The Effects of Fat and Non Fat Dry Matter Concentration and Storage Time on the Physical Properties and Acidity of Yoghurts Made with Probiotic Cultures

2006 ◽  
Vol 12 (6) ◽  
pp. 467-476 ◽  
Author(s):  
Ö. Gün ◽  
N. D. Işsikli

The effects of fat and non fat dry matter (NFDM) concentration and storage time on the physical properties and acidity of yoghurts made using commercial probiotic cultures (ABY and ABT-1) were investigated by using response surface methodology. All yoghurts made with ABY and ABT-1 cultures exhibited shear thinning behaviour. The power low model was used to describe the shear thinning behaviour of yoghurt samples. The flow behaviour index ( n) and the consistency coefficient ( m) were determined. NFDM levels in milk strongly affected syneresis, apparent viscosity at a constant speed of 100rpm, flow behaviour index and the consistency coefficient. Titratable acidity and pH were mainly affected by the storage time. Under all conditions examined, yoghurt made with ABT-1 culture had higher apparent viscosity, consistency coefficient and pH value than those of the yoghurt made using ABY culture.

Author(s):  
Firuze Emilia Ergin

In this study, the effects of the incubation temperature and type of starter culture on the physical properties, including graininess and visual roughness, of ayran were determined. Ayran samples were produced from milk inoculated with two different starter cultures (Yo-Mix 410, Yo-Mix 883) and incubated at temperatures of 37 or 45°C, and then stored at 4°C for 15 days. As incubation temperature decreased the number and perimeter of grains and syneresis decreased and the amount of exopolysaccharide (EPS) increased in ayran samples. The high amount of EPS resulted in low syneresis value, the number and perimeter of grains and visual roughness in ayran samples. The apparent viscosity and consistency coefficient values of ayran samples produced from milk incubated at 37°C were higher than those from milk incubated at 45°C. The Power law model was found more satisfactory to describe flow behaviour of all ayran samples. The rheological properties of ayran samples changed with measurement temperature. As the measurement temperature increased from 5°C to 15°C, the apparent viscosity and consistency coefficient values of ayran samples were significantly decreased. The activation energy values for apparent viscosity of ayran samples varied depending on the incubation temperature, type of starter culture and storage period.


2021 ◽  
Vol 69 (3) ◽  
pp. 100
Author(s):  
M. Ananda Rao ◽  
M. V. Pavan Kumar ◽  
Lenka Srinu

The effects of two anionic dispersants (polymeric-carboxy methyl cellulose: CMC and inorganic-sodium tripolyphosphate: STPP) on the rheological properties of coal water slurries (CWS) of varying solid loading were reported and compared. The rheological data was obtained in the shear rate range of 60-160 s<sup>-1</sup> and the data was fitted using power law model. For lower solid concentrations (10% and 20%), shear thickening behaviour was observed while shear thinning nature was seen for the higher solid loadings (30%,40% and 50%) for CWS with both the dispersants. For all slurries, an increase in flow behaviour index values was seen with the increase of dispersant loading. For CWS of 10% and 20% solid loadings, lower values of flow behaviour index was observed with CMC as dispersant. On the other hand, lower values for flow behaviour index was seen with STPP as dispersant for CWS of 30%, 40% and 50% solids loading. Although CMC was found very effective in reducing the apparent viscosity at lower dosages unlike STPP, the apparent viscosity values are quite sensitive to the loading of CMC as dispersant in comparison to STPP. This observed trend may be due to aggressively induced negative charges upon the adsorption of CMC on coal particles at the tested dispersant dosages.


2014 ◽  
Vol 660 ◽  
pp. 38-42 ◽  
Author(s):  
Azriszul Mohd Amin ◽  
Mohd Halim Irwan Ibrahim ◽  
Rosli Asmawi ◽  
Najwa Mustapha

Influence of sewage ratio or Fat Oil Grease (FOG) on the feedstock rheological characteristic for optimal binder formulation in metal injection moulding is evaluated besides Polypropylene (PP) as a backbone binder. Powder loading of 62% of water atomised SS316L being used here to determine the possibility of the best binder formulation which could be optimised for optimal powder loading base on rheological characteristic analysis. Two binder formulations of PP to SF being selected here are 60/40, 50/50 and 40/60 accordingly with the powder loading of 62% each binder formulation. The analysis will be base on viscosity, shear rate, temperature, activation energy, flow behaviour index and moldability index. It is found that from rheological result views, binder with composition of 60/40 and 50/50 exhibit pseudoplastic behaviour or shear thinning where the viscosity decrease with increasing shear rate. For 40/60 binder ratio is not suitable since the behaviour of the flow indicates dilatants behaviour. After considering all the criteria in terms of flow behaviour index, activation energy, viscosity and mouldability index, binder with ratio of 60/40 is evolve as a good selections.


