Comparative effects of high hydrostatic pressure versus thermal processing on quality attributes and volatile profiles in non-concentrated and concentrated tomato juice.

High hydrostatic pressure (HHP) is a commercial non-thermal technology for fruit juice, but the interactive effects of prior evaporation concentration and subsequent HHP pasteurization on juice quality have not been systematically evaluated. In this study, the effects of HHP and thermal processing on quality attributes and volatile compounds of both non-concentrated and concentrated tomato juice were comprehensively investigated using HPLC, LC-MS, and GC-MS. The results demonstrated that thermal processing caused significantly greater degradation of color, all-trans-lutein, all-trans-β-carotene, and ascorbic acid than HHP in both juice types. By contrast, total lycopene, total phenols, and caffeic acid remained stable across all processing conditions. Furthermore, the concentration step significantly altered the volatile profile of tomato juice and exerted a cumulative effect on the changes induced by subsequent HHP or HTST treatment. Collectively, these findings confirm that HHP offers distinct advantages for lightly concentrated tomato juice, thereby providing a theoretical basis for its production.