Impact of Processing on Flavor Volatiles and Physicochemical Properties of Pomegranate Juice

Abstract

This study was undertaken to investigate the effect of pasteurization and concentration techniques on somephysicochemical parameters, volatile flavor compounds and polyphenols composition of clear pomegranate juice and toevaluate the use of cut-back process for improving the quality of the juice concentrate. The results showed no markedchanges could be observed in titratable acidity, total sugars and pH value, whereas ascorbic acid content and colorparameters of the juice were affected by pasteurization. A total of 27 compounds were identified in fresh pomegranatejuice: 7 monoterpenes, 6 esters, 5 aldehydes, 3 alcohols, 4 ketone, 1 ether and 1 alkane hydrocarbon. Concentration andpasteurization processes resulted in loss of the two major aroma compounds (Ethyl acetate and Ethyl propanoate)whereas pasteurization alone resulted in loss of one monoterpene (3-Carene). Pomegranate juice prepared by cut-backprocess retained all the 27 aroma compounds found in fresh juice but in slightly lower concentration. Twenty threephenolic compounds were identified and quantified in pomegranate juice. Pyrogallol was the predominating polyphenolin addition to varying concentrations of gallic acid, 4 Epi-catechin, 4-amino benzoic, protocatchouic, catechin,chlorogenic acid, chatechol, P-OH-benzoic acid, ellagic acid, P-coumaric acid and ferulic acid. Concentration processresulted in considerable increase in polyphenols concentration whereas pasteurization lowered its concentration to agreat extent. The highest polyphenol concentration was found in pomegranate juice from cut-back process. It is to beconcluded that cut-back process could be a promising process in producing better quality juice.