Optimization of Ultrasound-Assisted Microwave Encapsulation of Peanut Oil in Protein-Polysaccharide Complex

Abstract

Research background. Peanut oil (Arachis hypogaea L.) is a rich source of unsaturated fatty acids. Consumption of peanut oil has been reported to have biological effects on human health. Unsaturated, especially poly-unsaturated fatty acids (PUFA), found in peanut oil are highly susceptible to oxidation, resulting in the formation of noxious compounds during processing and storage. The aim was to prevent peanut oil PUFA from oxidation by encapsulation in a protein-polysaccharide complex using the microwave drying process. Experimental approach. The combination effect of corn starch (CS) and whey protein isolate (WPI) was evaluated for ultrasound assisted microwave encapsulation of peanut oil to prevent oxidative degradation. The effect of independent parameters, viz. CS:WPI ratio (1:1 to 5:1), lecithin (0–5 %), ultrasonication (0–10 min) and microwave power (150–750 W) on encapsulation of peanut oil was evaluated using response surface methodology (RSM). The process responses viz., viscosity and stability of emulsion, encapsulation efficiency, peroxides value, antioxidant activity, free fatty acids (FFA), moisture, angle of repose and flowability (Hausner ratio, HR and Carr’s Index, CI) were recorded and analysed to optimize the independent variables. Results and conclusions. The viscosity of all the emulsions prepared for encapsulation by ultrasonication ranged 6.90 to 14.40 cP having more than 90 % stability over 7 days. The observed encapsulation efficiency was 21.82–74.25 % for encapsulated peanut oil. Encapsulation efficiency was significantly affected by CS:WPI ratio and ultrasonication. The peroxide value, antioxidant activity and FFA ranged between 1.789–3.723 mg/kg oil, 19.81–72.62 % and 0.042–0.127 %, respectively. Physical properties such as moisture content, angle of repose, HR and CI was observed 1.94–8.70 % (w.b.), 46.5–58.3⁰, 1.117–1.246 and 10.48–22.14 %, respectively. The physical properties were significantly affected by surface characteristics of the encapsulates. The higher efficiency (74.25 %) of the peanut oil encapsulation could be achieved at optimized condition of 1.25 CS:WPI ratio, 0.25 % lecithin, 9.99 min ultrasonication and 355.41 W microwave power. Novelty and scientific contribution. The findings contribute to the fields of food science and technology by offering a practical approach to preserving the nutritional quality of peanut oil and enhancing its stability by encapsulation, thereby promoting its potential health benefits for consumers and applications in various industries such as dairy and bakery.