High-pressure processing (HPP) can produce tomato juice of high quality and safety with a short shelf life under
refrigeration temperatures. Long-term higher temperature storage studies are rare and temperature tolerant
products are challenging to develop. The effect of high-pressure processing (HPP) on the total quality (colour,
microbial counts, phytochemical levels, antioxidant and enzymatic activities) and stability (retention over
time) of tomato juice during long-term storage was investigated. Thermal processing (TP) was used as a control
treatment, and overall, two different ambient conditions (20 °C and 28 °C) were tested. Immediately after processing,
HPP products proved superior to TP ones (enhanced redness, total carotenoids and lycopene, stable
total phenols and inactivation of pectin methyl esterase). During initial storage (30 d) most quality attributes
of HPP juice remained stable. Prolonged storage, however, led to losses of most quality attributes, although
HPP (20 °C) showed lower quality degradation rate constants comparison to TP and HPP (28 °C).
Industrial Relevance: There is a demand for ambient stable tomato products, especially in some parts of theworld,
and current industrial practices (canning, pasteurisation) either compromise in product quality or require refrigeration
conditions. High-pressure processing has been investigated as milder technology, with a potential to
deliver superior quality. The drawback is that is also requires chill storage. The results of this study show how
quality parameters behave in a high-pressured tomato product and pave the way for further development that
could optimise this technology. This could be of economic importance for the tomato juice industry to develop
new products stable in ambient temperatures and perhaps beneficial for cutting down the refrigeration costs
under specific conditions