Hydroalcoholic extraction of antioxidant compounds in Japanese grape pseudofruits

Abstract

The pseudofruit of Japanese grape is rich in sugar and phenolic compounds but little explored for extracting antioxidant compounds. The objective of the study was to extract and evaluate the antioxidant capacity of these pseudofruits harvested at two maturation stages: the development phase (DP) and the mature phase (MP). The pseudofruits were evaluated regarding the centesimal composition and physicochemical characteristics and submitted to extraction with 100% water, 50% ethanol, and 100% ethanol. For the extracts, we determined the phenolic compound content and the antioxidant activity using radical capture methods ABTS and DPPH. Pseudofruits may be considered a good source of dietary fiber, regardless of the maturation stage, proving to be a promising raw material for use in foods. Moreover, pseudofruits in the MP presented an increase in the contents of soluble solids, reducing and non-reducing sugars, and titratable acidity, attributed to the formation of the galacturonic acid during the maturation process. Among the solvent used, extraction with 50% ethanol resulted in a larger phenolic compound content and better antioxidant activity, especially for the pseudofruits in the DP, characterizing them as a vegetable matrix of excellent antioxidant capacity and with potential for application in foods and drugs.