PERFORMING INSTITUTION:
FOOD SCIENCE & HUMAN NUTRITION
CLEMSON UNIVERSITY
CLEMSON, SOUTH CAROLINA 29634

PRODUCTION OF ANTIMICROBIAL AND ANTIOXIDANT FILMS FROM ACID WHEY

OBJECTIVES: Objective 1 - Develop an antimicrobial food coating material using acid whey. Acid whey will be thermally-processed then natural food-grade biocides (nisin and lauric acid) will be mixed with the concentrate. The whey will be coated onto the surface of blue cheese that has been inoculated with Listeria monocytogenes. The survival of Listeria monocytogenes will be evaluated during refrigerated storage. Objective 2 - Develop a flexible film material from acid whey using a heat extrusion process. Acid whey will be processed using a heat film formation process that has been used with soy, corn, and wheat material to produce a flexible film material. The heat-extrusion process is used since this method requires no organic solvents and is the process used to mass-produce commercial plastics. Objective 3 - Develop a natural antioxidant containing flexible film material from acid whey using a heat extrusion process. Acid whey will be processed using a heat film formation process that has been used with soy, corn, and wheat material to produce a flexible film material capable of reducing oxidation in packaged food products. The traditional plasticizing agent (glycerol) will be replaced with rice bran oil concentrate. We have previously shown that rice bran oil concentrate has the potential to be an excellent agent against food oxidation. An Omnion OSI instrument will be used to evaluate the antioxidation potential of the rice bran oil containing film.

APPROACH: Objective 1. The development of an antilisterial coating for soft cheeses using acid whey. The whey will be thermally processed and partially dried (if necessary) to achieve a 12 log reduction of Clostridium botulinum (commercial sterility) and to achieve a viscous paste consistency. A small amount of glycerol (<10%) may be added to allow the coating to maintain a semi-pliable consistency. A 10 4 cfu/ml broth culture of Listeria monocytogenes ATCC 15313 will be applied to the surface of blue cheese. The blue cheese wheels will be stored under commercial refrigerated conditions (4C) and samples will be taken to enumerate L. monocytogenes each week for 7 weeks. Objective 2. Development of a flexible film from dried acid whey will follow previously successful protocols used to form films from soy, corn, and wheat protein/flour raw materials. Acid whey will be dehydrated then combined with glycerol at various levels before heat extrusion. At first, heat extrusion will be in a batch system then as the time, temperature, and plasticizer (glycerol) levels are optimized, a continuous system will be developed. The batch system consists of a heated, Carver press in which the dried mixture is placed into a mold. Objective 3. A natural antioxidant containing flexible film material will be produced using the same procedures outlined in Objective 2 with glycerol being replaced with rice bran oil concentrate.

NON-TECHNICAL SUMMARY: The U.S. is the world's largest, single country, exporter of whey products. Because of their undesirable characteristics, acid whey products have little commercial value and are therefore typically disposed of as a waste product. Approximately 18 billion kg of acid whey are produced in the U.S. annually. Disposal of acid whey is a costly process to the dairy industry. The primary impact of this research will be increased profitability to dairy producers and processors by expanding the value-added market for acid whey.

PROGRESS: 2002/01 TO 2002/12
We have identified three potential sources of natural rice bran oil antioxidants (two oil and one powder). We have developed procedures for the use of the oil as well as the powder source. Using the Oxidative Stability Instrument we have determined that all these RBO antioxidant products are very heat stable in milk fat systems and therefore can be added at any point in the manufacturing process. The optimal point of addition will vary depending on the manufacturer's processing design and system. We have also determined that the antioxidant can be added after the drying process as an oil mist.

IMPACT: 2002/01 TO 2002/12
Increased shelf-life of high fat containing dairy powders. Improve international competitiveness of US in export of whole milk powders.

PUBLICATIONS: 2002/01 TO 2002/12
Osorio, L. F. 2002. Effect of drying technologies and natural rice bran oil anitoxidants on the stability of whole milk powder. PH.D. Dissertation. Clemson University

PROJECT CONTACT:

Name: McGregor, J. U.
Phone: 864-656-3397
Fax: 864-656-0331
Email: johnny@clemson.edu
URL: http://www.clemson.edu/foodscience