NOVEL MECHANICAL TREATMENTS OF BIOMATERIALS

During the last few years novel mechanical techniques have been shown to have great potential in food processing. Sterilization of food mate rials by high pressure treatment at relatively low temperatures has be en intensively investigated with promising results. Microbial spore st erilization by adiabatic expansion of water pressurized to over 600 MP a has been demonstrated. The sterilization of Bacillus stearothermophi lus spores has been achieved by six consecutive adiabatic expansion cy cles at temperatures below 70 degrees C. Twin-screw extrusion has been successfully applied to destroy allergens in proteinaceous food and f eed materials such as soy flour, but could not be demonstrated with so ybean. hulls of high carbohydrate content. It has been shown that alle rgens of buckwheat and soy pours can be partially destroyed by high sh ear using twin-screw extrusion cooking. Microparticulation technology using a jet mill has been employed to increase the surface hydrophobic ity of proteinaceous particles milled to less than 3 mu m in diameter in order to prepare fat replacers Biodegradable loose fill packing, ma terial has been prepared from corn starch by extrusion cooking. An ext rudate prepared with high amylose (70 g/100g) starch containing about 9 g/100g of polyvinyl alcohol and 9 g/100g moisture was shown to be a high quality biodegradable, shock absorbing packing material. The biod egradable packing fill obtained also had a good bulk density, elastici ty and compressibility. Clearly novel mechanical methodologies such as high pressure, high shear, and microparticulation techniques offer gr eat potential in food and feed processing, and in the production of en vironmentally friendly, biodegradable packing materials.