Hot air drying and freeze drying pre-treatments coupled to explosion puffing drying in terms of quality attributes of mango, pitaya, and papaya fruit chips

To further improve the quality of traditional combined hot air and explosion puffing drying (AD-EPD) dehydrated tropical fruit, freeze drying, as a pre-drying treatment, combined with explosion puffing drying (FD-EPD) was applied to dry mango, pitaya, and papaya fruit. Comparative study of AD-EPD and FD-EPD in terms of physicochemical, texture, color, microstructure, and rehydration properties of the three tropical fruit chips was done. Compared with AD-EPD, the crispness and the volume ration of the three tropical fruits were significantly improved when EPD coupled with FD. The lowest color difference, as well as high retention of physicochemical characteristics was found in FD-EPD prepared chips. The improvements of texture and color in FD-EPD dried fruit chips were confirmed using a 15-member sensory evaluation. In terms of integrated quality of the three tropical fruit chips, FD-EPD could be further applied to process valuable materials. Practical applications Drying has been applied to extend the shelf-life of seasonable fruit. With the development of drying industry, more and more advanced drying technologies are required. Explosion puffing drying (EPD) is a novel drying technology, which has many advantages, such as improving product's quality, increasing the drying rate and reducing the cost. Freeze drying (FD), as one of the innovative drying methods can be applied to combine with EPD (FD-EPD) to dry tropical fruit (mango, pitaya, and papaya). The tropical fruit chips dried by FD-EPD are presented integrated quality. Overall, FD-EPD will be a promising drying technology for preparing tropical fruit chips.