Effect of Ripening Stages and Oven Drying on the Carotenoid Composition of Goji Berry (Lycium barbarum L.) Fruits

Abstract

In this study firstly, pH, titratable acidity, water soluble solid (°Bx) and carotenoid content of goji berry fruits in three different ripening stages (mature green, intermediately ripe, fully ripe) were determined. Secondly, the fully ripe goji berry fruits were dried at 50, 60 and 70 °C in an oven drying and the changes in carotenoid composition and kinetic parameters were investigated. Thermal degradation of carotenoids in goji berry fruit fitted to the first order reaction model and k, t1/2, Q10 and Ea values were calculated. Changes in the carotenoid composition were observed as a result of the ripening of the fruit. Lutein was found as the predominant carotenoid at mature green goji berry fruit, while zeaxanthin dipalmitate was at intermediately and fully ripe goji berry. Chlorophyll a and b were detected in the mature green fruit but not in the intermediately and full ripe fruit. The results demonstrated that drying temperature is an important factor affecting carotenoid degradation in goji berry fruits and different ripening stages have important effect on the carotenoid content of goji berry.