Quality And Acceptability Of New Rice Varieties (Oryza Sativa L.) In Kilombero District, Morogoro Tanzania

ABSTRACT

The objectives of this work were to study the quality and acceptability of new rice varieties (Oryza sativa L.). The rice varieties (TXD88, NERICA4, NERICA1, TXD85 and TXD306) were analyzed for rough rice quality indices, proximate composition, milling quality, cooking time, physicochemical properties and sensory evaluation. The rough rice quality indices were 5.96 – 14.62% (immature grains); 30.91 – 36.78g (1000 grains’ weight); 7.81 – 9.05mm (length) and 3.14 – 3.65 (length/width ratio). All five varieties with respect to rough rice quality indices were good. The proximate composition for the five varieties were variable with respective ranges being 11.86 – 13.40%; 7.41 – 9.00%; 0.77 – 1.02%; 1.73 – 3.01%; 1.14 – 1.23%; and 74.25 – 76.97% for moisture, crude protein, crude fibre, crude fat, ash and NFE respectively. These were found to be significantly different except for ash content (P< 0.05). The results revealed that the five varieties had proximate composition not far from those documented varieties. The milling quality parameters were 0.001 – 0.304%; 0.61 – 3.20%; 15.46 – 57.16%; 14.75 – 55.05% and 65.65 – 70.31% for dockage, chalkiness, brokens, head rice and total recovery respectively. All 5 varieties were significantly different (P< 0.05) in the measured milling quality indices with variety TXD88 ranking highest in all milling parameters. The cooking time for the 5 varieties ranged from 19.34 – 24.14 min with variety NERICA1 being the best by having the shortest cooking time and the worst being TXD85 which had the highest cooking time. The rest of the 3 varieties had intermediate cooking times that were not significantly different (P< 0.05). The physicochemical properties values were 15.03 – 27.25% (amylose); 37.33 – 84.00mm (gel consistency) and 2 – 4 (ASV). All were significantly different (P< 0.05). Based on these results NERICA varieties were higher in amylose content. Sensory evaluation results showed that TXD88 was the most significantly preferred compared to other varieties. The preference was significantly different (P< 0.05) for all sensory attributes. It was concluded in this study that TXD88 was best in sensory quality, milling processes and low amylose content. Also, NERICA varieties were higher in protein and amylose content and TXD306, NERICA4 and TXD88 had gel consistency values implying that they are soft when cooked. TXD88 variety was the best rice variety due to its low amylose content and scored high in taste. This is consistent with the principle that there is an inverse relationship between amylose content and taste.