A novel peptide was extracted from wheat germ globulin and purified using ion-exchange chromatography, gel filtration chromatography, and semi-preparative reversed-phase high-performance liquid chromatography (RP-HPLC). The sequence of the peptide was found to be Glu-Cys-Phe-Ser-Thr-Ala (ECFSTA). Its immunomodulatory effects were evaluated, and the results showed that ECFSTA could enhance phagocytosis of RAW 264.7 cells and significantly increase their secretion of nitric oxide (NO), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), and reactive oxygen species (ROS). ECFSTA activated macrophages mainly through the pattern recognition receptors (PRRs) of toll-like receptor 2 (TLR2) and toll-like receptor 4 (TLR4), and the production of ROS simultaneously stimulated macrophages to produce TNF-α. Thus, ECFSTA could be used as an immunomodulator and might be a promising component of functional foods.
Summary
Proteins and peptides must be degraded and modified in the gastrointestinal (GI) tract prior to absorption; this process changes their physicochemical and biological properties. Mulberry leaf protein (MP) and its hydrolysates (HMP) have favourable antioxidant activities. To investigate, in vitro and separately, the effects of GI digestion and intestinal digestion on the stability of MP and HMP, we monitored the changes in secondary structures, amino acids, molecular weights and antioxidant activities. We found that MP was more hydrolysed by pepsin than by pancreatin, unlike HMP. The final digests of MP and HMP were mainly composed of polypeptides (0.5–6.5 kDa) and oligopeptides (<0.5 kDa), respectively. The GI digestion influenced MP and HMP differently; GI digestion increased the antioxidant efficiency of MP and decreased that of HMP. For the intestinal digests, the antioxidant activities of MP and HMP also differed. The 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and 2,2′‐azinobis (3‐ethylbenzothiazoline‐6‐sulphonic acid) diammonium salt (ABTS) radical quenching abilities of MP and HMP at 1 mg mL−1 were comparable to or exceeded that of L‐glutathione (GSH) and 6‐hydroxy‐2,5,7,8‐tetramethychroman‐2‐carboxylic acid (trolox). Meanwhile, the erythrocyte haemolysis rates of MP, HMP and their GI products at 0.05–1.0 mg mL−1 were significantly lower than that of the 2,2′‐azobis (isobutyramidine) dihydrochloride (AAPH) control. Both MP and HMP can be used as natural antioxidants and may promote digestive health.
Summary
Wheat bran was fermented at 28 °C for 7 days under 70% humidity by Aspergillus niger, Aspergillus oryzae and Aspergillus awamori. Total phenolic content (TPC) of the unfermented sample was 1531.5 μg g−1 wheat bran. After the fermentation of Aspergillus awamori, Aspergillus oryzae and Aspergillus niger, TPC reached 5362.1, 7462.6 and 10 707.5 μg g−1, respectively. The antioxidant activity in the extractions of fermented wheat bran also increased significantly compared with the unfermented sample (P < 0.05). Aspergillus niger showed the greatest capacity to release bound ferulic acid (416.6 μg g−1). Aspergillus oryzae and Aspergillus awamori had the advantages of releasing more chlorogenic acid (84.0 μg g−1) and syringic acid (142.3 μg g−1), respectively. The destructive effect of Aspergillus niger on wheat bran structure was the strongest, followed by that of Aspergillus oryzae. This effect of Aspergillus niger may be due to its higher cellulase, xylanase, arabinofuranosidase and β‐xylosidase activities. Besides, Aspergillus oryzae possessed higher β‐glucosidase activity, and Aspergillus awamori had higher α‐amylase and feruloyl esterase activities. Aspergillus niger may be the best to release bound phenolic acids in the three Aspergillus species. These will provide the helpful information for understanding mechanism of the fermentation by Aspergillus species releasing bound phenolic in wheat bran.
Aspergillus niger CTBU isolated from local decayed bamboo shoot residue was employed to solid-state fermentation (SSF) of bamboo shoot residue to elevate the content of phytosterols. Strain acclimatization was carried out under the fermentation condition using bamboo shoot as substrate for fermentation performance improvement. The optimal fermentation temperature and nitrogen level were investigated using acclimatized strain, and SSF was carried out in a 500-ml Erlenmeyer flask feeding 300-mg bamboo shoot residue chips under the optimal condition (33 °C and feeding 4 % urea), and 1,186 mg (100 g)(-1) of total phytosterol was attained after 5-day fermentation, in comparison, only 523 mg (100 g)(-1) of phytosterol was assayed in fresh shoots residue. HPLC analysis of the main composition of total phytosterols displays that the types of phytosterols and composition ratio of main sterols keep steady. This laboratorial scale SSF unit could be scaled up for raw phytosterols production from discarded bamboo shoot residue and could reduce its cost.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.