Palatable functional cucumber juices supplemented with polyphenols-rich herbal extracts

Abstract

This study aimed to produce a palatable functional cucumber juice: non-supplemented cucumber juice, control juice (J-con), and supplemented with different herbal extracts. Four juices were prepared and evaluated, as supplemented with the ethanolic extracts of cinnamon, mint, ginger, and clove denoting as; J-cin, J-min, J-gin, and J-clov, respectively as compared to J-con. HPLC analysis indicated that J-clov followed by J-min were the richest juices in the phenolic and flavonoid compounds compared to control. Pyrogallol, catechin, gallic, and chlorogenic acid were the most prominent phenolics in J-clov, while hesperidin and apigenin-6-arabinose were the most abundant flavonoids. Clove extract showed the highest (p ≤ 0.05) antioxidant activity (80%), followed by the mint extract. Clove and mint extracts significantly reduced the growth of the tested bacteria and fungi. The antioxidant activities in all juices significantly (p ≤ 0.05) decreased during the storage period (0, 2, 4, and 6 months) at 25 °C as polyphenols and flavonoids content declined. The pH and vitamin C significantly decreased; however, the titratable acidity increased. Clove and mint extracts (p ≤ 0.05) reduced the decay of total sugars by reducing the microbial load. J-clov showed the highest sensorial taste and flavor scores; however, J-min and J-cin were the best colors.