Towards enzymatic conversion of non-conventional starchy materials for glucose syrup production: A review

Glucose syrup is a viscous liquid that plays an important role in food and non-food applications due to its broad functionality. Commercially, glucose syrup is mainly obtained by acid hydrolysis of starches from cereals (e.g., corn, wheat, and rice) as well as from roots or tubers including cassava and potato. However, it has become imperative to explore novel starch sources and more environmentally sustainable methods for producing glucose syrup, such as enzymatic hydrolysis. This review explores research on the use of enzymatic hydrolysis of non-conventional starchy materials for glucose syrup production. It provides an overview of the current scenario of demand for alternative starch sources and enzymatic processes, including the industrial route for glucose syrup processing by biocatalysis. Moreover, new opportunities for the food and non-food sectors were detailed. The findings suggest that underexploited sources have potential as an alternative to commercial crops, paving the way towards increased use of these raw materials in glucose syrup production. Furthermore, the enzymatic process should be carefully evaluated due to the complexity that different sources can exhibit. However, there is a significant research gap in this area, and challenges need to be overcome.