Valorization of cocoa shell: Impact of high voltage electrical discharge and drying technology on properties of cocoa shell

Abstract

There is a growing interest for use of cocoa shell for the enrichment of different food products and for resolving problem of disposal of shell. High voltage electrical discharge (HVED) is a non-thermal technology that could solve problems linked to use of cocoa shell (contaminants and undesirable components). This paper investigated the broader impact of HVED on the properties of cocoa shells and how much influence drying (freeze- and oven- drying), which needs to be conducted, actually has on these properties. After the treatments, oil binding capacity increased in freeze-dried samples from 1.598 to 2.054 g/g. Also, water was easier to remove from HVED-treated oven-dried samples (by 1.75%). HPLC analysis showed that HVED caused better preservation of (−)-epicatechin and (−)-epicatechin gallate after oven-drying. Klason lignin contents slightly increased and differential scanning calorimetry showed higher thermostability of cocoa shell especially after HVED and freeze-drying because peak shifted for 11.54°C. Practical applications Cocoa shell is a valuable by-product of the chocolate industry, and it presents a problem for the environment. High voltage electrical discharge (HVED) would be a sustainable solution for this problem. After the HVED treatment, drying process is needed, and this study presents insights in a combination of these two technologies on cocoa shell properties. These results show that cocoa shells can be modified with these processes and are suitable for application in different food products.