유자(Citrus junos) 과육 및 과피 첨가 발효에 따른 천년초(Opuntia humifusa)의 이화학적 특성 및 기능성 변화

Abstract

In this study, Opuntia humifusa was fermented with Citrus junos and its physicochemical and functional properties were investigated. O. humifusa (Oh) was combined with C. junos flesh (Oh-CF), peel (Oh-CP), or whole fruit (Oh-CFP) and fermented at 30℃ for 14 d. The number of lactic acid bacteria rapidly increased to 7.1 log CFU/mL during the initial 10 d of fermentation, resulting in decreases in pH and soluble sugar contents of Oh samples. Total polyphenol content increased 4-5 folds in all samples during fermentation. Isorhamnetin content was highest in Oh after 14 d of fermentation whereas naringin and hesperidin contents were highest in Oh-CP after 6 d. Antioxidant activity of samples increased approximately 3-4 folds during fermentation. DPPH radical scavenging ability was highest in Oh-CFP after 10 d of fermentation whereas reducing power was highest in Oh after 14 d. α-Glucosidase inhibitory activity (GIA) of samples fermented with C. junos was higher than that of acarbose (0.85 μg/mL), with the highest GIA observed for Oh-CFP fermented for 14 d (0.38 μg/mL). Favorable essential oils such as limonene, pinene, linalool, terpinene and terpinolene were detected in samples with C. junos. The addition of C. junos flesh and peel would be useful for enhancement of physicochemical and functional properties (antioxidant and GIA activities) of O. humifusa, which could be effectively improved by modulating the fermentation period. ? 2021 Korean Society of Food Preservation. All rights reserved.