Effect of High Pressure Processing on Functional Ingredient and Quality of Apple Juice
Hans Journal of Food and Nutrition Science
Apple juice is one of the popular beverages in Taiwan, but after conventional heat processing, it will destroy its nutrients and affect the appearance and quality that reduce consumer willingness to buy. Polyphenol oxidase (PPO), peroxidase (POD) and Pectin methyl esterase (PME) can cause browning of fruit juices as the key enzymes of affecting the appearance quality. In this study, we utilize the high-pressure processing technique to destroy the enzymes activity and maintain the nutrients.
... the nutrients. First, the apple juice is divided into three groups: untreated (Control), traditional heat treatment (Thermal Processing, TP) and High Pressure Processing (HPP). The results show apple juice has no significant change on pH, soluble solids, titratable acidity. However, apple juice can reach the safety standard with 100 MPa for 10 minutes processing. PPO and POD, the key enzymes affecting appearance quality of apple juices, do not significantly decrease. PME activity in apple juice reduces at 300 MPa, 10 and 20 minutes treatment, 0.17 ± 0.012 -0.19 ± 0.026 [ΔOD min −1 (g of fw)]. For nutrients, the apple juice can reach the considerable vitamin C 145.9 mg L −1 content, the same to the control group 200 MPa for 10 minutes treatment. Soluble proteins affecting turbidity in apple juice reduce when treated with 200, 400 MPa pressure treatment. The heat-sensitive apple juice with high-pressure treatment can achieve the same sterilization effect to conventional heat treatment, and is better than the traditional thermal processing in maintaining the nutritional value and appearance quality. Based on the above results, the high-pressure treatment not only does not affect the physical ingredient juice, but also reserves better nutrients compared to the heat treatment.