Biochemistry Of Preharvest Sprouting In Cereals

This chapter focuses on the causative agents and the biochemical changes present in the germinated cereal grains which are believed responsible for the deleterious effects on end-product quality. It looks specifically at typical end-product processes, particularly for wheat-based foods, and provides some indication of the damage that can result from different degrees of sprouting. Any evaluation of preharvest sprout damage should be certain, therefore, that increased levels of enzyme are actually due to field sprouting and not to immaturity. Certain germinative enzymes, because of their specificities, are known to have extremely deleterious effects on quality. It is important, therefore, to know as much as possible about their chemical and physical properties. The carbohydrases of germinating cereals include α- and ß-amylases, debranching enzymes, cellulases, and glucanases, as well as many glucosidases. The chapter discusses the specific enzymes which are believed responsible for storage protein hydrolysis. Criteria of importance are the specificity of the enzyme, proximity to substrate, and high enzymic activity.