Sinapic acid equivalent

Was Done as Sinapic Acid Equivalent Method of Khattab et al. (2010)... 

These results concurred with the findings of Thiyam et al. (2006a) that rapeseed meal extracts contained free sinapic acid, which was equivalent to just one-tenth of the content of sinapine. This was further illustrated by the Iree-phenolic fractions of the meal extracts that could recover the free sinapic acid safisfactorily. Usually in analysis, the phenofic extracts are hydrolysed with NaOH and the released-phenolics are extracted with diethyl ether, ethyl acetate or both. Comparisons between the aqueous fraction (rich in sinapine) before and after hydrolysis producing the released fraction (rich in sinapic acid) showed reasonable results with minimum hydrolysis losses affecting the accuracy of the process. Additionally, fiactionation of the 70% methanolic extract showed comparable extraction efficiency to the original extract before fractionation. 

Sinapine Equivalent SinapicAcid Sinapic Acid Content... 

Evaluation of the fractionated and non-fractionated 70% methanolic rapeseed meal extract added to stripped rapeseed oil at a concentration that was equivalent to 500 pmol/kg oil of total phenolic compounds (as quantified by HPLC, 330 nm) was compared with sinapic acid. The fractionated free-phenolic compounds (free-phenolic fraction), which contain over 85% sinapic acid, showed a similar pattern with the sinapic acid standard with respect to the inhibition of both the hydroperoxides and propanal in the emulsion. This was observed for both the cases, that is, hydroperoxide inhibition and propanal inhibition. The effectiveness of the fractionated free-phenolic componnds (free-phenolic fraction) may be dne to the high concentration of sinapic acid in the extracts. These extracts, when added to a 10% o/w system at a concentration of 500 pmol/kg oil exhibited differences in the potencies with respect to inhibition of the primary and secondary prodncts of oxidation. 

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