The Potential of Common Cereals to form Retrograded Resistant Starch

Resistant starch (RS) has been recognised as a functional fibre with many health-promoting effects. RS exists in four forms - RS1, RS2, RS3, and RS4. The RS3 type is generated by amylose retrogradation typically resulting from food processing procedures. The aim of this study was to demonstrate the potential ability of six agriculturally important cereals to generate type RS3 resistant starch after retrogradation of their amylose. In comparison with all tested cereals, the statistically significant highest level of RS3 (5.28% ± 0.68) was detected in triticale, mainly in the Pinokio, Presto, Tricolor, and Kendo cultivars. Significant highly content was also found in rye (4.93% ± 0.73), especially in Selgo, Esprit, Dankowskie Nowe, and Apart cultivars, in comparison with wheat, spring and winter barley, tritordeum and oat. There were unsignificant differences between triticale and rye in RS3 levels. Wheat contained less RS3 (3.87% ± 0.55) in comparison to triticale and rye. The best wheats with this trait were the Athlet, Boka, Trane, Versailles, and Torysa cultivars. The content of RS3 in barley was not high (2.35% ± 0.45 in winter barley, 2.51% ± 0.25 in spring barley), similar to tritordeum (2.26% ± 0.36). The RS3 content in high amylose barley mutant Glacier was two-fold higher than in other tested barley cultivars (P < 0.01). Only minimal level of RS3 can be generated from oat seed starch (0.41% ± 0.09). These results indicate that plant species as well as crop cultivar screening are important for the identification of suitable natural sources of resistant starch. Concerning the production of functional foods, it is important to recognize that valuable bread cereals such as wheat and rye are superior sources of this type of dietary fibre and are highly beneficial to the human health. However, it is advisable to continue for other years in these annual results and localities too.