•A method for detection of pyrethroids residue in vegetables has been developed.•Polystyrene-coated magnetic nanoparticles were employed as adsorbents.•The detection limits were lower than traditional methods.•The adsorbents can be recycled after use via simple wash.A detection method using polystyrene-coated magnetic nanoparticles based extraction technique coupled to HPLC was developed for trace amount of pyrethroids residue detection in vegetable matrixes. The recoveries for five kinds of commonly used pyrethroids were in the range of 91.6%–116.2%. The sensitivity and precision of the method were satisfactory with the limits of detection and limits of quantification in the range of 0.0200–0.0392 ng g−1 and 0.072–0.128 ng g−1, respectively. The intra-day and inter-day relative standard deviations for the recoveries of the analytes were lower than 6.8% and 10.7%, respectively. The nanoparticles can be washed and recycled after use. The results indicate that the developed method was efficient, fast, economical and environmentally friendly. The method was successfully applied to detect the pyrethroids residue in ten pairs of commonly consumed organic and conventional fresh vegetables in Singapore. Pyrethroids residue was detected in four kinds of conventional vegetables and one kind of organic vegetable.

The effects of rice bran wax coating on the physicochemical properties such as firmness, weight loss, titratable acidity (TA) and soluble solid content (SSC) of cherry tomatoes were studied during cold storage. The chemical and nanostructure properties of chelate-soluble pectin (CSP) were also investigated by high-performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). The results indicated that there was no significant difference of firmness between control (2.48 N) and waxed (2.87 N) fruits at the end of storage (20 days), while the weight loss of waxed fruits (13.54%) was lower than that of control fruits (16.02%). And the degree of esterification (DE) of both fruits decreased after cold storage by FTIR. The structural analysis by atomic force microscopy (AFM) indicated that rice bran wax coating inhibited the degradation of CSP. The CSP molecular widths ranged from 15 to 250 nm, and the vertical heights varied from 0.2 to 2.0 nm. Greater frequency (Fq) of large width and length CSP was found in waxed fruits than in control fruits. The results suggest that rice bran wax coating was an effective way to preserve fresh fruits.

•Chitosan based coatings were applied for Chinese cherry storage.•Coatings extended physicochemical quality deterioration of Chinese cherry.•Pectin molecular nanostructures were characterised by atomic force microscopy.•Coatings inhibited nanostructure degradation of pectin from Chinese cherry.The effects of chitosan-based coatings on the postharvest performance Chinese cherry during a twenty days storage period were investigated. The chitosan-based coatings effectively delayed postharvest ripening parameters including weight loss, decay rate, firmness, soluble solid content (SSC) and titratable acidity (TA). The most effective treatment was a combined chitosan and nano-SiOx coating, which led to 51% less weight loss, 32% less decay rate, 57% more firmness, and less SSC and TA content changes than the control group. This combined coating also maintained a higher content of sodium carbonate-soluble pectin (SSP), and inhibited pectin chain degradation. Qualitative and quantitative analysis revealed that the firmness of fruit was closely related to nanostructural morphologies and SSP chain width. In addition, modifications of SSP were correlated with fruit softening, especially SSP polymers and branched chains. These results demonstrate the effect of chitosan and nano-SiOx coating on extending the shelf life of Chinese cherries during postharvest storage.

Vacuum impregnation was used to improve the quality attributes of fresh-cut papayas. Vacuum pressure of 5 kPa was applied for 5 min, then calcium lactate (1%, w/w) and pectin methylesterase (PME) (15 U/ml), alone and in combinations (calcium lactate plus PME), were vacuum impregnated into fresh-cut papaya cubes. Papaya cubes were stored at 4 °C, and the quality of fresh-cut papaya was studied at intervals for 8 days. The hardness and chewiness levels of fresh-cut papayas that were treated with calcium lactate and PME were 8.02 and 7.83 times of untreated fresh-cut papayas at day 8, respectively. After vacuum impregnation, colour of fresh-cut papayas changed significantly (P < 0.05) and an overall weight loss was observed as well. Chelate-soluble pectin (CSP) was extracted and its content correlated well with texture properties of fresh-cut papayas. Qualitative and quantitative analyses of CSP were conducted using atomic force microscopy. The proportion of chain widths greater than 45 nm had increased 35.0% in fresh-cut papayas vacuum impregnated with calcium lactate and PME at the end of storage. The results indicate that a combination of calcium ions and PME was able to maximally preserve the quality attributes of fresh-cut papayas and extend the shelf life.

