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Title: PINEAPPLE JUICE CONCENTRATED BY OSMOTIC EVAPORATION

Author
item Shaw, Philip - Phil
item LEBRUN, MARC - CIRAD, FRANCE
item DUCAMP, MARIE-NOELLE - CIRAD, FRANCE
item JORDAN, MARIA - USDA, FL
item Goodner, Kevin

Submitted to: Journal of Food Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/2000
Publication Date: 3/20/2002
Citation: Shaw, P.E., Lebrun, M., Ducamp, M., Jordan, M.J., Goodner, K.L. Pineapple juice concentrated by osmotic evaporation. Journal of Food Quality. 2002. v. 25. p. 39-49.

Interpretive Summary: Pineapple juice is heated during the process used to make concentrated juice, and this heat processing changes the flavor of the resulting juice. A milder process, called direct osmosis concentration, can produce concentrated juice without heating during the process. Such concentrated juices have more fresh juice flavor than heat-concentrated juice. We prepared concentrated pineapple juice by direct osmosis concentration and examined the concentrated juice by analysis and by a taste test to determine how much the juice had changed because of this mild concentration process. The concentrated juice had about two-thirds of the flavoring present in the original juice. This is a much higher level of flavor in the concentrated juice than when heat processing is used. Tasters were able to tell a difference between the original juice and juice made from the concentrated product, but pineapple flavor can be added back to the concentrated juice to restore the lost flavorings.

Technical Abstract: Pineapple juice was concentrated by osmotic evaporation to produce a 51 Brix concentrate that was reconstituted to single strength juice for evaluation. Headspace gas chromatography (HSGC) showed that the concentrate retained an average of 62% of the volatile components present in the initial juice. A sensory panel preferred initial juice over reconstituted concentrate, and noted a decrease in desirable flavor top notes as well as some processed flavor in the concentrate. Similar HSGC analysis of four other commercial juice samples showed a wide range of quantitative values for volatile components, with the initial juice being similar to the weakest of these commercial juices. Analysis of concentrated juice extracts permitted identification of additional less- volatile components not monitored directly by HSGC of the juice, and relatively low levels of these components were present in the initial juice, also. Although this nonthermally produced concentrate retains more volatile components than when traditional thermal processing methods are used, addition of aqueous aroma to the concentrate may be required for satisfactory flavor.