© WILEY-VCH Verlag GmbH, 69451 Weinheim, 2002 0038-9056/2002/0707-0273 $17.50+.50/0 Starch/Stärke 54 (2002) 273–284 273 Review 1 Introduction Membrane technology is a method to recover processing solids and treat water for recycling in many food process- ing industries. Several reviews have been published that describe how membrane technology has been applied to grain processing, including the starch processing industry [1, 2]. These provide a general overview of previous re- search. A comprehensive review of membrane applica- tions in the starch processing industry should be helpful because membrane technology is changing rapidly and the starch industry is facing new challenges. Membranes are becoming more robust and allowing more applica- tions in severe environments. Membrane materials are improving rapidly; applications found to be marginal or unfavorable toward membrane application a decade ago can now be economically feasible. Furthermore, the starch processing industry has ever increasing needs for higher value and maximum yields from every facility, due to more restrictive environmental regulations and increas- ing landfill and waste treatment costs. Membrane tech- nology will help provide solutions for many of these chal- lenges. Application of membrane technology has several advan- tages for the starch processing industry. Costs of remov- ing water to concentrate starch and coproducts can be re- duced. Up to 90% savings in energy have been reported using membranes compared to evaporation. Membranes have the ability to achieve separations without application of heat to the product, improving coproduct quality [1]. Reduction of exposure to heat is conventionally thought to improve nutritional quality and digestibility of proteins. However, few publications have studied the effects of membrane technology on nutritional quality when heat exposure has been reduced [3]. Membranes can be used to allow recovery and recirculation of water used in processes, reducing water needs. Some process streams from membrane filtration may be more efficiently handled by evaporators due to reduced surface fouling of heated evaporator surfaces [4]. New coproducts could be devel- oped using membrane technology. Waste treatment costs could be reduced by using membranes to recover solids Kent D. Rausch Food and Bioprocess Engineering, Agricultural Engineering Department, University of Illinois at Urbana – Champaign, Urbana, USA Front End to Backpipe: Membrane Technology in the Starch Processing Industry The starch processing industry is characterized by streams that vary in diversity and complexity and that require extensive processing to achieve high end product quality. Water removal and product separations are two fundamental processing steps that im- pact product quality and processing economics. Many uses have been found for mem- brane technology in the starch processing industry; these include pretreatment of fresh water, recovery of solids and wastewater treatment. In many cases, membrane appli- cations have increased quality of products, decreased energy costs and reduced dis- posal issues relating to waste treatment. Membranes can be used to filter many types of fluids in potato, wheat and corn starch isolation processes with varying degrees of success. Robust membrane materials have been developed with unique processing capabilities suited for the needs of the starch processing industry. Membranes have been used commercially to increase product quality while reducing costs, such as in syrup and sweetener clarification. Membrane technology has shown promise for re- ducing evaporation costs, improving product recovery and removing solids prior to wastewater treatment. In many applications, the cost of dewatering using membranes was a fraction of the cost of traditional methods. Membranes can be used to recover proteins from dilute process streams, but more work is needed regarding changes in nutrient quality when membranes are used in place of conventional separation tech- nologies such as centrifugation, vacuum belt filtration and evaporation. There is need for detailed discussion of analyses regarding economics of long term operation and maintenance of membranes as part of a processing system. Keywords: Membrane filtration; Starch processing Correspondence: Kent D. Rausch, Food and Bioprocess En- gineering, Agricultural Engineering Department, University of Illinois at Urbana – Champaign, 1304 W. Pennsylvania Avenue, Urbana, IL 61801 USA. Phone: +1-217 265-0697, Fax: +1-217 244-0323; e-mail: krausch@uiuc.edu. Based on a presentation at the International Starch Technology Conference, Urbana, Illinois, USA; June 4–6, 2001.