scholarly journals Optimization of the Rheological and Sensory Properties of Stirred Yogurt as Affected by Chemical Composition and Heat Treatment of Buffalo Milk

2013 ◽  
Vol 2 (6) ◽  
pp. 55 ◽  
Author(s):  
Dimitris Petridis ◽  
Georgia Dimitreli ◽  
Stella Chrysalidou ◽  
Pantelina Akakiadou
Keyword(s):  
Heat Treatment ◽  
Rheological Properties ◽  
Flow Behavior ◽  
Whey Proteins ◽  
Fat Content ◽  
Buffalo Milk ◽  
Sensory Properties ◽  
Sensory Characteristics ◽  
Regression Equations ◽  
Color Intensity

<p>The effects of fat content and the supplementation of milk with Sodium Caseinates (SCN) and Whey Proteins Concentrates (WPC) on the rheological and sensory properties of stirred yogurt made from buffalo milk were investigated. Whether the heat treatment of the milk affected the rheological behavior and the sensory characteristics of the samples was also evaluated. Principal Component Analysis (PCA) was used to assess in detail the relative contribution of whey proteins, caseins and fat on the rheological properties and sensory characteristics of the samples. Furthermore, it related the instrumental and objective sensory data to consumer perception (hedonic response of non-trained panelists). The objective acidity and white color intensity were positively correlated and increased with increasing casein content. Fat interacted synergistically with caseins to increase all the hedonic attributes, apart from odor. As far as rheological properties are concerned, elastic modulus (G'), instantaneous elasticity (G<sub>g</sub>), retarded elasticity (G<sub>R</sub>) and Newtonian viscosity (?<sub>0</sub>) were positively correlated with increasing casein content. However, tan ? was negatively correlated with the aforesaid attributes and increased with increasing fat content. Whey proteins in the presence of fat determined the magnitude of flow behavior index (n). The lactic acid concentration (%) and the b component of color (yellow color intensity) were affected positively by SCN and WPC addition but in the absence of fat. In all regression equations the effect of process temperature was found to be insignificant. Finally, the consumer-optimized composition of the fat and the added SCN can be used to formulate a marketable product.</p>

scholarly journals Effect of Protein Supplementation, Fat Globule Size and Storage Time on the Rheological and Sensory Properties of Buffalo Milk Stirred Yogurt

2014 ◽  
Vol 3 (5) ◽  
pp. 31 ◽  
Author(s):  
Georgia Dimitreli ◽  
Dimitris Petridis ◽  
Pantelina Akakiadou ◽  
Stella Chrysalidou
Keyword(s):  
Rheological Properties ◽  
Storage Time ◽  
Flow Behavior ◽  
Buffalo Milk ◽  
Protein Supplementation ◽  
Color Intensity ◽  
Newtonian Viscosity ◽  
Fat Globules ◽  
Globule Size ◽  
Fat Globule

<p>In the present study the physicochemical (acidity, color measurements), rheological (viscosity measurements and viscoelastic properties) and sensory (objective and hedonic) properties of stirred yogurt made from buffalo milk were evaluated. Yogurt samples with two fat globule sizes (large: 2.9 ?m; small: 0.87 ?m) were prepared with or without the addition of Whey Protein Concentrates (WPC) or Sodium Caseinates (SCN), and stored at 4 °C for testing at day 1 and 7 after preparation. SCN addition resulted in increased lactic acid concentration, rheological properties (except loss tangent - tan ?), white color intensity and sensory viscosity. The effect of WPC on the aforesaid properties was lower when compared to SCN. Small fat globule size also increased the rheological properties apart from tan ?, brightness and sensory viscosity of yogurt samples. Increasing storage time resulted in reduced viscosity, increased acidity and rheological properties apart from tan ? and apparent viscosity. The greater decline rates were obvious for Newtonian viscosity at zero shear rate (?<sub>0</sub>) and instantaneous elasticity (G<sub>g</sub>) in yogurts with added SCN and WPC and large globule size and lower or negligible in samples without additives. In contrast, tan ? increased at a lower rate when SCN were added in products with large fat globules. Storage time increased the value of flow behavior index (n) in yogurts with large fat globules and, more rapidly, the value of elastic modulus (G') in the presence of SCN and WPC. The small globule size in the absence of additives produced the lowest response of b and, when WPC was present, the lowest white color intensity. The sensory viscosity reduced the most during storage in yogurt samples with no protein addition.</p>

scholarly journals Effects of Buffalo and Cow Milk Mixtures Enriched With Sodium Caseinates on the Physicochemical, Rheological and Sensory Properties of a Stirred Yogurt Product

