열처리 조건에 따른 한국산 배(Pyrus pyrifolia Nakai)즙의이화학적 특성 변화

Abstract

Korean pear juice heat-treated at various temperatures (110, 120, 130, 140, and 150oC) and times (1, 2, 3, 4, and 5 hr) was analyzed to determine total polyphenol, total flavonoid, free sugar, and 5-HMF contents, and DPPH free radical-scavenging activity. Total polyphenol, total flavonoid, and 5-HMF contents, and antioxidant activities increased, whereas fructose content decreased with increasing heat treatment temperature and time (p ± 0.007 mg/g with treatment at 150oC for 1 hr (unheated pear juice: 0.233 ± 0.024 mg/g). Highest total flavonoid content was 561.49 ± 16.93 µg/g with treatment at 150oC for 4 hr (unheated pear juice: 1.50 ± 0.20 µg/g). IC50 value was highest, 1.93 ± 0.01 mg/g, at 150oC for 2 hr, whereas that of unheated pear juice was 64.58 ± 0.99 mg/g. Glucose content was not affected by treatment conditions, whereas fructose content decreased with treatment at 140oC for 3 hr. Highest 5-HMF content was 5,594.93 ± 6.43 ppm at 150oC for 5 hr (unheated pear juice: 2.04 ± 0.21 ppm). Correlation coefficients were observed among total phenolic, total flavonoid, and antioxidant activities, and between fructose and 5-HMF at significance level (p < 0.001).