Effects of parboiling and other hydrothermal treatments on the physical, functional, and nutritional properties of rice and other cereals

Background and objectives: Parboiling is a hydrothermal treatment, rarely used in cereals other than rice, which consists in three sequential steps: grain conditioning or soaking, cooking, and drying. The aim of this process was to partially gelatinize the starch to seal fissures/cracks and therefore improve milling yield. This review aims to discuss the reported effects of parboiling and similar hydrothermal treatments on the physicochemical, nutritional, processing, and storage properties of rice but mostly of other cereals. Findings: Independently of the type of cereal, parboiling leads to changes in physicochemical, nutritional, and technological properties. However, the standardization and commercial scaling of these processes have been limited. Conclusions: The parboiling effect varies according to the grain intrinsic properties and the processing conditions. Some cereals behave similar to rice, but others are affected oppositely. Further research is needed to better understand the effects of parboiling and hydrothermal treatments in cereal grains, and for the development of a standardized methodology for hydrothermally treating grains. Significance and novelty: The understanding of the effects and the proper implementation of these hydrothermal treatments in corn could lead to significant enhancements in grains properties that could play a key role to solve hunger, malnutrition, and related food security problems.