2014 ◽  
Vol 3 (6) ◽  
pp. 54
Author(s):  
Dimitris Petridis ◽  
Georgia Dimitreli ◽  
Kalliopi Vlahvei ◽  
Christodoulos Deligeorgakis
Keyword(s):  
Flow Behavior ◽  
Buffalo Milk ◽  
Sensory Profile ◽  
Interactive Effects ◽  
Cow Milk ◽  
Elastic Behavior ◽  
Color Intensity ◽  
Flow Behavior Index ◽  
Yellow Color ◽  
Milk Mixture

<p>The physicochemical, rheological and sensory (objective and hedonic) properties of stirred yogurt made from buffalo and cow milk mixtures enriched with Sodium Caseinates (SCN) were evaluated. Five different milk mixtures (buffalo:cow; 0:100, 25:75, 50:50, 75:25, 100:0) with or without the addition of 1% SCN were fermented so as to produce 10 different yogurt samples. According to the results, SCN addition increased the brightness (L*), the elastic behavior, the viscosity (instrumental and sensory) and the flow behavior index (n), while it reduced the yellow color intensity (b*) of yogurt samples. Addition of milk affected significantly all the instrumental variables apart from the green color intensity (a*) and so happened but sparsely with the interactive effects between milk mixture and SCN addition. Redundancy analysis was proved a successful tool to elucidate the complex physicochemical, rheological and sensory profile of the stirred yogurt samples. Loss tanget (tan ?) and b* were indicative for high cow milk concentrations and the rest of attributes fashion with high buffalo milk concentrations, apart from n which favored samples with high cow milk enrichment and SCN addition. Panelists prefered adequately a stirred yogurt rich in buffalo milk concentration (75-100%) and low in cow milk (0-25%), enriched with SCN, with texture perceived as adequate fatty and viscous.</p>

Effect of interactions between denatured whey proteins and casein micelles on the formation and rheological properties of acid skim milk gels

1998 ◽  
Vol 65 (4) ◽  
pp. 555-567 ◽  
Author(s):  
JOHN A. LUCEY ◽  
MICHELLE TAMEHANA ◽  
HARJINDER SINGH ◽  
PETER A. MUNRO
Keyword(s):  
Heat Treatment ◽  
Rheological Properties ◽  
Loss Tangent ◽  
Whey Proteins ◽  
Skim Milk ◽  
Casein Micelles ◽  
Heated Milk ◽  
Tan Δ ◽  
Reconstituted Milk ◽  
Acid Milk Gels

The effect of interactions of denatured whey proteins with casein micelles on the rheological properties of acid milk gels was investigated. Gels were made by acidification of skim milk with glucono-δ-lactone at 30°C using reconstituted skim milk powders (SMP; both low- and ultra-low-heat) and fresh skim milk (FSM). The final pH of the gels was ∼4·6. Milks containing associated or ‘bound’ denatured whey proteins (BDWP) with casein micelles were made by resuspending the ultracentrifugal pellet of heated milk in ultrafiltration permeate. Milks containing ‘soluble’ denatured whey protein (SDWP) aggregates were formed by heat treatment of an ultracentrifugal supernatant which was then resuspended with the pellet. Acid gels made from unheated milks had low storage moduli, G′, of <20 Pa. Heating milks at 80°C for 30 min resulted in acid gels with G′ in the range 390–430 Pa. The loss tangent (tan δ) of gels made from heated milk increased after gelation to attain a maximum at pH ∼5·1, but no maximum was observed in gels made from unheated milk. Acid gels made from milks containing BDWP that were made from low-heat SMP, ultra-low-heat SMP and FSM had G′ of about 250, 270 and 310 Pa respectively. Acid gels made from milks containing SDWP that were made from ultra-low-heat SMP or FSM had G′ values in the range 17–30 Pa, but gels made from low-heat SMP had G′ of ∼140 Pa. It was concluded that BDWP were important for the increased G′ of acid gels made from heated milk. Addition of N-ethylmaleimide (NEM) to low-heat reconstituted milk, to block the —SH groups, resulted in a reduction of the G′ of gels formed from heated milk but did not reduce G′ to the value of unheated milk. Addition of 20 mm-NEM to FSM, prior to heat treatment, resulted in gels with a lower G′ value than gels made from reconstituted low-heat SMP. It was suggested that small amounts of denatured whey proteins associated with casein micelles during low-heat SMP manufacture were probably responsible for the higher G′ of gels made from milk containing SDWP and from milk heated in the presence of 20 mm-NEM, compared with gels made from FSM.

