Effect of thermal treatment on physical properties and stability of whipping and whipped cream

Rheological properties of dairy desserts: Effect of rice bran protein and fat content

Rice bran protein (RBP) is an alternative plant protein that can be used in a wide range of foods due to its unique functional, nutritional, and hypoallergenic properties. The interactions of RBP with other biopolymers have revealed its feasibility for application in dairy products such as whipped cream and dairy desserts. Therefore, the effects of RBP and fat content on the rheological properties of dairy desserts were investigated. The pH value was not influenced by protein, but the nonfat milk solid content was changed by fat and protein content. All the desserts showed thixotropic properties which were mainly related to the molecular disentanglement at high shear rates. By increasing fat like RBP, the apparent viscosity (η_a ) was increased. Rheological parameters such as n value, thixotropic index, storage (G'), and loss moduli (G'') were increased by RBP. Moreover, the dairy desserts containing RBP and whole milk presented generally higher G', G'', complex modulus, and complex viscosity values, and lower tan δ values. The RBP enriched samples also had a higher hardness and gumminess. Syneresis was decreased by RBP, which was related to the formation of ordered mesh-like structures which enabled the entrapment of more water. There was a positive correlation between the rheological, textural, and physical properties of the dessert with added RBP, and therefore dairy dessert attributes can be improved along with fat reduction. However, a sensory evaluation is needed to unravel the acceptability rate of RBP in fat reduction from the view point of consumers. PRACTICAL APPLICATION: Rice bran protein (RBP) has nutritional and hypoallergenic properties which enable it to apply to many products such as dairy desserts. One of the main concerns in dairy technology is the growing interest in low-fat products due to health problems. RBP showed unique properties which makes the creamy behavior. The rheological results have elucidated the creaminess associated with RBP and can assist in the proper simulation of mouthfeel.

Effect of basil seed gum and κ-carrageenan on the rheological, textural, and structural properties of whipped cream

BACKGROUND

Basil seed gum (BSG) is a novel polysaccharide that has been found wide application in the food industry. It can be used in whipped cream due to its thickening and emulsifying properties. The effect of BSG and κ-carrageenan on the structure-rheology relationships of whipped cream was evaluated.

RESULTS

The viscosity of cream containing BSG was higher than that of carrageenan. Basil seed gum resulted in a strong capacity to improve the viscosity of the cream. Rheological results showed the low-frequency dependence of the elastic modulus was improved by BSG, which had a strong effect on the rigidity of the emulsion. The fracture strain of the creams containing BSG or κ-carrageenan was between the normal cream and acidified caseinate stabilized emulsion foam. It was found that the protein segments of BSG could be adsorbed at the oil-water interface, resulting in the formation of a pseudo-gel network, which creates a stronger molecular protein network in the whipped cream. Microstructure study revealed that whipped cream containing κ-carrageenan exhibited some flocculation, which could be caused by non-adsorbed polysaccharides or proteins. In contrast, cream containing BSGshowed more voids, which have considerably decreased by fat content and enhance the foam structure.

CONCLUSION

As a result, synergistic interactions between proteins and polysaccharides (BSG and κ-carrageenan) could promote the development of a cross-linked network. Indeed, due to its high levels of hydrophilicity, BSG absorbs water, acts as a thickening agent, and competes against caseinate at the interfaces and is incorporated into whipped cream to provide a more desirable physical structure for the product. © 2021 Society of Chemical Industry.

The Perspective of Nectarine Fruit as a Sugar Substituent in Puddings Prepared with Corn and Rice Starch

It has been long recognized that fruits are healthy diet compounds as they are excellent sources of health-beneficial bioactive components (polyphenols, minerals, vitamins, organic acids, etc.). The diversification of the consumer’s taste calls for an expansion of food options and novel ingredients. Puddings are a well-known food choice introduced in the human diet at a very early age because of their easy and high digestion. Four formulations with two types of starch (corn and rice) were selected as object of analysis. Nectarines were incorporated as a purée, and lyophilized powder. The nectarine variety “Gergana”, used for the preparations, is a local variety with proven beneficial properties. The study aimed at analyzing the physical (moisture, ash, color, water-holding capacity, water activity, density and syneresis), textural (firmness, gumminess, cohesiveness, springiness, and chewiness), nutritional, and sensory characteristics of the nectarine-enriched puddings. The outcomes obtained from this study provided significant information about the possible application of the formulations in the children’s daily menus. All four formulations had distinct peachy aroma. The formulations prepared with nectarine purée resulted in a better sensory perception about their texture, and better water-holding capacity. At this point, the formulation prepared with lyophilized fruit and rice starch has the most promising results. Sufficient evidence leads to further exploration of the perspective of fruit-enriched puddings in order to improve their technological and health-promoting properties.

