Evaluation of physical properties of rice cultivars in Nigeria

Aderemi Bunmi Kutelu

Master's thesis

Abstract:

Abstract Rice, Oryza sativa, is a cereal whose grain has been the third most important food item after wheat and maize. Several cultivars of rice are planted in different ecological zones of Nigeria. However, available information on the physical properties of the rice grains of Nigerian rice cultivars is still insufficient. This study therefore evaluated the physical properties of the grains of five Nigerian rice cultivars (FARO 37, FARO 44, FARO 52, FARO 66, and FARO 67). Paddy rice grains were obtained from the International Institute for Tropical Agriculture (IITA), Nigeria. The milling properties of paddy (raw) rice grains were evaluated after parboiling 5 kg of each rice and subsequently milling using a standard milling machine used for commercial purposes. The size and shape, morphometrics, and colour properties of the paddy rice grains, milled rice grains, and cooked rice grains were also evaluated using standard methods. The cooking properties of milled rice grains were also evaluated using standard methods. Results showed significantly higher paddy grain and milled grain length and length-to-width ratio in FARO 66 than the other cultivars. The paddy grains were extra-long in shape and slender in size while the milled grains were long in shape and slender in size. The percentage of milling recovery was highest (76%) in FARO 67. On the other hand, only FARO 37 and FARO 44 had up to 50% head milled grains. Results also showed significant variations in the physical properties of the paddy grains and milled grains of the five Nigerian rice cultivars. Cooking time of the rice significantly varied from 20.70±0.54 minutes for FARO 44 to 24.70±0.54 minutes for FARO 37. Also, cooked grain length ranged from 10.25±0.06 mm to 11.63±0.15 mm, width from 2.85±0.06 mm to 3.30±0.14mm, thickness from 2.10±0.12 mm to 2.55±0.06 mm, and elongation ratio from 1.53±0.04 to 1.66±0.04. The water uptake ratio also ranged from 3.92±0.07 in FARO 37 to 4.62±0.06 in FARO 67. Results also showed significant variations in the colour properties of the paddy grains, milled grains, and cooked grains of the five Nigerian rice varieties.

Keywords

Nigerian cultivars, Paddy, Staple food, Milling, Oryza glaberrima, Oryza sativa, Physical properties, Colour, Nigeria

Language used: English

Date on which the thesis was submitted / produced: 28. 4. 2024

Thesis defence

• Date of defence: 3. 6. 2024
• Supervisor: Ing. Olga Leuner, Ph.D.
• Reader: Karolína Němcová, Ing.

Czech University of Life Sciences Prague

Faculty of Tropical AgriSciences

Master programme:
Tropical Crop Management and Ecology