Rheological properties of milk gels formed by a combination of rennet and glucono-δ-lactone

2000 ◽  
Vol 67 (3) ◽  
pp. 415-427 ◽  
Author(s):  
JOHN A. LUCEY ◽  
MICHELLE TAMEHANA ◽  
HARJINDER SINGH ◽  
PETER A. MUNRO
Keyword(s):  
Heat Treatment ◽  
Rheological Properties ◽  
Large Scale ◽  
Whey Proteins ◽  
Skim Milk ◽  
Rheological Behaviour ◽  
Intermolecular Forces ◽  
Heated Milk ◽  
Rennet Coagulation ◽  
Tan Δ

The effects of heat treatment of milk, and a range of rennet and glucono-δ-lactone (GDL) concentrations on the rheological properties, at small and large deformation, of milk gels were investigated. Gels were made from reconstituted skim milk at 30 °C, with two levels each of rennet and GDL. Together with controls this gave a total of sixteen gelation conditions, eight for unheated and eight for heated milk. Acid gels made from unheated milks had low storage moduli (G′) of < 20 Pa. Heating milks at 80 °C for 30 min resulted in a large increase in the G′ value of acid gels. Rennet-induced gels made from unheated milk had G′ values in the range ∼ 80–190 Pa. However, heat treatment severely impaired rennet coagulation: no gel was formed at low rennet levels and only a very weak gel was formed at high levels. In gels made with a combination of rennet and GDL unusual rheological behaviour was observed. After gelation, G′ initially increased rapidly but then remained steady or even decreased, and at long ageing times G′ values increased moderately or remained low. The loss tangent (tan δ) of acid gels made from heated milk increased after gelation to attain a maximum at pH ∼ 5·1 but no maximum was observed in gels made from unheated milk. Gels made by a combination of rennet and GDL also exhibited a maximum in tan δ, indicating increased relaxation behaviour of the protein–protein bonds. We suggest that this maximum in tan δ was caused by a loosening of the intermolecular forces in casein particles caused by solubilization of colloidal calcium phosphate. We also suggest that in combination gels made from unheated milk a low value for the fracture stress and a high tan δ during gelation indicated an increased susceptibility of the network to excessive large scale rearrangements. In contrast, combination gels made from heated milk formed firmer gels crosslinked by denatured whey proteins and underwent fewer large scale rearrangements.

scholarly journals Natural Yogurt Stabilized with Hydrocolloids from Butternut Squash (Cucurbita moschata) Seeds: Effect on Physicochemical, Rheological Properties and Sensory Perception

Fluids ◽  
2021 ◽  
Vol 6 (7) ◽  
pp. 251
Author(s):  
Sergio A. Rojas-Torres ◽  
Somaris E. Quintana ◽  
Luis Alberto García-Zapateiro
Keyword(s):  
Shear Rate ◽  
Physicochemical Properties ◽  
Rheological Properties ◽  
Yield Stress ◽  
Food Industry ◽  
Physical Stability ◽  
Sensory Properties ◽  
Sensory Characteristics ◽  
Cucurbita Moschata ◽  
Technological Properties

Stabilizers are ingredients employed to improve the technological properties of products. The food industry and consumers have recently become interested in the development of natural ingredients. In this work, the effects of hydrocolloids from butternut squash (Cucurbita moschata) seeds (HBSS) as stabilizers on the physicochemical, rheological, and sensory properties of natural yogurt were examined. HBSS improved the yogurt’s physical stability and physicochemical properties, decreasing syneresis and modifying the samples’ rheological properties, improving the assessment of sensory characteristics. The samples presented shear thinning behavior characterized by a decrease in viscosity with the increase of the shear rate; nevertheless, the samples showed a two-step yield stress. HBSS is an alternative as a natural stabilizer for the development of microstructured products.

Physical properties of UHT light cream: impact of the high-pressure homogenization and addition of hydrocolloids

2021 ◽  
pp. 1-8
Author(s):  
Virgínia Nardy Paiva ◽  
Lucas de Souza Soares ◽  
Rodrigo Stephani ◽  
Álvaro Augusto Pereira Silva ◽  
Antônio Fernandes de Carvalho ◽  
...  
Keyword(s):  
High Pressure ◽  
Rheological Properties ◽  
Emulsion Stability ◽  
Flow Behavior ◽  
Milk Proteins ◽  
Fat Content ◽  
Elastic Behavior ◽  
High Pressure Homogenization ◽  
Low Fat ◽  
Rheological Characterization

