Physico-chemical characteristics and antioxidant activity of goji fruits jam and jelly during storage

Abstract

Since the 1990s, when the news about antioxidants and their benefits to health has begun to spread to the general public, statements about the benefits of antioxidants ranged from preventing colds to cancer treatment. Fruits and vegetables are excellent sources of antioxidants. Since the beginning of the 21st century, goji berries have become increasingly popular in Europe and North America and have been promoted in advertisements and in the media as an anti-aging remedy. Goji is a relatively new name given to Lycium Barbarum and Lycium chinense, two nearby species, with a long history of use as medicinal and food plants in East Asia, particularly in China. In the present paper are presented analysis results of Goji fruits and food products made from goji fruits (jam and jelly). Storage conditions are important factors for jams and jelly quality. The objective of this study was to monitor the physicochemical stability, antioxidant activity and sensorial profile of goji fruits jam and jelly. Special attention was paid to total phenolic and flavonoid content, antioxidant activity, total soluble solids, titratable acidity, pH and sensorial characteristics. Our results showed the antioxidant activity of the goji fruit, values which correlate well with the results obtained for total phenolic (351±7.25 mg GAE/100g ) and flavonoid content (53.06±1.23 mg QE/100g). The antioxidant activity of the goji fruits was maintained also in the finished products obtained in the present study jam (60.98 %) and jelly (41.96 %). Both goji fruits jam and goji fruits jelly showed no significant variations of physico-chemical characteristics and sensorial parameter scores after storage at refrigeration temperature for 10 days.