Location: Dairy and Functional Foods
2012 Annual Report
2: Develop technologies to modify the level and stability of selected biological active compounds (BACs) in milk and cheese. 2.a: Determine effects of common milk processing procedures and storage conditions on the concentration and stability of the selected BACs in milk. 2.b: Determine the effects of cheese manufacturing techniques and aging on the concentration and stability of selected BACs in cheese and correlate to changes in quality traits. 2.c: Develop low-salt high-moisture model cheese to determine effects of low-salt environment on the concentration and stability of BACs during aging and correlate to changes in quality traits.
One phase of the project will characterize the naturally occurring BACs in milk and identify sources of milk with high levels of BACs; in particular, milk from multiple organic and conventional farms in mid and eastern Pennsylvania will be evaluated for BACs to determine quality and seasonal variations. Another phase will develop technologies to modify the levels and stability of selected BACs in milk and cheese. Milk will be obtained from organic and conventional farms and processed at the DFFRU milk processing pilot plant with portions being used to manufacture high-moisture cheese (Queso Blanco). The effects of common dairy industry milk processing procedures and storage conditions on the concentration and stability of selected BACs will be evaluated. In another phase of the project, low-sodium high-moisture cheese model will be created to evaluate the effect of the low-sodium environment on the stability of the BACs and the quality traits of the cheese.
Multiple organic, grass-fed, and conventional dairies are currently being recruited for a study in which the dairies would supply milk samples at regular intervals over the next two years. Samples will undergo extensive state-of-the-art analyses to create a database from which seasonal and farm system operation effects can be compared, thus improving our understanding of the quantity and source of variation of biologically active compounds (BAC) found in milk (Objective 1b) and giving insight into ways to enhance or stabilize the BAC when processing the milk into dairy products.
Compounds exhibiting antihypertensive (lowers blood pressure) and antioxidative activities (protects against harmful molecules known as free radicals in the body) are currently being evaluated in milk and cottage cheese obtained from both conventional and organic farming systems. Assays to quantify antioxidative activities of protein mixtures have been successfully adapted for use with milk and dairy products. Assays measuring antihypertensive activities are currently being studied to find the best method to use with dairy products. Initial experiments showed that, for both milk and cottage cheese, protein mixtures display antioxidative activities at similar levels, regardless of farming system used. Work is continuing to identify the exact compounds that are responsible for the biological activities in these dairy products. The results of this study will provide a quantitative measure of these biological activities in milk from different farming systems and will give insight into ways to increase the concentrations of these compounds in dairy foods to benefit the dietary and health needs of American consumers.
Although high pressure processing of high moisture cheese, such as Queso Fresco, may have the potential to improve the safety of the cheese, the effect of the process on the quality traits of the cheese must be evaluated to determine if they are altered. ARS scientists completed evaluating the effect of high pressure processing on the protein breakdown in cheese over time and how it relates to texture-function as well as health-related properties. Information from this study will help develop cheese manufacturing protocols for safe cheese that meets the expectations of the consumer as well as help establish the health value of dairy products.
Guo, L., Van Hekken, D.L., Tomasula, P.M., Tunick, M.H., Huo, G. 2012. Effect of salt on microbiology and proteolysis of Queso Fresco cheese during storage. Milchwissenschaft. 67(1):74-77.
Olson, D.W., Van Hekken, D.L., Tunick, M.H., Tomasula, P.M., Molina-Corral, F., Gardea, A. 2011. Mexican Queso Chihuahua: functional properties of aging cheese. Journal of Dairy Science. 94(9):4292-4299.
Paul, M., Nunez, A., Van Hekken, D.L. 2012. The effect of milling on proteins in model Queso Fresco cheeses. Advances in Bioscience and Biotechnology. 3:1-6.
Tunick, M.H. 2011. Choosing techniques for analysis of food components and additives. In: Otles, S., editor. Methods of Analysis of Food Components and Additives. Second Edition. Boca Raton, FL: CRC Press-Taylor & Francis Group. p. 1-14.
Tunick, M.H., Van Hekken, D.L., Iandola, S.K., Tomasula, P.M. 2012. Characterization of Queso Fresco during storage at 4 and 10 deg C. Journal of Food Research. 1:308-391.
Van Hekken, D.L. 2012. Quality aspects of raw milk cheeses. Food Technology. 66:67-78.
Tunick, M.H. 2011. Cheese flavors: chemical origin and detection. In: Foster, R.D., editor. Cheese: Types, Nutrition and Consumption. Hauppage, NY: Nova Publishers. p. 207-220.