Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: The study carried out in the past year focused on investigating the interactions between soy proteins (SP) and micellar casein (MCN) and the effect of concentration and temperature on these interactions. PARTICIPANTS: Increasing the protein content of foods and beverages has attracted significant interest in recent years. The combination of various proteins may bring advantages in terms of rheological characteristics and processing behavior as compared to individual protein systems. One combination of interest is a mixture of soy proteins and milk proteins. A critical element in designing milk protein-soy protein blends with palatable textures is establishing the range of compositional and environmental conditions that promote compatibility and homogeneity. The study that was carried out in the past year focused on investigating the interactions between soy proteins (SP) and micellar casein (MCN) and the effect of concentration and temperature on these interactions. Individual and mixed SP-MCN systems of 10% and 15% concentration were prepared and heat treated for 15 min at 40, 60 and 95C. After cooling to 20C, the rheological properties were determined. Viscosity and yield stress of SP, MCN and mixtures increased with concentration. SP systems exhibited shear thinning behavior, which became more pronounced with increasing concentration. Treatment of 10% SP-MCN at 95C resulted in mixtures with Newtonian behavior and lower viscosity as compared to the non-heat treated mixture. This mixture also had good storage stability, with no sedimentation being observed after 2 months of storage under refrigeration. The data generated in this study can be used to develop protein based products with unique rheological properties and high storage stability. TARGET AUDIENCES: The results of this work are expected to directly impact the Food Industry, which will be able to design of new foods or ingredients based on milk and soy proteins. Ultimately, this is expected to benefit all consumers. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The data generated in this study can be used to develop protein based products with unique rheological properties and high storage stability.
Publications
- Beliciu C.M. and Moraru C.I. 2010. Protein-protein interactions in native casein-soy protein mixtures. A rheological study. Submitted to Food Hydrocolloids
- Wihodo M. and Moraru C.I. 2010. Effect of Pulsed Light treatment on the physical properties of casein films. Submitted to Journal of Food Engineering
- Wihodo M. and Moraru C.I. 2010. Physical and chemical methods used to enhance the structure and mechanical properties of protein films. Review paper. Submitted to Journal of Food Engineering
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Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: The study that was carried out in the past year focused on investigating the synergistic interactions between tara gum and xanthan gum, which are commonly used as thickening agents in the manufacture of food products. This study was carried out with help from an undergraduate student. Dissemination of the results of the study will be done in the future, when more substantial results will be generated. PARTICIPANTS: Carmen I. Moraru - PI, Stefan Latev - undergraduate researcher TARGET AUDIENCES: The main target audience for this project is the Food Industry. The findings of this study might offer technical solutions for thickening of food products that can lead to cost reductions. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Xanthan and tara-bean gums are commonly used in the food industry as thickening agents. Our work focused on analyzing whether blends of these gums can produce higher viscosity solutions as compared to solutions of the individual gums. In tour study we varied the total concentration of the gum solutions, as we hypothesize that different concentrations can have different synergies. As the prices of tara and xanthan are comparable, a synergistic interaction between the two can results in cutting costs for the food industry by using a lower concentration of blends of the gums to achieve the same viscosity that only one of the gums would normally produce. Solutions of Tara and Xanthan were prepared at four different concentrations: 0.25 g/L, 0.5 g/L, 1.0 g/L and 2.0 g/L. The ratios of tara to xanthan were 0.5, 1 and 1.5. The visco-elastic properties of the solutions were analyzed. Xanthan gum solutions were considerably more viscous than tara gum solutions of the same concentration. At a concentration of 0.5g/L, all blends produced higher viscosity than xanthan alone. In all other concentrations the blends produced lower viscosity than xanthan alone, but they still showed a synergistic interactions as their viscosities were higher than what would be expected from a non-synergistic mixture of tara and xanthan. A trend that was observed in all concentrations is that the blends with all different ratios produced similar viscosities. This suggests that only very little amount of either tara and xanthan in a solution of the other can produce the maximal synergistic interactions and varying the ratio may not have a significant further effect. For cost reduction purposes, given that the price of tara and xanthan are roughly the same, our work identified opportunities of using smaller concentrations of blends to produce the same viscosity as xanthan alone at the concentration of 0.5 g/L.
