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Effects of Selected Synthetic and Natural Antioxidants on the Oxidative Stability of Shea Butter (Vitellaria paradoxa subsp. paradoxa)

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Shea butter is a plant fat extracted from kernels of shea nuts, the seeds of shea trees (Vitellaria paradoxa). The extracted fat, which has a long history of use in sub-Saharan Africa for medicinal, culinary, and other applications, serves as cocoa butter equivalents (CBEs) in the manufacture of chocolate and is an ingredient for cosmetics in the international market. Since shea butter contains relatively high levels of unsaturated fatty acids (more than 50 %), oxidation can occur during extraction and during post-harvest processing and storage. This study investigated the protective effects of synthetic butylated hydroxytoluene (BHT) and selected natural antioxidants (rosmarinic acid and gallic acid) on shea butter against oxidation. Each antioxidant (0.02%) was added to shea butter and the mixtures were placed at 90°C for 0, 72, and 144 h to accelerate oxidation. Measures of oxidation indicated the shea butter was protected from oxidation by addition of the antioxidants. The addition of antioxidants to shea butter produced no significant changes in the parameters used to measure oxidation (e.g. peroxide values, conjugated dienes and TBARS), as well as in the levels of major fatty acids. The natural antioxidants were almost as effective as the synthetic antioxidant.
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