Thermal regulation of hydrolysis, oxidation, and structural integrity in palm oil: A biochemical and FTIR-PLSR assessment.

This study examined the influence of controlled temperature-time conditions on early biochemical deterioration of palm oil extracted from intact fruits. A broad thermal matrix (25-95 °C; 1-48 h) was applied to quantify changes in extractable oil recovery, free fatty acids, iodine value, carotenoids, conjugated dienes, conjugated trienes, fatty acid composition, and FTIR spectral characteristics. Increasing temperature and duration significantly reduced measured free fatty acid levels and decreased the calculated iodine value, while inducing predictable oxidation and relative changes in fatty acid composition. FTIR spectra indicated preservation of the triacylglycerol backbone, with gradual intensity changes consistent with mild thermoxidative modification. FTIR-PLSR models demonstrated analyte-dependent predictive performance, with the strongest prediction observed for extractable oil recovery (Q2 = 0.727; RPD = 1.94) and moderate predictive capability for free fatty acids (Q2 = 0.577; RPD = 1.56), while iodine value, carotenoids, conjugated dienes, and conjugated trienes showed limited predictive performance. These findings provide insight into thermal degradation pathways and suggest the potential of FTIR-PLSR as a rapid screening approach for evaluating the quality of extracted palm oil during post-harvest handling.