The shiitake mushroom is the most commonly cultivated edible mushroom in the world, and is rich in protein. This study aims to obtain the peptides with α-glucosidase inhibition activity from shiitake mushroom protein hydrolysate. The conditions of enzymatic hydrolysis of shiitake mushroom protein were optimized by response surface test. The results showed that the optimal conditions were as follows: the E/S was 3390 U/g, the solid–liquid ratio was 1:20, the hydrolysis temperature and time were 46 °C and 3.4 h, respectively, and the pH was 7. The active peptides were separated by gel filtration and identified by LC-MS/MS analysis and virtual screening. The results indicated that fourteen peptides were identified by LC-MS/MS. Among them, four new peptides (EGEPKLP, KDDLRSP, TPELKL, and LDYGKL) with the higher docking score were selected and chemically synthesized to verify their inhibition activity. The IC50 values of EGEPKLP, KDDLRSP, TPELKL, and LDYGKL for α-glucosidase inhibition activity ranged from 452 ± 36 μmol/L to 696 ± 39 μmol/L. The molecular docking results showed that the hydrogen bond and arene–cation bond were the two major interactions between four peptides and 2QMJ. The hydrogen bonds were crucial to the inhibition activity of α-glucosidase. The results indicate the potential of using the peptides from shiitake mushroom protein as functional food with α-glucosidase inhibition activity.
Olive (Olea europaea L.) is a very important woody tree and favored by consumers because of the fruit’s high-quality olive oil. Chloroplast genome analysis will provide insights into the chloroplast variation and genetic evolution of olives. The complete chloroplast genomes of three accessions (O. europaea subsp. cuspidata isolate Yunnan, O. europaea subsp. europaea var. sylvestris, and O. europaea subsp. europaea var. frantoio) were obtained by next-generation sequencing technology. A total of 133 coding regions were identified in the three chloroplast genomes without rearrangement. O. europaea subsp. europaea var. sylvestris and O. europaea subsp. europaea var. frantoio had the same sequences (155,886 bp), while O. europaea subsp. cuspidata isolate Yunnan (155,531 bp) presented a large gap between rps16 and trnQ-UUG genes with six small gaps and fewer microsatellites. The whole chloroplast genomes of 11 O. europaea were divided into two main groups by a phylogenetic tree and O. europaea subsp. cuspidata formed a separate group (Cuspidata group) with the other subspecies (Mediterranean/North African group). Identification of consistency and diversity among O. europaea subspecies will benefit the exploration of domestication events and facilitate molecular-assisted breeding for O. europaea.
3 November 2020 in International Journal of Food Science and Technology
Black apple is a new elaborated product obtained from whole fresh apple through fermentation at controlled high temperature (60~90°C) and humidity (relative humidity of 50~90%). The appearance, color, texture, and taste of black apple changed dramatically compared with those of fresh apple. In this study, changes in the physicochemical and phytochemical properties, volatile profiles, and antioxidant capacity of apple during the fermentation process were investigated. Results showed that the browning intensity and color difference increased continuously during the whole 65-day fermentation process (p < 0.05). Sugars decreased in the whole fermentation process (p < 0.05), whereas the contents of organic acids increased first and then decreased with prolonged 35 days of fermentation (p < 0.05). Total polyphenol content of black apple showed an increase of 1.5-fold as that of fresh apple, whereas 12 common polyphenolic compounds present in fresh apple decreased dramatically in the whole fermentation process (p < 0.05). The analysis of flavor volatiles showed that high-temperature fermentation decreased the levels of alcohols and esters and resulted in the formation of furanic and pyranic compounds, which are the main products of Maillard reaction (MR). Antioxidant activities of black apple were enhanced compared with those of fresh apple, and results indicated that the enhancement of antioxidant activities was related to the polyphenols and products of MR.