Capsaicin and tocopherol in red pepper seed oil enhances the thermal oxidative stability during frying.

Thermal oxidative stability of red pepper (Capsicum annuum) seed oil added with different levels of capsaicin or tocopherol as antioxidant during heating up to 48 h at 140±5°C was studied. Lipid oxidation of soy and pepper oil with different levels of capsaicin (0.12, 0.24%) and tocopherol (0.3, 0.6%) were evaluated during storage at 1400C for 0, 12, 24 and 48 h by monitoring peroxide value (PV), thiobarbituric acid reactive substances (TBARS) and chemiluminiscence (CL). Capsaicin content of crude pepper oil (0.16 mg/ml) was much higher than that of commercial brands (0.004-0.02 mg/ml). Oleate content was significantly (p<0.05) higher in soy oil (53.7%) than pepper oil (9.5%), however, linoleate and linolenate contents were significantly (p<0.05) higher in pepper oil (70.6, 5.8%) than in soy oil (25.9, 5.8%). TBARS, PV, and CL of pepper oil were significantly (p<0.05) lower than soy oil after frying. TBARS and CL values of pepper oil with different levels of capsaicin or tocopherol showed significantly (p<0.05) lower values than untreated pepper oil during frying and storage. TBARS and CL values of 0.6% tocopherol treated pepper oil showed significantly (p<0.05) lower values than those of soy oil. The study suggests that capsaicin and tocopherol may play a key role to prevent the thermal oxidation of pepper oil during frying.