Effect of chemical and physicochemica propertied of mixed rice on cooking qulity.(Thai)

Abstract

The main cultivar Khao Dawk Mali 105 mixed with other varieties (Suphan Buri 60, Pathum-Thani
1, Chai-nat 1 and RD 23) with 20, 30 and 40 % were evaluated for chemical, physicochemical and cooking
properies. It was found that in mixed rice with Khao Dawk Mali 105, the amylose content of all treatments
were different (p≤0.05) but not different in lipid content (p>0.05). The protein content of mixed rice
Pathum-Thani 1 at all mix ratios, RD 23 (20%) and Chai-nat 1 (20%) are not different from Khao Dawk Mali 105 (p>0.05). Pathum-Thani 1 and Suphan-Buri 60 in mix ratios of 20, 30 and 40% and Chai-nat 130 %, the highest peak viscosity were not different with Khao Dawk Mali 105 (p>0.05). The relationship between different properties was determined using linear regression. (p≤0.05) Amylose content showed a positive correlation with peak viscosity, break down ,final viscosity, set back ,enthalpy of gelatinization, onset temperature, temperature at the end of gelatinization % retrogradation and cooking time water holding and hardness (R² = 0.685, 0.575, 0.754, 0.497, 0.563, 0.697, 0.875, 0.756, 0.911 and 0.942) respectively. Protein content showed a positive correlation with set back enthalpy of gelatinization,%retragradation water holding and hardness
(R²=0.583 0.518 0.445,0462 and 0.814) respectively but amylose content showed a negative with peak viscosity cooking loss and stickiness R²=-0.563, -0.995 and-0.590 and protein content showed a negative correlation with cooking loss R²=-0.647. For sensory evaluation found that select Pathum-Thani 1 (all percentage mixed rate rice) Suphan-Buri 30 % and Chai-nat 1 20% had not deference likeness Khao Dawk Mali 105 in cooking properties. (p
≤0.05)