.67% of IV. On the other hand, suitable reaction conditions found for II were 40 °C, 0.50 M lactose and 0.50 M GlcNAc and 2.0 U/mL of enzyme.

Extraction, purification and preliminary characterization of polysaccharides from Hyriopsis cumingii (HCPS) were carried out. Firstly, the extracting parameters for HCPS extraction were optimized by using three-factor-three-level Box–Behnken design and response surface methodology based on the single-factor experiments. As results, the optimum conditions were extracting temperature 80 °C, extracting time 4.5 h and the ratio of extraction solvent (water) to raw material (v/w) 8. Under these conditions, the experimental yield of crude HCPS was 3.66%. Secondly, the crude HCPS was purified by DEAE-Cellulose 52 chromatography and Sephadex G-100 chromatography to afford 3 fractions, HCPS-1, HCPS-2 and HCPS-3. The recovery rates based on crude HCPS used were 26.91%, 30.18% and 3.93% for HCPS-1, HCPS-2 and HCPS-3 respectively. Based on the characterization results of HCPS by Fourier transform-infrared spectroscopy, high performance liquid chromatography and gas chromatography, we found that HCPS-3 was quite different from HCPS-1 or HCPS-2.

Monomers of (−)-epigallocatechin (EGC), (−)-epigallocatechin gallate (EGCG), (−)-epicatechin (EC), (−)-epicatechin gallate (ECG), (−)-epigallocatechin 3-O-(3-O-methyl) gallate (EGCG3″Me) and (−)-3-O-methyl epicatechin gallate (ECG3′Me) (purity, >97%) were successfully prepared from extract of green tea by two-time separation with Toyopearl HW-40S column chromatography eluted by 80% ethanol. In addition, monomers of (−)-catechin (C), (−)-gallocatechin (GC), (−)-gallocatechin gallate (GCG), and (−)-catechin gallate (CG) (purity, >98%) were prepared from EC, EGC, EGCG, and ECG by heat-epimerization and semi-preparative HPLC chromatography. With the prepared catechin standards, an effective and simultaneous HPLC method for the analysis of gallic acid, tea catechins, and purine alkaloids in tea was developed in the present study. Using an ODS-100Z C18 reversed-phase column, fourteen compounds were rapidly separated within 15 min by a linear gradient elution of formic acid solution (pH 2.5) and methanol. A 2.5–7-fold reduction in HPLC analysis time was obtained from existing analytical methods (40–105 min) for gallic acid, tea catechins including O-methylated catechins and epimers of epicatechins, as well as purine alkaloids. Detection limits were generally on the order of 0.1–1.0 ng for most components at the applied wavelength of 280 nm. Method replication generally resulted in intraday and interday peak area variation of <6% for most tested components in green, Oolong, black, and pu-erh teas. Recovery rates were generally within the range of 92–106% with RSDs less than 4.39%. Therefore, advancement has been readily achievable with commonly used chromatography equipments in the present study, which will facilitate the analytical, clinical, and other studies of tea catechins.

The total polyphenol content and the antioxidant activity of kudingcha made from Ilex kudingcha C.J. Tseng were determined by Folin–Ciocalteu reagent, and DPPH, FRAP, and TEAC methods, respectively. The crude extract (CE) of kudingcha and its four fractions of chloroform (CfF), ethyl acetate (EaF), n-butanol (nBF), and water (WtF) were prepared and subjected to antioxidant evaluation and analysis by high performance liquid chromatography. The extracts of kudingcha contained large amounts of caffeoylquinic acid (CQA) derivatives, including 3-CQA, 5-CQA, 3,4-diCQA, 3,5-diCQA, and 4,5-diCQA, and showed potent antioxidant activity. The antioxidant activities of CE and its fractions decreased in the order of EaF > nBF > CE > WtF > CfF, according to the DPPH assay and FRAP assay, which were the same, with the exception of the rank order of CfF and WtF, as the TEAC assay. Furthermore, a satisfactory correlation between total polyphenol content and antioxidant activity was observed.

