Impact of different dehydration methods on physicochemical and functional properties of guava ( Psidium guajava']java L.) powder prepared from white and pink pomaces

This study investigated the effects of various dehydration methods (hot-air drying, vacuum drying and freeze drying) on chemical composition, physicochemical and functional properties of white and pink guava pomaces, which were residues from fruit juice processing. Since freeze drying dehydrated materials under low temperature and pressure, this method preserved colors, nutritional and bioactive compounds including dietary fibers, lycopene and total phenolic content better than hot-air and vacuum drying. The highly preserved compounds and unique texture of freeze dried materials led to increased properties such as water absorption capacity, antioxidant capacities and anti-diabetic activities. In addition, when comparing between cultivars, the dried pomace of pink guava contained higher dietary fibers, lycopene and total phenolic content than those of the white guava. The information from this study reinforces the concept of 'zero-waste' by using guava pomaces as co-products of fruit processing and as sources of functional ingredients for the development of food and healthcare products.