Effect of antioxidants on reduction of lipid oxidation in canned coconut milk

Abstract

Changes were investigated in the odor of canned coconut milk during storage at ambient temperature (35°C) and their impact on consumer acceptance. Canned coconut milk samples were treated with antioxidants to reduce lipid oxidation that caused off-odor. Butylated hydroxytoluene (BHT), α-tocopherol and quercetin were used as antioxidants. After processing, the relative concentrations of δ-octalactone and ethyl octanoate in canned coconut milk without antioxidant (CCM) were 1,706.87 ng/g and 883.78 ng/g, respectively. Samples treated with BHT (CCM-B) and α-tocopherol (CCM-T) showed significant reductions in the relative concentrations of δ-octalactone (relative concentration in CCM-B = 1,118.06 ng/g and CCM-T = 514.78) and ethyl octanoate (relative concentration in CCM-B = 382.91 ng/g and CCM-T = 172.23 ng/g). In addition, coconut milk treated with α-tocopherol had the lowest relative concentrations of δ-octalactone (499.24 ng/g) and ethyl octanoate (230.67 ng/g) after storage for 2 mth. The coconut milk treated with quercetin (CCM-Q) had the highest δ-octalactone (4,466.43 ng/g) and CCM had the highest ethyl octanoate (3,948.86 ng/g). Sensory analysis of samples after storage for 2 mth showed that the panelists could detect a stronger rancid, creamy odor in CCM, CCM-Q and CCM-B than in CCM-T. The thiobarbituric acid reactive substances value (0.15 mg/L) in canned coconut milk treated with α-tocopherol after storage for 2 mth was significantly lower than for the non-treated one (0.36 mg//L), CCM-B (0.24 mg/L) and CCM-Q (0.29 mg/L). Thus, α-tocopherol could retard or inhibit lipid oxidation in canned coconut milk either after processing or during storage.