MECHANICAL PROPERTIES OF COLLAGEN FIBER AND POWDER GELS

Mechanical properties and water holding capacity (WHC) of collagen gels were evaluated using two ingredients with different particle size and shape. The variables evaluated were ingredient concentration (3, 5, and 10%, w/w), NaCl addition (0 and 2% w/w), heat treatment temperature (25, 60, and 90C), gel formation temperature (10 and 25C), and the soluble/insoluble protein ratio. The collagen ingredients produced strong, highly elastic gel networks with stress at fracture values from 0.4 to 68 kPa and values for the elasticity modulus from 1.4 to 17 kPa, for the range of variables studied. The gel network strength and WHC were enhanced by a decrease in particle size, lower incubation temperatures, and by increases in soluble protein, ionic strength of the medium and heat treatment temperature. PRACTICAL APPLICATIONS Collagen has a unique molecular structure that provides ingredients of interest for incorporation into food products and other biomaterials, showing different technological properties depending on the process conditions. Once the effect of size and shape of the particle, temperature, pH, and salt addition on the mechanical properties, water holding capacity and physico-chemical characteristics of bovine collagen gels is known, process parameters and formulations can be optimized, in order to establish desirable texture properties for food products and other biomaterials.41684286

Boiling point of aqueous D-glucose and D-fructose solutions: Experimental determination and modeling with group-contribution method

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Boiling points of aqueous solutions affect the design and operation of evaporators. Hence, boiling points of aqueous solutions of D-glucose and D-fructose were experimentally determined at soluble solute concentration from 10 to 60% sugar by mass and pressure from 20 to 93.6 kPa. The experimental data were correlated with data predicted by the calculation of the activity coefficients with the UNIFAC-Lyngby model using different approaches for decomposition of the molecular structure: the aliphatic groups and the cyclic groups. Moreover, the rise in experimental boiling point of the aqueous sugar solutions was evaluated by the Duhring's rule. It was observed that the cyclic approach resulted in better accuracy for liquid-vapor equilibrium prediction and the non-ideality of these solutions are relevant in the boiling point rise, confirming that the rise in boiling point of aqueous D-glucose and D-fructose concentrated solutions is significant to the design of heat and mass transport operations. (C) 2010 Elsevier B.V. All rights reserved.29913241Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CNPq [130396/2008-7, 306250/2007-1]FAPESP [0856258-8

SOLID-LIQUID EQUILIBRIUM OF TRIOLEIN WITH FATTY ALCOHOLS

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Triacylglycerols and fatty alcohols are used in the formulation of cosmetic, pharmaceutical and food products. Although information about the phase transitions of these compounds and their mixtures is frequently required for design and optimization of processes and product formulation involving these substances, these data are still scarce in the literature. In the present study, the solid-liquid phase diagrams of two binary systems composed of triolein + 1-hexadecanol and triolein + 1-octadecanol were evaluated by differential scanning calorimetry (DSC) and optical microscopy. The experimental data were compared with predicted data by solving the phase equilibrium equations using an algorithm implemented in MATLAB. The liquid-phase activity coefficients were calculated using the Margules equation (two-and three-suffix) and the UNIFAC model (original and modified Dortmund model). The approaches used for calculating system equilibrium allowed an accurate prediction of the liquidus line with low deviations from the experimental data.3013343Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2008/56258-8, 2009/54137-1]CNPq [304495/2010-7, 480992/20009-6, 140718/2010-9

An assessment of the texture of acidified sodium caseinate gels with added inulin using response surface methodology

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)This work evaluated the effect of inulin concentration (0-6.0% w/w) on the mechanical properties and microstructure of gels composed of sodium caseinate (CN) (1.5-6.5% w/w) at pH 4.6. Inulin did not statistically affect the elastic modulus and rupture properties of the studied gels but affected the nonlinear mechanical behaviour. Samples with higher inulin concentrations (6% w/w) presented strain-weakening deformation behaviour, whilst gels with lower inulin concentrations were strain hardening. The presence of inulin resulted in a more closed-pores network. Gel deformability increased as CN concentration was enhanced, reaching a maximum of 0.60 at 5.58% (w/w) CN, but was not affected by inulin concentration.643353359Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq [301869/2006-5