Impact of hot oil treatment and chili pepper variety (Capsicum annuum L.) on capsaicinoid content and flavor volatile profiles

This study investigated the impact of hot oil treatment (180°C) by comparing the chili oil (the mixture of chili peppers and oil post-splashing) with the raw dry chili peppers from three distinct origins on the pungency, flavor profile, and fatty acid composition. Analyses conducted before and after treatment revealed that hot oil application led to a 1.1- to 3.95-fold increase in capsaicinoid content and significantly enhanced the diversity of volatile compounds. Gas chromatography-mass spectrometry (GC-MS) identified 26 key aroma-active compounds. Concurrently, significant alterations in specific fatty acid levels were observed. Orthogonal partial least squares-discriminant analysis (OPLS-DA) highlighted significant modifications in the relative abundances of key volatile classes, including ketones, alcohols, aldehydes, and acids, attributable to the treatment. Critically, OPLS-DA identified both common and origin-specific key differential flavor compounds contributing to the distinct flavor profiles of the treated peppers. These findings provide novel insights into the dynamic changes and potential pathways (e.g., compound release, degradation, or formation) of flavor transformation during hot oil processing of chili peppers and offer valuable data for optimizing flavor development in chili pepper-based food products. • Hot oil treatment elevates capsaicinoid content and increases 26 key aroma-active compounds. • Hot oil treatment alters relative abundance of four volatile classes: ketones, alcohols, aldehydes, and acids. • OPLS-DA identified origin-specific differential flavor compounds. • Compound release, degradation, and formation are the key processes elucidated.