Determination of glycaemic index of selected rice landraces of Nepal using INFOGEST model.

Background: The current investigation was carried out to crudely assess and characterise the starch hydrolysis parameters and determine the estimated glycaemic index (eGI) of the selected rice landraces of Nepal (ie, Anadi white (Aw), Bhotange white (Bw) and Kalo Nuniya white (Kw)).

Method: INFOGEST harmonised in vitro protocol using pancreatic amylase instead of pancreatin for the intestinal phase was used to estimate the glycaemic index and starch digestibility parameters of the selected rice landraces of Nepal.

Results: The study showed rice landraces with similar starch contents had significantly different (p<0.05) in vitro starch digestibility parameters, that is, hydrolysis index, eGI, rapidly digestible starch, slowly digestible starch, resistant starch and total hydrolysed starch with Bw showing the lowest eGI of 51.77±2.48 followed by Kw with eGI of 55.35±1.05 and Aw showing the highest eGI of 60.60±1.03.

Conclusions: None of the landraces fell under the high GI class (>70). B_w fell under the low GI class (<55). This study offers novel qualitative and quantitative insights into the digestive fate of Nepalese rice landraces, providing a foundation for creating rice-based recipes with a lower GI and sheds light on their nutritional value, providing a foundation for further research into their metabolic benefits. It also advocates for integrating these lesser-known landraces into global efforts to address diet-related diseases, enhancing the nexus of agriculture, nutrition, and public health. Using in vitro enzymatic methods provides an efficient means of assessing the GI of food products, offering valuable insights into their potential impact on postprandial blood glucose levels. However, the heterogeneity in the application of in vitro methods for starch digestion makes comparing the results difficult. The current study is preliminary, and further research using standardised methods such as INFOGEST is warranted to validate these findings and expand our knowledge of the glycaemic properties of rice landraces through more interlaboratory findings and clinical trials involving human subjects.