Crude capsule polysaccharides (CCP) were prepared from the culture of Streptococcus equi subsp. zooepidemicus C55129 and were partially purified through an anion-exchange column chromatography to afford partially purified capsule polysaccharides (PCP). The main component of CCP and PCP was hyaluronic acid. In vitro antioxidant assay, the capsule polysaccharides showed strong inhibition of lipid peroxidation and hydroxyl radical scavenging activity and moderate 1,1-diphenyl-2-picryldydrazyl radical scavenging activity. In addition, CCP exhibited much stronger reductive power than PCP. For antioxidant testing in vivo, CCP and PCP were orally administrated over a period of 15 days in a d-galactose induced aged mice model. As results, administration of capsule polysaccharides inhibited significantly the formation of malondialdehyde in mice livers and serums and raised the activities of antioxidant enzymes and total antioxidant capacity in a dose-dependent manner. However, the antioxidant activity of CCP was lower than that of PCP. The results suggest that the capsule polysaccharides from Streptococcus equi subsp. zooepidemicus C55129 have direct and potent antioxidant activities.

Optimization of medium composition for the production of exopolysaccharides (EPS) from Phellinus baumii Pilát in submerged culture and the immuno-stimulating activity of EPS were carried out. Firstly, the medium components having significant effect on EPS production were screened out to be glucose, yeast extract and diammonium oxalate monohydrate by using a 2(7−3) fractional factorial design. Secondly, the concentrations of the three factors were optimized using central composite design in response surface methodology. As results, a quadratic model was found to fit for EPS production, and the optimal medium composition was determined as following (g/l): 34.12 glucose, 4 peptone, 5.01 yeast extract, 0.88 diammonium oxalate monohydrate, 0.75 MgSO4 and 1 KH2PO4 and 0.0075 thiamine (VB1). A yield of 2.363 ± 0.04 g/l for EPS was observed in verification experiment. Finally, EPS from P. baumii Pilát was found to have direct immuno-stimulating activity in vitro on splenocyte proliferative response and acid phosphatase activity in peritoneal macrophages in a dose-dependent manner.

The antioxidant activities of crude Hyriopsis cumingii polysaccharides (HCPS) were evaluated both in vitro and in vivo. In vitro antioxidant assay, HCPS (crude and its purified fraction) could scavenge hydrogen peroxide, free radicals of superoxide anion and 2,2-diphenyl-1-picryl-hydrazyl, chelate ferrous ion and reduce ferric ion. Except for metal ion chelating activity, HCPS-3 exhibited much higher antioxidant activities than crude HCPS, HCPS-1 and HCPS-2. For antioxidant testing in vivo, different doses of crude HCPS were orally administrated over a period of 15 days in a d-galactose induced aged mice model. As results, administration of crude HCPS inhibited significantly the formation of malondialdehyde in mice livers and serums and raised the activities of antioxidant enzymes and total antioxidant capacity in a dose-dependent manner. The results suggested that HCPS had direct and potent antioxidant activities.

The production, characterization and antioxidant activities in vitro of exopolysaccharides (EPS) from endophytic bacterium Paenibacillus polymyxa EJS-3 were investigated. For EPS production, the preferable culture conditions were 24 °C and pH 8 for 60 h with sucrose and yeast extract as the carbon and nitrogen sources, respectively. Notably, sucrose concentration was the prominent factor, and the maximum yield of EPS (22.82 g/L) was obtained at a sucrose concentration of 160 g/L. The crude EPS was purified by chromatography of DEAE-52 and Sephadex G-100, affording EPS-1 and EPS-2 with molecular weights of 1.22 × 106 and 8.69 × 105 Da, respectively. They were composed of mannose, fructose and glucose in a molar ratio of 2.59:29.83:1 and 4.23:36.59:1, respectively. In addition, both crude and purified EPS showed strong scavenging activities on superoxide and hydroxyl radicals, and their antioxidant activities decreased in the order of crude EPS > EPS-2 > EPS-1.

