Evaluation of the quality of West African shea butter (Vitellaria paradoxa)

The demand for shea butter (SB) and formulations thereof has been increasing since the beginning of 2000, because of its valuable composition and applications in cosmetics, nutraceutical and pharmaceutical industries. However, there are numerous quality problems associated with the production, processing and packaging. The objective of our study was to determine the quality and purity (identity) of West African produced SB through physico-chemical, olfactory and microbial analyses. We used Purge & Trap and Short Path Thermal Desorption Technique, combined with GC and GC-MS analyses to determine volatile and semivolatile components. We also determined saponiflable and unsaponifiable fractions, oil content in whole nuts using n-hexane, investigated nut traits, melting points, sensory traits, color, microbial load or total plate counts in the butters samples. We found variations in fatty acids, cinnamate and triglycerides. In addition to ethyl cinnamate, short chain FFA, hydrocarbons, sesqueterpenes, terpenes, lipid oxidation derived volatile compounds were measured. There were significant variations within the same country of origin, such as Guinea in oil content, nut size, weight, color, fungal load and insect damages. We detected microbial loads such as Aspergillus spp., molds and insect larvae (for example almond moth Ephestia cautella) which deteriorate the raw material. The fungus present on nuts / butter may affect the fatty acid profile due to secretion of their own components, enzymatic reactions or degradation products, such as lipase secreted by the fungi thereby increasing the FFA content, and shifting the fatty acid profile to undesirable concentration, i.e. exceeding the target for FFA of <2%. In most cases, we found heat stress related odor and degradation components. The aroma / flavor / odor traits varied significantly. The color of SB varied from beige to off-white, to a mild yellow, ivory to a bright yellow, and had a slight nutty/smoky odor to it. Refining the shea butter removed the color and odor making it white and odorless. Establishment of integrated R&D program to ensure development of improved, standardized production, harvesting, processing, formulation and packaging system for a viable, effective, safe and affordable SB for regional and international markets has been suggested.