Progress 10/01/00 to 09/30/04
Outputs
This work determined that protein solubilization of red meat is achieved optimally with the following conditions, pH 2.5, 1 part meat to 9 parts 2 mM Citric Acid. Recovery is maximized at pH 5.5. It was also determined that protein gels formed from solubilized proteins have higher water binding capacity and gel strength than those from non-solubilized proteins. In addition, protein gels formed without the aid of salt from solubilized proteins have higher gel strength than non-solubilized proteins and have a gel strength equivalent to, or better than protein gels formed with the aid of salt and non-solubilized proteins. These results have not only functional significance for processed meat formulation, but nutritional ones as well. In terms of processed meat formulations, results suggest that water binding and gel strength can be improved through the application of solubilized proteins. Improved water binding and gel strength enhances not only quality, but shelf-life of
processed meats. The nutritional implications are that solubilized proteins could possibly be used in place of salt and phosphates in processed meat formulations. The role of salt is two-fold, salt solubilization of proteins to improve bind (water and protein) and enhance meat flavor. Many times salt addition is dictated by its effect on protein functionality as opposed to flavor enhancement. The addition of solubilized proteins to processed meat formulations might allow salt addition to be dictated by flavor instead of functionality improvements. For consumers susceptible to hypertension, products with lower salt would be more appealing. In addition, phosphates are also added to enhance bind. However, like salt, phosphate usage also has its drawbacks. From the highest permitted level, 0.5%, to about 0.3% phosphates can produce an astringent metallic flavor. Phosphates can react with fat during the cooking process to produce a soapy flavor. High dietary phosphate intake also reduces
calcium adsorption, which can lead to osteoporosis in post menopausal women and the development of brittle bones in renal patients. Replacing phosphate enhancement with same source solubilized proteins would remove an additive from the processed meat label and again enhance consumer product appeal.
Impacts
The work from this study suggests that protein solubilization is a process that recovers a highly functional and valuable protein from low valued red meat. The recovered protein is very low in fat (<1%) and has the ability to form strong gels with good water holding capacity without the addition of salt. Typically the level of salt added in processed meats is dictated by the amount needed to improve their binding ability. Usually processed meats are made from low-valued red meat with low binding ability. Almost 2% salt is needed to help the proteins bind properly. Fat also plays an important role in the binding ability of these emulsified products. Low salt and low fat formulations are typically plagued with not being able to hold water and bind as well as higher salt and fat formulations. Protein recovered using this process could therefore be utilized to improve the binding ability of low salt and fat processed meats. Salt and fat could just be added for flavor. This
could have a significant impact on improving the nutritional quality of processed red meat products in order to help consumers challenged with obesity and/or high blood pressure.
Publications
- James JM, Bellmer D, Mireles DeWitt CA. 2004. Changes in gel attributes of beef heart when treated by acid solubilization-isoelectric precipitation and the surimi process. J Food Sci 69(6):C473-479.
- Mireles DeWitt CA, Gomez G, James JM. 2002. Protein extraction from beef heart utilizing acid solubilization. J Food Sci 67(9):3335-3341.