In the present study, β-d-galactosidase from Bacillus circulans was proved to be a suitable biocatalyst for the production of lactosucrose (β-d-Galp-(1→4)-α-d-Glcp-(1→2)-β-d-Fruf, I) and its analogues from lactose and sucrose. During the hydrolysis of lactose, the formation of four transfer products was followed by high performance liquid chromatography with refraction index detector. In addition, the transfer products were isolated from the reaction mixture and identified to be I, β-d-Galp-(1→3)-α-d-Glcp-(1→2)-β-d-Fruf (II), β-d-Galp-(1→4)-β-d-Galp-(1→4)-α,β-d-Glcp (III), and β-d-Galp-(1→4)-β-d-Galp-(1→4)-α-d-Glcp-(1→2)-β-d-Fruf (IV) by mass spectrometry with an electrospray ionization source and nuclear magnetic resonance spectroscopy. The order for the production of the transfer products was III > I > IV > II in the initial stage of the reaction, and the same relationship was also observed for the hydrolytic rates of transfer products. Furthermore, the effects of synthetic conditions including reaction temperature, reaction time, concentration of substrate, molar ratio of donor/acceptor, and enzyme concentration on the formation of transfer products were examined. We found that the optimal synthetic conditions were different for the production of I and II. Under the optimal conditions, the amount of total transfer products kept increasing during the early 4 h incubation, and a maximum yield of 146 g/L for total transfer products was obtained at 4 h of reaction.

The crude extract (CE) was obtained by extracting the powder of Sargassum pallidum with a solution of 70% ethanol. Then, CE dissolved in distilled water was fractionated with chloroform (Cf), ethyl acetate (EtOAc), and n-butanol (n-BuOH), respectively, affording four fractions of Cf, EtOAc, n-BuOH and aqueous. First, the contents of total polyphenols, vitamin C (VC) and vitamin E (VE) in CE and its four fractions were determined. As results, the contents of total polyphenols in CE and its fractions decreased in the following order: aqueous fraction > n-BuOH fraction > EtOAc fraction > CE > Cf fraction. The aqueous fraction had significantly higher VC content (1.82%) compared with CE and fractions of Cf, EtOAc, and n-BuOH (P < 0.05). The contents of VE in CE and its fractions were all in low level compared with the total polyphenol content and VC content. Second, the antioxidant activities in vitro of CE and its four fractions were evaluated. Among all the fractions, EtOAc fraction exhibited the highest total antioxidant activity (0.52 μmol FeSO4 equivalent/mg extract), while fractions of EtOAc and n-BuOH exhibited the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and capacity of chelating iron ions, respectively. In addition, a higher content of total polyphenols (52.08 mg chlorogenic acid equivalent/g extract) and reducing power (0.505 at A700) for aqueous fraction were noticed. Finally, it was found that the extracts of S. pallidum contained large amounts of phlorotannin dimers and trimer based on the analytical results of ultra high performance liquid chromatography–mass spectroscopy. The results suggest that S. pallidum can be a good source of natural antioxidant.

The extraction procedure of oligosaccharides from chickpea seeds was optimized and sufficient extraction was achieved with 50% of ethanol-water in a ratio of 10:1 for solvent to defatted chickpea meal at 50 °C for 30 min. Under the optimal extraction conditions, the contents of oligosaccharides in 19 cultivars of chickpea seeds were determined by HPLC. The results showed that the main α-galactooligosaccharides (α-GOS) in chickpea seeds were raffinose, stachyose, verbascose and an unknown glycoside, which was isolated, purified, and identified as ciceritol. Ciceritol, the main sugar in all the chickpea samples, accounted for about 50% of the total α-GOS. There were considerable variations in the levels of α-GOS and sucrose between species, especially verbascose which could only be detected in 7 samples. With the highest amount of α-GOS and a low amount of sucrose, the 171 was the best choice for obtaining α-GOS for use as a prebiotic in functional foods.

