Shelf life extension of peeled oranges by citric acid treatment

Abstract

The microbial spoilage of peeled oranges was caused predominantly by Gram negative bacteriaEnterobacter agglomerans, andPseudomonasspp., and yeastsCryptococcus albidus, Rhodotorula glutinis, andSaccharomyces cerevisiae. Infusion of fruits with citric acid solution (0.1, 0.25, 0.5, and 1.0% w/v) during the peeling process reduced the surface pH of peeled fruits (from 6.0 to <4.6) and extended their shelf life in comparison with fruits infused with water only. Regardless of treatment method (dipping or infusion), maximal shelf life extension was attained with 0.5% w/v citric acid for 4°C storage or 1.0% w/v citric acid for 8 and 21°C storage. Infusion of 0.5% w/v citric acid extended shelf life of both peeled whole and chunked fruits. The extension of shelf life resulted primarily from the inhibition of spoilage bacteria.