Solubility Pattern of Simmondsins, Proteins and Phenolics of Defatted Jojoba Meal

摘要

Jojoba defatted meal contains toxic compounds mainly simmondsin and simmondsin 2-ferulate. The aim of the present investigation was to study the solubility pattern of simmondsin, simmondsin 2- ferulate, protein, non-protein nitrogen and phenolic compounds present in Jojoba meal at pH ranging from 1-12. Both the supernatant and precipitate resulting after extraction at a certain pH were analyzed for the above mentioned components. The simmondsins were identified and quantified by thin layer chromatography. The antimicrobial activities of the 12 pH extracts were evaluated. Results revealed that the precipitate containing lowest simmondsin 0.55, 0.55 and 0.74 g/100 g meal was achieved at pH 1, 2 and 12, respectively. Meanwhile simmondsin 2-ferulate amounted to 0. 67, 0.72 and 0.72 g/100 g meal, at pH 9, 1 and 2, respectively. Isoelectric point of jojoba meal protein showed to be between pH 3-4 with least solubilized protein 14.26-14.08% and highest precipitated protein in the residue 17.74-17.92% protein. Non-protein nitrogen ranged between 2-3.5% in supernatant and between 7-8.6% in the precipitate. Phenolic compounds extracted in the supernatant increase with increasing pH except at pH 4 and 8 where they exhibited some decrease. Normally, the phenolic compounds in the residue followed an opposite trend. Extract at pH 1 inhibited the growth of the five examined bacteria strains. Extracts of jojoba meal resulting from pH 2, 5, 6 and 8 showed inhibition of only one of the five bacterial strains. In conclusion, simmondsins can be effectively removed from the jojoba meal at pH 1, 2 and 12. Jojoba extract at pH 1 exhibited good antibacterial activity .