The influence of processing on selected physicochemical properties, antioxidant activity and sensory quality of Japanese quince (Chaenomeles japonica) fruit preserves

The main objectives of food processing is to keep perishable food in a stable form that can be stored after the production or to make a raw material more attractive to consumers. In the present study, Japanese quince fruit has been used to produce jams, jellies and candied fruits. Fruit and preserves were analyzed for moisture content, water activity, pH value, colour parameters, total polyphenols and vitamin C contents, antioxidant activity, and only preserves for sensory quality. The processing resulted in a significantly lower content of phenolic compounds in the jams (by about 89% in both 2018 and 2019) and jellies (by about 86% in both 2018 and 2019) compared to fresh fruit. Higher vitamin C concentration (by about by about 5% and 4% in 2018 and 2019, resp.), polyphenols content (19% and 26% in 2018 and 2019, resp.) and antioxidant activity (by about 13% and 26% in 2018 and 2019, resp.) were observed for jellies than jams. A shorter time of fruits candying proved to be a better processing option in terms of total polyphenol content and antioxidant activity. Longer fruit candying time positively affected the retention of vitamin C (15.5% for fruit candied 5 days and 14.2% for fruit candied 3 days) compared to fresh fruit. The fruit processing ensured highly acceptable sensory properties of all investigated products.