Use of an aspirator to separate meat and bone meal into high-ash and high-protein streams

Meat and bone meal (MBM) is a byproduct of the rendering industry. Novel feed and non-feed applications for the protein and minerals in MBM are being developed. MBM would have improved characteristics for these applications if the bone and soft tissue-derived panicles could be efficiently separated. An aspirator is a device that separates mixtures of particles based on the terminal velocity of each particle. The objective of this study was to evaluate whether an aspirator can be used to separate MBM into high-ash and high-protein fractions. It was found that the cohesive MBM particles tended to clog the hopper and aspirator column and foul the other interior surfaces of the aspirator, making continuous operation of the aspirator problematic, unless a modification was made. The results show that with this modification, and appropriate settings for feed rate and operating pressure, the aspirator produces two fractions, one that is considerably higher in ash, and one that is moderately higher in protein. Specifically, with an MBM feed rate of 8.0 g/s and an operating pressure of -116 Pa, the high-ash fraction was 52.0% ash (dry basis), compared to 34.5% ash in the unprocessed material. With a feed rate of 13.7 g/s and a pressure of -28 Pa, the high-protein fraction was 60.9% crude protein (dry basis), compared to 55.8% crude protein in the unprocessed material. The aspirator tested achieved a degree of separation that will facilitate the use of MBM in alternative applications.