Characterization and in Vitro Bioactivity of Green Extract from Fermented Soybean Waste

Abstract

Extracts were extricated from raw okara and okara fermented with Rhizopus oligosporus using a clean, green protocol; water was used as the extraction solvent and coupled with ultrasound assistance for enhanced extraction. In vitro anti-oxidant analyses for antioxidant potential and capacity, superoxide scavenging activity, and nitric oxide scavenging activity validated that fermented okara yielded superior bioactive performance compared to raw okara. Fermented okara extracts showed no toxicity to erythrocytes and successfully prevented induced haemolysis. After 48 h incubation at the highest tested concentration (100 mg/mL), fermented okara extracts could inhibit HepG2 cells by 48.47 ± 5.28%, which was significantly different from their effects on NIH 3T3 cells. Gas chromatography–mass spectrometry characterization of extracts validated amino acids to be the chief fraction responsible for the detected bioactivity of the fermented okara extract. The results derived in this study open up the possibility that biofermented okara extract may be a potential novel sustainable nutraceutical.

A metabolomics approach to evaluate post‐fermentation enhancement of daidzein and genistein in a green okara extract

“…Summing up, it may be concluded that the polyphenol profile of okara was enhanced post‐fermentation. This work furthered our previous studies 18,21 carried out to prove the nutritional enrichment of okara through biofermentation. The TPC and TFC were observed to have improved after fermentation.…”

“…The procedure followed for fermentation and sample extract preparation was based on the one performed by Gupta and Chen 18 . A quantity of 10 g of fresh okara was inoculated with a culture inoculum of 10 5 colony‐forming unit (CFU) R. oligosporus and incubated at 30 °C for 48 h. For extraction of phytocompounds, 1 g of fermented sample (procedure repeated for unfermented sample) was added to 7 mL extraction solvent (ethanol), macerated and ultrasonicated (200 W, 20 kHz; at a cycle of 0.7, 70% amplitude percentage) for 10 min in an ice‐bath.…”

Metabolomics as a Tool to Study Underused Soy Parts: In Search of Bioactive Compounds

“…Furthermore, metabolomics contributes to a better understanding of the biotransformation of bioactive compounds [158]. As a substrate for microorganisms, okara has been widely used in different fermented modes [159][160][161][162][163][164]. Rhizopus oligosporus, Bacillus subtilis WX-17, and Eurotium cristatum were used for okara fermentation, resulting in products with higher bioactivity, nutritional composition, and anti-diabetic potential [159][160][161][162][163][164].…”

Micronized Dietary Okara Fiber: Characterization, Antioxidant, Antihyperglycemic, Antihyperlipidemic, and Pancreato-Protective Effects in High Fat Diet/Streptozotocin-Induced Diabetes Mellitus

“…Nitric oxide toxicity increases exponentially when it reacts with superoxide radicals to form the highly reactive peroxynitrite anion (ONOO−). 44 …”