Effects of Germination Black Soy Milk Fermented with Lactobacillus plantarum TWK10 on Anti-Oxidative and Anti-Melanogenesis

Abstract

Black soybean germination or fermentation increases active ingredient bioavailability and anti-oxidative activity. This study investigated the effects of fermented and germinated black soy milk on anti-oxidation and melanogenesis inhibition. The total phenolic content (TPC; 42.66 ± 1.65 mg gallic acid equivalent/g) and total flavonoid content (TFC; 5.43 ± 0.54 mg quercetin equivalent (QE)/g) in ethanol extracts from Lactobacillus plantarum TWK10 (TWK10)-fermented nongermination black soy milk (FNGB) were significantly (p < 0.05) higher than those in ethanol extracts from nonfermented-nongermination black soy milk (NNGB). Although the TPC of ethanol extracts from nonfermented-germination black soy milk (NGB) and fermented-germination black soy milk (FGB) were not significantly different (p > 0.05), the TFC of FGB (1.79 ± 0.08 mg QE/g) was significantly higher than that of NGB (p < 0.05). The 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity of ethanol extracts from NNGB, FNGB, NGB, and FGB was significantly higher than that of water extracts at 10 mg/mL (p < 0.05). Furthermore, ethanol extracts from both FNGB and FGB significantly reduced the melanin content in zebrafish embryos at 100 µg/mL (p < 0.05) without causing death, malformation or bradycardia. Overall, the antioxidant activity of black soy milk significantly increased after TWK10 fermentation; moreover, ethanol extracts from FNGB and FGB could inhibit melanogenesis, indicating their potential as whitening ingredients.