Evaluation of physicochemical and antioxidant properties of black garlic during aging

Abstract

Black garlic was made by keeping the whole fresh garlic (Allium sativum L.) in a humidity controlled fermenter at high temperature for several days. In this study, the whole fresh garlic was converted into black garlic in a fermenter at 70-80°C for 6, 12, 18 and 24 days with two different samples which included raw garlic soaked in beer solution for 30 minutes and raw garlic without any treatments or additives. To clarify the change of black garlic during 24 days aging period and to identify the optimum aging conditions for producing black garlic, the physicochemical characteristics, phenolic content, and antioxidant activities were evaluated. The black garlic was extracted by using ultrasound and then filtered by filter paper. The moisture content and pH of black garlic decreased significantly during 24 days of aging, while browning intensity values of black garlic increased dramatically. The total phenolic content increased significantly until 12th day, and then dropped after that duration. The DPPH radical scavenging activity of black garlic also increased over time during processing. Keywords: black garlic; aging period; physicochemical characteristics; antioxidant contents; antioxidant activities