Rheological behaviour and microstructure of pea protein/κ-carrageenan/starch gels with different setting conditions (original) (raw)
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Gelled vegetable desserts containing pea protein, κ-carrageenan and starch
European Food Research and Technology, 2006
Due to recent animal diseases, cholesterol intake worries and strong demand for healthy food, there is a greater pressure for the direct consumption of vegetable proteins in food products. In this work, the objective is to develop alternative of strictly vegetable origin desserts based on gelled systems with required physical structure and perceived texture. For this reason, it is important to control the properties of the biopolymer mixtures and understand the phase separation behaviour under different physicochemical conditions. The firmness and storage modulus of different formulations of pea protein/κ-carrageenan/starch systems processed and cooled at different conditions are compared with those parameters obtained for commercial products. Formulation and thermal conditions were determined to influence the texture and storage modulus of the mixed systems. Confocal microscopic images showed that phase separation between pea protein and κ-carrageenan takes place, leading to the formation of two network systems. The binding of water effect, of the starch swollen granules, promotes the concentration of pea protein and κ-carrageenan, reinforcing the gel structure.
Phase separation, rheology and microstructure of pea protein–kappa-carrageenan mixtures
Food Hydrocolloids, 2007
Due to their interest in food industry, mixed systems of globular proteins and polysaccharides have been the subject of growing interest in recent years. In the particular case of this work, the focus is on mixtures of pea-protein-kappa-carrageenan. Phase diagrams of pea protein and k-carrageenan mixtures have been established at pH 7 above the isoelectric point (IEP) of the protein, 60 1C and two different ionic strengths (0.05 and 0.2 M). These systems led to phase separation probably arised by the depletion-flocculation mechanism. Under the same conditions, rheology and microstructure by confocal laser scanning microscopy (CLSM) of these systems in the mono and biphasic regions have been investigated. CLSM showed the formation of pea protein aggregates network in presence of k-carrageenan. Marked differences between mixtures in two-phase region and one component solutions were also evidenced in the rheological properties, with the behaviour being governed by the continuous protein-enriched phase. r
Rheological, Thermal and Microstructural Properties of Whey Protein-Cassava Starch Gels
Journal of Food Science, 1996
Mixed gels of cassava starch (CS) and a whey protein isolate (WPI), obtained by heating solutions of 10% total solids, pH 5.75 to 85°C, were characterized as a function of the starch fraction, θs, by axial compression, small-amplitude oscillatory rheometry, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Gelation did not occur for θs > 0.7. In the range 0<θs < 0.4 mixed gels showed higher mechanical (E, elastic modulus) and rheological (G′, storage modulus) properties than pure gels, with maximum values for θs= 0.2–0.3. Viscoelastic measurements as a function of time showed that gels containing higher levels of WPI developed a larger G. Blends of both biopolymers showed independent thermal transitions in DSC measurements, related to gelatinization and denaturation. Microstructure of a mixed gel formed at θs= 0.2 showed a continuous matrix formed by strands of WPI particle aggregates and an independent CS phase.
The Effect of Starch and Amidated Pectin on Rheological Behavior of Iota-Carrageenan Gels
Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Food Science and Technology, 2020
Experiments were conducted to study the rheological behavior of iota-carrageenan Gels to which potato starch and low-esterified amidated pectin were added. The rheological measurements of carrageenan jellies were performed by a texture analyzer at different concentrations of gelling agent (iota-carrageenan) and fixed concentrations of starch (1.3 %) and pectin (0.3%). Following the experiments, rheological patterns related to rupture force, rupture deformation and firmness of the gels were evaluated. Potato starch and low esterified amidated pectin at certain concentrations do not show synergistic effects with iota-carrageenan. The addition of low esterified amidated pectin or potato starch in iota-carrageenan gel results in a significant reduction in deformation and a minimal reduction in the rupture force.
Rheological properties of κ-carrageenan and soybean glycinin mixed gels
Food Research International, 2008
Low amplitude dynamic oscillatory measurements were used to investigate j-carrageenan/soybean glycinin mixed gel formation and rheological properties in the presence of native and denatured glycinin. The elastic modulus of mixed gel (20°C for 30 min) was decreased with the increase in concentration of soybean glycinin. However, during heating ramp (20-95°C) the elastic modulus showed a biphasic profile. The first phase exhibited a decrease in the elastic modulus while the second phase involved an increase in the elastic modulus. Cooling from 95 to 20°C and holding at 20°C for 30 min induced consolidation of protein network and gelation of j-carrageenan which also increased the elastic modulus with the increase in glycinin concentration. Gelation of j-carrageenan in the presence of gelled glycinin induced formation of phase-separated network. Native and denatured glycinin have different functions on large deformation of mixed gel, which is of practical significance for the food processors.
