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چکیده
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In this study, fifteen types of rice collected from Kurdistan region-Iraq were investigated by principle component analysis (PCA) in terms of physical properties and cooking characteristics. The dimensions of evaluated grains correspond to 5.05– 8.75 mm for length, 1.54–2.47 mm for width, and 1.37–1.95 for thickness. Equivalent diameter was in range of 5.23 – 10.03 mm, surface area took 13.30–28.25 mm². The sphericity analysis values varied from 0.32 to 0.56, aspect ratio from 0.17 to 0.39, volume of the grain was measured in range from 4.48 to 17.74 mm3, Hectoliter weight values were 730–820 kg/m3, and true density from 0.6 to 0.96 g/cm3. The broken ratio of grain was equal to 1.5–18.3 %, thousand kernel weight correspond to 15.88 to 22.42 g. The water uptake ratios for 30 min of soaking were increased at 60 °C compared to 30 and 45 °C. The PCA was used to study on the correlation of physical and cooking characteristics of collected rice and also to recognize the most effective factors. Results of PCA showed that the first (PC1) and second (PC2) components retained 63.4% and 34.8 % of the total variance, which PC1 was mostly related with hectoliter, broken ratio and moisture content characteristics while PC2 was mostly concerned with hardness and true density. For cooking properties, the first (PC1) and second (PC2) components retained 88.5% and 9.3 % of the total variance, respectively. PC1 was mostly related with Viscosity, spring value and hardness after cooking properties while PC2 was mostly concerned with spring value, hardness before cooking and hardness after cooking.
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