A preliminary study of high pressure processing effect on quality changes in ‘Nanglae’ pineapple juice during cold storage

Thermal processing affects sensory attributes and causes a loss in nutritional values of fruit juice products. This preliminary study was to clarify the effect of high pressure processing (HPP) as a non-thermal treatment on quality changes in ‘Nanglae’ pineapple juice. Fresh ‘Nanglae’ pineapple juice (100% juice) was prepared and treated under pressure at 400 and 600 MPa for 5 min. The condition of 80 ° C for 10 min was selected as conventional heat treatment (CHT). Changes in physical and chemical quality as well as microbiological quality in terms of aerobic plate count (APC) and yeast and mold (YM) were determined after treatment (0 day) and during storage at 5+1°C for 2, 4 and 6 days. The results were compared with the non-treated juice (control). It was found that after treatment, both HPP and CHT significantly reduced (P 0.05) between HPP treatment and control. In contrast, yellowness of sample with CHT significantly decreased (P 0.05) compared to non-treated one while in CHT sample the TSS significantly increased (P 0.05) between HPP and CHT, while non-treated sample had higher pH and lower TA than HPP and CHT after 6 days of storage. According to the results, it may conclude that HPP can preserve quality and maintain freshness of ‘Nanglae’ pineapple juice and is an alternative way for the juice production. However, further study should be carried on the optimization of HPP condition and its effect on other characteristics such as bioactive compound and nutrition value should be further studied.