Enzymatic Synthesis and Characterization of Structured Lipids from High-Oleic Peanut Oil for Novel Food Industry Applications

Peanut (Arachis hypogaea L.) products are the leading agricultural commodity in China, with Henan Province accounting for the largest portion of production. In 2023, the total cultivation area of peanuts in Henan was 19.6 million acres. Peanut oil (PO) is widely consumed for its distinctive nutty flavor, health benefits, and high smoke point. Recently, high-oleic peanuts have gained popularity due to their enhanced oxidative stability. The objective is to investigate the potential applications of high-oleic peanut oil (HOPO) in the food industry by synthesizing structured lipid (SL) via enzymatic catalysis and optimize the reaction conditions. Capric acid (C10:0) and HOPO were utilized as substrates for SL production, using the novel immobilized lipase Lipozyme® RM C (Rhizomucor miehei). A linear interpolation approach was used to optimize C10:0 incorporation under both solvent and solvent-free conditions, with variations in reaction time, molar ratio, and temperature. Scaled-up SL products were purified using short-path distillation and characterized in terms of lipid class distribution, triacylglycerol (TAG) species, thermal properties, and oxidative stability. Fatty acids analysis revealed that C10:0 incorporation was maximized at 55°C (58.67% ± 0.55 for solvent free reaction and 76.34 % ± 0.78 for reaction in hexane). At molar ratios greater than 6:1 (C10:0: HOPO) the incorporation rate was observed to slow down. These findings demonstrate a promising potential of peanut oil strucutred lipid (POSL) for possible applications in the food industry.