Effects of Pretreatments on Separating the Seed Coat from the Cotyledon of Black Bean

Abstract

Separation of seed coat from the cotyledon could result in an additional black bean food ingredient. The objective of this study was to develop a standard milling procedure that can achieve optimum seed coat removal from black bean seed. Black beans were cooked in boiling water for 0, 5, 10, and 20 min or were tempered to 10, 20, 30, 40 and 50% moisture. Then all samples were dried to the original moisture content in ambient air or at 90°C. Pretreated black beans were milled using a burr mill and a roller mill. Seed coat was removed by aspiration. Seed coat yield was greater with tempered than with boiled seed dried at 90°C. The chemical and physical changes in the bean flours were less in tempered-dried pretreatment than with cooked-dried pretreatments. Higher seed coat separation with less changes in flour is important in food applications with health benefits.