Fish fillet is easily spoiled during storage. Antimicrobial edible coating of gelatin extracted from fish skins and bones and tea polyphenol (TP) was developed to inhibit the spoilage of fish fillet during cold storage. For coating containing 0.4 % TP and 1.2 % gelatin, the pH only slightly increased from 6.17 at day 0 to 6.32 at day 17 of cold storage, while the pH of control coating increased to 6.87 at day 17. Atomic force spectrometry was used to analyse the nanostructure of myofibril, which is the major component of fish muscle. The results showed that the length of myofibril from 0.4 % TP and 1.2 % gelatin group was greater than 15 μm, while the diameter and height were 3.38 and 0.59 μm, respectively, which exhibited the most intact nanostructure after 17 days of cold storage. Meanwhile, matrix-assisted laser desorption–ionisation–time-of-flight mass spectrometry result showed that TP delayed the degradation of myosin light chain 3 and troponin T in myofibril. Gas chromatography–mass spectrometry of volatile organic compounds (VOCs) also showed that 0.4 % TP and 1.2 % gelatin coating group had minimal production of spoilage markers, such as 1-octen-3-ol, 2-methyl propanoic acid and dimethyl sulfide. The microbial analysis showed that the aerobic mesophilic/psychrotrophic count, yeasts and moulds of 0.4 % TP and 1.2 % gelatin group were significantly lower than the control group. Therefore, 0.4 % TP and 1.2 % gelatin coating showed the best antimicrobial effect and can be used to maintain the nanostructure of fish fillet and prevent the spoilage during cold storage.

•Natural ingredients were screened to develop egg substitutes.•Image analysis detected the relative differences between different cakes.•FTIR and AFM analyses revealed structural differences among cakes.•PPI + 0.1% XN + 1% SL was promising as an egg substitute in cakes.Cakes are important confectionery and are enjoyed socially within groups. Eggs are important components of cakes, providing emulsification, flavour, colour, and many other properties. However, because of various health concerns and religious beliefs, some consumers cannot enjoy traditional cakes made with eggs. In the current study, isolated pea protein (PPI), xanthan gum (XN), and emulsifier mixtures were investigated to prepare eggless cakes and their roles were determined. The physicochemical properties of the batter and final cake products, the microstructure of the final cakes, and structural properties of starches and glutens at the meso-scale were characterised. The eggless cake recipe containing PPI, 0.1% XN and 1% soy lecithin (SL) was found to be close to the control traditional cakes in terms of specific gravity (1.01 vs. 1.03), crumb colour (a* at 0.09 vs. −0.04), and crumb pore properties (average pore area both 0.20 mm2). Cakes with formulation R4 were most similar to the control cakes with respect to the 1047/1022 relative intensity of the IR spectra of starches (both 0.55) and the nanostructures of glutenins. Therefore, formulation PPI+0.1% XN+ 1% SL was considered as a potential candidate recipe for substituting eggs in cakes.Download high-res image (376KB)Download full-size image

•Gellan combined with CaCl2 made the texture of fish gelatin (FG) similar to beef gelatin (BG).•The modified FG had similar helix/coil ratio and aggregate dimension as BG.•CaCl2 promoted gellan crosslinks and led to segregation of FG-gellan.•FG-gellan complexation improved gelatin texture through H-bond.Fish gelatin (FG) is more suitable for consumption by religious people than mammalian gelatin. One common modification method of FG is mixing FG with polysaccharides. However, the mechanism is not clear. We found that FG gel containing 0.1 g/100 mL gellan, 20 mmol/L CaCl2 and 6.67 g/100 mL FG (180 Bloom) matched gel strength, hardness, cohesiveness, chewiness as well as gelling temperature (Tg) and melting temperature (Tm) of commercial beef gelatin (BG) (240 Bloom). The modified FG was also observed by the result of helix/coil ratio and spherical aggregates. The modification decreased the diameter of FG's aggregates from 472 to 249 nm, which matched with BG (272 nm, P < 0.05). Co-existence of segregative gellan-gellan fibrous aggregates and associated FG-gellan amorphous structure were also identified at the modified FG by atomic force microscope (AFM). The helix/coil ratio and diameter of spherical aggregates were inversely correlated, the mechanism behind was the strength of gelatin association. The involvement of hydrogen bond and presence of FG-gellan complex have been validated by urea addition and Fourier transform infrared (FTIR) spectroscopy. A schematic model was proposed. As modified FG successfully matched the of texture properties of BG, it is promising to replace BG with FG.

