Digestibility of rice

Topic 1

Digestibility of rice: impact of variety, processing and cooking.

Background

The rate and extent of starch amylolysis is an important determinant of the magnitude and duration of the glycaemic response for starch-rich foods. In cooked rice this depends on several intrinsic (amylose/amylopectin ratio, size and morphology of the starch granule, protein and lipid content, etc.) and extrinsic (processing, degree of cooking, storage conditions) factors. Previous research has demonstrated, for instance, that hydrothermal processing of rice (parboiling), the cooking practice and the storage of cooked rice affect the rate and extent of starch gelatinisation/retrogradation, the formation of di-sulphite bondings in the protein matrix and starch lipid-amylose complexation and hence rice susceptibility to amylase.

Aim

In this study we will investigate the impact of rice variety, hydrothermal processing (parboiling) and domestic cooking of rice on carbohydrate digestibility parameters and will try to investigate the chemical-physical factors responsible for the observed differences.

Approach

After cooking,  rice sample are digested by means of in vitro standardized models and the kinetics of glucose release is measured colorimetrically. We will use a defined set of commercial rice samples of known variety, treated with defined  hydrothermal processes, prepared according the standard cooking instructions (samples will be provided by MARS Food, Belgium).

Some references:

1. Parboiling of rice: changes in starch and protein and their relation to cooking properties  Doctoraal Proefschrift Veerle Derijcke, KULeuven 2007
2. Slowly and rapidly digestible starchy foods can elicit a similar glycemic response because of differential tissue glucose uptake in healthy men 1-3. Coby Eelderink, Marianne Schepers, Tom Preston, Roel J Vonk, Lizette Oudhuis, and Marion G Priebe  Am J Clin Nutr doi: 10.3945/ajcn.112.041947.

For more information please contact Edoardo Capuano.