Processing Stability and Antioxidant Activity of Anthocyanins from Nitraria tangutorum and Lycium ruthenicum : A Comparative Study with Microencapsulation for Quality Retention

Abstract

Abstract To address anthocyanin degradation during processing, this study investigated the stability and antioxidant activity of anthocyanins from Nitraria tangutorum (Qinghai) and Lycium ruthenicum from three origins (Qinghai, Gansu, Xinjiang), and evaluated the protective efficacy of microencapsulation. Anthocyanin profiles were characterized using LC–MS/MS. Lycium ruthenicum from Qinghai exhibited the highest total anthocyanin content (10.79 mg/g), the strongest antioxidant activity, yet it was the most susceptible to pH and light stresses, and highly sensitive to thermal stress. In contrast, Nitraria tangutorum from Qinghai displayed superior stability. Exploratory geoclimatic correlation, based on four sampling sites, suggested that high-altitude environments are associated with the accumulation of bioactive compounds, which may also exacerbate processing-induced instability; these preliminary findings require validation with larger datasets. Notably, microencapsulation significantly enhanced anthocyanin retention under thermal, light, and pH stresses (e.g., 14–19% increase at 60 °C), effectively balancing the activity–stability trade-off. This approach preserves both pigment coloring properties and nutritional quality, providing a basis for high-value utilization of natural pigments based on regional characteristics.