Quantitation of antioxidant levels of soy-fern fermentation by DPPH assay

Abstract

Fermentation biotechnology is one of the approaches to addressing the issues of food security worldwide, where the demand for healthier and safer foods is becoming mainstream. Even though fermentation has been practiced since ancient times, there are still an infinite number of topics that can serve as subjects for fermentative investigation. Among the popular nutraceutical research is the antioxidant properties of plants. In this study, the radical scavenging activities of soy-fern fermentation by mixed probiotics (13 species) have been quantified using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Four treatments were set up: soy-fern-probiotics, soy-fern, soy-probiotics, and soy. These treatments were fermented (submerged) for up to 72 h. Samples were taken at 0 h, 24 h, 48 h, and 72 h and were analyzed via a 96-well plate microplate photometer. Results showed that the production of antioxidants peaked at 24 h in soy-fern-probiotics and soy-fern (82.82% and 82.77%, respectively), suggesting that the presence of fern molecules could have affected the production of antioxidant molecules. It is also observed that the probiotics have less impact on the antioxidant levels. The analysis of variance (ANOVA) showed that there is a significant difference in this timeframe when compared to other timeframes. On average, the succession of antioxidant levels is as follows (highest to lowest): 24 h, 48 h, 0 h, 72 h. Overall, the level of antioxidants depends on the substrates, fermenting microorganisms, type of fermentation, and fermentation time. More studies on this matter are highly recommended.