Composition and structural characterization of peanut crude oil bodies extracted by aqueous enzymatic method

Abstract

Peanut is rich in oils and proteins, which are found in oil bodies (OBs) and protein bodies (PBs), respectively. In this study, composition of proteins, neutral lipids, and phospholipids in crude OBs extracted by aqueous enzymatic extraction were analyzed. Distribution of oil, protein, and phospholipid in OBs was observed by confocal laser scanning microscopy (CLSM). Major proteins identified in OBs included oleosin, caleosin, and steroleosin. Lipoxygenase, arachin, conarachin, allergen, and ferritin, were also loosely associated with the surface of crude OBs. There were weak interactions between adsorbed proteins and OBs, such as electrostatic interactions, hydrophobic interactions, and hydrogen bonding. Results showed that fatty acids of crude OBs were rich in oleic acid (40.70 %) and linoleic acid (35.01 %). Phospholipids were mainly composed of phosphatidyl choline, phosphatidyl inositol, phosphatidyl ethanolamine, and phosphatidic acid, with relative contents of 54.87, 23.04, 16.76, and 5.33 %, respectively. CLSM of OBs revealed oil droplets evenly distributed in aqueous phase and uniform distribution of proteins and phospholipids at oil droplets surface. This study provides new insights into composition and structure of peanut OBs and theoretical basis for demulsification.