Location: Dairy and Functional Foods
2013 Annual Report
Evaluate the impact of high temperature short time(HTST) and ultrahigh temperature (UHT) processing on the physical and/or chemical properties of milk proteins and minerals on the molecular level, and explore the implications of processing technologies on the bioactivity and bioavailability of key dairy ingredients.
Evaluate milk-based films and coatings as a means to reduce and/or improve packaging associated with food processing.
Studies to evaluate the effect of processing on digestion of milk have begun by comparing raw, homogenized, and heat treated (pasteurized or sterilized) whole and skim milk. Initial experiments are comparing fatty acids, clot sizes, and other parameters in the milk during and following each treatment to measure simulated gastrointestinal digestion of the protein and lipids in the milk. Preliminary results suggest that fatty acids break off of triglycerides at different rates during gastric and intestinal digestion, with most of the breakdown occurring by the first hour of intestinal digestion. Homogenization of the milk appears to increase this effect. The solid particles suspended in milk are reduced in size by a factor of ten during gastric digestion, and clot to form a stable dispersion during intestinal digestion. The clot size was larger when skim milk was used. This information may be helpful for designing processing schemes that relate sustainable processing technologies to food security, as well as provide a new view of the impact of processing on the health and nutrition of dairy and other food products. Parts of this project are performed in collaboration with project -091 (Objective 2).
Although they are inexpensive sources for the production of edible dairy-based packaging films, acid whey (AW) and dried milk (DM) present strong challenges when it comes to forming polymers that have enough structural integrity for film-casting and handling, due to their very high content of lactose. To produce films from AW and DM, the procedures for formulation of the solutions, for film-casting and drying, and for various testing procedures are being optimized as a function of several operating parameters. The order of film-making ingredients (water, protein/lactose mix (AW, DM or casein), plasticizers, crosslinkers, pH adjustment) has tremendous effects on polymerization rate and the proteins, and thus the microscopic and macroscopic structure of the films. The prevention of lactose crystallization by incorporation of various polysaccharide crosslinkers is showing great potential. Calcium caseinate is being used as a template to understand the formulation/structure/properties relationships of the complex AW and DM films (Objective 3).
Farrell Jr, H.M., Brown, E.M., Malin, E.L. 2013. Higher order structures of the caseins: a paradox? In: McSweeney, P.L.H., Fox, P.F., editors. Advanced Dairy Chemistry, Volume 1A: Proteins: Basic Aspects, 4th edition. New York, NY: Springer Publisher. p 161-184.
Leggett, L.N., Tomasula, P.M., Van Hekken, D.L., Porto Fett, A.C., Shoyer, B.A., Luchansky, J.B., Renye Jr, J.A., Farkye, N. 2012. Effect of storage at 4 and 10 C on growth of Listeria monocytogenes in Queso Fresco. Journal of Food Safety. 32:236-245.