Comparison of freeze-drying and hot air-drying on Asian pear (Pyrus pyrifolia Nakai Niitaka') powder: changes in bioaccessibility, antioxidant activity, and bioactive and volatile compounds

The bioaccessibility, antioxidant activity, and bioactive and volatile compounds of freeze-dried Asian pear powder (FDAPP) and hot air-dried Asian pear powder (HDAPP) were investigated. Compared to FDAPP, HDAPP exhibited significantly (p<0.05) higher total phenolic, arbutin, and bioaccessible phenolic contents and the ferric reducing ability of plasma for the free phenolic fraction. However, all antioxidant activities for the bound phenolic fraction were lower in HDAPP, which could contribute to the release of bound antioxidant components due to cell rupture in the HDAPP. Based on the volatile profile, hot air drying provided a sweet as well as attractive flavor in the Asian pear powder (APP). Considering economic viability, higher levels of bioactive compounds, and desirable aromatic properties, hot air drying is the better option compared to freeze-drying for APP production, which could be used as a functional ingredient in food products.