Targeted metabolomics reveals differential anthocyanin profiles in blueberry juice after thermal versus ultra-high pressure processing.

This study compared thermal processing (TP; 85 °C, 30 min) and ultra-high pressure processing (UHP; 300-600 MPa, 5-15 min) in terms of their impacts on anthocyanin profiles and the metabolic composition of blueberry juice. TP produced significantly higher total anthocyanin, flavonoid, and phenolic contents alongside stronger antioxidant activity than UHP (p < 0.01). Targeted metabolomics revealed that differential metabolites mapped to the phenylpropanoid biosynthesis pathway under TP: three anthocyanin monomers and five proanthocyanidins increased by 19-181%, while three cyanidin-type monomers decreased by 17-20%, indicating concurrent release and degradation. UHP triggered minor metabolic shifts, with anthocyanin species largely unaltered. These outcomes reflect distinct effects: TP liberates anthocyanins through heat-induced release and proposed endogenous enzyme inactivation, while UHP preserves native anthocyanin profiles through mild non-thermal disruption. Collectively, TP and UHP exert opposing impacts on juice anthocyanins, offering practical guidance for selecting processing technologies to produce anthocyanin-rich juices.