Exploring aroma changes in thermally and ultrasonically processed pomegranate juice based on multidimensional gas chromatography and multivariate statistical analysis.

Abstract

Flavor deterioration during juice processing limits industrial-scale pomegranate juice (PJ) production. To evaluate the effects of thermal and non-thermal processing on PJ flavor, three samples-pasteurized (PS), high-temperature short-time treated (HTST), and ultrasound-treated (US)-were analyzed against a fresh control (FJ). Totally 144 volatiles were identified by the combination of GC-MS and GC × GC-TOF-MS. Among, 16 was screened out as key aroma-active compounds of different PJs through GC-olfactometry/aroma intensity and relative odor activity values analysis. Quantitative descriptive analysis revealed pronounced variations in cooked flavor intensity across thermally processed samples (PS, HTST), while US exhibited a sensory profile comparable to FJ. Partial least squares regression aligned with the sensory profile. Further OPLS-discriminant analysis identified 8 and 11 key markers differentiating FJ from processed PJs, and thermal (PS, HTST) from non-thermal (US) treated PJs, respectively. Precursor addition elucidated formation pathways of major off-flavor compounds (dimethyl sulfide, methanethiol) in processed PJs.