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

Abstract

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.

Physicochemical and digestion characteristics of flour and starch from eight Canadian red and green lentils

“…Extraction of starch from the flour matrix largely enhanced the starch digestibility as shown by increased RDS (17.8–32.7%) and SDS (39.4–47.2%), and lowered RS (20.6–41.3%) (Table ). Changes in starch digestibility can be explained by the physical barrier of the flour matrix before extraction (Kim et al ., ), and the interactions between starch molecules and other components in flour, such as protein (Annor et al ., ), lipids (Dupuis et al ., ) and phenolic compounds (Barros et al ., ). Both factors could limit the starch availability to hydrolysing enzymes.…”

C‐type starches and their derivatives: structure and function

“…The weak digestibility of legume starch is closely related to the high content of amylose—more than 23% in native starch and up to 51.7% in faba (or “fava”/broad) bean, for example (Table ). Amylose proportion is positively correlated with RS content, referring to the formation of type‐3 and type‐5 RS during food processing . Moreover, the higher degree of crystallization, larger particle size, and fewer pores and cracks on the granule surface usually lead to poor digestibility of the starch granule.…”

In-vitro digestibility, rheology, structure, and functionality of RS3 from oat starch

“…However dual autoclaving-retrogradation process resulted in starches that showed an additional peak at 13° and increase in peak intensity at 20° inclusive of the major X-ray diffraction peaks which reflects formation of amylose-lipid complex. A typical amylose-lipid complex contains a hydrophobic fatty acid tail, which is buried inside an amylose helix that helps to develop further entanglement among starch molecules and thereby increasing resistance to digestive enzyme breakdown (Dupuis et al, 2014). Peaks at 13° and 20° are the typical peaks of the V-type pattern resulting from dual autoclaving-retrogradation treatment (Thomas & Atwell, 1999).…”

“…The differences in the resistant starch content among the varieties might be due to the following factors: source of starch, granular size, amylose-amylopectin ratio, branch length in amylopectin, percent crystallinity, amylose lipid complex, and pores within the granules (Ashwar et al, 2016a;Dupuis, Liu, & Yada, 2014). On dual autoclaving-retrogradation process the type 3 resistant starch content (RS3) of oat varieties increased significantly to the range of 25.81-38.88 % (Table 2).…”