Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/14/2004
Publication Date: 5/15/2004
Citation: Garcia, R.A., Onwulata, C.I., Ashby, R.D. 2004. Water-plasticization of extruded material made from meat and bone meal and sodium caseinate. Journal of Agricultural and Food Chemistry. 52(12):3776-3779. Interpretive Summary: Meat and bone meal (MBM) is a high protein agricultural commodity made from the inedible parts of farm animals. MBM currently has few applications other than as animal feed. Due to legislative changes in the U.S. and other countries, the use of MBM in animal feed is being progressively restricted. A looming glut of MBM has inspired the search for alternative uses. Our research group developed a process to turn a mixture of MBM and milk protein into a hard plastic material. We showed that the stiffness of the material can be adjusted by adjusting its moisture, a property that increases the range of potential applications for this material. We also made some comparisons to similar, commercially available materials, and found that our plastic material compares favorably, for certain applications. This research creates a new potential use for MBM. The bio-based plastic produced may be useful as a substitute for some traditional petrochemical-based plastics.
Technical Abstract: Meat and bone meal (MBM) is a high protein agricultural commodity that currently has few applications other than as animal feed. Unmodified MBM has poor functional properties, due to its low solubility. Our results from pilot plant trials demonstrate that MBM can be extrusion processed along with sodium caseinate to produce a useful plastic material. We developed this material for use as a dog chew toy. For this application, elastic modulus (stiffness) is a key characteristic. Our results detail the relationship between ambient relative humidity and equilibrium moisture content (MC) in the material. The influence of MC on glass transition temperature and elastic modulus reflects the plasticization of this material by water. Based on comparison to a commercially available dog chew, the range of stiffness achievable with our material, 0.25-2.50 GPa, encompasses values appropriate for a dog chew. Our results show that a particular desired stiffness can be maintained by applying an edible moisture barrier to the surface of the material.