Higher Apparent Viscosity Research Articles

Sucrose substitution by polyols in sponge cake and their effects on the foaming and thermal properties of egg protein

Three polyols (maltitol, xylitol, and erythritol) were used to replace sucrose in sponge cake formulation and their effects on the foaming and thermal properties of egg protein in liquid whole egg (LWE) and the qualities of resulted sponge cake were investigated. It turned out that, the presence of maltitol acted closest to sucrose in sponge cake system. LWE with both sucrose and maltitol had relatively higher apparent viscosity and temperature of protein denaturation, while the substitution by xylitol and erythritol increased these parameters to a smaller extent. Surface tension and pH values of LWE solution with different sweeteners presented no significant difference. The replacement of sucrose by polyols increased %overrun and air phase fraction of LWE foam, indicating an increase in foaming ability, while the replacement by xylitol and erythritol reduced the foaming stability significantly (P < 0.05). The observation of microstructure of LWE foam also confirmed the effects of sucrose and polyols on the foaming properties of LWE. When compared to sucrose, the treatment with maltitol resulted in similar specific volume of sponge cake, while xylitol and erythritol significantly (P < 0.05) decreased this parameter. Positive linear relationship was observed between foam stability and specific volume of resulted sponge cake in this study.

Effect of culture on the rheological properties of fermented milk during refrigeration

In order to study the rheological properties of fermented milk during the storage period,a rheometer was used to measure the apparent viscosity,hysteresis loop area,viscosity and elasticity modulus of samples fermented by six different cultures. The results showed that all six kinds of fermented milk became thinner with shear time lengthened and were viscoelastic fluid. Sample 3 and 4 not only had higher apparent viscosity also better stability on 18 th day. The apparent viscosity were 0.202 and 0.229 Pa( s,respectively,and hysteresis loop area were 8340 and 4335( Pa·r) / min.

Enhancement of Gleditsia sinensis gum rheological properties with pressure cell treatment in semi-solid state

The apparent viscosity, molecular weight, and molecular weight distribution are important physical properties that determine the functional properties of galactomannan gum. Gleditsia sinensis gum (GSG) in semi-solid state was pressure cell treated over a range of temperature (30–110°C) under nitrogen maintained at a pressure of 1.0–4.0MPa. Physicochemical properties of GSG samples both before and after the pressure cell treatment were characterized. These include measurements of rheological properties by LVDV-III Ultra Rheometer, molecular weight and radius of gyration by light scattering, and changes in surface morphology by scanning electron microscopy. GSG had the highest apparent viscosity at a treatment temperature of 30°C; further increase in temperature led to decrease in apparent viscosity. The apparent viscosity of GSG can be efficiently improved at room temperature and low pressure. The process of pressure cell treatment of GSG in semi-solid state could be industrialized for enhancement of rheological properties of galactomannan gum.

Formation and properties of aqueous compatible colloidal blends between pre-gelatinized maize starch and zein

This study investigates the formation and properties of compatible binary colloidal blends between pre-gelatinized (uncomplexed and complexed with stearic acid) maize starches (hydrophilic component) and commercial zein (hydrophobic component) with the aim of creating a bipolymeric material with unique properties. The blends were formed under alkaline condition (0.1 M NaOH) with 3:1, 1:1 and 1:3 starch: zein (w/w) ratios. The 3:1 starch–zein blends showed best stability or compatibility. Blends made with starch complexed with stearic acid had better stability than those with uncomplexed starch. Most of the blends were not freeze-thaw stable except for 3:1 starch (complexed with stearic acid)-zein blend. The blends with better stability had higher apparent viscosity, and a microstructure showing uniform mix of starch – zein as observed by confocal laser scanning microscopy. The likely reason for the compatibility of starch and zein is the change in surface activity of zein, possibly due to deamidation, in 0.1 M NaOH as shown by the negative zeta potential values. The pre-gelatinized maize starches also show negative zeta potential values. In conclusion, compatible binary colloidal blends can be produced between pre-gelatinized maize starch and commercial zein using 0.1 M NaOH.

