077: Investigation of Cold Plasma Pre-Treatment for Enhancing the Biofunctionality of Sorghum Millet

Introduction

Sorghum millets are subjected to cold plasma treatment to investigate the modification in nutritional, functional and digestibility properties, which can have a desirable effect on the end-product quality.

Methods

Sorghum grains were treated using a cold atmospheric pressure plasma jet (CAPJ) for varying exposure durations. The CAPJ was powered by a commercial sinusoidal AC source operating at 0-10 kV and 30-35 kHz frequency, with argon gas used for plasma discharge at an exposure distance of 10 mm. After treatment, the grains were ground to a particle size of 500 microns and stored at 4°C for subsequent analysis of their physicochemical, functional, thermal, pasting, and digestibility properties.

Results

Exposure to cold plasma modified the sorghum’s physicochemical, functional, morphological, thermal, and pasting properties and degree of gelatinization. The results indicated a drop in the proteins and moisture after the treatment and an insignificant alteration in mineral content. An increase in water absorption capacity (1.59-1.81 g/g) and a decrease in oil absorption capacity (1.01-1.26 g/g) were found at the highest time and lowest time, respectively. Cold plasma-treated samples also showed fewer crystalline regions than the control, as indicated by FTIR and XRD patterns. SEM images revealed changes in flour starch granular structure. Thermal treatment (DSC) improves the amorphous zones, which in succession raises the energy required for gelatinization. CP treatment has also influenced the structure of the starch, affecting its pasting behavior. Resistant starch was modified, and the degree of gelatinization altered significantly (p < 0.05) for the samples treated at extended durations.

Significance

Cold plasma treatment can be an emerging technology that contributes to understanding the physicochemical, functional, structural, thermal, and pasting properties of sorghum. The treatment will also potentially enable the production of flour with desirable attributes and contribute to the development of gluten-free foods from cold plasma-treated millet.

Authors: Vipasha, Jatindra K Sahu and Kumar Mallikarjunan