A direct spectrophotometric determination of butylated hydroxyanisole in lard and in hardened lard

Abstract

T IlE USES and advantages of antioxidants in edible fats and oils have been adequately described in the literature (5, 6, 10, 11) ; however the development of methods for the determination of these antioxidants has lagged considerably behind the application of these stabilizers in fat products. With a few exceptions (1, 7, 10, 13) all of the published methods for the estimation of edible antioxidants in fats and oils depend upon the formation of a color complex which can be measured in the region of the visible spectrum (1,2,3,9,12). These eolorimetric methods are suited for systems containing one or more antioxidants when they are present in appreciable quantities.Two areas of partieular deficiency encountered in the above methods are that they do not allow rapid and convenient procedures nor are they effective for small quantities of antioxidant(s), i.e., a few parts per million (p.p.m.). Since butylated hydroxyanisole [BHA ; 2-(and 3 -) tert-butyl-4 -hydroxyanisole] and butylated hydroxytoluene (BHT; 3,5-di-tert-butyl-4hydroxytoluene) are of particular interest in fat technology, it is necessary to have available a convenient method for their quantitative determination over a practical range of concentrations having 100 p.p.m, as its higher limitY Hall and Clark (7) have reported the detection of BHA and other antioxidants by infrared analysis, and this approach may offer definite possibilities for the development of a quantitative method of analysis.Whetsel et al. (13) have developed a direct spectrophotometric method for the determination of BHA and propyl gallate in commercial antioxidant preparations. Their method takes advantage of the iso absorptive points of the absorption curves os the two substances; however its practical limitations in the low range of antioxidant concentrations have not been explored, nor does it provide either the presence or separation of oleaginous materials. In a recent publication (10) a method for analyzing butylated hydroxytoluene in lard and shortenings was described. This method utilizes ehr0matographic separation for the isolation of the antioxidant in the eluate, which is then analyzed for BHT by using its ultraviolet absorption curve between 240 and 320 rn~. This is a satisfactory method for the analysis of BHT (BHA being noninterfering) ; however its applicability over an extended range of antioxidant concentrations has not been reported.The present paper describes a method for determining butylated hydroxyanisole in lard and in hardened (iodine value less than 10) lard by means of a direct spectrophotometrie technique and allows the

A new method for quantitative determination of BHA

“…conversion to the methyl esters, has been undertaken. In addition, fatty acid methyl esters and triglycerides of high and low trans isomer content have been analyzed by the entire committee and established as secondary standards for the method as published (1).…”