Evolution of lipid characteristics and minor compounds in hazelnut oil based on partial least squares regression during accelerated oxidation process

This study used partial least squares regression (PLSR) to explore the evolution of the oxidative characteristics (peroxide value, p-anisidine value, conjugated diene value), antioxidant capacity (DPPH and ABTS assays), fatty acids, bioactive compounds (tocopherols, squalene, carotenoids and phytosterols) and free radicals in hazelnut oil during accelerated oxidation for 40 days. After 25 days of oxidation, hazelnut oil entered a highly oxidative state; as radicals began to be heavily generated, the antioxidant capacity decreased significantly. The contents of tocopherols, squalene, carotenoids, linoleic and linolenic acid were significantly reduced, which was significantly negatively correlated with the oxidative degree of hazelnut oil. In addition, electron spin resonance (ESR), which is an effective nondestructive method of measuring radicals, could be used online to detect the oxidative degree of hazelnut oil. Carotenoids and tocopherols play important roles and may be provide effective selection of the natural antioxidants to prevent hazelnut oil oxidation. •Comprehensive understanding quality of hazelnut oil during the oxidation process.•ESR technique can as a nondestructive method of measuring oxidation in hazelnut oil.•Fatty acid composition of hazelnut oil was identified precisely by GC × GC-TOF/MS.•PLS models was useful application for understanding the oxidation evolution.