Korla pear juice treated by ultrafiltration followed by high pressure processing or high temperature short time

Abstract

Korla pear juice was treated by ultrafiltration (UF) followed by high pressure processing (HPP, 500 MPa at ambient temperature for 10 min) or high temperature short time (HTST, 110 °C for 8.6 s). Total plate count (TPC) and yeast & mold (Y&M) were reduced by 3.05 and 3.36 log10 CFU/mL after UF, and further reduced below the detection level (≤10 CFU/mL) after the following HPP or HTST. Clarity of UF-HPP and UF-HTST juices were 99.66% and 95.89%. Ascorbic acid and total phenols were greater in UF-HPP juice compared to UF-HTST juice, whilst ΔE of UF-HPP juice was smaller than that of UF-HTST juice with the corresponding values of 0.04 and 1.15. During 56 days of storage at 4 °C, all samples showed microbial safety. Minor changes of clarity had been found in UF-HPP juice with the value from 99.66% to 99.11%, while it was significantly decreased from 95.89% to 94.00% in UF-HTST juice during storage. Less decrease in total phenols and antioxidant capacity during storage were observed in UF-HPP juice compared to UF-HTST juice. UF-HPP process can be used as an alternative approach to produce high quality korla pear juice with a shelf life of more than 56 days at 4 °C.