engleski

Influence of processing on anthocyanin contents and antioxidant capacity in strawberry juices

Introduction: Anthocyanins, pigments responsible for strawberry colour, are very sensitive and could easily be degraded during processing. Moreover, they are known as biologically active compounds which are a result of its antioxidant capacity (AC). It is of great importance to protect anthocyanins to obtain products with nice colour and health benefits. Strawberry juice, which could be cloudy as well as clear, should be produced in a way to provide minimal losses of pigment. The aim of this work was to investigate the influence of four different pre treatment ways on the stability of anthocyanins and AC during processing strawberries into clear and cloudy juices. Methodology: Strawberry fruit (Fragaria ananassa × Duch.), cultivar Alba, grown in Croatia, was used to produce four clear and four cloudy juices with small scale equipment. Before pressing, fruits were chopped and treat as followed: (a) without any treatment, (b) treated with maceration enzymes, (c) blanched and (d) blanched and treated with maceration enzymes. After pressing, 4 cloudy juices were pasteurized while 4 clear juices were previously clarified and then pasteurized. In fruit and juices anthocyanins were determined by a spectral method based on bisulfite bleaching. The AC was evaluated by ABTS method. Results and Discussion: Anthocyanin contents decreased during juice production but not remarkably. All juices produced from blanched pulp had a lower amount of anthocyanins in comparison to other juices. Higher level of anthocyanins was found in all cloudy juices. In contrast to anthocyanin content, the highest AC was obtained in juices blanched and treated with maceration enzymes which prove that not only anthocyanins contribute to AC. Conclusions: Blanching and enzyme treatment could be recommended to produce high quality strawberry juices due to very high AC and not remarkably lower anthocyanin contents in comparison to other juices.

strawberry; juice; anthocyanin; antioxidant capacity

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