The effect of three gums on the retrogradation of indica rice starch.

Retrograded starch (RS(3)) was produced from indica rice starch with three kinds of gums (konjac glucomannan, KGM; carrageenan, CA, USA; and gellan, GA, USA) by autoclaving, respectively, and the effect of the gums on the retrogradation behavior of starch was estimated. The influences of polysaccharide concentration, sodium chloride concentration, autoclaving time, refrigerated time, and pH value on RS(3) formation were discussed. Except for sodium chloride's persistent restraint on RS(3), the others all forced RS(3) yields higher at first, but lowered it after the peak value. The influencing sequence of these impact factors was: sodium chloride concentration > polysaccharide concentration > autoclaving time > refrigerated time > pH value. The results also proved that in the three gums, KGM plays the most significant role in RS(3) changing. It was concluded that the incorporation of each of these three gums into starch, especially KGM, results in an increase or decrease of RS(3) under different conditions. This phenomenon could be taken into consideration when developing starchy food with appropriate amount of RS(3).