21
100 DP and then remains constant (Eerlingen et al. 1993a, b). DP level of 10–100 is
necessary for the formation of double helix (Gidley et al. 1995).
RS4
RS4 is chemically modified starch and include modifications like esterification,
acetylation, etherification, phosphorylation or crosslinking. RS4 is further grouped
into subcategories based on their solubility in water and the experimental protocols
used for analysis (Nugent 2005). Chemical modifications of starch prevent its digestion by blocking the access to hydrolytic enzymes and by the formation of atypical
links (Sajilata et al. 2006; Kim et al. 2008).
RS5
Besides structural characteristics, other factors intrinsic to starch rich foods can
affect enzyme activity and hence starch hydrolysis. These factors include the
amylose- lipid complexes, the presence of native α-amylase inhibitors in starchy
foods and non-starch polysaccharides. RS5 is formed by the complexation of amylose with lipids (Fuentes-Zaragoza et al. 2011).
Sources
Naturally cereals, seeds and other starch rich foods are excellent sources of SDS and
RS (Charalampopoulos et al. 2002; Gani et al. 2020). Among non processed foods,
unripe bananas are the richest source of RS (47–57%). Unripe banana flour was
prepared with 17.5% RS, 73.4% total starch and 14.5% dietary fibre (Rodriguez
et al. 2008). Tuber starch like potato shows B-type crystallinity which is highly
resistant to enzymatic hydrolysis. Raw potato starch contains almost 75% RS
(Bednar et al. 2001). Whole grains are rich sources of RS, dietary fibre and oligosaccharides while as flour group contains low concentrations of RS (Slavin 2004).
Flour contains two principal components viz. protein and starch, where as whole
cereal grain contains the pericarp, aleurone layers and germ that provides the lipids
and fibre. Processing of cereal grains alters their chemical composition. The RS
content of whole cereal grains was found to be five times higher than their respective flours (Bednar et al. 2001).
Pulse grains contain high contents of RS (Rochfort and Panozzo 2007). RS and
total dietary fibre contents of 24.7% and 36.5%, respectively were found in legumes.
Various factors are responsible for higher contents of RS in legumes. C-type pattern
of crystallinity found in leguminous starches makes them more resistant to
Resistant Starch and Slowly Digestible Starch
100 DP and then remains constant (Eerlingen et al. 1993a, b). DP level of 10–100 is
necessary for the formation of double helix (Gidley et al. 1995).
RS4
RS4 is chemically modified starch and include modifications like esterification,
acetylation, etherification, phosphorylation or crosslinking. RS4 is further grouped
into subcategories based on their solubility in water and the experimental protocols
used for analysis (Nugent 2005). Chemical modifications of starch prevent its digestion by blocking the access to hydrolytic enzymes and by the formation of atypical
links (Sajilata et al. 2006; Kim et al. 2008).
RS5
Besides structural characteristics, other factors intrinsic to starch rich foods can
affect enzyme activity and hence starch hydrolysis. These factors include the
amylose- lipid complexes, the presence of native α-amylase inhibitors in starchy
foods and non-starch polysaccharides. RS5 is formed by the complexation of amylose with lipids (Fuentes-Zaragoza et al. 2011).
Sources
Naturally cereals, seeds and other starch rich foods are excellent sources of SDS and
RS (Charalampopoulos et al. 2002; Gani et al. 2020). Among non processed foods,
unripe bananas are the richest source of RS (47–57%). Unripe banana flour was
prepared with 17.5% RS, 73.4% total starch and 14.5% dietary fibre (Rodriguez
et al. 2008). Tuber starch like potato shows B-type crystallinity which is highly
resistant to enzymatic hydrolysis. Raw potato starch contains almost 75% RS
(Bednar et al. 2001). Whole grains are rich sources of RS, dietary fibre and oligosaccharides while as flour group contains low concentrations of RS (Slavin 2004).
Flour contains two principal components viz. protein and starch, where as whole
cereal grain contains the pericarp, aleurone layers and germ that provides the lipids
and fibre. Processing of cereal grains alters their chemical composition. The RS
content of whole cereal grains was found to be five times higher than their respective flours (Bednar et al. 2001).
Pulse grains contain high contents of RS (Rochfort and Panozzo 2007). RS and
total dietary fibre contents of 24.7% and 36.5%, respectively were found in legumes.
Various factors are responsible for higher contents of RS in legumes. C-type pattern
of crystallinity found in leguminous starches makes them more resistant to
Resistant Starch and Slowly Digestible Starch