An enzymatic method to tenderise golden pomfret (GP, Trachinotus blochii) flesh by marinating with bromelain (BML) solution was developed to produce GP fish balls with a texture similar to those of yellowtail fusilier (YF, Caesio cuning). Treatment with BML reduced the hardness, chewiness and gel strength significantly but increased the resilience of GP fish balls. As a result, 0.4% (enzyme-substrate ratio, w/w) BML-treated GP fish balls had the same texture properties as YF fish balls. Meanwhile, changes in myofibrillar proteins in the fish balls were determined using sodium dodecyl sulphate polyacrylamide gel electrophoresis, matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry and atomic force microscopy. The results indicated that BML degraded myosin light chain and troponin T effectively, without affecting actin. BML treatment generated protein fragments with significantly smaller sizes, thereby improving the tenderness of the flesh. The length, width and height of the myofibrils from 0.4% BML-treated fish ball were 6.42, 1.52 and 1.48 μm, respectively, which were not significantly different from the myofibrils of YF fish balls, indicating that the similar nanostructure determined the comparable texture properties. Gas chromatography-mass spectrometry analysis showed that 0.4% BML decreased the amount of hexanal, hexadecane, 1-octen-3-ol and 2,6,10,14-tetramethylpentadecane but increased the ratio of heptadecane from 18.14 to 38.23% in the treated fish balls, making the flavour of 0.4% BML-treated GP fish balls similar to that of YF balls. Overall, the results suggest that 0.4% BML-tenderised GP could be a promising alternative to YF to produce quality fish balls.

•Exponential and linear models were more suitable to study fish ball mass transfer.•Added gelatin increased the mass transfer coefficient of fish balls during boiling.•Added gelatin decreased the hardness and chewiness of fish balls.•The added gelatin did not affect the nanostructure of fish balls.•The added gelatin decreased nutrient loss during boiling.The effect of fish gelatin addition on mass transfer, nutrient loss, texture and nanostructure of fish balls was investigated. Mass transfer models were built and the root-mean-square-errors were 0.1432, 0.3178 and 0.1000 for exponential, power-law and linear models, respectively. After gelatin addition, the mass transfer coefficient/model parameter and moisture content increased, and the hardness and chewiness of fish balls decreased. Myofibrils were imaged using atomic force microscope (AFM). The length of the myofibrils was greater than 15 μm before and after boiling for 10 min; however, they decreased to around 14 and 11 μm after 20 and 30 min boiling, indicating degradation of myofibrils. Meanwhile, there was no significant difference among different groups, suggesting that the added gelatin did not affect the nanostructure of the fish balls. Furthermore, increasing gelatin addition resulted in fewer water-soluble proteins and peptides in the boiling water. The results suggest that added gelatin increased the mass transfer coefficient/model parameter by increasing the moisture content and decreasing the nutrient loss. It also improved the texture by decreasing the hardness and chewiness, and did not affect the nanostructure of fish ball myofibrils.