Carbonyl Iron Suspension With Core–Shell Structured Fe3O4@SiO2 Nanoparticle Additives and its Magnetorheological Property

Magnetorheological (MR) fluids are known to be colloidal suspensions of magnetic particles dispersed in nonmagnetic fluid, are capable of being solid-like under applied magnetic field and liquid-like by removing the magnetic field [1-3]. Their rheological properties such as yield stress and shear viscosity can reversibly and instantly be changed as a result of dispersed magnetic particles building up chain-like structure under a magnetic field due to magnetic dipole-dipole interaction between particles, and this phenomenon has great potential in designing diverse high performance engineering products including active damper system, torque transducer and MR polishing equipment [4-6]. Generally, high yield stress and low apparent viscosity without magnetic field as well as good stability and durability have become very crucial factors for the MR fluid application. Among various magnetic materials, carbonyl iron (CI) particles have been adopted as a superior candidate for MR fluids due to their high saturation magnetization as well as their appropriate particle size. However, the large density mismatch between CI particles and medium oil leads to serious sedimentation drawback. Therefore, many strategies have been explored to solve this problem [7, 8].

Effects of different cooking methods of oatmeal on preventing the diet-induced increase of cholesterol level in hypercholesterolemic rats

BackgroundThe aim of present study is to investigate the influences of brewing and boiling on hypocholesterolemic effect of oatmeal in rats fed with a hypercholesterolemic diet.MethodsFifty-six male Sprague–Dawley rats were divided into 5 groups of 8 rats each with similar mean body weights and serum cholesterol concentrations. Rats were fed with the experimental diets containing 10 % of oatmeal from two Chinese oat varieties which were brewed or boiled for 30 days. The lipids levels in serum, liver, and faeces were determined.ResultsThe effects of feeding boiled oatmeal on lowering lipid concentrations in plasma and liver were more significant than that of brewed oatmeal (P < 0.05). Feeding boiled oatmeal was also more efficient in increasing fecal total lipids, cholesterol and bile acids as compared to feeding brewed oatmeal (P < 0.05). Boiled oatmeal had higher apparent viscosity and soluble β-glucan content than the brewed oatmeal did (P < 0.05).ConclusionThese results indicated that the capability of boiled oatmeal in improving cholesterol metabolism is better than that of brewed oatmeal, which is mainly attributed to its higher soluble β-glucan content and apparent viscosity.

Fundamental investigation of foam flow in a liquid-filled Hele-Shaw cell

The relative immobility of foam in porous media suppresses the formation of fingers during oil displacement leading to a more stable displacement which is desired in various processes such as Enhanced Oil Recovery (EOR) or soil remediation practices. Various parameters may influence the efficiency of foam-assisted oil displacement such as properties of oil, the permeability and heterogeneity of the porous medium and physical and chemical characteristics of foam. In the present work, we have conducted a comprehensive series of experiments using customised Hele-Shaw cells filled with either water or oil to describe the effects of foam quality, permeability of the cell as well as the injection rate on the apparent viscosity of foam which is required to investigate foam displacement. Our results reveal the significant impact of foam texture and bubble size on the foam apparent viscosity. Foams with smaller bubble sizes have a higher apparent viscosity. This statement only applies (strictly speaking) when the foam quality is constant. However, wet foams with smaller bubbles may have lower apparent viscosity compared to dry foams with larger bubbles. Furthermore, our results show the occurrence of more stable foam-water fronts as foam quality decreases. Besides, the complexity of oil displacement by foam as well as its destabilizing effects on foam displacement has been discussed. Our results extend the physical understanding of foam-assisted liquid displacement in Hele-Shaw cell which is a step towards understanding the foam flow behaviour in more complex systems such as porous media.

