Effect of microwave and decortication on functional, nutritional and sensory properties of sorghum

Abstract

BACKGROUND : This study investigated the effect of microwave pretreatment (1000 W for 10 min) and decortication at different levels (0%, 5%, and 10%) of sorghum grain on cooking quality, nutritional, functional, and sensory properties. RESULTS : Findings indicated that microwave pretreatment of sorghum grains significantly (p ≤ 0.05) reduced cooking time from 60 min to about 20 min for whole grains, with decortication reducing cooking time further by exposing the endosperm (reducing cooking time to 10 min). Microwave pretreatment reduced endothermic transition enthalpy, indicating starch pregelatinization. Microwave pretreatment and cooked sorghum grain had far lower starch digestibility than white bread (a reference food). However, decortication and microwave treatment in combination, increased starch digestibility with an increase in rapidly digestible starch (RDS) and a decrease in resistant starch (RS) compared to untreated grains. The treatments also decreased in vitro protein digestibility. Flavor of cooked decorticated sorghum grains was milder, less sweet with lower maize flavor intensity than cooked whole sorghum grains. CONCLUSION : Combining microwave pretreatment and decortication effectively reduces cooking time, yielding a quick-cooking sorghum grain. SIGNIFICANCE : This study demonstrates that microwave pretreatment and decortication can be used to manufacture a convenient, quick-cooking sorghum grain for health-conscious consumers seeking nutritious food options.