Saalia, F.K.Johnson, P.T.Baffour, L.C.University of Ghana, College of Basic and Applied Sciences, School of Biological Sciences, Department of Nutrition and Food Science2017-01-132017-10-132017-01-132017-10-132015-06http://197.255.68.203/handle/123456789/21300Thesis (MPhil) - University of Ghana, 2015Rice production in Ghana is faced with the major challenge of low patronage. This is due to its poor physical and sensory quality rendering it ‘low grade’ rice. Among the many local varieties of rice in Ghana, Viwonor is perceived to be a low grade rice whereas Jasmine 85 a high grade. Large quantities of rice are imported to address the issue of quality and quantity gap. Protein energy malnutrition (PEM) is a serious nutritional problem facing many countries including Ghana. Cowpea (Vigna unguiculata) is an important legume rich in minerals and proteins. One of the most common and effective processes for improving the quality of legumes is sprouting. Addition of value to low grade rice which otherwise would be underutilized (in spite of its nutritional value) through the development of cowpea fortified extruded breakfast cereal will help in diversifying and improving the market potential of rice produced in Ghana. The main objective of this work was to study the characteristics of rice-sprouted cowpea extrudates and evaluate their performance and acceptability as a breakfast cereal. Differences in rice cultivars significantly influenced (p<0.05) its physical properties with lower % head rice being measured in Viwonor rice. Relatively higher apparent amylose, Gelatinization Temperature (GT) class and hardness index was measured in Viwonor rice. This is an indication of longer cooking quality and hence low quality rice. Protein contents and solubilities of cowpea significantly decreased (p<0.05) with increasing sprouting time in all buffers. The SDS-PAGE results showed no significant variability in the number of protein bands for each germination day and by the different buffer solutions. Generally, cowpea proteins of higher molecular weight (45 and 66 KDa) were mostly extracted in all buffers. Cowpeas that were sprouted for three days were far more digestible by pepsin and pancreatin enzymes than those that were not sprouted for that long. Increasing germination time of cowpea seeds significantly decreased (p<0.05) the amount of accessible thiols with or without the denaturant. Cowpeas were sprouted for 1, 2 and 3 days in addition to a control (unsprouted) and used to make breakfast cereal formulations with Viwonor rice flour (low grade) using the Central Composite Rotatable Design (CCRD). 13 flour formulations were generated and extruded using a twin screw extruder under the following conditions; barrel temperature = 2000C; screw speed =1200 rpm; die diameter = 4.0 mm and moisture content=25%. Consumer preference test was done on the extrudates. ANOVA was performed and the mean acceptability score was used to select the 3 most preferred extrudates. Extrudate 7 (22% 2 day sprouted cowpea + 78 Viwonor rice) was rated the most preferred extrudate; followed by extrudate 1 and 2 with 30% unsprouted cowpea +70% Viwonor rice and 30% 3 day sprouted cowpea + 70 Viwonor rice. The corresponding flour formulation for the best 3 extrudates was used in extruding additional 3 extrudates from Jasmine 85 rice (control). A total of 6 extrudates were obtained. The SDS-PAGE results show that both rice and cowpea proteins contributed to the protein structure of the extrudates. Extrudates produced from unsprouted cowpea (Extrudates 1 and 4) showed the highest rate of hydrolyses by pepsin while the sprouted cowpea – based extrudates were low. Extrudates made from Jasmine 85 rice were characterized with higher expansion ratios and bulk densities. Lower hardness values were measured among the Jasmine 85 - based extrudates. Bubbles belonging to class 1 (0.01 – 0.1 mm2) and 2 (0.1 – 3 mm2) were dominantly present in all extrudates. The WS (sulphur containing) sensors of the Electronic Nose system separated the extrudates based on sprouted cowpea whereas the WC (arom-aliph compounds) sensors were responsible for discriminating the extrudates based on unsprouted cowpea. With respect to the Electronic Tongue sensing system, Viwonor - based extrudates enriched with sprouted cowpea (extrudates 2 and 3) were characterized by sourness whereas Jasmine 85 - based extrudates with sprouted cowpea (extrudates 5 and 6) were characterized by astringency and bitter aftertaste. Extrudates made with unsprouted cowpea flours (extrudates 1 and 4) were perceived to be less bitter and astringent aftertaste.xix, 156p. illenThesisUniversity of Ghana