Quality characteristics and antioxidant activity of onion vinegar and black onion vinegar [양파와 흑양파를 이용하여 제조한 식초의 품질 특성 및 항산화 활성]

Abstract

In this study, we investigated the physicochemical characteristics and antioxidant activity of fermented vinegar using onion and black onion. When the onion and black onion were fermented in alcohol for 8 days, the alcohol content in both onion vinegar (OV) and black onion vinegar (BV) increased, whereas their sugar content decreased. The alcohol content was higher in OV than that in BV. When the onion and black onion were fermented in acetic acid for 20 days, the pH of both OV and BV decreased, whereas their total acidity increased. After fermentation, the main free sugars of OV and BV were fructose and glucose, and they were higher in BV than in OV. The major organic acids in OV and BV were acetic acid and malic acid, and the content of acetic acid was higher in BV than that in OV. In addition, OV and BV increased 1,1'-diphenyl- 2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS+) radical scavenging activities in a dose-dependent manner. Furthermore, DPPH and ABTS+ radical scavenging activities were greater in black onion juice than in onion juice. The BV showed a higher DPPH and ABTS+ radical scavenging activities than OV. Therefore, BV is the more suitable antioxidant functional vinegar through radical scavenging activity. ? 2022 The Korean Society of Food Preservation