| Red palm oil (RPO) is a mildly refined crude palm oil containing at least 500 μg/g carotenoids and 800 μg/g tocopherols and tocotrienols. The major carotenoids found in RPO are the provitamin A α- and β-carotene RPO has been suggested to be an effective food-based strategy to combat vitamin A deficiency. The present study was designed to examine the oxidative and thermal stability of RPO, and secondly to assess the in vitro bioavailability, cellular uptake, conversion to vitamin A and potential mutagenicity of β-carotene oxidation products formed during storage.; RPO carotenoids were stable during storage in the dark at room temperature. The storage time for the carotenoids to deplete 50% (t1/2) at this condition was one year and carotenoid degradation followed zero order kinetics. In the absence of tocopherols, the t1/2 value was only 18 h and the degradation kinetics changed to first order. In RPO, tocopherols degraded faster during storage than when carotenoids were removed. RPO was not suitable for frying. Heating of RPO for 15 min degraded more than 90% of the carotenoid. These results suggest that it is important to keep RPO from light, oxygen and excessive heat treatment.; Epoxy β-carotene was found as the main carotenoid degradation product in RPO during storage. Epoxy β-carotene was subjected to a simulated gastric and small intestinal digestion. The micellarized compounds were fed to Caco-2 cells to determine cellular accumulation and cleavage to vitamin A. β-Carotene epoxides were readily accessible for absorption but the degree of micellarization depend on the presence of other carotenoids and food matrix. Cellular accumulation of these compounds by Caco-2 cells indicates their availability for absorption. However, the relative accumulation of β-carotene epoxides was lower than β-carotene. Also, epoxy β-carotene was converted to vitamin A less efficiently than β-carotene. The bacterial reverse mutation assay demonstrated that epoxy β-carotene was mutagenic in S. typhimurium TA102 but not in TA98, TA100 and TA97.; This study indicated that RPO was stable during storage, however RPO was not suitable for frying. Proper storage conditions were important to preserve the carotenoids in RPO. Oxidation products of carotenoids, mainly β-carotene epoxides, accumulated during storage. Although these compounds are accessible, bioavailable and exhibited partial provitamin A activity, consumption of β-carotene epoxide is not recommended given their potential toxicity as mutagens. Information acquired from these studies has provided the basic information on the potential of RPO as a food-based source of provitamin A in areas with high prevalence of vitamin A deficiency. These data can be used to aid for future studies investigating the relationship between consumption of RPO and modulation of vitamin A deficiency. |
