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Initial Viscosity (initial + viscosity)
Selected AbstractsStarch-lipid composites in plain set yogurtINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 1 2009Mukti Singh Summary Starch-lipid composites (SLC) were used to replace milk solids in yogurt mixes. The effects of the SLC on the yogurt fermentations and rheology were studied. The rate of fermentation was evaluated by the change of pH during the fermentation of yogurt. The syneresis of yogurt was observed over 3 weeks of storage. Small amplitude oscillatory shear flow measurements of the storage modulus, the loss modulus, and the loss tangent were obtained using a vane geometry. Yogurt mixes with milk solids partially replaced by SLC fermented at a similar rate than as with no milk solids replaced. Initial viscosity was higher for yogurt mixes with higher levels of SLC. The higher initial viscosity did not affect the gel structure. The addition of SLC above a level of 3% strengthened the gel and resulted in no syneresis for yogurt samples stored for 3 weeks at 4 °C. [source] Study of epoxy toughened by in situ formed rubber nanoparticlesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Jun Ma Abstract The effect of rubber nanoparticles on mechanical properties and fracture toughness was investigated. Rubber nanoparticles of 2,3 nm were in situ synthesized in epoxy taking advantage of the reaction of an oligomer diamine with epoxy. The chemical reaction was verified by gel permeation chromatography (GPC) and 1HNMR, and the microstructure was characterized by transmission electron microscope. The rubber nanoparticles caused much less Young's modulus deterioration but toughened epoxy to a similar degree in comparison with their peer liquid rubber that formed microscale particles during curing. Fifteen wt % of rubber nanoparticles increased fracture energy from 140 to 840 J/m2 with Young's modulus loss from 2.85 to 2.49 GPa. The toughening mechanism might be the stress relaxation of the matrix epoxy leading to larger plastic work absorbed at the crack tip; there is no particle cavitation or deformation; neither crack deflection nor particle bridging were observed. The compound containing rubber nanoparticles demonstrates Newtonian liquid behavior with increasing shear rate; it shows lower initial viscosity at low shear rate than neat epoxy; this provides supplementary evidence to NMR and GPC result. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Optimizing Preparation Conditions for Heat-denatured Whey Protein Solutions to be Used as Cold-gelling IngredientsJOURNAL OF FOOD SCIENCE, Issue 2 2000C.M. Bryant ABSTRACT: Heat-denatured whey protein solutions are used to make ingredients that gel at low temperatures. This study examines the influence of holding temperature (65 to 90°C), holding time (5 to 30 min), protein concentration (2 to 12 wt%) and pH (3 to 8) on the rheology and appearance of heat-denatured whey protein solutions. The optimum preparation conditions required to produce non-gelled transparent solutions of heat-denatured proteins were established. The rate of cold-gelation after the addition of 200 mM NaCl to the heat-denatured whey protein solutions increased as their initial viscosity increased. It was possible to produce gels with different cold-gelling characteristics by altering the thermal preparation conditions. [source] EFFECT OF HYDROTHERMAL TREATMENT ON THE PHYSICOCHEMICAL, RHEOLOGICAL AND OIL-RESISTANT PROPERTIES OF RICE FLOUR,JOURNAL OF TEXTURE STUDIES, Issue 2 2009DEOK NYUN KIM ABSTRACT Rice flour was thermomechanically modified by steam-jet cooking and the physicochemical, rheological and oil-resistant properties of the resulting product were characterized. Compared with native rice flour, the steam jet-cooked rice flour exhibited significantly increased hydration properties. Its pasting properties were also characterized by cold initial viscosity, decreased setback and the lack of peak viscosity. The shear-thinning behaviors of the steam jet-cooked rice flour were satisfactorily fitted into the Carreau equation. In addition, dynamic viscoelastic measurements showed that the liquid-like nature was more dominant over the solid-like properties. When incorporated into frying batter formulations, the steam jet-cooked rice flour increased the batter viscosity and pickup. The use of steam jet-cooked rice flour also enabled fried batters to control the moisture loss effectively. Furthermore, the wheat flour replacement with 20% steam jet-cooked rice flour in batters led to dramatic reduction of oil uptake by around 40%. PRACTICAL APPLICATIONS This study introduces a hydrothermal treatment (steam-jet cooking) as a new technique to impart better functional properties to rice flour. Specially, the steam jet-cooked rice flour exhibited oil-resisting properties when incorporated into frying batters, consequently producing fried foods with reduced content of oil and calorie. [source] Morphology and fracture properties relationship of epoxy-diamine systems simultaneously modified with polysulfone and poly(ether imide)POLYMER ENGINEERING & SCIENCE, Issue 9 2005M.I. Giannotti An epoxy-diamine system was simultaneously modified with two immiscible thermoplastic polymers, polysulfone (PSF) and poly (ether imide) (PEI), to develop tough materials without adding high quantities of modifiers, in order to avoid the processibility problems caused by the high initial viscosity of the mixtures. The mechanical behavior of blends containing 10 and 15 wt% total thermoplastic was analyzed and compared with the generated morphologies. The scanning electron micrographs (SEM) of the broken surfaces showed that when a small part of PEI is replaced by PSF, drastic changes in morphology, leading to co-continuity between the phases, occurred together with fracture (critical stress intensity factor, KIC) improvements. As an additional advantage, no noticeable decrease in the elastic modulus (E) of final materials was observed. POLYM. ENG. SCI., 45:1312,1318, 2005. © 2005 Society of Plastics Engineers [source] | |||||||||||||