LAUSR

BACKGROUND Citrus fruit peels are considered as process waste in fruit juice industry but they are a valuable raw material due to their volatile and bioactive components. Drying is one of the most usual methods to preserve this material. In this study, four drying processes (convective drying: CD, microwave drying: MD, conductive hydro drying: CHD, and freeze drying: FD) were applied to the peels of four kinds of citrus fruits (orange, bitter orange, grapefruit and lemon). RESULTS The influence of dehydration on the aroma and phenolic composition, microstructure and color properties were studied in detail. It was determined that drying increased the amount of both phenolics and volatiles in the dried samples. While MD and FD methods provided better preservation of the color and phenolics of the samples, MD and CD processes increased the amount of aroma substances. CONCLUSION The MD method would be more suitable for drying citrus peels, with a consideration of application power, due to its shorter duration and its positive effects on the phenolic and aroma components. This article is protected by copyright. All rights reserved.