14A-21 |
Development of a semi-continuous calcium caseinate film process |
P. M. TOMASULA, Dairy Processing & Products Research Unit., USDA-ARS-Eastern Regional Research Center, 600 E. Mermaid Ln., Rm. 3032, Wyndmoor, PA 19038-8598, M. F. Kozempel, Food Safety Intervention Technologies Research Unit, USDA-ARS-Eastern Regional Research Center, 600 E. Mermaid Ln., Rm. 3024-B, Wyndmoor, PA 19038-8598, and A. J. McAloon, Crop Conversion Science & Engineering Unit, USDA-ARS-Eastern Regional Research Center, 600 E. Mermaid Ln., Rm. 3026, Wyndmoor, PA 19038-8598. Calcium caseinate (CaCas), a casein derived from milk, has unique properties that make it a suitable biodegradable polymer for use in films. Films made from CaCas and glycerol (GLY) have physical properties like those of petrochemical films. CaCas films are made in the laboratory using a casting process in which an aqueous CaCas-GLY solution is spread out on a flat surface and allowed to air dry overnight. The film is then peeled from the surface. However, films must be made in a continuous process to produce them in quantity and economically. If the film is made by casting onto a moving belt, the films must dry quickly, spread evenly over the belt material, and be easily removed from the belt. Our objective was to determine the drying kinetics of CaCas-GLY solutions at various concentrations and examine the adhesion characteristics of the resulting films on different belt materials. CaCas-GLY solutions of various concentrations were dried under low and high relative humidity and moderate termperature conditions. Moisture content was followed as they dried. Also, various materials were tested to find one suitable for forming a continuous film, a belt with good wetting ability and release characteristics when the film dried. Samples (nominal 70 x 120 mm) of film solutions were dried in a continuous hot air dryer to simulate continuous drying. Results indicate that drying solutions of 10% solids greatly reduces the cost and results in films equivalent to those made from more dilute solutions. Of the belt materials tested, film solutions wetted polyethylene belt material forming a uniform layer that stayed on the belt by surface tension. The films formed in approximately 6 hr at 35C and were easily removed. Based on these results, a continuous process is under development that will permit production of biodegradable films made from dairy proteins.
Session 14A, Dairy Foods: General developments in dairy technology I
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