Impact of West African treatment practices on phenolic profiles in shea kernels

The triglyceride fraction of shea kernels is a sustainable alternative to palm fat. The phenolics, e.g. antioxidants like flavonoids, remain less explored. Local treatment practices are likely to impact the phenolic profile, and thus the biological value of shea. This study aimed to identify phenolics in shea kernels, and to investigate how 21 different treatment practices influenced the phenolic profile of kernels. To do so, a methanolic extraction combined with a RP-LC-ESI-TOFMS profiling method was implemented. 32 phenolics, one polyol, and two jasmonic acid derivatives were identified, 16 reported in shea for the first time. Short initial storage (< 7 days) and extended sun-drying (> 5.5 days) resulted in highest phenolic content, with boiled kernels containing relatively more flavan-3-ols (up to 120 mg/100 g) and condensed tannins. Fermentation resulted in increased quercetin levels (up to 115 mg/100 g). The study demonstrates kernel treatments to significantly influence their phenolic profile.