Drying Optimisation to Obtain Carotenoid-Enriched Extracts from Industrial Peach Processing Waste (Pomace)

In this study, peach pomace (PP) moisture reduction using conventional oven-drying was investigated by implementing the Box-Behnken experimental design, considering two major process variables, time-t and temperature-T. The purpose was the optimisation of the process to obtain PP extracts as rich as possible in total carotenoids (TCn). It was shown that effective moisture removal up to a final level of approximately 24%, could be achieved after 8.27 h (496 min) at 70 degrees C. Under these optimised drying conditions, the maximum carotenoid yield was 84.57 +/- 8.56 mu g CtE g(-1) dm. This yield was by almost 63% lower than that achieved using fresh (non-dried) samples. Temperatures higher than 70 degrees C were demonstrated to be even more detrimental in this regard, yet from the model built, it was made clear that prolonged drying time may bring about a more pronounced negative effect on the total carotenoid yield. The drop in total carotenoid content of PP as a result of drying was accompanied by a significant decline in the antiradical activity of PP extracts.