This work investigated the polyanion-initiated gelation process in fabricating chitosan−tripolyphosphate (CS-TPP) nanoparticles intended to be used as carriers for delivering tea catechins. The results demonstrated that the particle size and surface charge of CS-TPP nanoparticles could be controlled by fabrication conditions. For preparation of CS-TPP nanoparticles loaded with tea catechins, the effects of modulating conditions including contact time between CS and tea catechins, CS molecular mass, CS concentration, CS-TPP mass ratio, initial pH value of CS solution, and concentration of tea catechins on encapsulation efficiency and the release profile of tea catechins in vitro were examined systematically. The study found that the encapsulation efficiency of tea catechins in CS-TPP nanoparticles ranged from 24 to 53%. In addition, FT-IR analysis showed that the covalent bonding and hydrogen bonding between tea catechins and CS occurred during the formation of CS-TPP nanoparticles loaded with tea catechins. Furthermore, studies on the release profile of tea catechins in vitro demonstrated that the controlled release of tea catechins using CS-TPP nanoparticles was achievable.

A convenient chemoenzymatic procedure for the synthesis of p-aminophenyl glycosides of sialyl N-acetyllactosaminide has been developed from p-nitrophenyl N-acetyl-β-d-glucosaminide as starting material through three steps: synthesis of p-nitrophenyl N-acetyllactosaminide with β-d-galactosidase, chemical reduction of the p-nitrophenyl group, and sialylation with sialyltransferase. The p-aminophenyl glycosides were then successfully biotin-labeled through the coupling with N-(+)-biotinyl-6-aminohexanoic acid to afford biotinylated oligosaccharides with an aminohexanosyl group and phenyl group as the spacers between the biotin and glycan. Furthermore, the biotin-labeled sugars were shown to be useful for immobilization and assay of the carbohydrate–lectin interactions by an optical biosensor based on surface plasmon resonance.

When α-d-GlcNAc-OC6H4NO2-p and β-d-(6-sulfo)-GlcNAc-OC6H4NO2-p (2) were used as substrates, β-N-acetylhexosaminidase from Aspergillus oryzae transferred the β-d-(6-sulfo)-GlcNAc(unit from 2 to α-d-GlcNAc-OC6H4NO2-p to afford β-d-(6-sulfo)-GlcNAc-(1→4)-α-d-GlcNAc-OC6H4NO2-p (3) in a yield of 94% based on the amount of donor, 2, added. β-d-(6-sulfo)-GlcNAc-(1→4)-α-d-Glc-OC6H4NO2-p (4) was obtained with α-d-Glc-OC6H4NO2-p as acceptor in a similar manner. With a reaction mixture of 2 and β-d-GlcNAc-OC6H4NO2-p (1) in a molar ratio of 6:1, the enzyme mediated the transfer of β-d-GlcNAc from 1 to 2, affording disaccharide β-d-GlcNAc-(1→4)-β-(6-sulfo)-d-GlcNAc-OC6H4NO2-p (5) in a yield of 13% based on the amount of 1 added.

•The nanoparticles fabricated from protein, polysaccharides and lipid.•The enhancement effect of food macromolecule nanoparticles on bioavailability of polyphenol.•The structure behavior of nanoparticles during digestion.•The metabolism of polyphenols after encapsulation in the nanoparticles.Diet polyphenols—primarily categorized into flavonoids (e.g., flavonols, flavones, flavan-3-ols, anthocyanidins, flavanones, and isoflavones) and nonflavonoids (with major subclasses of stilbenes and phenolic acids)—are reported to have health-promoting effects, such as antioxidant, antiinflammatory, anticarcinoma, antimicrobial, antiviral, and cardioprotective properties. However, their applications in functional foods or medicine are limited because of their inefficient systemic delivery and poor oral bioavailability. Epigallocatechin-3-gallate, curcumin, and resveratrol are the well-known representatives of the bioactive diet polyphenols but with poor bioavailability. Food macromolecule based nanoparticles have been fabricated using reassembled proteins, crosslinked polysaccharides, protein–polysaccharide conjugates (complexes), as well as emulsified lipid via safe procedures that could be applied in food. The human gastrointestinal digestion tract is the first place where the food grade macromolecule nanoparticles exert their effects on improving the bioavailability of diet polyphenols, via enhancing their solubility, preventing their degradation in the intestinal environment, elevating the permeation in small intestine, and even increasing their contents in the bloodstream. We contend that the stability and structure behaviors of nanocarriers in the gastrointestinal tract environment and the effects of nanoencapsulation on the metabolism of polyphenols warrant more focused attention in further studies.Download high-res image (209KB)Download full-size image

