Interesterifikasi enzimatik bahan baku berbasis minyak sawit untuk produksi cocoa butter equivalents

Abstract

Cocoa butter (CB) is an ideal fat that contributes to the desirable textural and sensory properties of chocolate confectionery products. At below room temperature, CB is hard and brittle, but when it is consumed it melts completely in the mouth with a smooth, cool sensation. Cocoa butter equivalents (CBEs) have been designed to physicochemical properties compatible with those of CB and can be used to replaced CB in chocolate confectionery formulation. Palm oil is an important oil source in the development of substitutes or equivalents of CB. Enzymatic interesterification of fat blends containing palm oil fractions (refined, bleached, deodorized palm oil, RBDPO; palm olein; and soft palm midfraction, sPMF) with fully hydrogenated soybean oil (FHSO) (transesterification) or with stearic acid (acidolysis) at various reaction times and weight ratios were studied for the production of CBEs. The objective of this research was to evaluate the synthesis of CBEs by enzymatic interesterification of palm oil based starting materials. The CBEs were isolated from the crude interesterification mixture by fractional crystallization in organic solvent. Triacylglycerol (TAG) composition, solid fat content (SFC) and slip melting point (SMP) were analyzed in the starting materials, the interesterified products and the fractionation products. Enzymatic interesterification of the substrates resulted in the formation of a complex mixture of acylglycerols and free fatty acids (FFA). Concentration of several TAGs increased, some decreased, and several new TAGs were formed. Enzymatic transesterification reaction were predicted to reach equilibrium after 8-12 hours, whereas acidolysis reaction after 36-48 hours of reaction times. Synthesis of target TAGs (POS, SOS) increased with increasing proportion of FHSO or stearic acid (up to 5:4 weight ratio of palm oil fractions/stearic acid) in the substrates. Fractional crystallization of the fatty acid-free acylglycerols (neutralized interesterified products) gave the fat products (CBEs) whose their TAG distributions were comparable to that of CB. According to the CAOBISCO definition of CBE, only eight of the transesterified products and four of the acidolysis products can be termed as CBE. The substrates (palm oil fractions/FHSO) weight ratios to produce the fat products qualified as CBEs were 1:1 (except palm olein/FHSO), 2:3 and 1:2, while the substrates of RBDPO/Stearic Acid and sPMF/Stearic Acid at weight ratios were 5:4 and 5:5. The substrates criteria of transesterification were concentration ratio of (POO+POP)/(PSS+SSS) ≤ 0.85, and the POP content ≥ 14.85%, whereas acidolysis were concentration ratio of (POO+POP)/S ≤ 1.32, and the POP content ≥ 29.67%. The products criteria of enzymatic transesterification were concentration ratio of (POO+POP)/(PSS+SSS) ≤ 0.76, concentration ratio of (POS+SOS)/(POO+POP) ≥ 1.65, and concentration ratio of (POS+SOS)/ (PSS+SS) ≤ 1.32, whereas enzymatic acidolysis were concentration ratio of (POO+POP)/(PSS+SSS) ≤ 0.45, concentration ratio of (POS+SOS)/ (POO+POP) ≥ 1.85, and concentration ratio of (POS+SOS)/ (PSS+SS) ≤ 0.84. The criteria of substrates and enzymatic interesterification products could be used as parameter for the production of CBEs. The CBEs products of transesterification had lower POP content than that of CB, whereas acidolysis had lower POP and SOS content than that of CB. In the same reaction conditions, enzymatic transesterification produces target TAGs faster than that of acidolysis. In the same process of fractionation, enzymatic transesterification produces more the fat products qualified as CBEs than that of acidoysis. The resulting changes in the TAG composition of the substrates were reflected in the SFC and SMP values. The relationship between TAG composition (TAG groups) and the SFC value at each measuring temperature can be expressed in a multiple linear regression model. The SFC values of the substrates, the interesterified products and the fractionation products at various measuring temperature could be predicted from various groups of TAG, either single or combined.

Cocoa butter (CB) merupakan ingridien yang berkontribusi penting terhadap sifat-sifat tekstural dan sensori produk coklat confectionery. Di bawah suhu ruang, CB bersifat keras dan brittle, tetapi ketika dimakan, CB meleleh sempurna di mulut dengan tekstur creamy yang lembut dan sensasi dingin. Hal ini sebagai konsekuensi dari komposisi kimia CB yang unik, yang hampir 80% didominasi oleh tiga triasilgliserol (TAG) simetrik, yaitu palmitat-oleat-palmitat (POP), palmitat-oleat-stearat (POS) dan stearat-oleat-stearat (SOS). Cocoa butter equivalents (CBE) didesain dengan komposisi TAG dan sifat pelelehan kompatibel terhadap CB, sehingga dapat menggantikan CB serta dapat dicampur dengan CB pada proporsi berapa pun dalam formulasi coklat. Minyak sawit merupakan salah satu bahan baku penting untuk pengembangan cocoa butter substitutes (CBS) atau equivalents (CBE). Minyak sawit kaya dengan TAG POP yang dapat dimodifikasi menjadi TAG POS dan SOS secara interesterifikasi enzimatik menggunakan katalis lipase spesifik-1,3.