Enzymatic polishing of pearl millet grains: A novel approach to reduce decortication losses

Abstract

The study aimed to develop an enzyme-assisted method as an alternative to conventional abrasive polishing for pearl millet grains to minimize nutritional losses. Millets, known for their high nutritional value, typically undergo abrasive decortication, which removes the bran and outer layers but also results in significant nutrient loss. To address this, an enzyme assisted process was formulated to selectively degrade the outer layers of pearl millet grains using cellulase, xylanase and pectinase enzymes. The extent of dry matter loss from abrasive polishing ranged from 10.60 % to 18.54 %, accompanied by substantial reductions in nutrient content. In contrast, enzyme-assisted decortication effectively weakened the pericarp with minimal nutrient loss. The enzyme extract was characterized by analyzing total soluble solids, reducing sugars, glucose, xylose, galacturonic acid, tannins, and phytates to assess pericarp degradation. Process optimization was carried out using response surface methodology and artificial neural network–genetic algorithm modelling approaches. The findings demonstrated the potential of enzyme-assisted decortication as a nutritionally superior and efficient alternative to traditional methods.