Changes in quality indices of frozen cherry fruits under their surface treatment with sodium alginate solution

Abstract

Cherry fruit are valuable crop for technical processing, which quickly deteriorate during storage. Therefore, it is possible to extend the processing time by developing new technologies for raw materials storage and processing. Freezing is among the technologies . The purpose of the research is to assess the quality of frozen cherry fruit under their treatment with sodium alginate solutions. The objective of the study is to determine the effect of frozen cherry fruits treatment with sodium alginate solution on their physical and chemical parameters. The studies were conducted during 2016−2018 on cherries fruits of the Alpha and Memory Artemenko varieties selected at the Pomology Research Station named after L.P. Symyrenko. Cherry fruit were immersed in a 2, 3 and 5 % sodium alginate solution and kept for 5−10 minutes. They were further removed and packaged into 0.5 kg plastic bags and frozen at −24 °C, followed by storage at −18 °C. In frozen cherry fruits, the water-holding capacity for the Memory Artemenko varieties is 5.6 % and 9.5 % for Alpha , which is 2.3–2.5 % higher than the processed fruits with a solution of sodium alginate. The content of dry soluble substances in the cherry fruit varieties of Pamyat’ Artemenko and Alpha made 15.89 and 15.84 %. During the freezing, it decreased by 4.2–5.2 %. In the processed cherry fruit they were slightly less – 0.6−1.9. The content of titratable acids in the cherry fruit variety of Memory Artemenko and Alpha was 1.74 and 2.02 %. During the freezing, their content decreased by 18.8−19 %. Cherry fruit treated with sodium alginate had a smaller loss in the content of titratable acids of 8.9−16 %. The smallest losses of 8.9–9 % were in cherry fruit pre-treated with 5 % sodium alginate solution. Cherry fruit pretreatment with alginate solution before their freezing made it possible to improve the quality of cherry fruit while maintaining water-holding capacity by 2.3–2.5 %, dry soluble substances by 0.6–1.9 %, and titratable acids by 8.9–16 %, ascorbic acid − 8,1–17,4%. Key words: cherry fruit, alginate, soluble substances, acids, water-holding capacity.