3.5.3. P-anisidine value (P-AV)
P-anisidine value measures the secondary oxidation product of the oil and is important to check the oxidative quality of fats and oils. P-anisidine value for all the samples were determined up to 45 days of storage (Fig. 3). The results indicated that the use of Senjed peel aqueous extract resulted in significant inhibition of P-anisidine value. The negative control group (T0) exhibited the highest P-anisidine value (i.e. 2.98, 6.31 and 9.51 on 15, 30 and 45th day of storage) whereas the least P-anisidine value (i.e. 1.23, 2.55 and 3.11 on 15, 30 and 30th day of storage) were observed with positive control group TTBHQ. It is observed that the P-anisidine value increased slightly but steadily as storage time extended and indicated that P-anisidine value reduced as the concentration of extracts increased. According to Elaigwu et al. (2019), an acceptable P-anisidine value for well-refined oils is between 1 and 10 mmol kg-1, whereas oils with high levels of polyunsaturated fatty acids might have higher levels even when fresh. Comparing the antioxidant potential of the positive control group (TTBHQ) with all treatments, T750 group represented the lowest P-anisidine value which was close to the TTBHQ group. Thus, Senjed peel aqueous extracts could be considered as a good natural antioxidants to stabilize the cold-pressed sesame oil.