FLAVOR DEGRADATION IN DEHYDRATED CONVENIENCE FOODS - CHANGES IN CARBONYLS IN QUICK-COOKING RICE AND BENGALGRAM DHAL

The carbonyl profiles of quick-cooking rice and Bengalgram (Cicer arie tinum) dhal are reported. Freshly processed rice contained formaldehyd e, acetaldehyde, acetone, butanal and hexanal, while freshly processed Bengalgram dhal contained 2,4-decadienals, propanal and 2-enals in ad dition to the above compounds. Incorporation of vanaspati (hydrogenate d vegetable oil) and refined sunflower oil enhanced the proportion of acetone in quick-cooking rice and dhal. On storage, the proportion of hexanal, 2,4-decadienal and 2-heptenal, 2-octenal and 2-nonenal increa sed, while the proportion of acetone decreased considerably. The conce ntration of total carbonyls increased considerably on storage. Most of the additional aldehydes were formed from the oxidative degradation o f linolenic and linoleic acids which decreased on storage. The rate of autoxidation, as measured by changes in peroxide value, was highest i n untreated rice and dhals followed by samples containing refined sunf lower oil, while the samples containing vanaspati autoxidized the slow est. Copyright (C) 1996 Elsevier Science Ltd