Preservation of raw watermelon juice up to one year by hyperbaric storage at room temperature

Abstract

Raw watermelon juice previously studied for 21 days by hyperbaric storage (HS) at 75 MPa and uncontrolled/naturally variable room temperature (RT ≈ 25 °C), was kept further under 75 MPa/≈25 °C for one year. The results revealed that compared to the results previously reported (21 days), HS up to one year caused an additional reduction of initial loads (total aerobic mesophiles/psychrophiles), by at least ~1.0 log CFU/mL (to below the detection limit), while Enterobacteriacae/yeasts and moulds were kept below the detection limit (1 log CFU/mL). The microbial shelf-life was so increased up to at least one year, whilst with refrigeration the juice reached unaccepted levels just in 7 days (previously reported).

Total soluble solids and pH under HS were close to the initial values, while cloudiness and colour presented only slight variations. Nevertheless, a visual colour evolution was observed.

These results indicate hyperbaric storage at room temperature as a clearly more efficient preservation comparatively with refrigeration, showing a good potential to considerably increase the shelf-life of highly perishable foods, while reduce the energy consumption and the environmental impact.