High hydrostatic pressure treatment of fruit, fruit products and fruit juices: a review on phenolic compounds

Phenolic compounds are healthy substances, therefore amount of phenolic compounds in fruits/fruit juices are important for customers. Flavonoids are the most com­mon and widely distributed group of plant phenolics. Fruits and fruit juices are among the best sources of polyphenols in the human diet because of their high content in most fruits. Processing fruits can change their content of phenolic compounds and heat treatments usually decrease phenolic compounds in fruits. Minimising losses of these bioactive compounds during processing and storage are one of the priorities and challenge for manufacturers. High hydrostatic pressure (HHP) is a technology which can be used instead of thermal process such as pasteurization and can be combined with thermal process for sterilization. This study discusses the impact of HHP processing conditions on the stability of phenolic compounds in fruits and their products after process, during storage and compares with thermal process. Matrix of food and processing parameters such as pressure, temperature, time are important for retaining of phenolic compounds. In general, several authors have proven that HHP treatment on different fruit products slightly modified their content of phenolic compounds. There has not been much research comparing HHP with thermal processes on effects of phenolic compounds in fruits and fruit products, and researches generally indicate that HHP is better than thermal processes on retaining phenolic compounds.