Stability of an isotonic beverage based on sweet whey permeate added with cape gooseberry (Physalis peruviana L.)

Abstract

Carbohydrate and mineral content in whey permeate is similar to that of commercially available sports drinks, most of which are formulated without functional ingredients. The aim of this study was to evaluate the physicochemical stability of two formulations of isotonic beverage from whey permeate obtained by membrane separation (ultrafiltration), added with cape gooseberry fruit (Physalis peruviana L.). Physicochemical and microbiological stability, total polyphenol and carotenoid content, antioxidant activity (ABTS and DPPH) and sensory profile were evaluated during two-months of refrigerated storage at 4 °C. The results showed high physicochemical stability (pH, acidity, and total soluble solids) for the functional beverage. Important differences were observed in osmolality, which increased from 304.83 to 324.13 mOsm kg-1 for the non-hydrolyzed drink (BIUN) and from 330.1 to 350.53 mOsm kg-1 for the hydrolyzed drink (BIUH). The average content of total phenols was 9.64 and 9.72 mg-AG.100 g-1 for the BIUN and BIUH beverages, respectively. There was a reduction in the antioxidant activity of the drinks by both DPPH and ABTS analysis during storage time. Total carotenoid content decreased from 0.095 to 0.076 mg β-carotene.100 g-1 and from 0.115 to 0.076 mg β-carotene.100 g-1 for the BIUN and BIUH beverages, respectively. The sensory profile showed that both drinks had high overall quality.