Changes in total anthocyanin content and antioxidant activity in sweet cherries during frozen storage, and air-oven and infrared drying

Abstract

Introduction. Sweet cherries are important dietary components, based mainly on their content of antioxidant compounds related to health benefits. Different preservation procedures cause changes in the content of these compounds. Our work aimed at evaluation of changes in the total anthocyanin contents and antioxidant activities in fresh, frozen and dried sweet cherry fruits. Materials and methods. The total anthocyanin content of edible parts of sweet cherries was studied under different postharvest conditions. The total antioxidant activities were studied using total phenolic content and ferric reducing antioxidant power assays. Results and discussion. We report higher amounts of phenolics and anthocyanins in wild crops compared with orchard-grown and ‘Black Gold’ cultivars. Phenolics and anthocyanins of wild and cultivated samples degraded differently during frozen storage at −18 °C for six months, with a more pronounced effect on anthocyanins than on phenolics, which retained approximately half of their amounts. Black Gold sweet cherries showed much less degradation than wild crops. We found good retention of anthocyanins in air-oven-dried sweet cherries for up to 8 h at 60 °C compared with infrared-dried cherries, which showed 48% anthocyanin degradation at 60 °C. While anthocyanins drastically degraded at higher temperatures (70−80 °C), the antioxidant activity increased. Conclusion. Fresh and processed sweet cherries may find potential applications as natural colorants, antioxidants and nutraceuticals, related to their content of phenolics/anthocyanins, antioxidant properties and intended use.