Superheated Steam for Drying Avocado Pulp: Kinetic Model and Changes in Polyphenol Content

Abstract

Avocado contains a variety of essential nutrients and important phytochemicals. At present, the drying method is widely used to increase the commercial life and availability of avocado pulp. In this study, the drying characteristics of avocado pulp by freeze drying (FD) and superheated steam drying (SHD) methods were evaluated. The SHD process occurred faster than FD, respectively, by 4 and 15 h. The loss of polyphenols and antioxidant activity of avocado flesh on drying process was relatively high, depending on the drying method and temperature. SHD has a lot of superiority that is a suitable drying method for avocado pulp. The empirical data on avocado pulp drying were used to build mathematical models that simulate moisture ratios against operating times. The statistical values revealed that the Wang and Singh model and the Page model were appropriate to depict dehydration behaviour for avocado pulp by FD, whereas the Page and Modified Page models were appropriate for the SHD method.