Author(s):  
Wiqayatun Khazanah ◽  
Nurliana Nurliana ◽  
Rini Safitri

One of the Acehnese traditional food  preserved by the addition of salt, acid and dried was sie balu. The preservation method may lead to changes in the structure and nutritional content. Sie balu with the addition of vinegar, garlic and ginger can reduce the value of water activity (aW), pH and bacterial counts. This condition affects the physical properties and sensory of sie balu. Irradiation can control pathogenic microorganisms in meat without affecting the physical condition. Low-dose irradiation is able to maintain the desired sensory attributes nutritious food products. This study aims to determine the characteristics of the sensory and physic sie baluthat irradiated with increasing doses and the shelf life of 3-6 weeks. Sie balu was made of 10 kg fresh beef, dried in the sun to dry, vacuum and irradiated at doses of 5, 7 and 9 kGy. Sensory test conducted by taste sie balu by trained panelists and fill out the hedonicform. The physical properties based on pH and aW. The microbe total calculated used Total Plate Count.The results showed that the irradiation dose significantly (P <0.05) affected on microbe total, aroma, color, texture and taste of sie balu. Storage time does not affect the sensory properties. Irradiation dose and storage time significantly (P <0.05) on pH and aWsiebalu. The study concluded that irradiation can improve the physical properties, sensory and microorganisme reductionof sie balu.


2013 ◽  
Vol 19 (No. 4) ◽  
pp. 148-153 ◽  
Author(s):  
P. Novotná ◽  
A. Landfeld ◽  
K. Kýhos ◽  
M. Houška ◽  
J. Strohalm

Fruit pulps contain fine particles of the flesh of the original fruit that are suspended in the fruit juice. This suspension has a tendency to settling or separation during measurements of its rheological properties in the rotational rheometer with coaxial cylinders (especially if the greater gap is used). In this case the use of a mixer is convenient. The mixer can serve as a tool for measurement of rheological properties and at the same time it can prevent the settling and it is not sensitive to the occurrence of greater particles in the measured fluid. The helical ribbon mixer was used in this work for measurement of five samples of fruit pulp. The mixer was calibrated by the use of Newtonian fluid of known viscosity (honey). The radius of the inner cylinder of hypothetical rotational rheometer was predicted from the assumption that mixer and cylinder exhibit the same torque necessary for the rotation at the same rotational speed. The average shear rate in the mixed pulp was predicted by using the relation valid for power law fluids and rheometer with coaxial cylinders. The radius (where the average shear rate was calculated) was chosen by the requirement that the shear rate would be almost independent of changes in the flow behaviour index valid for measured pulps. Firstly the flow behaviour index was predicted as a slope of torque vs. rotational speed dependence in log-log co-ordinates. It was found that the flow behaviour index varies in the range 0.2&ndash;0.3. The radius was predicted from a graph where shear rates for 0.2 and 0.3 are the same. Then the average shear rates were calculated from rotational speeds for individual flow behaviour indexes. Rheological properties measured by using a mixer correspond to those measured with a rotational rheometer with coaxial cylinders satisfactorily only in the case that the creeping flow regime was kept in the mixed fluid. The fruit pulps are strongly non-Newtonian fluids with very low values of the flow behaviour index around 0.2.


2016 ◽  
Vol 30 (2) ◽  
pp. 135-141
Author(s):  
Leidy M. Chacua ◽  
Germán Ayala ◽  
Hernán Rojas ◽  
Ana C. Agudelo

AbstractThe rheological behaviour of vinasses derived from sugar cane was studied as a function of time (0 and 600 s), soluble solids content (44 and 60 °Brix), temperature (10 and 50°C), and shear rate (0.33 and 1.0 s−1). The results indicated that vinasses were time-independent at 25°C, where shear stress values ranged between 0.01 and 0.08 Pa. Flow curves showed a shear-thinning rheological behaviour in vinasses with a flow behaviour index between 0.69 and 0.89, for temperature between 10 and 20°C. With increasing temperature, the flow behaviour index was modified, reaching values close to 1.0. The Arrhenius model described well the thermal activation of shear stress and the consistency coefficient as a function of temperature. Activation energy from the Arrhenius model ranged between 31 and 45 kJ mol−1. Finally, the consistency coefficient as a function of the soluble solids content and temperature was well fitted using an exponential model (R2= 0.951), showing that the soluble solids content and temperature have an opposite effect on consistency coefficient values.


