Abstract:
Lycium chinense juice is rich in a variety of nutrients and ingredients for health, and concentrated juice is its important circulation type. In order to explore the effect of concentration methods on the quality characteristics of
Lycium chinense juice, the heating concentration (HC), vacuum concentration (VC), secondary freezing concentration (SFC), heating-assisted primary freezing concentration (HAPFC), and vacuum-assisted primary freezing concentration (VAPFC) were applied in the present work, and the color, reducing sugar, sugar fraction, organic acid fraction, total phenols, total flavonoids, carotenoids, DPPH and FRAP of
Lycium chinense juice before and after concentrated were measured. The results showed that VC treatment showed better color protection than the other treatment groups, as well as retained higher reducing sugar in concentrated juice, and less effect on malic acid and tartaric acid degradation. The total phenols and total flavonoids of
Lycium chinense juice concentrated by VC were higher 8.76%~21.40% and 5.41%~13.77% than other groups, respectively. The DPPH free radical scavenging capacity and ferric ion reducing capacity of
Lycium chinense juice concentrated by VC owed higher 6.98%~29.77% and 5.97%~26.76% when compared with the other groups, beside lower carotenoids degradation. Therefore, VC showed the best protection effects on the quality characteristics of
Lycium chinense juice during concentration and it is a suitable way to concentrate
Lycium chinense juice.