Preparation of dextrin. Enzyme-resistant citric acidmodified dextrin (CA–dextrin) was prepared following
the method of Kapusniak et al. (2008). Thus, potato
starch was sprayed with a hydrochloric acid solution (0.5% w/v) to obtain a final HCl concentration of 0.1%
on a dry starch basis (dsb). The citric acid solution (0.5%
w/v) was then added to obtain a final organic acid concentration of 0.1% dsb. Thoroughly mixed sample was
dried at 110ºC to obtain a final moisture content below
5%. Dried sample (10 g) was placed in an anti-pressure
bottle (SIMAX), capped and heated at 130ºC for 3 h
in an ELF 11/6 EUROTHERM CARBOLITE oven
(Hope, England). The product was cooled in a desicca- tor and milled to powder. Dextrin was then washed with
80% EtOH to remove an excess of citric acid, and low
molecular weight material formed during dextrinization,
dried overnight at 50ºC, and then at 110ºC for 1 h, and
finally milled in a cyclone lab sample mill (UDY Corp.,
USA).