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Enzymatic interesterification of palm oil midfraction blends for the production of cocoa butter equivalents

Author: S. Soekopitojo;P. Hariyadi;T. R. Muchtadi;N. Andarwulan

Abstract

Interesterification of fat blends containing palm oil midfraction (PMF) and fully hydrogenated soybean oil (FHSO) at various weight ratios, catalyzed by an immobilized Thermomyces lanuginosa lipase (Lipozyme TL IM), was studied for production of cocoa butter equivalents (CBEs). CBEs have chemical and physical properties compatible with those of cocoa butter (CB) and can be used to replace CB in chocolate confectionery product. The CBEs were isolated from the crude interesterification mixture by fractional crystallization in organic solvent. Triacylglycerol (TAG) composition of the starting blends, the interesterified blends and the fat products were analyzed by reversed-phase high performance liquid chromatography (RP-HPLC) in combination with refractive index (RI) detector. Enzymatic interesterification of the substrates resulted in the formation of a complex mixture of acylglycerols and free fatty acids. Concentration of several TAGs were increased, some were decreased, and several new TAGs were formed. The main TAGs of PMF (POP, POO) and TAGs of FHSO (PSS, SSS) were decreased, whereas the desired CB TAGs (POS, SOS) were increased. Our research indicated that acyl exchange occured mainly between the palmitoyl group from the PMF and the stearoyl group from the FHSO. Fractional crystallization of the fatty acid-free acylglycerols in hexane and acetone gave the fat products whose their TAG distributions were comparable to that of CB but that they also contain diacylglycerol (DAG). The substrate weight ratio of PMF to FHSO to produce a fat product containing the highest major TAGs component of CB (POS and SOS) was 1:2.

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