Factors Affecting the Quality Attributes of Unripe Grape Functional Food Products

Abstract

Unripe grapes with sour taste can be processed into various products such as verjuice and sour grape sauce. They have gained popularity because of increasing consumers' demands for natural and functional foods. It was aimed to detect some physicochemical properties and the antioxidant capacity of unripe grape products. Five verjuice and five sour grape sauce samples were analyzed and the mean of the values 2.41 for pH, 0.97 for water activity, 5.63 for soluble solid content, 3.83% for titratable acidity, 6.721 g/L for total sugar content and 473.96 mg/L for total phenol content were obtained. Antioxidant contents of the samples were detected between 0.010–0.231 and 0.035–0.885 μmol TE/mL by FRAP (ferric reducing ability of plasma) and TEAC (Trolox-Equivalent Antioxidant Capacity) assays, respectively. Variation in the result of analysis depends on factors such as varieties, maturation stage, harvesting time, genotypic differences and environmental stress. Unripe grape products could be good alternatives for functional nutrition with their physicochemical and antioxidant properties. Practical Applications The food industry is looking for new, available and low-cost alternatives to supply the demand of the consumers on functional and natural foods. Grapes are a good source of antioxidant-rich food products by making them functional and also extending their shelf life. Unripe grape products such as verjuice and sour grape sauce, used as a flavoring and acidifying agent, could also be considered natural sanitizers. Unripe grape products, directly or as an additive in foods, could contribute to the functional and natural food production.