High hydrostatic pressure treatment for manufacturing of red bean powder: A comparison with the thermal treatment

The traditional process of manufacturing red bean powder (RBP) using high temperature and extensive cooking causes quality changes, such as an off-flavor, destruction of colors, and a reduced nutritional value of the product. In this study, RBP was manufactured using a novel process of wet grinding, high hydrostatic pressure (HHP), and freeze-drying. The impact of HHP treatment in this innovative manufacturing process on the microbial count, antioxidant activity, anti-nutritional factors, and physicochemical properties of RBP was evaluated by comparison with the conventional method of thermal treatment. Microbial populations in final RBP were reduced to 1.83, 1.55, and 1.05 log CFU/g when treated using HHP 400, 500, and 600 MPa, respectively. HHP treatment improved the nutritional profile and reduced the effects of anti-nutritional factors in RBP. The most effective reduction of trypsin inhibitor activity and phytic acid content was achieved using HHP at 600 MPa for 5 min. Total phenols, flavonoids, proanthocyanidins and total antioxidant capacity in HHP treated RBP were more effectively preserved than in thermally treated RBP. Preparation of RBP using a novel manufacturing process involving HHP treatment rather than a thermal treatment improved physico-chemical and functional properties and enhanced microbiological safety.