Optimization for Reduced-Fat / Low-NaCl Meat Emulsion Systems with Sea Mustard (Undaria pinnatifida) and Phosphate

The effects of reducing fat levels from 30% to 20% and salt concentrations from 1.5% to 1.0% by partially substituting incorporated phosphate and sea mustard were investigated based on physicochemical properties of reduced-fat / low-NaCl meat emulsion systems. Cooking loss and emulsion stability, hardness, springiness, and cohesiveness for reduced-fat / low-NaCl meat emulsion systems with 20% pork back fat and 1.2% sodium chloride samples with incorporation of phosphate and sea mustard were similar to the control with 30% pork back fat and 1.5% sodium chloride. Results showed that reduced-fat / low-NaCl meat emulsion system samples containing phosphate and sea mustard had higher apparent viscosity. The results of this study show that the incorporation of phosphate and sea mustard in the formulation will successfully reduce fat and salt in the final meat products.

The Rheology and Physical Properties of Fermented Probiotic Ice Creams Made with Dairy Alternatives

Abstract In this study, cow (W)’s milk was replaced by soy (S), coconut (C) and various combinations of coconut or cow milks with soy milk in order to produce fermented probiotic ice cream. The changes in ice cream eating qualities and physical properties were evaluated. Fermented ice cream containing vegetable milks showed a slower melting rate and higher apparent viscosity and particle size and also lower total acceptability than fermented cow milk ice cream (control). Ice creams containing Lactobacillus acidophilus (La-05; L) showed a lower melting rate and higher apparent viscosity and particle size than ice creams containing Bifidobacterium bifidum (Bb-12; B). Regardless of the starter culture used, all of sensory analysis scores decreased in ice creams with higher soy milk amount. The vegetable milks may offer ice cream manufacturers an alternative source of cow milk as a functional ice cream.

Emulsion Mapping in Pork Meat Emulsion Systems with Various Lipid Types and Brown Rice Fiber.

This study was conducted to evaluate emulsion mapping between emulsion stability and cooking yields, apparent viscosity, and hardness of reduced-fat pork emulsion systems. The reduced-fat emulsion systems were supplemented with different lipid types and brown rice bran fiber (BRF) concentrations. Compared to the control with 30% back fat, lower emulsion stability and higher cooking yield of meat emulsion systems were observed in T1 (30% back fat+1% BRF), T2 (30% back fat+2% BRF), T3 (30% back fat+3% BRF), T4 (30% back fat+6% BRF), and T15 (10% back fat+10% canola oil+2% BRF). Lower emulsion stability and higher apparent viscosity were observed in T1, T2, T3, T4, and T8 (20% back fat+3% BRF) compared to the control. Lower emulsion stability and higher hardness was detected in all treatments compared with the control, except T5 (20% back fat), T10 (10% back fat+10% canola oil+2% BRF), T11 (10% back fat+10% olive oil+2% BRF), T12 (10% back fat+10% grape seed oil+2% BRF), and T13 (10% back fat+10% soybean oil+2% BRF). This approach has been found particularly useful for highlighting differences among the emulsified properties in emulsion meat products. Thus, the results obtained with emulsion mapping are useful in making emulsified meat products of desired quality characteristics, partially replacing pork back fat with a mix of 10% back fat, 10% canola oil and 2% BRF was most similar to the control with 30% pork back fat.

Improvement of glucoamylase production using axial impellers with low power consumption and homogeneous mass transfer

