Jin Hwan Leea, Chung Eun Hwangb, Kwang Sik Sonb, Kye Man Chob,*
aDivision of Research Development and Education, National Institute of Chemical Safety (NICS), Ministry of Environment, Daejeon, 52725, Republic of Korea
bDepartment of Food Science, Gyeongnam National University of Science and Technology, Jinju 34111, Republic of Korea
* Corresponding author : Kye Man Cho
Abstract
This research was the first to demonstrate the variations of nutritional constituents, glucosidase properties and antioxidant activities in soybeans during different solid state fermentation times (germination→5 periods for 12 days) with Tricholoma matsutake. Total isoflavones were significantly reduced (2661.54→1559.04 μg/g) with the increase of aglycone contents (107.61→1285.66 μg/g, 12 times) for fermentation, whereas amino acid and fatty acid slightly increased. Among them, daidzein (43.2→43.6→421.9→721.4→634.0 μg/g), genistein (52.7→24.4→339.5→546.6→512.8 μg/g) and glutamic acid (0.3→1.7→3.9→6.6→16.1 mg/g) markedly increased between germinated and fermented soybeans. Total phenolic contents and antioxidant abilities also considerably increased, especially, ABTS displayed the predominant scavenging capacities (33.1→94.8%) at 200 μg/ml, followed by DPPH (11.9→87.0%) and hydroxyl (11.2→49.2%) radicals. Interestingly, α-glucosidase inhibition (11.8→84.9%) and β-glucosidase (3.1→40.3 unit/g) exhibited the highest activities after 9 days. Our results implied that fermented soybeans may be contributed to enhance the soybean value in nutrition and biological effect aspects to development of new functional foods.
Keywords: Soybean; Solid state fermentation; Tricholoma matsutake; Isoflavone; Antioxidant activity; Glucosidase