Physicochemical properties, phytochemicals, and biological activities of heat-treated Elaeagnus multiflora juice and vinegar

열처리 보리수 과즙과 식초의 이화학적 특성, phytochemicals 및 생리활성

In this study, vineger was produced after heat treatment of Elaeagnus multiflora juice and its fermentative characteristics were investigated. The heat-treated juice and vinegar of E. multiflora were similar in fruit color, with b values (redness) of 39.48 (juice) and 37.56 (vinegar). After 10 days of fermentation of E. multiflora fruit, the acetic acid bacteria viable cell number, pH, acidity, reducing sugar content, and alcohol content were 4.59-4.62 log CFU/mL, 3.14-3.45, 0.2-2.12%, 0.69-35.24 mg/mL, and 0.2%, respectively. The heat-treated juice and vinegar showed significantly higher radical scavenging and digestive enzyme inhibitory activities than untreated samples, and the levels of soluble phenolics, soluble flavonoids, flavan-3-ol derivatives, and phenolic and derivatives were increased. Additioinally, the heat-treated vinegar contained major organic acids, such as acetic acid (21.82 mg/mL), and major flavan-3-ols and phenolic acids, such as catechin ($72.24{\mu}g/mL$), catechin gallate ($273.36{\mu}g/mL$), epigallocatechin gallate ($68.35{\mu}g/mL$), protocatechuic acid ($12.84{\mu}g/mL$), and salicylic acid ($42.29{\mu}g/mL$). At $25{\mu}L/mL$ treatment, DPPH and ABTS radical scavenging activities and ${\alpha}$-glucosidase and pancreatic lipase inhibitory activities were 79.66%, 93.99%, 90.12%, and 64.85%, respectively. This result suggested that it is possible to produce new types of vinegar and beverages, using heat-treated E. multiflora juice.

본 연구에서는 보리수 과즙에 열처리 후 식초를 제조하고 발효특성을 조사하였다. 열처리 보리수 과즙과 식초는 보리수 열매 색깔과 거의 유사하였으며, 적색도인 b 값은 각각 39.48(과즙)과 37.56(식초)이었다. 보리수 과즙을 발효하였을 때 10일 경과 시 초산균수는 4.59-4.62 log CFU/mL, pH는 3.14-3.45, 산도는 0.2-2.12%, 환원당은 0.69-35.24 mg/mL 및 알코올은 0.2%이었다. 비열처리 과즙보다 열처리 과즙이 라디칼 소거활성과 소화효소 저해활성이 높았고, 이에 상응하여 수용성 phenolics, 수용성 flavonoids, flavan-3-ols 유도체 및 phenolic acids 유도체 함량이 높았다. 한편 열처리 식초의 주요 유기산은 acetic acid(21.82 mg/mL)이었고 주요 flavan-3-ols와 phenolic acids 화합물은 catechin($72.24{\mu}g/mL$), catechin gallate($273.36{\mu}g/mL$), epigallocatechin gallate($68.35{\mu}g/mL$), protocatechuic acid ($12.84{\mu}g/mL$) 및 salicylic acid($42.29{\mu}g/mL$)가 검출되었다. $25{\mu}L/mL$ 처리 시 DPPH와 ABTS 라디칼 소거활성 및 ${\alpha}$-glucosidase와 pancreatic lipase 저해활성은 각각 79.66%, 93.99%, 90.12% 및 64.85% 이었다. 이 결과로부터 보리수 과즙의 열처리 방법을 활용한 새로운 형태의 기능성 식초 혹은 음료를 개발할 수 있을 것으로 사료된다.