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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/2935

Title: Grain quality evaluation of rice from breeding lines and local collections in Ghana
Authors: Adu-Kwarteng, Evelyn
Issue Date: 15-Feb-1999
Series/Report no.: 2735;
Abstract: Rice is gaining increasing popularity in Ghana among both rural and urban dwellers. However more than 60 % of the nation’s annual requirements is still imported to meet demand levels while many local varieties are considered to be of inferior quality. Local research on the crop has generally lacked grain quality components, both for our local varieties and the breeding lines used in Crop Improvement Programmes. Twenty (20) rice varieties made up often breeding lines (B.L.) and ten local varieties (L.V.) were studied. The samples were analysed for grain size, shape and appearance, milling quality, total ash, potassium, calcium, phosphorus, protein content, amylose content, cooking quality and pasting characteristics (rheological properties). Mean values for grain length, length-to-width ratio, total milling recovery, broken grain fraction and degree of whiteness were higher for the B.L. (7.04 mm, 3.12. 67.2 %. 38.08 % and 76.90 respectively) than the LV. (6.61 mm, 2.66. 63.50 %, 30.24 % and 73.96 respectively). Among the LV., grain chalkiness score and 1000 grain weight had higher mean values (2.4 and 28.7 g respectively) than the B.L. (1.1 and 26.14 respectively). Mean protein, albumin, total ash, potassium and calcium contents were higher among the L.V. (8.14 %. 0.33 %. 0.56 %. 87.05 mg!100 g and 24.11 mg/100 g respectively) than the B.L. (7.54 %. 0.28 %. 0.52 %, 85.44mg/100 g and 21.74 mg/100 g respectively) while phosphorus. Amylase, water uptake and volume expansion (during cooking) ratios were lower in the L.V. (131.74 mg/100 g, 22.11 %. 2.89 and 3.49 respectively) than in the B.L. (167.98 mg/100 g, 27.20%, 2.94 and 3.65 respectively). Cooking time was shorter among the B.L. (mean: 19.20 minutes) than in the L.V. (mean: 19.95 minutes). Amylograph peak viscosity and iscosit breakdown were higher among the LV (mean 710 B U and 301 B U respectively than the B.L. (mean: 615 B.U. and 175 B.U. respectively) while hot paste. cold paste and setback viscosities were higher among the B.L. (mean: 440. 944.5 and 329.5 B.U. respectively) than the L.V. (mean: 409. 817.5 and 107.5 B.U. respectively). Significant differences existed between varieties for most of the parameters studied. Among the L.V. significant correlations existed between amvlose and the following parameters: cooking time (r = 0.64), breakdown and setback viscosities (r = -0.74 and 0.67 respectively). However for the B.L. correlation with amylose existed only for cold paste viscosity (r = 0.62). For the formulated rice-based snack from selected varieties, there was a high acceptability rating for the product although varietal differences existed.
Description: A thesis submitted to the Board of Postgraduate Studies, Kwame Nkrumah University of Science and Technology, Kumasi, in partial fulfilment of the requirement for the award of the Degree of Master of Philosophy, 1999
URI: http://hdl.handle.net/123456789/2935
Appears in Collections:College of Science

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