Effect of partial acid hydrolysis and heat-moisture treatment on formation of resistant Tuber starch

Structural characteristics of resistant starch (RS) were investigated. Tuber starches, hydrolyzed with IN HCl at 35degreesC for 8 hr followed by autoclaving-cooling treatment, were heated at 100degreesC for 16 hr after adjusting the moisture content to 20 or 30%. RS content of the tuber starches ranged from 5.4 to 22.7% depending on the source and type of treatment. Gelatinization parameters of RS isolated from partially acid-hydrolyzed starch with autoclaving-cooling followed by heat-moisture treatment (HMT) showed higher enthalpy (DeltaH) values and lower peak temperature (T-p) compared with non-acid-hydrolyzed RS. R values, the difference between completion and initial temperatures, and DeltaH of RS increased by HMT. The X-ray diffraction patterns of potato and sweet potato RS isolated from partially acid-hydrolyzed starch with autoclaving-cooling showed distinct sharp peaks at 15, 25, 27, and 28degrees, which decreased by HMT.