Long glucan chains reduce in vitro starch digestibility of freshly cooked and retrograded milled rice

Structural factors governing starch digestion and glycemic responses and how they can be modified by enzymatic approaches: A review and a guide

“…Tao et al (2019) showed that rice starch with longer AM chains has lower viscosifying potential upon heating probably because the longer AM chains more easily aggregate and form a network around the starch granules that prevents starch granule expansion and swelling. In terms of digestibility, long (DP > 1000) and intermediate (DP 121-1000) sized AM chains are negatively correlated with the rate of starch digestion in freshly cooked rice grains with low to normal AM content (3%-34%) (Alhambra et al, 2019). Furthermore, the extent of digestion of gelatinized wheat starch is negatively related to the portion of medium-sized AM chains, which thus may self-associate rapidly (Obadi et al, 2020).…”

“…Leached AM either arranges itself into single or double helical configurations or forms complexes with hydrophobic compounds (e.g., AM-lipid complexes) . Starch AM content is negatively related with its digestibility Zhong et al, 2020) even for regular starches with AM contents (0%-35%) that are not considered high-AM starches (Alhambra et al, 2019;Frei et al, 2003;Syahariza et al, 2013). High-AM starches are a good source of RS that elicits low postprandial glycemic responses and exerts health benefits that are often linked to its fermentation by the colonic microbiota (Belobrajdic et al, 2019;Harris, 2019;.…”

“…Recently, the importance of the fine molecular structure of AM for starch digestion has been considered in detail. Alhambra et al (2019) reported that the rate of digestion of retrograded rice starch in cooked grains was negatively correlated with the content of AM chains with DP 121-1000 and DP > 1000. With a more sophisticated AM structural characterization, Gong et al (2019) showed that besides AM content, the relative content of short and medium AM chains was negatively related with the rate of digestion of retrograded rice starch.…”

“…Relevant in this context is that mashed potatoes, which by their own nature contain disintegrated cellular matrices and have long AP chains, have a very high GI (Foster-Powell et al, 2002). However, for freshly cooked rice grains, the rate of starch digestion decreases with (i) the contents of long AP chains (defined as chains with DPs 25-36 and DP ≥ 37) (Alhambra et al, 2019), and (ii) the ratio of long to short AP chains (Syahariza et al, 2013). An element to consider here is that an interplay between starch structure (long AP chains) and the surrounding cellular matrix in cooked intact plant tissues may synergistically impact starch digestibility.…”

Balancing the double‐edged sword effect of increased resistant starch content and its impact on rice texture: its genetics and molecular physiological mechanisms

“…RS2 represents starch that is in the form of B and C native crystalline structures arranged in a compact radial pattern, found in high amylose cereals, remains as ungelatinized resistant granules (Sajilata et al, 2006). RS3 is retrograde starch formed when cooked rice is cooled (Alhambra et al, 2019). During this process, the starch structure becomes re-associated to form a semi-crystalline double helical structure between amylose and amylopectin which subsequently restricts enzymatic hydrolysis.…”