Aquaculture ◽  
2009 ◽  
Vol 288 (3-4) ◽  
pp. 205-215 ◽  
Author(s):  
K. Phillips ◽  
P. Bremer ◽  
P. Silcock ◽  
N. Hamid ◽  
C. Delahunty ◽  
...  

2020 ◽  
Vol 49 (1) ◽  
pp. 71-82
Author(s):  
A Akhter ◽  
MM Hossain ◽  
M Habib ◽  
MA Hashem ◽  
MS Ali

An experiment was conducted to find out the effect of oat meal as a source of dietary fiber to formulate enriched broiler nugget. For this purpose, nuggets were prepared into four different groups such as treatment 1: 10% wheat flour nugget, treatment 2: 20% wheat flour nugget, treatment 3:10% oat meal nugget and treatment 4: 20% Oat meal nugget. All parameters were analyzed at 0, 15th and 30th days of storage period. The proximate composition of different nuggets batter was analyzed and highly significant differences were found in dry matter (%) and pH. Dry matter was lower, while pH was higher in control nugget (Treatment 1). Significant differences were found in crude protein (%), ether extract (%) among different nuggets, as well as among different storage time. Significantly higher DM (%), Ash (%) and EE (%) was found in broiler meat with 20% oat meal, while higher crude protein (%) were found in broiler meat+10% wheat flour. Crude protein (%) and DM (%) increased, while Ash (%) and EE (%) decreased with increase of storage time.  The storage period had significant effect on different biochemical (FFA, POV and TBARS value) and microbial (TVC, TCC and TYMC) tests. In all cases, the values were increased with increase of storage time. The surface color (CIE L*, a*, b*) of nuggets of different treatments at different storage period were measured.  No significant differences in b* value were found among broiler meat nuggets and storage time. On the other hand, different types of nuggets and storage period had a significant effect on L* and a* value. Significantly higher a* value was found in broiler meat with 10% wheat flour (T1). In sensory analysis, no significant differences were found in flavor, off-flavor, juiciness, tenderness and overall acceptability among four types of sausages. It could be concluded that addition of oat meal as a source of dietary fiber did not differ the overall acceptability of broiler meat nuggets compare to broiler meat nuggets with wheat flour. Bang. J. Anim. Sci. 2020. 49 (1): 71-82


2021 ◽  
Vol 36 (5) ◽  
pp. 1-12
Author(s):  
Emine Yalman ◽  
Tolga Depci ◽  
Gabriella Federer-Kovacs ◽  
Hani Al Khalaf

This study investigates the possibility of using rice husk ash as an additive to develop an environmentally friendly and low-cost drilling fluid system. The rice husk ash was added as an additive to water-based bentonite drilling fluids at different concentrations ranging from 2 wt% to 15 wt%. Rheological and filtration properties of each drilling fluid developed were measured by using a viscometer and standard low-pressure low-temperature filter press. Subsequently, cutting carrying index, minimum annulus velocity required to clean bottom of the well efficiently, flow behaviour index and permeability of mud cakes of the formulated systems were calculated in order to assess performance of the systems. The results demonstrated that the rheological and properties were improved depending on concentration of rice husk ash introduced. With the introduction of 15 wt% concentration of rice husk ash, while apparent viscosity and yield point increased by 60% and 183%, respectively, thixotropy and plastic viscosity decreased by 29% and 63%, respectively. On the other hand, drilling fluid with 4% wt% content of rice husk ash reduced the fluid loss by 10%. Moreover, results showed that cutting carrying index, minimum annulus velocity required to clean bottom of the well efficiently and flow behaviour index of the enhanced with the exploitation of rice husk ash in the drilling fluid. This study showed that rice husk ash as a promising additive to use in the water-based bentonite drilling fluids when properly implemented, and hence reducing the impact on the environment, and the total cost for drilling.


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