Significantly influenced by complex cell morphology, glucoamylase fermentation using Aspergillus niger is characterized by high apparent viscosity and shear-thinning rheology. In this study, the influence of liquid flow field patterns on morphology, broth rheology, mass transfer and glucoamylase production was investigated by applying two different configurations with radial (Ruston Turbine, RT) and axial (Wide-blade hydrofoil upward-pumping, WHu) flow impellers. It was found that empirical correlations for averaged quantities, such as the mass transfer coefficient and viscosity, cannot reasonably explain the observations. Therefore, numerical simulation was carried out to study the detailed characteristics of local field in lab-scale bioreactors. The results showed, under similar glucose and oxygen uptake rates, that the WHu configuration formed relatively homogeneous viscosity and mass transfer fields, while the RT configuration was accompanied with significant heterogeneities. Under these conditions, the fraction of active mycelia in pellets could be highly correlated with enzyme production, and a novel parameter (Active Part Percentage, APP) was defined to introduce the effects of flow field on pelletized morphology. The WHu impellers facilitated the formation of pellets and hairy structures, with a higher APP of the pellets. As a result, the culture with the axial flow impeller configuration exhibited a larger glucoamylase production rate (+25%) and product yield on sugar (+23%) and yield on energy (+60%) in comparison to the radial flow impeller. Computational fluid models were proposed to in-depth understand such results based on local mass transfer and viscosity values, since the average values are similar over the entire fermentation processes.

The effect of addition of selected vegetables on the microbiological, textural and flavour profile properties of yoghurts.

Vegetables, apart from having high nutritional value, also contain considerable amounts of dietary fibre and other components, which may affect physico-chemical properties of fermented milks, e.g. viscosity, texture, susceptibility to syneresis, flavour profile etc. The present work was established to study the effect of selected vegetables addition on the rheological, textural, microbiological and flavour profile parameters of yoghurts. The vegetable preparations (carrot, pumpkin, broccoli and red sweet pepper) were added (10% w/w) to the processed cow's milk fermented with DVS yoghurt culture. Texture profile analysis, determination of viscosity, susceptibility to syneresis and descriptive flavour evaluation were conducted at the 1st, 7th and 14th day after production. Additionally, microbiological studies were performed for 28 days, at 7-day intervals. The highest apparent viscosity and adhesiveness were obtained for the carrot yoghurt, whereas yoghurt with pumpkin was the least susceptible to syneresis. The other texture parameters were not affected by the addition of vegetables. Broccoli and red sweet pepper flavours were dominating in the fermented milks fortified with these vegetables, whereas carrot and pumpkin flavours were less distinctive. Yoghurt supplemented with red sweet pepper got the highest sensoric acceptability. The number of starter bacteria was not influenced by the vegetable additives, except for pumpkin yoghurt, which contained lower population of lactobacilli. Among all tested vegetables, carrot additive had the greatest potential to improve yoghurt structure, whereas red sweet pepper imparted the most acceptable flavour.

Quality Characteristics and Rheological Properties of Barhi Date ( Phoenix Dactylifera L. ) Jams with Addition of Carrot and Pumpkin Purees

Sensory evaluation, color parameters, mineral determination, rheological properties and nutritional value of Barhi date jam prepared with substituted by carrot or/and pumpkin purees at concentrations 25, 50 and 75% were studied. The lowest jam sample in lightness (34.86) and the highest in yellowness (51.71) which prepared by Barhi date 25%: carrot 75%. In addition, panelists results showed that the best jam sample in overall acceptability (35.7) was jam prepared with Barhi date 25% : carrot 75% followed by jam prepared with Barhi date 50% : pumpkin 50% (33.9). Caloric values of Barhi date jam samples containing carrot and pumpkin purees recorded the values ranged between 398.87 k. cal. for jam sample containing Barhi date 50%: pumpkin 50% to 379.17 k. cal. for the control jam sample. It was clearly appeared that the control jam sample had significant (P0.05) increase in potassium content (101.36 ppm) followed by 95.00 and 86.98 ppm which recorded by Barhi date 25%: pumpkin 75% and Barhi date 50%: carrot 25%: pumpkin 25%, respectively. Calcium content (14.25 ppm) was significant (P0.05) increase in jam sample prepared by Barhi date 50%: carrot 25%: pumpkin 25%, followed by 11.68 ppm which given by Barhi date 50%: carrot 50%. The relationship between shear stress (!) and shear rate () for all prepared date jam samples were nonlinear, and the flow behavior index of all prepared date jams were less than unity indicating a non-Newtonian behavior of the samples, with a pseudo-plastic type. Jam prepared from Barhi date 25%: carrot 75% had higher plastic viscosity value being 58.43 (Pa.s) followed by 49.04 (Pa.s) which given by jam sample prepared by Barhi date 50%: carrot 50% at temperature (20oC). The highest apparent viscosity was found for jam sample prepared from Barhi date 25%: carrot 75% followed by Barhi date 50%: carrot 50% when compared to control date jam and other prepared jam samples. Finally, our results indicated that jam prepared from Barhi date 25%: carrot 75% is the best sample in color properties, texture, viscosity and sensory acceptability followed by jam prepared from Barhi date 50%: pumpkin 50%.

