Abstract: As natural resources of food,medicine and chemical products,the development and utilization prospects of pitaya stems are broad.In order to explore the antioxidant activity and skin cream effects of red pitaya stems and white pitaya stems,the study took aloe as the control to examine their Fe³⁺ reducing power,the ability to remove DPPH and ABTS free radicals,and their total polyphenols content.Meanwhile the moisturizing and sun-protecting effects of the skin cream were evaluated.The results showed that the overall antioxidant activity of the stem of red pitaya was the highest.Its radical scavenging rates of ABTS and DPPH are 0.18 mmol/g Trolox and 0.14 mmol/g Trolox equivalent,respectively,the Fe³⁺ reducing power is 0.17 mmol/g Trolox equivalent,and the total polyphenols is 8.69 mgGAE/g.The skin cream made from Stem of red pitaya gel has a good effect of moisturizing,and it can effectively resist ultraviolet light in 270,300 and 320 nm.Based on above analysis,the development of the pitaya stem has a promising prospect,and this research could provide theoretical reference and technical basis for the deep development and utilization of the pitaya stem.

Key words: pitaya stem, antioxidant, total polyphenols, moisturizing, sun-protecting