A novel and efficient immobilization of β-d-galactosidase from Aspergillus oryzae has been developed by using magnetic Fe3O4–chitosan (Fe3O4–CS) nanoparticles as support. The magnetic Fe3O4–CS nanoparticles were prepared by electrostatic adsorption of chitosan onto the surface of Fe3O4 nanoparticles made through co-precipitation of Fe2+ and Fe3+. The resultant material was characterized by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, vibrating sample magnetometry and thermogravimetric analysis. β-d-Galactosidase was covalently immobilized onto the nanocomposites using glutaraldehyde as activating agent. The immobilization process was optimized by examining immobilized time, cross-linking time, enzyme concentration, glutaraldehyde concentration, the initial pH values of glutaraldehyde and the enzyme solution. As a result, the immobilized enzyme presented a higher storage, pH and thermal stability than the soluble enzyme. Galactooligosaccharide was formed with lactose as substrate by using the immobilized enzyme as biocatalyst, and a maximum yield of 15.5% (w/v) was achieved when about 50% lactose was hydrolyzed. Hence, the magnetic Fe3O4–chitosan nanoparticles are proved to be an effective support for the immobilization of β-d-galactosidase.

Kudingcha made from Ilex kudingcha C.J. Tseng is a potent antioxidant in vitro and rich in polyphenolic compounds. For better utilization of the resource, response surface methodology was used to optimize the extraction conditions of polyphenolic antioxidants from kudingcha. In the present study, the total polyphenol content (TPC) and IC50 of scavenging activity on 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical were considered as the response values. Through optimization, the optimal extraction conditions with ethanol as extraction solvent were as follows: ethanol concentration 71%, extraction temperature 74 °C and time 61 min for TPC (235.24 mg chlorogenic acid/g); ethanol concentration 70%, extraction temperature 71 °C and time 60 min for potent scavenging activity on DPPH free radical (IC50 480.87 μg/mL). While for water as a solvent, the optimal conditions were extraction temperature 91 V and time 36 min for TPC (198.45 mg chlorogenic acid/g) and extraction temperature 92 °C and time 36 min for potent DPPH free radical scavenging activity (744.74 μg/mL). Similar parameters were obtained for extraction with higher TPC and lower IC50 of scavenging activity on DPPH free radical when using either ethanol or water as solvent. Our results suggest that the same optimal conditions can be used to get extract of kudingcha with higher TPC and lower IC50 of scavenging activity on DPPH free radical with ethanol or water as solvent.Highlights► Response surface methodology was used to determine the extraction parameters for kudingcha extract with higher total polyphenol content (TPC) and lower IC50 value of scavenging activity on 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical. ► Optimal extraction conditions with ethanol solution as extraction solvent were ethanol concentration 72%, extraction temperature 68 °C and time 59 min. ► Optimal extraction conditions with water as extraction solvent were extraction temperature 91 °C and time 32 min. ► The regression models obtained were accurate and adequate for the extraction of polyphenol antioxidants from kudingcha with ethanol solution or water as extraction solvent.

Nanochemoprevention by oral consumption was developed by the encapsulation of (−)-epigallocatechin-3-gallate (EGCG) with nanoparticles that were electrostatically assembled from bioactive caseinophosphopeptides and chitosan, which was highly biocompatible and able to enhance the bioavailability of EGCG.