Detection of Rancid Groundnut Oil and its Differentiation from Castor Oil

Abstract

AbstractPhysico‐chemical study, over a set of oxidized, bleached, neutralized groundnut oil samples and admixed samples of groundnut and castor oils, have been carried out to determine any possible deviation in their quality parameters, caused due to these treatments. Detection of rancid groundnut oil and its differentiation from castor oil can be accomplished qualitatively by use of methanolic sulfuric acid decomposition and ferrous ions induced cleavage methods. Few chemical spray reagents have also been selected and applied for detection and differentiation purpose on thin layer chromatoplates. Among the reagents, ferrous thiocyanate, potassium iodide and starch, alkaline permanganate, combinations of hydroiodic, hydrochloric, acetic acids and starch and hydroiodic acid and starch, found working as brown, blue, and yellow coloured sports could be seen for rancid groundnut oil on thin layer chromatoplates. Fresh groundnut and castor oils were silent in all the estimations, suggesting a clear distinction between castor oil and rancid groundnut oil.