Commercial cassava starch was modified with 1 % (w/w) lactic acid solution and irradiated with ultraviolets: UVBA (280 to 420 nm), UVB (310 to 330 nm) or UVC (254 nm) for 7 to 15 hrs. The acidified starches irradiated with UVB or UVC for 7, 9 and 11 hrs achieved the desired baking expansion. No significant change in the specific volume of cassava rolls was shown for the starches irradiated with UVB for 9 hrs and UVC for 7 and 9 hrs. UVB irradiation for 9 hrs gave the highest specific volume (12.23 (+,ฑ) 0.12 cm('3)/g). With the rapid viscosity analysis, the peak viscosities of the starches irradiated with UVB for 7 and 9 hrs were 196.55 (+,ฑ) 2.41 and 195.67 (+,ฑ) 0.83 RVU, and with those irradiated UVC were 176.55 (+,ฑ) 1.83 and 169.54 (+,ฑ)3.24 RVU, respectively

these were higher than the values obtained from the other treatments. A correlation between the peak viscosity and the specific volume of the starches was observed (r('2) = 0.81). The starch irradiated with UVB or UVC for 9 hrs showed a significant increase in the pasting temperatures and these are agreed with the higher peak temperatures determined with differential scanning calorimeter, indicating formation of network structure. But the transition enthalpy of the starches irradiated with UVB or UVC for 7 and 9 hrs did not significantly change from that of the commercial starch. In addition, no change in the relative crystallinities and the typical Apattern of the X-ray diffractions of the starches was found. Molecular size distributions showed a decrease in the amylose of the commercial starch (DPn 2173) to DPn 1551 and 1427 by UVB, and to DPn 1216 and 1096 by UVC for 7 and 9 hrs, respectively. Electron micrographs showed similar fracture appearance and slight exocorrosion on the granule surfaces. Texture analysis showed the deformation curves of the cassava rolls similar to the wheat rolls, and satisfactory sensory qualities in the cassava rolls were obtained.