Analysis of non-volatile organic acids in fermented and dried cocoa beans by high performance liquid chromatography
1990
Jinap, S. (Pertanian Malaysia Univ., Serdang, Selangor. Department of Food Science) | Dimick, P.S.
A high performance liquid chromatographic method for analysis of non-volatile acids (oxalic, citric, tartaric, succinic, malic and lactic) in fermented and dried cocoa beans is described. Bean samples were pulverized in dionized water using a Polytron Homogenizer (Brinkman) for 20 sec and centrifuged at 14000 rpm for 45 min at 25 degrees C. The extract was alkalized to pH between 8-9 and passed through intermediate base anion exchange resin; the acidic fraction was eluted after adding 10 sulphuric acid to the column. Polyphenols in the fraction were then eliminated by passing the acidic fraction through a reverse phase SEP-PAK that had been pre-wet with methanol. The eluate was analyzed for non-volatile acids using Organic Acid Column (Bio-Rad) with 0.1N H2SO4 as a mobile phase at 65 degrees C. The acids were detected at 214 nm and quantified by comparing peak height of sample to those of standards. The method demonstrated excellent reproducibility and recoveries of the added acids.
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