CHEMICAL AND TECHNOLOGICAL STUDIES ON POMEGRANATE FRUIT PRODUCTS

Abstract

The present investigation aimed compare the effect of different processing methods on some physico-chemical properties of two Egyptian pomegranate fruits (Manfalouty and Wardey) and their products (fresh and concentrated juices, jellies) as well as to assess the potential of utilization of pomegranate by-products (seeds and peels). Two methods of extraction were applied whole fruit and blending). Clarification was performed by either adding 0.2% gelatin or centrifugation at 4000rpm/15min, and pasteurization at 79-81oF for 30min. The obtained results indicated that juice obtained from arils alone showed higher yield, but lower anthocyanin, pectin, phenolics and antioxidant activity compared to that from whole pomegranate fruit. Clarification and pasteurization methods caused noticeable decrements in Vitamin C, anthocyanin, pectin, tannins and antioxidant activity contents of pomegranate juice for the two varieties. The phenolic compounds of Manfalouty showed higher contents of vanillic, chlorogenic, ferulic and ellagic acid compared to Wardey juice. Storage of Manfalouty and Wardey concentrated juice decreases total sugars, vitamin C, tannins, and anthocyanin contents. The rate of decrease was higher in samples stored at room temperature (250C) than those stored at 40C. The phenolic compounds, showed higher contents for Protocatechoic, P-Coumaric, Chlorogenic and Ellagic acids, Catechin and Epicatechin for Manfalouty than Wardey peels. Concerning pomegranate waste, methanol peel extracts of pomegranate varieties showed similar marked effects on the inhibition of linoleic acid oxidation. For the potency of microbial activity, the highest inhibition zone was noticed for Staphylococcus aureus by methanol extract. While, the lowest detected value was for B. subtilis. No significant between acceptability qualities of jellies extracted pectin from peels and pectin commercial. From pomegranate seed, oil was obtained. Fatty acid profile of the seed oil illustrated that the predominant fatty acid was oleic acid, followed by linoleic acid and stearic acid. The percents of saturated /unsaturated fatty acids were 0.05 and 0.04 % in Wardey and Manfalouty, respectively. Keywords: Pomegranate, Peels, Juice, Seed oil, Antioxidant, Antimicrobial, Tannins, Anthocyanin, Total Phenols