Potentially bioaccessible phenolics, antioxidant capacities and the colour of carrot, pumpkin and apple powders - effect of drying temperature and sample structure

The study aimed to examine carrot, pumpkin and apple powders produced by hot-air-drying (50, 60, 70 degrees C) of samples with different levels of fragmentation (cut, grated, blended). The drying temperatures and sample structure were shown to be important determinants of the quality of the powders. The best colour stability of carrot, pumpkin and apple was found for the grated sample dried at 70 degrees C, the blended sample dried at 70 degrees C and the blended sample dried at 70 degrees C, respectively. The highest antiradical capacity and reducing power were found for powders obtained after drying the cut samples at 70 degrees C. Total phenolics and free radical quenchers were well bioaccessible in vitro. In turn, the reducing power was markedly reduced after drying at 50 degrees C. The analysed powders are a valuable source of concentrated bioactive ingredients, which predisposes them to serve as functional food components.