Comparative studies on phenolic profiles, antioxidant capacities and carotenoid contents of red goji berry (Lycium barbarum) and black goji berry (Lycium ruthenicum)

Background: The study on phytochemical difference between red and black goji berry is limited. Methods: Antioxidant activities and phenolic profiles in terms of total phenol content, total flavonoid contents, condensed tannin content, monomeric anthocyanin content, and total carotenoid content of red goji berry (Lycium barbarum) and black goji berry (L. ruthenicum) were compared using colorimetric assays. Results: All goji berries were rich in phenolics. Black goji berry had the highest phenolic, condensed tannin content and monomeric anthocyanin content. Black goji berry samples possessed higher antioxidant capacities than red goji berry, while the red goji berry had the highest carotenoid content. Goji berries exhibited a positive linear correlation between phenolic compounds and antioxidant capacities. The average value of carotenoid content in red goji berry was 233.04 mu g/g. Conclusion: The phenolics and antioxidant capacities are much higher in black goji berry than red goji berry, while carotenoid content is much higher in red than black.