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Progress 10/01/02 to 09/30/03
Outputs
The objective of this research was to determine the applicability of protein solubilization on red meat and characterize the functionality of the product recovered from this process. The applicability of the protein solubilization process was initially tested on a red meat by-product, beef heart. Results from that study have been published and demonstrate that acid protein solubilization recovers almost 60% of the total protein from beef heart (Mireles DeWitt et al., 2002). SDS-PAGE analysis demonstrated that the recovered protein was primarily myofibrillar protein and chemical analysis demonstrated it was low in collagen. The albumins (sarcoplasmic proteins) were the major fraction characterized in the wastewater. Since the myofibrillar fraction typically represents about 60-70% of meat protein, our results suggests that a significant amount of the myofibrillar protein fraction was recovered. This has important implications with regard to improving protein
functionality as the myofibrillar proteins are typically responsible for the gel binding ability of red meat. Proteins such as collagen and the sarcoplasmic proteins are typically credited with interfering with gel formation. Further work focused on characterizing the gels formed from protein solubilized beef heart (James and Mireles DeWitt). In addition, a study characterizing gels from pork, heart and ground (not de-boned) picnic shoulder, was also performed (James and Mireles DeWitt, 2003). Results from both studies have demonstrated that gel attributes of red meat proteins are markedly improved when processed by protein solubilization. For example, in the first study characterizing gels from beef heart, water holding capacity was improved almost 2-fold as a result of acid solubilization. Addition of salt only improved water holding capacity of the acid solubilized protein slightly. The improved water holding capacity directly translated to improvements in cook yield. When salt was
not added, the cook yield improved from 68% in untreated beef heart to 99% in acid solubilized beef heart. In addition, results from ground (not deboned) pork picnic shoulder demonstrated that the recovered protein from a red meat product high in ash and connective tissue had improved cook yield and water holding capacity. Overall, data from these studies demonstrated that red meat treated by protein solubilization had significantly improved protein functionality. Protein functionality is important to the quality and economic value of processed muscle food products. Cooked products formulated with an excessive amount of low binding (or low water holding capacity) meat often experience excessive purge through loss of water, gelatin and/or fat. Purge loss is often viewed as a quality defect by the consumer and results in significant economic losses for the commercial processor. The most significant finding from these studies has been that salt is not necessary to produce strong gels
from protein recovered by protein solubilization.
Impacts
The work from this study suggests that protein solubilization is a process that recovers a highly functional and valuable protein from low valued red meat. The recovered protein is very low in fat (<1%) and has the ability to form strong gels with good water holding capacity without the addition of salt. Typically the level of salt added in processed meats is dictated by the amount needed to improve their binding ability. Usually processed meats are made from low-valued red meat with low binding ability. Almost 2% salt is needed to help the proteins bind properly. Fat also plays an important role in the binding ability of these emulsified products. Low salt and low fat formulations are typically plagued with not being able to hold water and bind as well as higher salt and fat formulations. Protein recovered using this process could therefore be utilized to improve the binding ability of low salt and fat processed meats. Salt and fat could just be added for flavor.
This could have a significant impact on improving the nutritional quality of processed red meat products in order to help consumers challenged with obesity and/or high blood pressure.
Publications
- James JM, Mireles DeWitt CA. 2003. Application of Acid Solubilization Isoelectric Precipitation to Low Value Red Meat. Oklahoma State University Animal Science Research Report. Available on web: http://www.ansi.okstate.edu/research/researchreport/index.html
- James JM, Mireles DeWitt CA. Composition, Color, and Gel Attributes of Beef Heart When Treated by Acid Solubilization Isoelectric Precipitation and the Surimi Process. J Food Sci, submitted November 2003.
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Progress 10/01/01 to 09/30/02
Outputs
Results to date demonstrated the applicability of the acid solubilization-isoelectric precipitation process on a red meat by-product, beef heart. These results have also demonstrated that nutritional composition of by-product with respect to fat content, cholesterol content and ash content is significantly improved upon treatment with acid solubilization. On going work has focused on characterizing the gels formed from beef heart, pork heart, and whole ground (not de-boned) pork picnic shoulder treated by this processes. Results have demonstrated that gel attributes are markedly improved as a result of acid solubilization treatment. In addition, salt solubilization does not appear to be critical to gel formation in treated by-product as it is in untreated by-product. Untreated beef heart without salt, had an average water holding capacity of about 1.2 g bound water/g protein. When salt was added to untreated beef heart, average water holding capacity increased to
about 1.4 g bound water/g protein. However, when the same beef heart was treated by acid solubilization the average water holding capacity increased by a factor of almost 1.8 without the addition of salt (2.2 g bound water/g protein) and a factor 2 with the addition of salt (2.4 g bound water/g protein). Cook yield improved from 68% in untreated beef heart to 99% in acid solubilized beef heart without the addition of salt. In every attribute measured by texture profile analysis, the attribute was in some measure increased as a result of treatment with acid solubilization. In addition, results from whole ground (i.e. not deboned) pork picnic shoulder treated by acid solubilization demonstrated that the recovered protein from a pork product initially high in ash/bone and connective tissue had improved cook yield, water holding capacity, and significant increases in many other of the gel attributes measured by texture profile analysis. Data demonstrates that application of an acid
solubilization process not only significantly alters gel attributes, but improves many of these attributes with respect to their potential ingredient functionality.
