Obtenção de gorduras zero trans por interesterificação quimica e caracterização para aplicação em alimentos / Obtaining zero trans fats by chemical interesterification and characterization for food applications

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

03/08/2009

RESUMO

Chemical interesterification has been used as the main alternative for obtaining zero trans plastic fats. In particular, interesterification of liquid oils with fully hydrogenated oils (or hardfats) is the most versatile way for producing zero trans fats, yielding fat bases with different properties for food applications. In this work, blends of soybean oil (SO)/fully hydrogenated soybean oil (FHSBO), with 10, 20, 30, 40 and 50% FHSBO (w/w) content and blends of canola oil (CaO)/fully hydrogenated cottonseed oil (FHCSO), with 20, 25, 30, 35 and 40% FHCSO (w/w) were interesterified under the following conditions: 20 minutes reaction time, 0.4% sodium methoxide, 500 rpm stirring, 100°C. The original and interesterified blends were examined for triacylglycerol composition, melting point, solid fat content (SFC), consistency, thermal behavior, microstructure, crystallization kinetics and polymorphism. Interesterification caused considerable rearrangement of triacylglycerol species, reduction of trisaturated triacylglycerol content and increase in monounsaturateddisaturated and diunsaturated-monosaturated triacylglycerols, lowering the initial melting points. The interesterified blends displayed reduced SFC at all temperatures and more linear melting profiles as compared with the original blends. Yield values showed a higher plasticity in the blends after the reaction, related to SFC. Iso-solid curves for original CaO:FHCSO blends indicated monotetic interactions, which were attenuated after randomization due to interesterification. Blend melting and crystallization thermograms were significantly modified by the randomization. Interesterification caused significant reductions in crystal diameter in all blends, in addition to modifying crystal morphology. Characterization of crystallization kinetics revealed that crystal formation induction period and maximum solid fat content were altered according to hardfat content in the original blends and as a result of the random rearrangement. Changes in Avrami model constant (k) and exponent (n) indicated, respectively, that ¿ as compared with the original blends ¿ interesterification decreased crystallization velocities and modified crystallization processes. X-ray diffraction analyses revealed that interesterification altered crystalline polymorphism of SO:FHSBO blends, but did not modify CaO:FHCSO blends crystalline habit. The 90:10, 80:20, 70:30 and 60:40 interesterified SO:FHSBO blends showed characteristics suited to application, respectively, as liquid shortening, table margarine, baking/confectionery fat and all-purpose shortenings/ biscuit-filling base; while the 80:20, 75:25, 70:30 and 65:35 interesterified CaO:FHCSO blends showed characteristics suited to application as soft margarines, spreads, bakery fats/all-purpose shortenings and icing shortenings, respectively

ASSUNTO(S)

gorduras zero trans interesterificação quimica gorduras plasticas oleos liquidos zero trans fats chemical interesterification plastic fats liquid oils

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