Rice in vitro digestion: application of INFOGEST harmonized protocol for glycemic index determination and starch morphological study

Abstract

Starch is the main sugar source present in staple foods. Understanding starch hydrolysis during digestion and the resulting glucose release can be important to strategically modulate starch digestion and glucose absorption. In vitro digestion methodologies are fundamental to evaluate starch hydrolysis length and rate, but the lack of uniformity between protocols prevent the comparison of results. In this context, three different Carolino rice varieties (i.e., Carolino white-Cw, Carolino brown-Cb and Carolino Ariete brown-CAb) were submitted to the INFOGEST harmonized in vitro digestion protocol for the evaluation of starch hydrolysis and subsequent glycemic index (GI) determination, and starch granules morphological study. Samples of Carolino rice presented total starch percentages between 64.52 (for Cb) to 71.52% (for Cw) with low amylose content (16.19-19.95%, varying in the following order Cb \ Cab & Cw). During digestion, between 39.43 (for CAb) to 44.48% (for Cb) of starch was hydrolyzed, classifying samples as medium GI foods (61.73-69.17). Starch hydrolysis was accompanied by a decrease of starch granules dimensions. For all samples, area decrease was higher than 59%, perimeter decrease was higher than 37%, feret diameter decrease was higher than 39% and minimum feret diameter decrease was higher than 32%. This work provides new insights to describe, both qualitatively and quantitatively, the fate of rice during digestion, and allowed establishing a comparative basis for the development of rice-based recipes with a lower GI.

Nutritional quality andin vitrodigestion of immature rice-based processed products

“…The oral phase was not simulated during in vitro digestion as the action of α-amylase during the limited digestion time (only 2 min) of the oral phase before amylase is inactivated by the acidic medium of the gastric phase is reported to be very limited. 58,59 In both varieties more than 60% of starch was hydrolysed after the first 5 min of intestinal digestion, which would be expected because digestion of starch is known to be fast and complete in rice. 57,60 According to Fig.…”

Standardized methods for testing the quality attributes of plant‐based foods: Milk and cream alternatives

“…Starch digestion : Starch digestion typically begins in the mouth, but is then completed in the small intestine, due to the presence of oral and pancreatic amylases (Tian et al., 2019). The rate and extent of starch hydrolysis can be assessed by measuring the formation of oligosaccharides, maltose, glucose, or reducing sugars in the supernatant collected from the sample, for example, using chromatographic methods (Ahmadi‐Abhari et al., 2013), chemical methods (Bustos et al., 2017), enzymatic methods (Chen et al., 2020; Fernandes et al., 2020), or glucose meters (Khatun et al., 2018; Sopade & Gidley, 2009).…”

Production of High Amylose and Resistant Starch Rice Through Targeted Mutagenesis of Starch Branching Enzyme Iib by Crispr/cas9

“…Glucose concentration quanti ed during the digestion process was normalized to percentage of total starch hydrolyzed, so that the GI index of the samples can be determined using the area under the curve (AUC) (Fernandes et al, 2020).…”