The Effects of High-Pressure Processing Pre-Treatment on Apple Fruit for Juice Production

One of the most difficult issues in the juice industry is to manufacture juices where processing processes minimise the impact on the native characteristics of the fruits. In this study, high-pressure technology was used on whole apple fruits in order to evaluate the effect on the juice production. Two varieties, cv. Limoncella and cv. Pink Lady, were considered. Preliminarily, the fruits were subjected to different pressures, and histological as well as pomological measurements were taken in order to identify the best treatment condition, which was established to be 600 MPa for 3 min. Juice samples were then characterised by measuring the colour, viscosity, total antioxidant capacity (TAC), and total phenolic content (TPC). The storage colour stability of the juices for both varieties showed not significant L* values between the untreated and pre-treated fruits. Juices obtained from pre-treated fruits had a viscosity significantly higher than that obtained from untreated ones. Interestingly, the TPC of high-pressure processing (HPP) pre-treated juice resulted in being significantly higher compared to the untreated ones. The HPP pre-treatment can be considered as a commercial application to modulate some quality standards for apple juice production.