Effect of the production method on the properties of RS3/RS4 type resistant starch. Part 2. Effect of a degree of substitution on the selected properties of acetylated retrograded starch

Resistant starch displays health-promoting properties. Starch preparations produced through acetylation of retrograded starch may be applied as a food additive. Apart from prebiotic properties, they may as well model the texture of a food product. The objective of this study was to determine the effect of retrogradation and acetylation conditions on properties of the produced RS3/4 type resistant starch. Native potato starch was used to produce starch pastes (1, 4, 10, 18 or 30 g/100 g), that were frozen, defrosted and dried. The resultant preparations of retrograded starch were acetylated with various doses of an acetic acid anhydride (3.25, 6.5, 13.0, 26.0 or 52.0 ml/100 g). The acetylated preparations of retrograded starch were characterised by increasing solubility in water and swelling power as well as a lower amylose content along with an increasing degree of their substitution with residues of acetic acid. Dependencies of: pasting temperatures, viscosity of the prepared pastes, and resistance of acetylated starch to the action of amyloglucosidase on the degree of substitution with acetic acid residues were described with a second degree polynomial function. The extent and range of changes were found to depend on the concentration of paste used to produce a retrograded starch preparation. The maximum resistance of RS3/4 preparations to the action of amyloglucosidase ranged from 28.7 to 45.9 g/100 g.