Tailoring the Textural Attributes of Butter Fat/Canola Oil Blends via Rhizopus arrhizus Lipase-Catalyzed Interesterification. 2. Modifications of Physical Properties

Abstract

The effects of sn-1,3 specific Rhizopus arrhizus lipase-catalyzed enzymatic interesterification on the physical properties of butter fat/canola oil blends [100% butter fat (w/w) to 60% butter fat/40% canola oil (w/w) (60:40)] were determined. Enzymatic interesterification (EIE) lowered and linearized the solid fat content (SFC) versus temperature profile of all noninteresterified (NIE) blends in the 5−40 °C range. The largest drops in SFC as a result of EIE occurred with native butter fat between 5 and 10 °C. Dropping points (DP) decreased 1−3 °C for all blends upon interesterification, and the decrease in DP as a function of canola oil proportion in the blend was more pronounced for the EIE than for the NIE blends (0.16 °C/wt % versus 0.10 °C/wt %, respectively). Isothermal crystallization behavior monitored turbidimetrically (onset of crystallization) showed that EIE did not alter the crystallization behavior of butter fat, yet did alter that of the blends. Rheological characterization included large and small deformation tests. Cone penetrometry, used to gauge the former, indicated that both blending and EIE diminished the hardness index (HI) in a nonlinear fashion. Reductions in HI resulting from EIE predominantly occurred within 12 h of interesterification. Oscillatory frequency sweep measurements at small amplitude showed that EIE blends had lower storage (G‘) and loss moduli (G‘‘) than their NIE counterparts. Blending of butter fat with canola oil and subsequent interesterification modified the crystal morphology and X-ray diffraction patterns of butter fat. Polarized light microscopy revealed that addition of canola oil led to slight aggregation of the crystal structure, whereas EIE led to more pronounced aggregation of the crystalline mass. X-ray diffraction analysis revealed a predominance of β‘ and a small proportion of β crystals for all samples examined with greater presence of β crystals in the EIE blends vis-à-vis the NIE blends. Long spacings increased from ∼41.5 to 44 Å following EIE. The fractal dimension of the butter fat/canola oil blends diminished from 2.59 to 2.50 following interesterification. These results suggest that changes in the rheological properties of butter fat induced by enzymatic interesterification were closely linked to changes in the SFC and, to a lesser extent, to the distribution of crystal mass within the fat crystal network. Keywords: Rhizopus arrhizus; butter fat; canola; interesterification; lipase-catalyzed; oil

Effect of storage on texture and microbiological stability of o-w emulsions with inulin

“…The presence of inulin aggregates in the analysed samples caused a floury taste in the mouth which negatively affected the analysed features. The fats present in butter, margarine, or spreads mostly have melting temperatures below the temperature of the mouth cavity temperature (Rousseau & Marangoni 1998). The solubility temperature of the amorphous forms of commercial high performance inulin with the degree of polymerisation ≥ 23 is much higher than 36.6°C, thus the crystal forms of inulin present in the analysed samples are more difficult to dissolve (Kim et al 2001;Bot et al 2004;Ronkart et al 2009).…”

Modificação bioquímica da gordura do leite

“…53,[61][62][63]70 Nos trabalhos desenvolvidos a partir de 2000, verificase o uso predominante de enzimas já adquiridas comercialmente na forma imobilizada. 15-22, 64-66,71 As enzimas mais empregadas para catálise da reação em estudo foram as lipases de Mucor miehei (anteriormente Rhizomucor miehei), 15 68 no qual esta mistura promoveu aumento do rendimento de interesterificação.…”

“…Muitas pesquisas que relacionam a influência desta reação sobre as características físicas do produto obtido têm sido desenvolvidas e, neste sentido, as propriedades mais estudadas são o conteúdo de gordura sólida, 56,58,62,63,70 as propriedades térmicas e de cristalização, 52 Entre as lipases avaliadas, as Lipozymes TM IM e RM IM foram escolhidas para os estudos adicionais no reator contínuo de leito empacotado. A lipase TM IM realizou a reação de forma mais rápida.…”

“…para verificar a melhora da espalhabilidade destes produtos 53,62,63,22,75 sob temperatura de refrigeração. Rousseau e Marangoni 62 estudaram a interesterificação enzimática da mistura de gordura do leite e óleo de canola para avaliar o potencial da lipase de R. arrhizus como agente modificador da textura da manteiga.…”

Structure and mechanical properties of fat crystal networks

“…This provided motivation to search for new "structural indicators" of the mechanical strength of fat crystal networks, that were somehow related to the next logical structural level; the microstnictural level of structure of the network. A rheological approach was adopted by Rousseau and Marangoni ; Rousseau and Marangoni, 1998b), the motivation for which stemrned h m work done on the fracta1 nature of colloidal gels and adapted to fat crystal networks (Vreeker et al,l992b). In order to introduce the reader to the developments made in the rheological analysis of fat crystal networks utilizing the progress in the colloidal field, we provide an introduction first to fkactal theory, and then to the application of fractal theory to colloidal gels.…”