31 - Water and energy management in cereals processing

Abstract

Publisher Summary Cereals have risen to be the world's primary food source because they are energy-dense and non-perishable on storage, having their energy stored as starch in a desiccated state. However, their dry state makes harvested cereal grains unpalatable, while ungelatinized starch is unavailable to the human digestive system. Therefore, cereals must be processed to enhance their palatability and to make their nutrients available for digestion. Processing of cereals involves (i) separation of the components of the cereal grain, to enhance the scope for selection and combination of ingredients, facilitate processing and improve the quality, distinctiveness and appeal of end-products; and (ii) thermal processing to gelatinize starch, to develop attractive textures and flavors, and to render products dry and shelf-stable. Like much of the rest of the food industry, cereal processing for food uses can be broadly divided into primary processing and secondary processing. Opportunities for enhanced energy and water efficiency arise, in principle, within both primary and secondary processing of cereals. In practice, these opportunities may be limited. However, increasing energy costs are encouraging greater scrutiny of energy use within cereal processing and efficiency improvements can generate significant economic benefits. This chapter examines the major industrial cereal processes for food uses, with a view to identifying specific and generic opportunities for enhanced energy and water efficiency. The focus is on energy and water usage within the cereal processes themselves. Mixing, thermal processing, and cooling are identified as generic operations that offer potential for energy savings. The chapter discusses the implications for water and energy efficiency of future trends in cereal processing.