Peanut oil and protein extraction using an aqueous enzymatic method and analysis of the characteristics of the emulsions produced

Abstract

Background and Objective: The high cost of enzyme preparation and the stable emulsion produced in the process limit the large-scale application of aqueous enzymatic method. In this study, a new aqueous enzymatic method for efficient peanut oil and protein extraction was optimized. And the composition, structure, and stability of the produced emulsions were characterized. Findings: Peanut emulsion proteins were mainly composed of oleosin, steroleosin, caleosin, lipoxygenase, and arachin. The composition of phospholipids in the emulsions was essentially the same as that in peanut raw materials. A surface protein wrapped the oil droplets. The ζ-potential, particle size, and surface protein concentration properties of the second step extracted the emulsion (E2) were consistent with those produced using the conventional aqueous enzymatic method, whereas the first step extracted the emulsion (E1) was more prone to unstable aggregation between oil droplets. The mechanical properties of shear deformation resistance (viscosity, storage modulus, and loss modulus) were better in E1 than in E2. Conclusions: Following new method, highest yields obtained for oil and protein were 95.48% and 80.74%, respectively. The new method reduced the conditions of enzymatic hydrolysis and accelerated the demulsification of emulsions. Significance and Novelty: The study provides a two-step aqueous enzymatic method for extracting emulsions and proteins from peanut. Process cost and efficiencies ensure industrial scale-up of the method.