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

Document Type : Original Article

Author

Institute of Food Technology Research, Agriculture Research Center, Ministry of Agriculture Giza, Egypt

Abstract

This study was undertaken to investigate the effect of pasteurization and concentration techniques on some
physicochemical parameters, volatile flavor compounds and polyphenols composition of clear pomegranate juice and to
evaluate the use of cut-back process for improving the quality of the juice concentrate. The results showed no marked
changes could be observed in titratable acidity, total sugars and pH value, whereas ascorbic acid content and color
parameters of the juice were affected by pasteurization. A total of 27 compounds were identified in fresh pomegranate
juice: 7 monoterpenes, 6 esters, 5 aldehydes, 3 alcohols, 4 ketone, 1 ether and 1 alkane hydrocarbon. Concentration and
pasteurization 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-back
process retained all the 27 aroma compounds found in fresh juice but in slightly lower concentration. Twenty three
phenolic compounds were identified and quantified in pomegranate juice. Pyrogallol was the predominating polyphenol
in 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 process
resulted in considerable increase in polyphenols concentration whereas pasteurization lowered its concentration to a
great extent. The highest polyphenol concentration was found in pomegranate juice from cut-back process. It is to be
concluded that cut-back process could be a promising process in producing better quality juice.

Keywords