Modification of the properties of milk-fat emulsions with the phase structure of "oil in water" in the dependence on the mass part of the lipoid and the stabilizing systems

The composition and properties of cream with fat levels from 30% to 70% were investigated. It has been established that the decrease of fat level and, accordingly, the increase of plasma level in the cream leads to significant changes in the physicochemical parameters of the fat emulsion. Accordingly, the production of low-fat dairy products requires adjustment of the cream properties. It has been shown that using different doses of structure stabilizers: QNA colloid as a consistency stabilizer in the amount of from 1 to 2% and the Dimodan emulsifier U/G – from 0 to 1 % (Danisco, Denmark) changes the physicochemical properties (effective viscosity, sedimentation stability) and organoleptic properties (consistency, taste) of cream with fat level 40%. It has been conducted mathematical modeling, aimed to calculate dosing for improving the properties of milk-fat emulsions, structure formation and further ensuring of the necessary consistency of cream pastes. Optimal doses of colloid QNA as a consistency stabilizer and a U/G Dimodan emulsifier have been determined. It has been established that their content should be 1,0% and 0,5%, relatively, for pastes with a fat level of 40%. The effectiveness of the joint action of consistency stabilizers and emulsifiers in obtaining milk-fat emulsions were defined by the level of effective viscosity. Moreover, the use of the emulsifier had less effect on the effective viscosity of the milk-fat emulsions. It has been found that using the structure stabilizers could improve the formation of low-fat products and the formation of the desired paste-like consistency of high-fat cream with a fat level of 70%. Thus, it is possible to adjust the composition and properties of raw material as a basis for milk-fat emulsions by optimizing the ratio of structure stabilizers. Comparative evaluation of the physicochemical properties of milk-fat emulsions and high-fat cream makes it possible to predict their potential for conversion into a creamy paste with a given consistency.

Tempering governs the milk fat crystallisation and viscoelastic behaviour of unprocessed and homogenised creams

The crystallisation behaviour of milk fat plays an important role in the functionality and sensory properties of fat-rich dairy products. In this study, we investigated the impact of tempering to 25 °C on the viscoelastic properties, particle size and thermal behaviour of 20% w/w unprocessed and homogenised creams prepared from bovine milk. The crystallisation properties were examined by synchrotron X-ray diffraction (XRD) at small (SAXS) and wide angle (WAXS) and differential scanning calorimetry (DSC). Oscillation rheology was performed to characterise the cream's viscoelastic properties. Homogenisation (35 MPa) reduced the average droplet size from 4.4 to 1.3 µm. After 24 h storage at 4 °C, milk fat structures showed triacylglycerol (TAG) 2L and 3L_{(001, 002, 003, 005)} lamellar stacking orders associated predominantly with the α and β' polymorphic forms. Tempering to 25 °C induced the complete melting of the 3L crystals and led to an irreversible loss in the elastic modulus (G') and a reduction in the viscous modulus (G'') once returned to refrigerated conditions, due to changes in the particle-particle interactions and structure of the reformed milk fat crystals. The results demonstrate that crystallisation behaviour of milk fat is influenced by droplet size and the rearrangement of triacylglycerol (TAG) upon tempering, and lead to changes in the viscoelastic behaviour of dairy products containing a high level of milk fat.

Catastrophic thermal destabilization of two-dimensional close-packed emulsions due to synchronous coalescence initiation

The mechanisms for phase separation in highly concentrated emulsions when subjected to a thermal phase transition remain to be elucidated. Here, we create a hexagonally close-packed monodisperse emulsion in 2D and show that during a cool-heat cycle, the emulsion fully destabilizes akin to phase separation. The mechanism for this catastrophic destabilization is found to be spontaneous coalescence initiation that synchronously occurs between every solidified droplet and its neighbors. This synchronous coalescence initiation establishes system-wide network connectivity in the emulsion causing large-scale destabilization. This system-wide coalescence initiation is found to be insensitive to droplet size and tested surfactants, but dependent on network connectivity and crystal content of individual droplets.