Impacts
Improvments in nutritional composition and protein functionality of meat by-product will enhance its value to food and pet food processors. Our research is quantifying how acid solubilization can be utilized to improve composition and protein functionality in red meat by-product.
Publications
- Mireles DeWitt, C.A., Gomez, G., and James, J.M. 2002. Protein Extraction from Beef Heart using Acid Solubilization. J Food Sci. 67(9): 3335-3341.
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Progress 10/01/00 to 09/30/01
Outputs
The focus of this project was initially to apply a protein solubilization process to meat and dairy by-products for the recovery of value-added functional protein concentrates. Attempts to apply this process to meat by-products have so far been very promising. Attempts to apply this process to dairy by-products, such as acid whey, have not been successful. As a result, the project has focused more on the recovery of protein concentrates from meat by-products. To date, we have successfully applied protein solubilization to meat by-product using beef heart as a model. Process parameters have been maximized for pH solubilization and subsequent isoelectric precipitation. The effect of salt addition on protein solubilization was evaluated. Results indicated that additon of NaCl at levels as low as 50 mM adversely affected protein solubilization. Maximum protein recovery was achieved without the addition of salt and calculated recovery yields have ranged between 75-85% of
the functional protein fraction. These yields are similar to results reported for seafood filets using a similar process. Compositional studies have also demonstrated that in addition to producing a functional protein concentrate, the resulting product has significantly reduced lipid, cholesterol, collagen, and ash content when compared to the starting material. Current research is focusing on maximizing production of sufficient protein concentrate on a lab-scale in order to quantitate protein functionality through texture profile analysis. Further measures of functionality will be quantitated by water-holding capacity, cook yield, emulsion stability, and emulsion activity index. In addition, we will also evaluate the role of this process as a microbial intervention step. These measurements are needed to gain a basic understanding of the potential value this type of functional protein concentrate may contribute when incorporated into processed foods. In addition, preliminary research
is also looking at how this product affects sensory properties when incorporated into a formulated product. Initial results, to date, have demonstrated that at the level of incorporation we have looked at (about 2%) no significant off-flavors or unacceptable colors are produced. Initial test have also demonstrated that the process does not significantly produce TBARS as a result of its application. However, this does not necessarily relate to long-term storage stability of either the lipid or protein fraction. As a result, future research will look at the frozen storage lipid and protein stability of the protein concentrate. In addition, in order to show practical application of the process we plan to apply the process parameters determined on beef heart to more complex meat by-product streams that typically are rendered. A mass balance of each of the value-added outputs from this process (protein concentrate, ash and collagen, neutral lipids) will also be made.
Impacts
Effective and responsible utilization of natural resources has become increasingly important as a result of increased awareness of the environmental consequences of waste. The question is no longer just are we not dumping resources, but are we maximizing the potential value and gain from our resources. The long-term goal of this project is to enhance the value of meat by-product through the successful application of a protein solubilization process. It is our belief that this process can be utilized to capture value from meat by-product by diverting part of it from the traditional rendering process. If this type of concentrate produced by protein solubilization can be demonstrated to compete with more traditional protein concentrates (whey and soy) in certain product formulations, there would be substantial potential value to the food industry.
Publications
- No publications reported this period
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Progress 10/01/99 to 09/30/00
Outputs
This project began October 1, 2000, and there is no progress to report this period.
Impacts
(N/A)
Publications
- No publications reported this period
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