Effects of fermentation on antioxidant properties and phytochemical composition of soy germ.

BACKGROUND: Traditional soy-fermented foods, such as miso, douche, natto, and tempeh have been widely used as a dietary supplement in Asian countries, and numerous reports on their phenolics and antioxidant activities have been published. Soy germ contains 10-fold higher phenolics than whole soybean, hence using soy germ as fermentation substrate will be more efficient than whole soybean. RESULTS: Soy germ fermented with Aspergillus niger M46 resulted in a high-efficiency bio-transformation of phenolics and flavonoids to their metabolites, and a diverse secondary metabolic product was also found to response oxidation stress of fungal colonisation. Its antioxidant activity against hydroxyl radicals and superoxide radicals (IC50 = 0.8 and 6.15 µg mL(-1) , respectively) was about 205-fold and 47-fold higher than those of unfermented soy germ (IC50 = 164.0 and 290.48 µg mL(-1) ), respectively. These results were similar to those observed for Trolox, and more active than those of BHT and hesperidin. The ß-glucosidase and α-amylase produced during fermentation were mainly responsible for mobilisation of the phenolics. CONCLUSION: Our results demonstrate that fermented soy germ has the potential to be a good dietary supplement for prevention of oxidative stress-related diseases, and the solid-state bioprocessing strategy could be an innovative approach to enhance the antioxidant activity of soy germ.

The applications of polysaccharides from various mushroom wastes as prebiotics in different systems.

The bases or stipes of mushrooms are normally discarded as low-economic value animal feed and compost. There are no known reports on deriving polysaccharides from these mushroom wastes for use as prebiotics. This study showed that the relatively low concentration (0.1% to 0.5%) of polysaccharides from Lentinula edodes stipe, Pleurotus eryngii base, and Flammulina velutipes base can enhance the survival rate of Lactobacillus acidophilus, Lactobacillus casei, and Bifidobacterium longum subsp. longum during cold storage. The polysaccharides had synergistic effects with the peptides and amino acids from a yogurt culture to maintain probiotics above 10(7) CFU/mL during cold storage, and they also had significant protective effects on these probiotics in simulated gastric and bile juice conditions to achieve beneficial effects in the host. These results showed that mushroom wastes, which are cheaper than other sources, could be an important, new, alternative source of prebiotics.

Fermentation of rice hull by Aspergillus japonicus under ultrasonic pretreatment.

The application of ultrasound for treating rice hull used as the fermentation substrate for xylooligosaccharides production was investigated. Aspergillus japonicus CY6-1 was selected to produce cellulolytic and xylanolytic enzymes from untreated rice hull (RH) and rice hull treated with ultrasound (USRH-M). The hemicellulose yield was increased to 1.4-fold with ultrasound, and treatment time was greatly shortened from 24h to 1.5h at 80 °C and 300 W/28 kHz. The morphology of RH from various pretreatments was observed with field emission scanning electron microscope (FESEM), revealing the surface structure of USRH-M smoother than that of RH. USRH-M was much easier to be utilized by fungi, to extend the stability of enzyme activity and to increase activities of CMCase, ß-glucosidase, and xylanase compared with those of untreated RH. The final fermentative products were xylotetraose, xylohexaose, and higher molecular weight xylooligosaccharides, achieving xylohexaose yield for USRH-M 80% higher than that for RH group.

Purification and properties of a novel phenolic antioxidant from Radix astragali fermented by Aspergillus oryzae M29.

The Chinese herb Radix astragalus (RA) has been widely used as a dietary supplement in Asia, and there are numerous reports on its bioactivities. However, there are no reports to date regarding the use of Aspergillus spp. in the culture medium of the RA plant for the production of phenolic antioxidants. In this study, utilizing the fungus Aspergillus to ferment the native RA has successfully resulted in a significant increase in the phenolic contents of RA, and the fermented RA also revealed much better antioxidant activity toward 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals, hydroxyl radical, superoxide radical and peroxyl radical than those of unfermented RA. Among these phenolics, a potent novel antioxidant was isolated and identified as 3,4-di(4'-hydroxyphenyl) isobutyric acid with a molecular weight of 272, by ESI-MS (electrospray ionization mass), ¹H NMR (nuclear magnetic resonance), ¹³C NMR, DEPT (distortionless enhancement by polarization transfer)-NMR, HMQC (heteronuclear multiple quantum coherence), and HMBC (heteronuclear multiple bond correlation) spectra. These data demonstrated that the solid-state bioprocessing strategy could be an innovative approach to enhance the antioxidant activity of RA.

Anticancer and antioxidant activities of the peptide fraction from algae protein waste.

Algae protein waste is a byproduct during production of algae essence from Chlorella vulgaris. There is no known report on the anticancer peptides derived from the microalgae protein waste. In this paper, the peptide fraction isolated from pepsin hydrolysate of algae protein waste had strong dose-dependent antiproliferation and induced a post-G1 cell cycle arrest in AGS cells; however, no cytotoxicity was observed in WI-38 lung fibroblasts cells in vitro. The peptide fraction also revealed much better antioxidant activity toward peroxyl radicals and LDL than those of Trolox. Among these peptides, a potent antiproliferative, antioxidant, and NO-production-inhibiting hendecapeptide was isolated, and its amino acid sequence was VECYGPNRPQF. These results demonstrate that inexpensive algae protein waste could be a new alternative to produce anticancer peptides.

Antioxidant properties of a new antioxidative peptide from algae protein waste hydrolysate in different oxidation systems.

Microalgae have been a popular edible food, but there are no known reports on the antioxidative peptides derived from microalgae. The algae protein waste, which is normally discarded as animal feed, is a by-product during production of algae essence from microalgae, Chlorella vulgaris. Algae protein waste was hydrolyzed using pepsin, and a potent antioxidative peptide of VECYGPNRPQF was separated and isolated. The peptide could efficiently quench a variety of free radicals, including hydroxyl radical, superoxide radical, peroxyl radical, DPPH radical and ABTS radicals, and performed more efficiently than that observed for BHT, Trolox and peptides from marine protein sources in most cases. The purified peptide also has significant protective effects on DNA and prevents cellular damage caused by hydroxyl radicals. In addition, the peptide has gastrointestinal enzyme-resistance and no cytotoxicity observed in human lung fibroblasts cell lines (WI-38) in vitro. These results demonstrate that inexpensive algae protein waste could be a new alternative to produce antioxidative peptides.