Location: Dairy and Functional Foods Research2011 Annual Report
1a. Objectives (from AD-416)
Develop simulation models that quantify the effects of process modifications on energy use, economics and greenhouse gas emission data for fluid milk processing plants. 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.
1b. Approach (from AD-416)
Research will be conducted to develop mathematical models that will be used to quantify the effects of various processing operations and parameters on energy use, economics, waste streams and greenhouse gas (GHG) emissions of fluid milk and other dairy and food processing plants. The models will be used in a simulation program that will also allow the examination of the impact of alternative processing techniques or alternative energy management systems on energy use, economics, waste streams and GHG emissions of processing plants and the nutrition of the products. The impact of high temperature short time (HTST), ultrahigh temperature processing (UHT), and alternative processing on some of the properties of the milk proteins and minerals on the molecular level will be evaluated using techniques that include HPLC, enzymatic digestions, and spectroscopic, microscopic and proteomics techniques. The bioactivity and bioavailability of a key dairy protein – mineral peptide will be evaluated using in vitro digestion simulation followed by analytical study. The mechanical and barrier properties of edible films and coatings as a function of technique of calcium caseinate and CO2-casein film preparation will be explored under a variety of humidity and temperature conditions to determine their application limits and potential to replace petrochemical films. Microscopy will be used to examine changes in protein conformation with environmental changes. Additional properties using ASTM techniques will also be determined.
3. Progress Report
Commercial whey protein isolate (WPI) contains the whey proteins, beta-lactoglobulin (beta-LG) (55%), alpha-lactalbumin (alpha-LA) (20%), and about 5% of minor whey proteins. It also contains about 20% GMP, which is a remnant of the cheesemaking process. GMP does not contain phenylalanine or aromatic amino acids making it a valuable food ingredient for phenylketonuria patients who cannot metabolize phenylalanine. Nutraceutical properties of GMP have been reported that include dental cavity prevention, appetite suppression, and immune system support. A new separation process, extending the environmentally friendly ARS and high pressure and supercritical carbon dioxide technologies, was developed to obtain optimal quantities alpha-LA, beta-LG, and GMP. A patent application is in preparation. This process represents an improvement over other processes which use solvents, salts, or ion-exchange. In the previous project plan, genipin was used as a crosslinking agent that lowered the solubility in water of edible films made from calcium caseinate (CaCas) relative to pure CaCas films. The solubility of the films was reduced to 40% with crosslinking. However, further studies with controls have demonstrated that films made under certain conditions of temperature and pH adjustment, without the addition of genipin, result in films that are as strong as those containing genipin and exhibit solubility that is reduced to about 15% in water. It was determined that the reaction of genipin with CaCas was incomplete. New experimental protocols were developed to examine the reaction kinetics of CaCas with genipin and are now being evaluated. The computer process simulation model is still under development. The Innovation Center for US Dairy, the International Dairy Foods Association, and a collaborator from the University of Arkansas visited a large local dairy plant with members of the DFFRU to obtain actual operating data to incorporate into the simulator. A manual for use of the simulator is also being developed and will be disseminated to select members of the industry for beta – testing, and then will be distributed freely upon publication of the simulator. The simulator will also be discussed in a webinar to be announced and co-sponsored with the dairy industry.
1. Applied high pressure to enhance microbial safety. Queso Fresco (QF) is a popular, soft and slightly-crumbly Hispanic-style cheese that is subject to frequent product recalls because of Listeria monocytogenes (Lm) contamination. Most processing methods that were designed to control pathogens target only the surface contamination, but cheeses are susceptible to contamination both on the surface and within the interior because of handling during manufacture. ARS researchers at Wyndmoor, PA, applied a process that used pressures of up to 87,000 pounds/square inch to control Lm on and within QF that was artificially contaminated with Lm. High pressure processing (HPP) instantly reduced the high numbers of Lm as well as much of the native microflora of the cheese. HPP has the potential to improve the safety and quality of soft cheeses such as QF, to reduce product recalls associated with Lm contamination and to extend the shelf-life of soft cheeses.
Mukhopadhyay, S., Tomasula, P.M., Luchansky, J.B., Porto Fett, A.C., Call, J.E. 2010. Removal of Salmonella Enteritidis from commercial† unpasteurized liquid egg white using pilot scale crossflow tangential microfiltration. Internationl Journal of Microbiology. DOI: 10.1016/j.ijfoodmicro.2010.07.009.