Publications
- No publications reported this period
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Progress 10/01/06 to 09/30/07
Outputs
OUTPUTS: A study on the creation of soy-based cheese product was conducted. The results of this study were communicated in form of a final report to the sponsor of the study. Partial or total dissemination of the results of the study to a broader audience may be done in the future, when more substantial results will be generated.
PARTICIPANTS: Carmen I. Moraru - principal investigator; Sean Schell - technician
TARGET AUDIENCES: The immediate target audience for this phase of the project was its sponsor, Turtle Mountain LLC. However, the findings of the project are meant to benefit the general population, particularly those consumers who, due to special nutritional, cultural or personal reasons, cannot or do not wish to consume cheese or other dairy foods, but at the same time would like to have access to a non-dairy alternative for cheese. Successful soy based cheese alternatives could also benefit the general population through a valuable content of micronutrients and phytochemicals. The Food Industry as a whole could benefit from this project, since the findings of this study might offer technical solutions for the development of cheese alternatives of desirable sensory and textural characteristics.
Impacts
The main goal of this phase of the project was to create structures and textures that would mimic the texture of cheese, by facilitating favorable intermolecular interactions between soy proteins and other selected non-dairy ingredients. As a first step, tofu was obtained. The creation of a strong, elastic network required the denaturation and disulfide bond formation by the 11S soy globulin in a tofu base, by heating up the tofu samples for 20 minutes at: 300F, 325F and 350F. After these heat treatments, the texture of the tofu became much stronger, more cohesive and elastic, and the values of the textural parameters increased as the treatment temperature increased. The new textures resembled a Mozzarella type texture, the closest to the Mozzarella characteristics being the tofu heated at 300F. In order to diminish the rubbery characteristic of the heat treated samples, several hydrocolloids that are usually used as fat mimetics were added. The use of a Xanthan / guar
gum mixture resulted in relatively soft texture and gritty mouthfeel. A modified starch resulted in a gritty mouthfeel and a pronounced rubbery character. Grittiness was also noticed for the samples containing carrageenan, although this additive was found to enhance slightly both the mouthfeel and the textural properties of the samples. Gluten was also used, but on one hand it did not change much the textural characteristics of the samples, while it induced an undesirable taste. When soy beans were replaced with a soy protein isolate (SPI), the tofu samples treated at 325F and 350F were elastic and had a level of firmness that were close to those of fat free or low fat Mozzarella cheese. The samples obtained with the Xanthan gum -guar gum mixture were rather grainy and did not have a particularly good texture after the heat treatments. The sample that was not heat treated was very creamy and it could potentially used as a soy spread. The samples obtained with the modified starch were
somewhat gritty, and only the sample heated at 325F was considered to have potential for future development. The samples obtained with carrageenan developed a high level of elasticity, and became too rubbery and brittle when treated at 325F and 350F; only the 300F treatment was acceptable. The elasticity and toughness were more comparable to Cheddar cheese than with Mozzarella cheese. Yet, in terms of the mouthfeel and deformation behavior, they were mimicking better a Mozzarella type cheese, with a stringy bite, less brittle texture than Cheddar cheese. The results obtained so far suggest that an elastic and cohesive network that better resembles cheese could be created by the enhancing the level of covalent bond formation in a soy protein base using heat treatment. The samples obtained in the current phase of the project are still far from the textural and sensory characteristics of natural cheeses but, with systematic work, the promising trends that were observed could be further
explored and developed towards the creation of a protein network that could be a very good base for non-dairy cheese alternatives.
Publications
- No publications reported this period
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