Stability of phenolic compounds in apple and strawberry: Effect of different processing techniques in industrial set up

Abstract

Different technologies commonly employed by the fruit processing industry affect the phenolic content. This study aimed to establish the extent to which different processing techniques and conditions, tested at an industrial scale, affect phenolics, color, and sensory attributes of fresh strawberries and apples. The effects of freezing, thermal treatments, and high-pressure processing were investigated. In strawberries, mild and standard thermal treatments showed similar patterns for most phenolic groups; an increase in proanthocyanidins, no change in ellagic acid conjugates, and a major decrease in flavonols and anthocyanins. In apples, mild treatments and high-pressure processing had similar effects in all phenolic groups, with increases in dihydrochalcones, hydroxycinnamics, and proanthocyanidins and decreases in flavonols. However, the standard thermal treatment increased flavonols and dihydrochalcones concentrations. This study shows that each fruit behaves differently, and both technology and processing conditions should be customized accordingly to preserve or even increase the phenolic content.

Keywords: Apple puree; Fruit-processing; Phenolic compounds; Strawberry puree.