Preserving pungency and color: thermal/storage stability of bioactive compounds in chili oil and shelf-life extension strategies

Chili oil is a complex food matrix rich in bioactive compounds. This study investigated the dynamic changes of capsaicinoids, carotenoids, total phenolics, and tocopherols in chili oil under different cooking temperatures (80 °C, 120 °C, 150 °C) and accelerated oxidation. Additionally, a strategy to enhance the storage stability of chili oil was proposed, and the protective mechanisms of combined antioxidants were elucidated. The results revealed that capsaicin content remained stable during continuous heating but decreased by 33.84 % after 25 days of accelerated oxidation. Total phenolics and tocopherols exhibited similar degradation patterns under both conditions. Among carotenoids, capsanthin showed a strong correlation with the antioxidant capacity of chili oil. However, carotenoids degraded rapidly under high temperatures and accelerated oxidation, leading to significant colour loss. The dual-antioxidant system (200 μg/g ascorbyl palmitate and 200 μg/g gallic acid) effectively inhibited the degradation of pungency (capsaicinoids) and colour (carotenoids), while reducing the peroxide value from 42.96 mmol/kg to 3.59 mmol/kg during 25 days of storage at 60 °C. This remarkable protection was achieved through the synergistic scavenging of both oxygen and lipid free radicals by the antioxidant combination. This approach extended the shelf life of chili oil from 35.57 days to 101.03 days. These results provide a theoretical guidance and practical solution for industrial-scale chili oil preservation.