Exploration of High-Nutritional-Quality Vegetable Oil Blend with Enhanced Oxidative Stability as a Frying Medium Substitute for Palm Oil

Abstract

Blending is a commonly utilized technique for enhancing the oxidative stability, nutritional quality, and physicochemical properties of vegetable oils. This study explored the potential of a vegetable oil blend consisting of common seed oils (sunflower, soybean, rapeseed, cottonseed, and corn oils), through partial least squares analysis, as a substitute for palm oil in the food preparation sector. Oxidative stability assays were conducted initially and after 14 and 28 days of incubation at 60 °C. These assays included radical inhibition activities between the optimal blended oil and palm oil through DPPH• inhibition activity and thermal stability via accelerated oxidation conditions with Rancimat (110 °C, 15 L/h) and conjugated diene and triene formation. The impact of each oil was assessed through correlation analyses and Pareto plots. The optimal blended oil consisted of soybean/sunflower/cottonseed/corn oils at a ratio of 2:1:4:4. It had an induction period (i.e., full rancidity) vastly enhanced to 5.38 h but was statistically significantly lower than the stable palm oil by ~50%. Prior to thermal incubation, the blended oil was more potent in inhibiting DPPH•, as it recorded 139.83 μmol of Trolox equivalents per kg of oil, ~53% more than palm oil. The conjugated diene and triene concentrations were similar for both oils at ~15 and ~7 mmol/kg oil, respectively. The Fourier-Transform Infrared spectra revealed the prevalence of cis fatty acids in the optimal oil blend and trans fatty acids in palm oil, indicating an enhancement in the nutritional quality of the vegetable oil blend. The results of the study could provide a nutritional oil blend that could be used as a substitute for palm oil in the food industry.