Food Hydrocolloids, 2019
The gelling of two commercial pea protein isolates (PPI) at 20% and 23% PPI concentration, and the effect of microbial transglutaminase (-0-and-5-U/g protein), were analysed. The final aim was to get PPI gels with textural properties enough to make meat and seafood analogues. The first PPI (-A-), was made by alkaline solubilization and isoelectric precipitation from pea flour. The second one (-B-), was obtained by aqueous dispersion of the pea flour and concentration of the soluble protein. The water and oil holding capacities of PPI-A suggested a higher degree of protein denaturation which was assessed by Dynamic thermo mechanical analysis (DMTA) and Fourier transform infrared spectroscopy (FTIR). FTIR data showed lower intermolecular β-sheet aggregates in PPI-B gels than in PPI-A. This result was consistent with the reticulated and well-interconnected network from scanning electron microscopy (SEM) of PPI-B gels in line with the higher strain amplitude (γ max), and the lower loss factor (tanδ) in PPI-B gels vs PPI-A gels. The MTGase enzyme significantly improved the structural quality of the PPI-B gels (high Q-factor) at 20% and 23% PPI. For all these reasons PPI B is more suitable for achieving consistent gels as bases for meat and seafood analogues.
Rheology of gelatin – starch systems. I. Influence of system composition
Revista De Chimie Bucharest Original Edition, 2013
Texture and sensory properties of foods are often correlated with the rheological behaviour of the system. In bakery products gluten -through its main components -gliadin and glutenin -is responsible for the viscoelastic behaviour, essential for the final quality and consumers' acceptance of the product. Replacing gluten in dietary products is not an easy task and attempts have been performed with various proteins. A series of starch -gelatin composite gels have been prepared and rheologically characterized to check the suitability of gelatin as gluten replacement. Amplitude sweeps, frequency sweeps and temperature tests were carried out to evidence the influence of starch:gelatin ratio on the overall rheological properties of the final products.
Food Hydrocolloids, 2005
Carrageenans, sulphated polysaccharides extracted from red seaweeds, are widely added to milk systems because of the gelation they promote and for their ability to recover a structure at rest after shearing. The gelation of iota-carrageenan is closely related to the helix-coil transition they undergo at approximately 48 8C in milk. Carrageenan gels (e.g. iota with and without nu precursors) were formed in milk or permeate by decreasing the temperature from 60 to 10 8C following various mechanical treatments, e.g. gelation and ageing of the gel at rest, gelation under shearing and ageing at rest. Gels were characterized rheologically during cooling and ageing, performed in the dynamic mode, to follow the mechanical recovery of the mixed systems at rest.
Carbohydrate Polymers, 2007
The mechanical and calorimetric properties of acid hydrolyzed hydroxypropylated pea starch (HPPS)/j-carrageenan (jC) cast films were investigated in relation to the rheological behaviour of the gelled film-forming dispersions. The mixture was prepared by mixing HPPS (25%, w/w), an easily slurried non-gelling polysaccharide, and a K + j-carrageenan (61% w/w) used for its gelling properties. Whatever the j-carrageenan content, the total ionic concentration (K +) was maintained constant to control the transition temperatures. Compared to individual components, the rheological properties of the hot mixtures at 60°C showed a dramatic increase of the viscosity. Upon cooling, stronger gels were formed compared to those of the pure j-carrageenan in similar ionic conditions. Meanwhile, these gels set and melted at temperatures around 10 and 20°C higher than those of the j-carrageenan alone in the same conditions. These phenomena were attributed to excluded volume effects between j-carrageenan and starch resulting in the increased concentration of the carrageenan forming the network. Drying was performed under controlled conditions at 25°C and 40% relative humidity. The glass transition temperature T g of HPPS at different water contents was obtained by calorimetry. The properties of the cast films were evaluated on the basis of mechanical and calorimetric measurements. Overall, the final film properties of the blends were similar to those of the films with starch alone. This means that the influence of the j-carrageenan on the solid-state behaviour of the blends was hidden, in spite of the strong influence of j-carrageenan on the rheological behaviour in the solution and in the gel state.
Rheological behavior of starch-based biopolymer mixtures in selected processed foods
Starch - Stärke, 2012
The objective of this review article is to investigate rheological behaviors of starch-based biopolymer mixtures in selected food systems. Numerous recently published studies on this subject were thoroughly screened and reviewed. This paper indicates rheological behaviors, which include viscoelasticity, texture, and viscosity, of starch-based biopolymer mixtures in selected food systems. It was found that starch-based biopolymer mixtures had different rheological behaviors that could affect the quality of processed foods. The main factors that affected rheological properties were the botanical sources of starches and the effect of mixing other biopolymers with starch. For instance, starch-based noodles prepared with potato starches were harder than noodles prepared with corn starch. Furthermore, the viscoelastic values of imitation cheese, which can be expressed by a storage modulus (G 0 ) and a loss modulus (G 00 ), increased with the addition of pregelatinized starch. In soup, another example of a starch-based biopolymer mixture, it was found that the presence of fenugreek polysaccharides (0.1-0.9% w/w) resulted in better development of viscoelastic properties with greater G 0 and G 00 compared with soups having no fenugreek polysaccharides added.