44C-34 |
Aroma of dried peaches |
D. E. BENITEZ, S. M. Kappes, and K. R. Cadwallader. Dept. of Food Science & Human Nutrition, Univ. of Illinois, Urbana-Champaign, 1302 W. Pennsylvania Ave., Urbana, IL 61801 The volatile components of peach have been extensively studied in regard to variety, species, maturation and impact of storage conditions. However, there is little published literature on the impact of processing, specifically dehydration practices, on the volatile composition of peach. The loss and formation of key aroma components during the dehydration of peach are of particular interest since they may directly relate to final product quality. The objective of this study was to determine predominant aroma components of dehydrated peaches. Fresh ripened peaches were obtained from a local market. Dehydrated peaches were produced by forced-air oven drying at 60*C for 24 h. Aroma profiles of fresh and dehydrated peaches was determined by descriptive sensory evaluation. Volatile components of dehydrated peaches were isolated by high vacuum distillation followed by liquid-liquid extraction (ether) of the distillate. Class fractionation of the aroma extracts was performed to separate neutral/basic and acidic components. Aroma-active components of peach fraction were identified by gas chromatography-olfactometry (GCO) and GC-mass spectrometry. Quantitation of 3-methylbutyric (isovaleric) acid was done by headspace solid-phase microextraction (SPME; Carboxen-PDMS fiber)-GC using internal standard (2-ethylbutyric acid) methodology. Aroma profiles of fresh and dehydrated peaches indicated that sweaty and burnt sugar (caramel) notes were formed upon dehydration, while green/pungent, floral, and fruity/estery notes decreased. GCO results showed that isovaleric acid was the most intense aroma-active component of dehydrated peach and was principally responsible for the typical sweaty (dried fruit-like) aroma character of the dehydrated product. Concentration of isovaleric acid (odor detection threshold of 250 ppb) in the dehydrated peach was 19.58 ug/g +-1.0006, which corresponded to an odor-activity value of 78. Isovaleric acid could serve as an indicator of dehydrated peach quality. Further investigations should focus on the mechanism responsible for the formation of isovaleric acid in dehydrated peach.
Session 44C, Fruit & Vegetable Products: Chemistry
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