•1H NMR was applied for metabolite analysis of E. coli.•The sub-lethal effect of electrolysed water on E. coli was investigated.•Multivariate analysis revealed the changes caused by electrolysed water stress.•Major metabolic pathways altered in E. coli were summarised.Electrolysed water (EW) is an activated liquid with a high oxidation-reduction potential. EW causes oxidative damage to pathogenic microorganisms and as a result, may have utility in the food industry. The molecular mechanism of EW's action is not understood. In this study, we exposed Escherichia coli ATCC 25922 to a sub-lethal concentration of EW and examined structural and metabolic changes. Atomic force microscopy revealed that EW caused damage to E. coli membranes. To understand the metabolic responses to EW perturbations in of E. coli, multivariate data analysis of NMR spectroscopy demonstrated that EW significantly influenced the metabolic state. This included reducing nucleotide and amino acid biosynthesis, suppressing energy-associated metabolism, altering osmotic adjustment, and promoting fatty acid metabolism. The results enrich our understanding of E. coli metabolic changes caused by EW perturbation and support the effectiveness of the NMR metabolomics as a valuable tool to analyse and evaluate such a complex biological system.Download high-res image (212KB)Download full-size image

•A portable and affordable sanitising unit was successfully developed.•Partial catholyte solution was reintroduced to produce neutral electrolysed water.•Box–Behnken design was used to develop models.•Electrolysed water generated with this unit showed strong bactericidal activity.The aim of this study was to develop and evaluate the characteristics and performance of a portable electrolytic sanitising unit. Free available chlorine (FAC), oxidation-reduction potential, and pH of electrolysed water were measured. Response surface methodology coupled with a Box-Behnken design was used to describe the input-output relationship and optimise FAC production. A partial catholyte solution was reintroduced to electrolysis for generating neutral electrolysed water. The result found that RuO2-IrO2/TiO2 electrode was very effective. A FAC concentration of 4 mg/L achieved >2 log CFU/mL reduction, while a FAC concentration of 40 mg/L achieved >6 log CFU/mL reduction in Escherichia coli O157:H7 and Listeria monocytogenes BAA-839. The developed sanitiser had a pH of 7.08 ± 0.08, and the commercial sanitiser had a pH of 3.77 ± 0.18. The developed sanitiser had similar bactericidal effects as the commercial sanitiser. The results revealed that the developed sanitising unit is promising for the control of foodborne pathogens.

•Broccoli was treated by low-concentration electrolysed water (LcEW) and mild heat.•Effects of treatment on microbial safety and nutritional value were assessed.•LcEW at 50 °C achieved highest reduction in E. coli O157:H7 and L. monocytogenes.•Mild heat exposure improved firmness by changing the pectin structure.The effects of low-concentration electrolysed water (LcEW) (4 mg/L free available chlorine) combined with mild heat on the safety and quality of fresh organic broccoli (Brassica oleracea) were evaluated. Treatment with LcEW combined with mild heat (50 °C) achieved the highest reduction in naturally occurring microorganisms and pathogens, including inoculated Escherichia coli O157:H7 and Listeria monocytogenes (P < 0.05). In terms of the antioxidant content of the treated broccoli, the total phenolic levels and ferric reducing antioxidant power remained unchanged; however, the oxygen radical absorbance capacity of the treated broccoli was higher than that of the untreated control. In addition, mild heat treatment resulted in an increase in firmness. The increased firmness was attributed to changes in the pectin structure, including the assembly and dynamics of pectin. The results revealed that mild heat induced an antiparallel orientation and spontaneous aggregation of the pectin chains. This study demonstrated that LcEW combined with mild heat treatment was effective to reduce microbial counts on fresh organic broccoli without compromising the product quality.

The effects of vacuum impregnation (VI) with 2% calcium lactate treatment on the VI properties (obtained from hydrodynamic mechanism and deformation–relaxation phenomena models), firmness, and pectin of Kyoho grapes were investigated. Fruit pectin was analysed by atomic force microscopy (AFM). VI was applied for 10–35 min at 25–45 °C and 5 kPa. The maximum values of effective porosity, εe (0.606%), and volume fraction, X (0.588%), occurred at 35 °C when the VI time was 15 min. No change was observed in the volumetric deformation (γ ≈ 0) of the grapes after the impregnation. The firmness significantly increased at 35 °C VI (from 12.93 to 14.47 N). According to the AFM results, calcium mainly inhibited the degradation of chelate-soluble pectin and sodium carbonate-soluble pectin short branches during the VI. Under the studied conditions, the validity of VI to incorporate calcium into fruit to improve the quality of grapes was verified, and a final corresponding product was obtained by VI.

