Validation of a Simple Extraction Method for Oil Bodies Isolated from Peanuts

Abstract

Peanut preserves lipids in the form of oil bodies (OBs) which have great potential to be used in the food industries. In this study, a simple aqueous extraction method is used to extract peanut OBs and its effect on the properties and the stability of the resulted emulsions is evaluated. The above‐mentioned method involves, successive mechanical steps in order to release OBs from their cell networks, followed by purification using different recovery pHs and washing. Results shows that crude OBs had a high amount of extrinsic proteins and low physical stability. Washing OBs twice with the increase in recovery pH decreased the extrinsic proteins, the lipid oxidation, and improved the storage stability. The physical and the oxidative stability of all OBs emulsions was significantly enhanced by heating. These results suggest that peanut OBs extracted using this aqueous extraction method, can be used to prepare natural emulsions with improved long‐term stability.Practical Applications: Peanut oil is widely used in food industries in the form of emulsified oil. OBs can be represented as a better alternative solution of stable emulsified oil with a high content of antioxidant and phytosterols. Our results shows that peanut OBs can be isolated and purified by a simple aqueous extraction method. Therefore, the OBs emulsion resultant from this extraction under specific conditions (pH recovery 8.0 and washing twice with the same pH) is physically and chemically stable. Heat treatment such as pasteurization and sterilization which are essential processing steps in food industries can enhance the OBs emulsion properties by giving the emulsion better physical stability, lipid oxidation, and shelf life.Crude OBs: i) Have high content of extrinsic proteins; and ii) are not physically stable non matter the pH recovery used for the isolation. Washed OBs: i) The pI increased with washing and the increase of pH recovery; ii) pH recovery 8.0 gave the most physically stable OBs; and iii) pH recovery 11.0 gave the most stable OBs to lipid deterioration. Heated OBs: i) Heat did not enhance the stability of OBs recovered by pH 6.8; ii) heat increased reversibly the OBs particle size; and iii) heat can improve the OBs shelf life.