•Yam with hot air-drying at 60 °C had higher allantoin content.•Yam with hot air-drying at 40 °C and 80 °C had higher resistant starch.•Blanching (100 °C for 1min) was effective to inhibiting enzymatic browning of yam.•Flavonoid ingredients of yam may be mainly substrate of enzymatic browning reaction.The effects of blanching (in boiling water for 1min) and different hot air drying temperatures (40 °C, 60 °C and 80 °C) on the polyphenol oxidase (PPO), peroxidase (POD) and antioxidant activities, main bioactive components, as well as the starch-related physicochemical properties of yam flours were studied. The results of PPO and POD activities, and total flavone and total soluble polyphenol contents showed that blanching was effective to inhibiting enzymatic browning of yams, and the substrate of enzymatic browning reaction may be mainly flavonoid ingredients. The sample of H-40 had higher allantoin and total soluble polyphenol content, stronger DPPH scavenging activity and reducing power. From the results of scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR), the blanching yams was found contain partly gelatinized starch granules, and had lower crystallinity. The H-40 and H-80 samples had higher RS contents and lower GI values. Furthermore, the protein and soluble amylose contents, solubility and swelling power at 90 °C of the blanching yams were lower than those of the yams without blanching. We can effectively apply these flours in various products based on their characteristics.

•Hypoglycemic activity of pear peel in streptozocin-induced type 2 diabetic mice.•Inhibitory activity of pear peel in α-glucosidase in vitro.•Evaluation of 8 pear varieties' antioxidant and anti-inflammatory potential.•Analysis of total polyphenols, total triterpenes, and main monomeric compounds.Total phenolic acids, total flavonoids, total triterpenes contents, and eleven monomeric compounds, derived from eight different pears' peel and pulp, were qualitatively and quantitively profiled utilizing HPLC and HPLC-MS. All the chemical components found in the peel were approximately 2 to 18 folds concentrated than those in the pulp. Their antioxidant (reducing power and 2, 2-diphenyl-1-picrylhydrazyl/DPPH assay) and anti-inflammatory (xylene-induced mouse ear edema assay) activities were comparatively evaluated. Correlation analysis and principal component analysis were utilized to seek bioactive components in antioxidant and anti-inflammatory activities. Subsequently, Yaguang pear (Pyrus ussuriensis Maxim, with high polyphenols content) was selected to investigate in vitro and in vivo anti-diabetic potential (α-glucosidase inhibition assay and hypoglycemic assay in streptozocin-induced type 2 diabetic mice). Eleven monomeric compounds were seriatim examined for α-glucosidase inhibitory activity to fish out anti-diabetic components. For the first time, this study delineated pear peel's anti-diabetic prospect of treatment for type 2 diabetes.

•Fritillaria thunbergii had a higher active component when hot air-dried at 60 °C.•F. thunbergii hot air-dried at 60 °C had more resistant starch.•Microwave drying caused significant damage to the crystal structure of starch.•Hot air drying at 60 °C is an effective method of drying F. thunbergii.This study was designed to investigate the effects of different drying methods on the main components, crystal properties, morphological properties, and in vitro digestibility properties of Fritillaria thunbergii Miq. flour. The results showed that the total peimine and peiminine contents ranged between 0.093% and 0.245%, insoluble amylose from 4.57% to 10.93%, and the water-binding capacity (WBC) from 144.09% to 192.28%. Compared with the sun-drying method, microwave drying significantly decreased the total peimine and peiminine content, protein, soluble amylose, resistant starch (RS), solubility, swelling power, and relative crystallinity, while increasing the insoluble amylose content and WBC. The microwave-dried sample showed significant changes in starch content, as evident from the scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy findings. Low levels of rapidly digestible starch and glucose and high RS levels were found in the hot air-dried and freeze-dried samples. Thus, F. thunbergii flour can be used as medicinal excipients, as health products, and in paints by these results. Furthermore, this flour finds more uses when subjected to chemical or physical treatment in medicinal, paint, and food processors.Download high-res image (283KB)Download full-size image

•The starch granules of microwave dried yam flour was gelatinization.•Freeze dried yam can as a source of hypoglycemic and lipid-lowering functional foods.•Hot air dried can be considered as an alternative method for sulphur fumigation dried.The effects of five different drying processes, air drying (AD), sulphur fumigation drying (SFD), hot air drying (HAD), freeze drying (FD) and microwave drying (MWD) for yams in terms of starch-related properties and antioxidant activity were studied. From the results of scanning electron microscopy (SEM), polarized optical microscopy (POM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR), the MWD sample was found to contain gelatinized starch granules. The FD yam had more slow digestible (SDS) and resistant starches (RS) compared with those processed with other modern drying methods. The bioactive components and the reducing power of the dried yams, were lower than those of fresh yam. When five dried samples were compared by principal component analysis, the HAD and SFD samples were observed to have the highest comprehensive principal component values. Based on our results, HAD would be a better method for yam drying than the more traditional SFD.