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 °C. Under these optimised drying conditions, the maximum carotenoid yield was 84.57 ± 8.56 μg CtE g−1 dm. This yield was by almost 63% lower than that achieved using fresh (non-dried) samples. Temperatures higher than 70 °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.