Encapsulation of tomato oleoresin using soy protein isolate-gum aracia conjugates as emulsifier and coating materials

Dry-heated Maillard reaction was applied in the preparation of protein-polysaccharide conjugates. Reaction mixtures containing soy protein isolate (SPI) and gum acacia (GA) were dry-heated at 60 °C and 79% relative humidity for 3, 6 and 9 days. An increase in degree of graft, a* (red) and b* (yellow) parameters was found with increasing reaction time. Structural feature analyses suggested that attachment of polysaccharides to SPI led to changes in spatial structure and unfolding of protein molecules. The conjugates of 6 days showed significantly higher levels of emulsifying properties. Emulsion prepared with SPI-GA conjugates had smaller values of d32 and higher apparent viscosity than those prepared with mixture of SPI and GA. Toxicity assay showed that conjugates exhibited better biocompatibility compared with traditional emulsifier. Furthermore, the conjugates were used as coating material to encapsulate the tomato oleoresin by spray-drying. Moisture content and microencapsulation efficiency of powder increased with an increase in conjugates concentration. The results of controlled release showed that conjugates particles could protect most of the lycopene from being released in the stomach. The lycopene in particles presented an improvement of stability against light, humidity and temperature.

Physical, Chemical, and Rheological Properties of Rice Husks Treated by Composting Process

A composting treatment was employed in an effort to improve the processability of rice husks. Changes in the chemical composition, physical structure, and rheological properties of modified rice husks were analyzed. The results indicated that the average diameter of compost-treated samples was significantly higher than that of the untreated samples because they were able to adhere to each other by the bacterial protein. Scanning electron microscopy images showed that the epidermis became rugged and lumpy because the composition of rice husks (cellulose, hemicellulose, lignin, and pectin) was partially decomposed, an effect confirmed by the chemical composition and FTIR analysis. Thermogravimetric analysis showed that the composted samples had better thermal stability than the untreated ones. Stress-strain curves showed that the treated samples displayed a moderately significant change of slope at about 0 to 10% strain, and they had better mechanical properties than untreated samples. Juxtaposing the rheological properties of both untreated and treated samples determined that the latter had higher apparent viscosity as a result of degradation and bacterial protein effects. All results indicated that the composting treatment changed the physical, chemical, and rheological properties of the rice husks, which are beneficial for its utilization and processability.

Investigating Foamed Bitumen Viscosity

Foamed bitumen is a binder of cold mix road recycling materials. It is necessary to understand the best foamed bitumen properties prior to mixing with aggregate materials. Viscosity is one of the important properties, which facilitate the foam to distribute across the aggregate phase in the mixing process, and form a well coated asphalt mix. Unfortunately, the understanding of foamed bitumen viscosity and its contribution in the development of mixture performance is still poorly understood. This paper discusses foamed bitumen viscosity which was explored based on theoretical studies and a series of laboratory investigation. Foamed bitumen was produced using bitumen Pen 70/100 at temperature of 180°C. The research method was developed in three activities, i.e. (1) the previous studies on the foamed bitumen rheology, (2) investigating flow behavior of foamed bitumen, and (3) estimating foamed bitumen viscosity using Kraynik equation.The research results can be summarized in the following three points. First, foamed bitumen consists of gas content and liquid bitumen, in which the value of foam viscosity increases with the gas content. Second, foam flow can be used to indicate the apparent foam viscosity. Foamed bitumen with a higher foaming water content (FWC) tends to have a decreased flow rate and hence higher apparent viscosity. Third, foamed bitumen viscosity estimated using Kraynik equation is affected by gas content and liquid bitumen viscosity. It was found that an ERm of around 35 (or at FWC of 6%) is the critical area of foam viscosity.

