Submitted to: Bioresource Technology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/27/2006
Publication Date: 11/1/2006
Citation: Garcia, R.A., Flores, R.A., Mazenko, C.E. 2007. Factors contributing to the poor bulk behavior of meat & bone meal and methods for improving these behaviors. Bioresource Technology. 98(15):2852-2858. Interpretive Summary: Meat & bone meal (MBM), a byproduct of the rendering industry, is primarily used as an ingredient in farm animal feed. Since the outbreak of mad cow disease in Europe and elsewhere, legislation has progressively restricted the feed use of MBM. A looming glut of MBM has spurred research to find new applications for it. Manufacturers who attempt to use MBM in the formulation of new products encounter some difficulties. MBM is a somewhat sticky, powdered material. It tends to clog up processing machinery if special care is not taken. This research revealed the most important factors contributing to the MBM's stickiness, and then explored potential treatments to alleviate the stickiness. Most of the stickiness is due to fat dispersed in the MBM. Removing the fat or making the fat less sticky by freezing or by use of a special additive were all effective in decreasing the stickiness and making it easier to process. This research has removed an important obstacle to MBM new application development.
Technical Abstract: Meat & bone meal (MBM), a product of the rendering industry, is a potential feedstock for numerous bio-based applications. Design of processing equipment for MBM is difficult due to MBM's cohesiveness; it flows less easily than many other granular materials, and it tends to foul the surfaces of processing equipment. This study examines the major factors contributing to MBM's poor bulk behavior, including moisture content, fat content, particle size distribution and temperature, and the relative importance of these factors. Potential methods for improving MBM's bulk properties, including use of an anti-caking agent, dehydration, fat extraction, milling and refrigeration are also studied. The effects of these factors were determined by standard laboratory measurements, including angle of repose and Hausner index, as well as by the rate of surface-fouling and dust generation using a pilot-scale aspirator. In contrast to past studies with other granular materials, moisture content was shown to have an insignificant effect on MBM's bulk behavior. The results, however, show that MBM fat is a major contributor to the cohesiveness between MBM particles and consequently to the bulk behavior of the MBM. Reduction of fat content resulted in a major change in MBM's bulk behavior, by all measures used. Less dramatic changes were achieved through refrigeration to solidify the fat and/or treatment with an anti-caking agent.