316 Impact of processing aids on the quality & cost of extruded rice crisps, on a single screw extruder.

COLIN MAIR and KEN MATSON. Extru-Tech, Inc., Sabetha, KS 66534.

A trial compared the effects of processing aids on the output, quality and profitability of extruded rice crisps. Rice crisps are not typically produced on single screw equipment; however, with the proper formulation and processing aid, high quality product can be made very cost efficiently. Testing was done on a long barrel, single screw extruder, comparing a control to two emulsifiers (a monoglyceride and Nu-RICE Emulsifier). Results: The control was difficult to extrude due to various negative conditions, surging, plugging of die openings and non-uniform, low volume output. The monoglyceride gave an improved shape, it decreased the surging and improved the die plugging somewhat. The rate of monoglyceride added was limited by its negative impact on bulk density. The rice emulsifier showed a significant improvement in shape, decreased surging, the elimination of die plugging and greatly increased the output, while reducing bulk density. Conclusion: It was necessary to add a processing aid to manufacture crisped rice on this extruder, without which product quality was unacceptable and production efficiencies low. Both emulsifiers improved quality but the rice emulsifier had a significant impact on production efficiency, giving a 30% reduction in cost of production. The trial demonstrated that, with good equipment and the right processing aid, a cereal producer can make high quality extruded rice crisps on a single screw extruder at very competitive processing costs.