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United States Department of Agriculture

Agricultural Research Service

Related Topics

Research Project: PROTEIN PROCESSING USING HIGH-PRESSURE GASES AND SUPERCRITICAL FLUIDS

Location: Dairy and Functional Foods

2010 Annual Report


1a.Objectives (from AD-416)
The objectives of this research are to:.
1)develop new, cost effective technologies for processing protein fractions from NFDM into food and non-food products by utilizing concepts from physical chemistry, (2) develop new environmentally benign processes for dairy protein modification that utilize supercritical fluids as reaction media and solute carriers; and.
3)develop new processes for producing enriched fractions of the whey and casein proteins to utilize surplus NFDM and whey.


3.Progress Report
Commercial whey protein isolate (WPI), a concentrated form of cheese whey, provides superb functional and nutritional properties when added to foods because it contains the whey proteins, beta-lactoglobulin (beta-LG) (60%) and alpha-lactalbumin (alpha-LA) (30%). Work is continuing to design a large-scale reactor that uses supercritical CO2 to fractionate WPI to produce kilogram quantities of enriched fractions of beta-LG and alpha-LA, but additional experiments were required this FY to adjust conditions to optimize yields. The protein products formed at the highest pressure and with a carefully selected combination of temperature, concentration, pH and timing, showed that the purity of the alpha-LA was tripled over previously reported results and possessed a good solubility in water, making it useful to enhance the nutritional profiles of baby formula and geriatric foods. Purified beta-LG and glycomacropeptide (GMP) were also produced after the addition of an ultrafiltration step to the CO2 process. Beta-LG is a highly-functional protein that forms strong gels that are useful in various food applications, while GMP is a bioactive peptide that can suppress appetite, acts as a prebiotic and has immunomodulatory actions.

In previous work, genipin was used as a crosslinking agent that improved the water resistance and lowered the solubility in water of edible films made from calcium caseinate. 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, were as strong as those containing genipin and exhibit solubility that is reduced to about 15% in water. Studies to improve the properties of the films and determine their optimal applicability under a variety of environmental conditions will be continued in the new project plan.

Studies were continued to build the computer process simulation model of the fluid milk process in anticipation of continuing this work in the new project plan. A literature search is also underway to obtain data for the model that links the composition of raw milk to the composition of milk after processing by homogenization, HTST or UHT pasteurization, or alternative pasteurization methods, and other unit operations. Compositional data will include mineral, vitamin, fat and protein content data, as well as information on the individual proteins, fats, and peptides, if available. The information will be used to determine if the simulator will be a useful tool in predicting the nutrition of milk, as well as the energy usage and greenhouse gas emissions/gallon of milk processed, as a measure of the sustainability of milk processing.


4.Accomplishments
1. Developed method for detection of glycomacropeptide (GMP) in whey protein. Whey protein concentrates (WPC) and isolates (WPI) from cheese whey are known as excellent sources of proteins that may enhance athletic performance and have excellent digestibility. They also contain the little-known protein, GMP, or glycomacropeptide, which can be present in whey protein in quantities of up to approximately 20%. GMP is a very interesting macro peptide with many proven nutraceutical properties that include dental cavity prevention, appetite suppression, and immune system support. Because a detailed method to measure the GMP content of WPC or WPI has not yet been made widely available, ARS researchers in Wyndmoor, PA, have designed and effectively implemented a procedure to characterize and measure the GMP in WPC or WPI using a step-by-step combination of laboratory spectroscopic and chromatographic techniques. This method requires less time for sample preparation and is more sensitive at low concentrations of GMP than the methods that have been previously reported. The technique will allow food researchers and processors to more accurately characterize the composition of whey protein products for more effective utilization in health-promoting beverages and foods.


5.Significant Activities that Support Special Target Populations
The DFFRU has established collaboration with members of the Northeast Pasture Consortium representing rural farm producers in the Northeast and includes research activities in projects to benefit small producers. Also, collaboration with Delaware State University, an HCBU, has trained train minority students for careers in Food Science and Food Safety. 4 students earned Masters’ degrees in 2009. Two of the students are now holding jobs in the food science field.


Review Publications
Bonnaillie, L., Tomasula, P.M. 2008. Whey protein fractionation. In: Onwulata, C.I., Huth, P.J., editors. Whey Processing, Functionality and Health Benefits. Ames, IA: Blackwell Publishing and IFT Press. p. 15-37.

Tomasula, P.M. 2010. Using dairy ingredients to produce edible films and biodegradable packaging materials. In: Corredig, M., Editor. Dairy-derived Ingredients: Food and Nutraceutical Users. Woodhead Publishing in Food Science, Technology and Nutrition. CRC Press; Woodhead Publishing. p. 589-624

Last Modified: 8/1/2014
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