Methodologies for Increasing the Resistant Starch Content of Food Starches: A Review

Research involving resistant starch (RS) is becoming more prominent. RS has the ability to modulate postprandial blood-glucose levels and can be fermented by the colonic microflora to produce short-chain fatty acids, which exert positive health benefits on the consumer such as increased colonic blood flow to ease colonic inflammation and a decreased risk of colon and/or other cancers. This paper reviews the effects of genetic manipulation on amylose levels in plants, enzymatic hydrolysis, physical treatments, chemical modifications, exposure to γ-rays, and the effects of lipid complexation on the RS content of starches from various botanical sources. All treatments reviewed increased the RS content; however, select treatments (namely genetic manipulation, enzymatic debranching, hydrothermal treatments, high hydrostatic pressure, most chemical modifications, γ-irradiation exposure, as well as lipid complexation) were more effective to varying degrees than were extrusion and mineral acid treatments. Various methods commonly used for measuring RS were compared. Additionally, the effects of food matrix components were also examined to gauge their effectiveness at inhibiting or enhancing RS formation, with lipids and gums known to be the most effective at enhancing (or apparently enhancing) RS. This review draws largely, but not exclusively, from research published post 2009.