•Examined organic compatible coagulants for preparing organic tofu.•Mixture of magnesium chloride and guar gum was promising organic coagulant.•Protein subunit components were not affected by organic coagulants.•Similar acceptability of organic and conventional tofu prepared.Organic tofu using organic compatible coagulants of magnesium chloride and three polysaccharides including carrageenan, guar gum and gum Arabic were generated. For MgCl2 coagulated tofu, carrageenan significantly increased the hardness from 969.5 g to 1210.5 g whereas guar gum (0.6 g) decreased the hardness to 505.5 g. Interestingly, gypsum and guar gum (0.6 g) increased the yield of tofu significantly. These organic compatible coagulants didn’t affect most of 7S and 11S protein subunits. Importantly, the overall-acceptability of organic tofu prepared with MgCl2 combined with guar gum or gypsum was almost the same as conventional tofu made with gymsum while having more beany-flavour. Among these organic coagulants, tofu made from 0.6 g guar gum and MgCl2 mixture was the most similar to that coagulated by conventional gypsum. Thus this mixture is promising as coagulant for making organic tofu.

•The yield of longan pericarp proanthocyanidins (LPPs) was 0.07%.•LPPs were identified containing dominant catechin/epicatechin monomeric units.•LPPs had antioxidant activity comparable to commercial grape proanthocyanidins.•LPPs inhibited α-amylase in reversibly uncompetitive mode.Longan pericarp proanthocyanidins (LPPs) were extracted and examined by structural and bioactive analyses. By 1H and 13C NMR spectra, LPPs were identified for the first time containing dominant catechin/epicatechin units with a mean degree of polymerisation of 3.3. Consistent with this result, electron spray ionisation (ESI) mass spectra revealed that the predominant LPPs were poly(epi)catechin with abundant A-type and B-type linkages. Matrix-assisted laser desorption ionisation time of flight (MALDI-TOF) mass spectra of LPPs showed dominant [M + Na]+ peaks that corresponded to procyanidin trimers–octamers. The presence of galloyl group in monomeric units of LPPs was confirmed by FT-IR, NMR, ESI and MALDI-TOF mass spectrometry (MS). Moreover, LPPs had a strong antioxidant activity of 1.23 × 104 µmol TE/g as measured by oxygen radical scavenging capacity (ORAC), and α-amylase inhibitory activity with IC50 for uncompetitive α-amylase inhibition of 0.075 mg/mL. These results indicate LPPs are promising antioxidant which could be applied as potential functional food components.

Firmness is one of the most important quality attributes of apricot fruits and is associated with chelate-soluble pectin (CSP). To elucidate the changes in CSP during postharvest, in vitro investigation of pectinase effects on CSP of apricot fruits was applied to simulate the in vivo changes in CSP fraction during postharvest. It was found that effects of pectinase (40 U/mg) treatment were similar to those of storage time on CSP nanostructures from the results of atomic force microscopy. Relative frequency of widths less than 31.25 nm was 3.6 % for control group, while it was 16.2, 52.0 and 65.5 %, respectively, for 1:10,000 (pectinase/CSP), 1:1,000 and 1:100 pectinase-treated groups. Most of the CSP lengths were 0.5–1 μm, while it was 0–1 μm for pectinase-treated groups. Pectinase treatment had some similar effects on CSP fraction as storage time.