Production of a transglutaminase from Zea mays in Escherichia coli and its impact on yoghurt properties

A gene from Zea mays coding a TGase was expressed in E. coli and identified by Western blotting. Under optimal expression conditions, the production and specific activity of refolded TGZ were 1.41 mg/L and 0.34 U/mg. The activated TGZ was employed to cross‐link milk proteins. The yoghurt treated with TGZ showed a lower syneresis, higher apparent viscosity and texture than untreated yoghurt. The properties of TGZ‐treated sample were better than those of MTG‐treated samples, so TGZ may have potential as an additive in yoghurt manufacture.

Dynamic ultra-high pressure homogenisation of milk casein concentrates: Influence of casein content

Milk casein concentrates with different casein-to-protein ratios (0.82 and 0.93), pH (5.8, 6.2 and 6.7) and level of applied ultra-high pressure homogenisation (UHPH) (0, 150 and 300 MPa) were studied. Samples with a casein-to-protein ratio of 0.93 at pH 5.8 and subjected to UHPH treatment at 300 MPa had the highest apparent viscosity and particle size followed by similar samples with a casein-to-protein ratio of 0.82. Water mobility was reduced at higher casein-to-protein ratio and with higher pH, while increased water mobility was observed in samples with a casein-to-protein ratio of 0.82 at pH 5.8 subjected to UHPH treatment at 300 MPa. The H-1 and P-31 NIVIR spectra revealed minor structural effects of adding casino-phospho-peptides and changing pH, but no effect of UHPH treatment, which indicate that UHPH treatment did not induce measureable structural changes in the individual proteins but rather induced changes in the tertiary structure or degree of polymerisation. Industrial relevance: Milk depleted from whey protein is advantageous to use in cheese production since it can be further processed without detrimental denaturation of whey protein which will result in reduced maturation of cheese. In combination with pH control and ultra-high pressure homogenisation of the milk casein concentrate structural changes in the protein can be obtained and new interesting milk based products can be developed. (C) 2014 Elsevier Ltd. All rights reserved. (Less)

Experimental Research on Apparent Viscosity Behavior of Cationic/Anionic Worm-Like Micelles

In this paper, cationic surfactant and anionic surfactant form worm-like micelles by self-assembly. The cationic surfactant is acryloxyethyl trimethylammonium chloride (DAC). The anionic surfactant is potassium erucic (KEU). Mixed the cationic surfactant and anionic surfactant, because the DAC molecule contain a double bond, then, polymerized the solution with VA - 044. By contrast many experiments, the purpose is to get the highest apparent viscosity. After comparing, when the molar ratio of n (KEU) : n (DAC) = 5:1, the largest viscosity of worm-like micelles is 1450mPa•s.

Rheological, emulsifying and thermostability properties of two exopolysaccharides produced by Bacillus amyloliquefaciens LPL061

The rheological, emulsification, thermostability and certain physicochemical properties of two purified exopolysaccharides from Bacillus amyloliquefaciens LPL061 were studied. EPS1 showed entangled spider mesh structure that composed of dense rope with homogeneous hexagonal particles under scanning electron microscopy. EPS2 had a porous sponge structure with uniform cylindrical particles. The two exopolysaccharides showed higher intrinsic viscosity and better emulsification activity with sunflower seed oil, rice oil, olive oil and peanut oil compared to guar gum. EPS1 is the most promising one for applications in the industry, as it had high intrinsic viscosity, apparent viscosity and thermostablity in aqueous solution, dense entangled structure and good emulsification activity.