EFFECT OF PROTEASE PRETREATMENT ON THE FUNCTIONAL PROPERTIES OF PROTEIN CONCENTRATE FROM DEFATTED PEANUT FLOUR

Abstract

ABSTRACTPeanut protein concentrate (PPC) was extracted from commercial defatted peanut flour (DPF) after protease pretreatment. The effect of proteolysis by Alcalase 2.4 L, papain and Protamex at various degrees of hydrolysis (DHs; 1–8%) on the yield and functional properties of PPC were investigated. Proteolysis remarkably increased the nitrogen solubility of DPF in acidic and basic conditions. Enzymatic degradation of denatured and insoluble proteins in DPF was mainly responsible for the increase of nitrogen solubility index. Compared with the control, the yield of PPC was significantly increased by enzymatic pretreatment. In terms of the functional properties, PPCs prepared by papain and Protamex at 4% or 8% DH had high emulsifying activity index. For all three enzymatic treatments, foaming capacity and foaming stability were significantly improved at various DH (P < 0.05). This study demonstrated that protease pretreatment was a highly effective way to extract PPC with good functional properties from DPF.PRACTICAL APPLICATIONSPeanut is an important oilseed crop and a well‐accepted food. After oil production through thermal treatment, the defatted peanut flour is the main by‐product, which possesses large amount of proteins. However, due to the low extraction yield and poor functional properties of these proteins, they are not well utilised in industry till now. In this work, protease was used to pretreat defatted peanut flour. The results indicated that this pretreatment could improve the yield and functional properties of peanut proteins. Functional properties of food proteins are important in food processing and food product formulation. Peanut protein with good emulsifying and foaming properties would have a potential application in some food system, such as salad dressing, sausages, bologna, soups, confectionery, frozen desserts and cakes and so on. Therefore, this work is helpful for extensive utilisation of peanut proteins.