Abstract The beneficial effects of a healthy diet on the quality of life have prompted the food industry to develop low-fat variants, but fat content directly affects the physicochemical and sensory properties of food products. The utilization of high-pressure homogenization (HP) and incorporation of hydrocolloids have been suggested as strategies to improve the physical stability and rheological properties of light cream. Thus, this study aims to analyze the associated effect of high-pressure homogenization (80 MPa) and three different hydrocolloids: microcrystalline cellulose, locust bean gum and xanthan gum, on emulsion stability and rheological properties of ultra-high-temperature (UHT) light cream (ULC) with a 15% w/w fat content. The stability of ULC was determined by the ζ potential of oil droplets and emulsion stability percentage. Rheological characterization was based on flow behavior tests and dynamic oscillatory measurements, which were carried out in a rheometer. Results showed that the high-pressure homogenization process did not influence the emulsion stability of the treatments. Moreover, the hydrocolloids added to systems present weak interactions with milk proteins since all ULC showed macroscopical phase separation. The samples presented the same rheological behavior and were classified as pseudoplastic fluids (n < 1). ULC treated at 80 MPa was significantly (P ≤ 0.05) more consistent than the treatments at 20 MPa. All ULC showed a predominant elastic behavior (G′ > G″), and a remarkable increase in both G′ and G″ at 80 MPa. The results presented in this study highlight the potential of HP for altering some rheological characteristics of UHT light cream, for example, to increase its consistency. These results are important for the dairy industry and ingredient suppliers, in the standardization of UHT light cream and/or to develop low-fat products.

scholarly journals Chemical and Sensory Parameters of Heat-treated Vacuum-packaged Broiler and Hen Fillet Products

2012 ◽  
Vol 27 (1) ◽  
pp. 54-58 ◽  
Author(s):  
Kristine Ramane ◽  
Envija Strautniece ◽  
Ruta Galoburda
Keyword(s):  
Heat Treatment ◽  
Moisture Content ◽  
Protein Content ◽  
Meat Products ◽  
Fat Content ◽  
Sensory Properties ◽  
Poultry Meat ◽  
Heat Treated ◽  
Sensory Parameters ◽  
And Storage

Chemical and Sensory Parameters of Heat-treated Vacuum-packaged Broiler and Hen Fillet Products The heat treatment of vacuum-packaged products - Sous vide processing method - that offers convenience and storage stability, combined with poultry meat marinating was used in the current study. The aim of this research was to evaluate the effect of a fruit-vegetable additive on chemical and sensory parameters of heat-treated vacuum-packaged poultry meat products made from broiler or hen fillets. The skinless fillets and other ingredients were packaged in polyamide/polyethylene (PA/PE) pouches, vacuum sealed, marinated, heat treated, and chilled rapidly. The following parameters were evaluated: moisture content (LVS ISO 1442:197), protein content (LVS ISO 937:1978), fat content (LVS ISO 1443:1973), ash content (ISO 936:996), degree of liking, and intensity of sensory properties (ISO 4121: 2003). The smallest changes in moisture content among the studied samples were observed in those prepared with the fruit-vegetable additive if compared to a raw fillet. In the process of heat treatment, the protein content in dry matter of broiler and hen fillet decreased (p<0.05), whereas fat content decreased in broiler fillet but increased in hen fillet (p<0.05). Sensory evaluation results showed that panellists preferred broiler fillet (6.6) and hen fillet (5.8) products which were prepared without the fruit-vegetable additive. Evaluation of the intensity of sensory properties showed that there do not exist significant differences in aroma, colour, flavour, and aftertaste of heat-treated vacuum-packaged hen and broiler fillet (p>0.05), but texture of broiler fillet products is more tender than texture of samples made from hen fillet.

scholarly journals Influence of biopolymers on the rheological properties of seafloor sediments and the runout behavior of submarine debris flows

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jun Kameda ◽  
Hamada Yohei
Keyword(s):  
Rheological Properties ◽  
Debris Flows ◽  
Extracellular Polymeric Substances ◽  
Flow Behavior ◽  
Mass Movement ◽  
Rheological Parameters ◽  
Natural Environments ◽  
Natural Systems ◽  
Chemical Conditions ◽  
Seafloor Sediments

AbstractSubmarine debris flows are mass movement processes on the seafloor, and are geohazards for seafloor infrastructure such as pipelines, communication cables, and submarine structures. Understanding the generation and run-out behavior of submarine debris flows is thus critical for assessing the risk of such geohazards. The rheological properties of seafloor sediments are governed by factors including sediment composition, grain size, water content, and physico-chemical conditions. In addition, extracellular polymeric substances (EPS) generated by microorganisms can affect rheological properties in natural systems. Here we show that a small quantity of EPS (~ 0.1 wt%) can potentially increase slope stability and decrease the mobility of submarine debris flows by increasing the internal cohesion of seafloor sediment. Our experiments demonstrated that the flow behavior of sediment suspensions mixed with an analogue material of EPS (xanthan gum) can be described by a Herschel–Bulkley model, with the rheological parameters being modified progressively, but not monotonously, with increasing EPS content. Numerical modeling of debris flows demonstrated that the run-out distance markedly decreases if even 0.1 wt% of EPS is added. The addition of EPS can also enhance the resistivity of sediment to fluidization triggered by cyclic loading, by means of formation of an EPS network that binds sediment particles. These findings suggest that the presence of EPS in natural environments reduces the likelihood of submarine geohazards.

Sign in / Sign up

Export Citation Format

Share Document