Quality changes and pasteurization effects of citrus fruit juice by high voltage pulsed electric fields (PEF) treatment

摘要

A non-thermal pasteurization technology, high Pulsed Electric Field (PEF) has been thought to be a new-alternative processing technology instead of heating. The objective of this study was to examine and compare the effect of PEF and High Temperature Short Time (HTST) treatments on the physicochemical, microbiological and sensory characteristics of citrus juices. Total sugar and titratable acidity values of fresh citrus juice and two treatments were not significantly different each other at P<0.05.The concentration of vitamin C in fresh citrus juice (31.2+-0.59 mg percent) was not significantly different with the value of PEF treatment (29.4+-0.75 mg percent) but was significantly higher than the value of HTST treatment (27.4+-0.75 mg percent). The color values (L, a, and b) in PEF treatment were significantly lower than the fresh citrus juice, but were higher than the values of HTST treatment. Both total bacterial cell counts (6.65+-0.08 log_(10)(cfu/mL)) and yeast counts (7.79+-0.07 log_(10)(cfu/mL)) in fresh citrus juice were significantly reduced by PEF (1.39+-0.14, 2.42+-0.1 log_(10)(cfu/mL)) as well as HTST treatment (0, 0). PE activity of fresh citrus juice (1.3+-0.12 units/mL) was significantly reduced by PEF treatment (0.11+-0.01 units/mL) and was totally inactivated by HTST treatment. Sensory evaluation scores in flavor, taste and overall acceptability between the fresh and PEF treated citrus juices (7.2-7.5) were not significantly different but the values of HTST treatment (5.1-5.8)were lower than others. Consequently, PEF treatment is thought to be a good alternative pasteurization method for fresh citrus juice to HTST treatment due to its strong pasteurization effect, reduced destruction of nutrients and good sensory characteristi