•Low concentration neutralised electrolysed water was combined with ultrasound.•Combination treatment showed broad spectrum bactericidal effect on coupons.•Air-dried cells were inactivated effectively by combination treatment.•Microorganisms' morphologies were damaged under combination treatment.•Combination treatment is promising for sanitisation in food industry.The sanitising effect of low concentration neutralised electrolysed water (LCNEW, pH: 7.0, free available chlorine (FAC): 4 mg/L) combined with ultrasound (37 kHz, 80 W) on food contact surface was evaluated. Stainless steel coupon was chosen as attachment surface for Escherichia coli ATCC 25922, Pichia pastoris GS115 and Aureobasidium pullulans 2012, representing bacteria, yeast and mold, respectively. The results showed that although LCNEW itself could effectively reduce survival population of E. coli ATCC 25922, P. pastoris GS115 and low concentration A. pullulans 2012 in planktonic status, LCNEW combined with ultrasound showed more sanitising efficacy for air-dried cells on coupons, with swift drops: 2.2 and 3.1 log CFU/coupon reductions within 0.2 min for E. coli ATCC 25922 and P. pastoris GS115, respectively and 1.0 log CFU/coupon reductions within 0.1 min for A. pullulans 2012. Air-dried cells after treatment were studied by atomic force microscopy (AFM)/optical microscopy (OM) and protein leakage analyses further. All three strains showed visible cell damage after LCNEW and LCNEW combined with ultrasound treatment and 1.41 and 1.73 μg/mL of protein leakage were observed for E. coli ATCC 25922 and P. pastoris GS115, respectively after 3 min combination treatment, while 6.22 μg/mL of protein leakage for A. pullulans 2012 after 2 min combination treatment. For biofilms, LCNEW combined with ultrasound also significantly reduced the survival cells both on coupons and in suspension for all three strains. The results suggest that LCNEW combined with ultrasound is a promising approach to sanitise food equipment.

•Shelf-stable carvacrol (1%, w/w) nanoemulsion (CRV) was produced by ultrasonification.•CRV reduced the level of Escherichia coli and Pichia pastoris in vitro.•CRV and acidic electrolysed water (AEW) were combined and tested on cabbages.•CRV and AEW achieved 0.43 more log CFU/g reduction of aerobic bacteria than water.Carvacrol is an effective antimicrobial agent originated from essential oils, this natural antimicrobial agent has higher consumer acceptance compared to chemical agents. Due to the low solubility of carvacrol in water, carvacrol was delivered as a nanoemulsion. A carvacrol nanoemulsion contained 3.5% (w/w) oil phase (1% carvacrol and 2.5% corn oil, w/w) and 3.5% (w/w) Tween 80 was produced by ultrasonification at 10 min using 100% amplitude; the median particle size was 309 ± 19 nm. The nanoemulsion was shelf-life stable for 1 month without any significant changes in particle size. When applied against Escherichia coli ATCC 25922 and Pichia pastoris GS115 growth in nutrient broth, carvacrol nanoemulsion (0.5% w/w carvacrol) achieved 3 log reductions of microorganisms. When microorganisms were fixed and dried on stainless steel coupon surface, the carvacrol nanoemulsion treatment was more effective on E. coli than P. pastoris with about 5 and 0.3 log reduction of viable count, respectively. The native microflora on shredded cabbages was challenged by combining carvacrol nanoemulsion and acidic electrolysed water (AEW) that contained ≤ 4 mg/L free available chlorine (FAC). The treatment reduced about 0.5 log of aerobic mesophilic and psychrotropic bacteria counts and the antimicrobial activity of carvacrol nanoemulsion and AEW lasted up to 2 days. The results indicated that carvacrol nanoemulsion is promising in controlling the safety of fresh-cut vegetables.

•Potential organic compatible sanitisers and their combinations were applied.•Similar effects on lettuce organic and conventional lettuce were found.•1% H2O2 combined with 4 mg/L electrolysed water showed promising results.•Treatment with H2O2 based sanitisers reduced the bacteria dimensions.Potential organic compatible sanitisers including electrolysed water (EW, 4 mg/L free available chlorine (FAC)), citric acid (0.6%), H2O2 (1%), and their combinations were applied on organic and conventional fresh-cut lettuce (Lactuca sativa Var crispa L.) to evaluate their effects on microbiological safety, physicochemical parameters and sensory analysis (including raw sample and boiled sample). The combination of 1% H2O2 with 0.6% citric acid led to the highest reductions of microbial loads (2.26 log CFU/g for aerobic mesophilic count (AMC) and 1.28 log CFU/g for yeasts and moulds); however, it also caused the highest electrolyte leakage rate (3.11% vs. 0.91% for control). The combination of EW with 1% H2O2 achieved 1.69 and 0.96 log CFU/g reductions for AMC and yeasts and moulds, respectively with electrolyte leakage rate of 1.41%. In terms of the content of polyphenolic compounds, firmness, colour and raw material sensory analysis, there were no significant differences among different treatments, and between organic and conventional counterparts. The results suggest that 1% H2O2 combined with 4 mg/L EW is a promising approach for treating organic fresh-cut lettuce.

