جستجوی مقالات مرتبط با کلیدواژه "rheological properties" در نشریات گروه "پزشکی"

Food products could be exposed to heat treatments during manufacture, storage, and distribution chains which can affect the rheological properties of hydrocolloid solutions. Viscosity is an important factor for quality evaluation in many food products. In the current study marshmallow seed mucilage, as a potential new source of hydrocolloid, was prepared at concentrations of 4, 6, and 8 % (w/v) and subjected to heat treatments at 30, 55, and 80 °C. Afterward, time-independent rheological behaviors of examined concentrations were assessed by using a rheometer.  The findings revolved around that marshmallow seed mucilage showed a pseudoplastic behavior (n<1) as well as in the power low model. In the mentioned model the consistency coefficient (K) of all analyzed concentrations significantly has been increased at different temperatures (p≤0.01). Also, the flow behavior index value changed from 0.5092 to 0.7934 and showed a significant decrease at higher temperatures (55 and 80 °C) and also as a result of increasing in concentration. The concentrations of 4 % and 8% showed the highest temperature-dependency of consistency coefficient and flow index, respectively. In contrast, the lowest temperature dependency of consistency coefficient and flow index were detected at 6 and 4 % mucilage solution, respectively. At low concentrations, Bingham and at high concentrations Casson models, in addition, Hershel-Bulkley model best fitted with the mucilage solution.

Use of aloe vera gel in dairy industries is important for increasing quality of dairy products. In the present study, effects of aloe vera gel with inulin and whey powder on survival of probiotic bacteria, rheological and sensory characteristics of yogurt were investigated.

Low-fat (1.5%) probiotic yogurts were prepared from pasteurized milks, 1% of starters and 2% combinations of Lactobacillus acidophilus with Bifidobacterium animalis at 40 °C and pH 4.4. Probiotic yogurts mixed with aloe vera gels at 0, 5, 10, 15 and 20% were stored seven days at 4 oC. Since the probiotic yogurt with 10% of aloe vera gel included the best sensory scores compared to other aloe vera gel concentrations after seven days of storage at 4 oC, this formulation was mixed with inulin at 0.5, 1 and 1.5% (w/w) or whey powder at 5, 10 and 15% (w/w). 

Sensory evaluations showed that the probiotic yogurt with 10% of aloe vera gel and 1.5% of inulin included the highest scores of flavor, texture, aroma, color and acceptance within the samples after similar storage conditions. The probiotic yogurt with 10% of aloe vera gel and 1.5% of inulin included the highest survival of Lactobacillus acidophilus and Bifidobacterium animalis, while controls (with no aloe vera gels) showed the lowest survival rates of Lactobacillus acidophilus and Bifidobacterium animalis. Apparent viscosity and serum separation of probiotic yogurt with 10% of aloe vera gel and 1.5% of inulin respectively increased three times and decreased to less than 4%, compared to controls and whey samples at similar shear rates and storage times.The pH decrease of probiotic yogurt with 10% of aloe vera gel and 1.5% of inulin was much slower than those of the control and whey samples during storage, including no serum separations during storage.

Aloe vera gel and inulin improved viability of probiotic bacteria and quality of yogurt samples during storage.

Dried carrot pomace (DCP) may be used as a thickening, coloring agent and also a carotenoid-fiber enriched component in food products formulations. The main objective of this study to investigate the effect of DCP from juice industries waste material on the physicochemical, rheological, nutritional properties of ketchup by partial replacement (0.7-3.5%) of tomato paste and the carboxy methyl cellulose. The physicochemical parameters of DCP, including: the moisture, fat, protein, ash, crude fiber, pectin, phenolic compounds content, water holding capacity and color properties were first analyzed. Then, different ketchup samples, based on DCP content variations, were formulated. The physicochemical properties of the formulations as well as the tomato lycopene and DCP β-carotene synergistic effect were studied. Based on the analytical data obtained, the samples with highest viscosity, lowest syneresis and the best color index with (0-2.1%) carrot pomace powder were selected for more detailed investigations to perform carotenoids measurements, color parameters specifications, rheological properties. Finally the formulation with 28% tomato paste, 3% glucose syrup, 0.4% carboxymethyl cellulose and 0.7% DCP was assigned as the best carotenoid-fiber enriched and healthy ketchup product.

The aim of this study was to determine the rheological properties of sponge cake batters andphysical (volume, density, moisture content, weight after baking and color) and sensory properties of spongecake formulated with four different levels of wild sage seed gum (0, 0.5, 0.75 and 1.0 %). Sponge cake battersformulated with gums showed pseudoplastic (shear-thinning) and thixotropic (time-dependent) behavior. Theapparent viscosity of cake batter significantly (P<0.05) increased with increasing gum levels. Increasing the levelof gum from 0.0 to 1.0 % significantly increased the volume of cake (P<0.05), while the density values wasdecreased from 345 to 333 kg/m3 with increasing gum levels. The crumb color of samples was affected by theaddition of wild sage seed gum. The sponge cake with 1.0 % gum exhibited a color, with L*, a* and b* equal to86.61, 1.50 and 39.35, respectively. Gum addition increased the volume and porosity of the cakes and resulted insofter products. 1.0 % wild sage seed gum is suggested to use in sponge cakes to obtain the cakes with theacceptable volume, appearance, texture and total acceptance.