This research work determined the physicochemical, cooking and milling characteristics of four Nigerian rice varieties namely Illa from Southern, Abakaliki South-East, Jemila North and Ofada from West.The physiochemical, milling and cooking properties of rice are solely determining the preference, choice and economy of rice. The four rice varieties grown in different region in Nigeria were investigated for cooking, milling and physical, cooking and chemical characteristics. The result from axial dimension classified all the studied rice varieties as long grains. Illa rice recorded highest value (43.96 g) of 1000 grain weight while lowest value of 20.46 g was observed in Ofada rice. The variation in grain shape were not significant at (P>0.05) and all the tested varieties fall within the slender shapes. All the tested samples displayed good Milling behavior. Ofada rice elongated more than other varieties. The broken percentage was higher and lower in Illa rice (36.72%) and Abakaliki (28.78%) respectively. There were similarities in milling recovering of rice varieties, but Illa had highest expansion (swelling) capacity while Ofada had lowest swelling power. Amylose and gelatinization temperature showed a good relationship, Ofada rice with higher amylose content had lowest gelatinization temperature. The determined cooking time of the rice sample varied from 5.56 to 6.77 mins, Jemila rice will cook faster than other varieties. Illa rice had highest value (353.76%) of water absorption capacity, followed by Abakaliki rice with 185.76% Water Absorption Capacity and Ofada rice which had 158.62% WAC. The lowest value (155.60%) of Water Absorption Capacity was found in Jemila rice variety.

This study determined the comparative study of the functional properties of some Nigerian and imported rice varieties. The result showed a significant difference in functional properties at (p>0.05). Illa (Nigerian) rice had the highest Water Absorption Capacity (WAC) (353.76%) and Oil Absorption Capacity (OAC) (218.32%) than the imported rice variety. The bulk density of both samples had less significantly different values. The percentage values of dispersibility (75.00%) were higher in Ofada (Nigerian) rice. Nigerian rice had a higher swelling index (10.91%). The amylopectin contents of tested rice varieties were 76.26, 76.55, 75.58, 74.37, and 77.55% for Illa, Abakaliki, Jemila, Ofada, and Imported rice, respectively. The result revealed that Imported rice had the highest value (77.55%) of amylopectin, followed by Abakaliki rice which recorded 76.55%, and Illa rice variety from the Southern region had 76.28%. In comparison, the Ofada rice sample had the lowest value (74.37%) of amylopectin content, followed by Jemila rice which recorded 75.58% of amylopectin content. The amylose content for Illa, Abakaliki, Jemila, Ofada, and Imported rice varieties was 23.73, 23.45, 24.42, 25.64, and 22.45%, respectively. Rice flour, with low amylose content, gives moistness, chewiness, and softness to the textures of the product. It showed that Ofada rice had the highest value (25.64%) of amylose content, followed by Jemila rice which recorded 24.42% of amylose content. The lowest value (22.45%) was found in imported rice, followed by Abakaliki rice with 23.45% and Illa rice sample with 23.73% of amylose content. It can be concluded that Nigerian rice is compared handsomely with imported rice in terms of functional properties, which determines the end-use and general acceptability of flour samples.

Thermal parameters of food flour moisture content and temperature give an insight in the development and prediction of models that meet the needs of process design models, it also determine the thermal load of a particular product during handling. The bulk density (ρ), thermal conductivity (k), specific-heat capacity (Cp) and diffusivity (α) of Illa and Ekpoma rice flour were studied at varied (MC) moisture content (%) level. The results showed significance in thermal properties values at the different MC levels. The MC increased from 10.56 to 18.50%, increased the specific heat capacity (Cp) from 5.72 to 48.61kJ kg-1 °C-1 and 6.84 to 29.41 kJ kg-1 °C-1 for Illa and Ekpoma rice variety respectively and thermal conductivity(k) from 0.03 to 1.56 W/m0C and 0.03 to 0.38 W m-1 °C-1 for Illa and Ekpoma rice flour samples. Thermal diffusivity(α) and bulk density (ρ) of the processed Illa and Ekpoma rice flour samples decreased across the MC range of 10.56 to 18.50% (d.b). Thermal diffusivity(α) decreased from 4.38 to 1.25 x 10-4 m2 s-1 and 3.42 to 1.30 x 10-4 m2 s-1 for Illa and Ekpoma rice flour respectively while the values of bulk density (ρ) decreased from 697.72 to 676.34 kg m-3 and 687.49 to 664.26 kg m-3 for Illa and Ekpoma rice flour respectively.The developed model equations can be applied in estimation of thermal parameters of rice flour. Finally, Ekpoma and Illa rice flour sample displayed good thermal characteristics and it can be used as an alternative to imported wheat flour.