•Nanoparticle was developed for quantifying trace pyrethroids in vegetable oils.•Polymer coated magnetic nano adsorbents were synthesised and characterised.•Magnetic solid phase extraction was developed for preconcentration.•The proposed method showed high sensitivity and is promising.To quantify trace pesticide residue in vegetable oil rapidly, low temperature cleanup combined with magnetic nanoparticle based solid phase extraction was developed to determine eight pyrethroids in vegetable oils, including tetramethrin, fenpropathrin, cypermethrin, decamethrin, fenvalerate, acrinathrin, permethrin and bifenthrin. Polystyrene coated magnetic nanoparticles were synthesised by a modified chemical coprecipitation combined with emulsion polymerisation method. The nanoparticles were afterwards characterised by Fourier transform-infrared spectroscopy, X-ray diffraction, transmission electron microscopy as well as vibrating sample magnetometer, and successfully employed as adsorbents for the magnetic solid phase extraction of pyrethroids which were cleaned up using low temperature approach in advance. Critical impact factors on the efficiency of the extraction method such as the mass of adsorbents used, volume and type of eluent solvent, extraction time as well as elution time were optimised subsequently. Regression analysis of the calibration curves of the eight pyrethroids yielded satisfactory correlation coefficients within the range of 0.980–0.998. Limit of detection and limit of quantification were calculated to be between 0.0290-0.0658 and 0.0890–0.1994 ng g−1, respectively. Intra-day and inter-day reproducibility at different concentration levels also produced satisfactory recovery rates of 83.18–112.79% with relative standard deviations not exceeding 10.84% and 12.01%, respectively, suggesting desirable stability of the proposed method.

•Firmness decreased with depolymerisation and degradation of pectin polysaccharides.•Chain length and width of pectins was linked to apricot firmness.•1% calcium and storage at 5 °C reduced cell wall degradation extending shelf life.•Basic unit lengths of apricot cell wall polysaccharides were investigated.Cell wall polysaccharides play an important role in postharvest fruit texture softening. Effects of calcium treatment combined with cold storage on the physical properties, polysaccharide content and nanostructure of apricots were investigated. Apricots were immersed in distilled water, 1% or 3% w/v calcium chloride, then stored at 5 °C or 10 °C. Storage at 5 °C significantly improved apricot quality and shelf life. Significant changes in the concentration and nanostructure of cell wall pectins and hemicelluloses revealed their disassembly and degradation during apricot storage. These modifications could be retarded by 1% w/v calcium chloride treatment. Meanwhile, the basic width units of apricot cell wall polysaccharide chains were 11.7, 31.2 and 39.1 nm for water-soluble pectin, 11.7, 17.6 and 19.5 nm for chelate-soluble pectin, and 15.6 and 23.4 nm for hemicellulose. The results suggest that texture of apricots can be effectively maintained by 1% calcium chloride treatment and storage at 5 °C.

•The potentiality of using soy protein as egg replacers for cakes was evaluated.•Baking additives improved the physical quality of batter and eggless cakes.•Porous nanostructures in glutenin were important to the final quality of cakes.•Soy protein is a promising egg replacer with the aid of 1% mono, diglycerides.To evaluate the feasibility of substituting eggs in yellow cake by a mixture of soybean proteins, plant polysaccharides, and emulsifiers, the batter properties, including specific gravity and viscosity; cake properties, including specific volume, texture, colour, moisture, microstructures, and structural properties of starch and glutens of the replaced cake and traditional cake containing egg, were evaluated. Replacing eggs with a soy protein isolate and 1% mono-, di-glycerides yielded a similar specific volume, specific gravity, firmness and moisture content (1.92 vs. 2.08 cm3/g, 0.95 vs. 1.03, 319.8 vs. 376.1 g, and 28.03% vs. 29.01%, respectively) compared with the traditional cakes baked with eggs. Structurally, this formulation comprised dominant gliadin aggregates in the size range of 100–200 nm and glutenin networking structures containing fewer but larger porosities. The results suggest that a mixture of soybean proteins and emulsifier is a promising substitute for eggs in cakes.