Theses and Dissertations

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Theses and Dissertations (Food Science & Technology)

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Browsing Theses and Dissertations by Author "Adeyemi, I. A."

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    Effect of Maize Fermentation on Some Physico-Chemical Properties of 'Ógi'.
    (Obafemi Awolowo University, 1985) Beckley, Olufela; Adeyemi, I. A.
    The effect of fermentation or souring period on some physico-chemical properties of ogi, manufactured by the wet- and dry-milling processes from downy mildew resistant white maize variety (DMR white) were evaluated. Determinations were carried out for titratable acidity, starch, diastatic activity, damaged starch, reducing and non-reducing sugars, liquefaction number, Brabender amylograph pasting characteristics and Adam's consistometer value. The results showed that titratable acidity increased from 0.18% to 0.37% lactic acid, while starch content was reduced from 89.2 to 70.5% with period of fermentation, although souring did not produce any appreciable change in starch content. Similarly, there was no appreciable change in diastatic activity, damaged starch and reducing and non-reducing sugars, except for samples fermented or soured for six days. Amylograph peak viscosity was higher for wet-milled ogi than dry-milled ogi being in the range of 1030 to 1250 B.U. and 210 to 960 B.U. respectively. Peak viscosity was observed to increase with souring period of maize flour. Set-back value, index of gelatinization and Adam's consistometer value were observed to decrease with either fermentation or souring period. The use of souring water in preparing ogi porridge, appreciably increased its titratable acidity, but produced ogi of poorer pasting viscosity.
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    An Investigation into the Keeping Quality of “Agidi”.
    (Obafemi Awolowo University, 1986) Oluwamukomi, Mathew Olusola; Adeyemi, I. A.
    The effect of storage time and temperature, souring period, surfactant and packaging materials on the keeping quality of Agidi was investigated. Changes in quality were evaluated by determining the moisture content, syneresis, iodine blue value, acidity and pH. The gel strength, microbial load and the sensory qualities were also determined. The results showed that moisture content of Agidi decreased while syneresis increased with storage time. With increase in storage period, the gel strength of Agidi also increased up to a maximum value and later decreased for samples stored at 28oC and 50°C. There was an increase in acidity value and a corresponding decrease in pH for agidi samples stored at 28°C. Agidi prepared from 4 day soured ogi had a higher syneresis value and a faster staling rate than that prepared from a 2 day soured ogi. The use of surfactant resulted in an increase in initial gel strength of Agidi wrapped in Leaves but with relatively no effect on canned Agidi. The total microbial load also increased with increase in storage temperature, the counts obtained being 750,000/g at 28°C and 2,484,000/g at 50°C after 9 days storage for Agidi wrapped in Leaves. Corresponding counts for canned samples were 2000/g and 6000/g respectively after 8 weeks of storage. Sensory observation showed that Agidi wrapped in Leaves, PVC and Aluminium foil had shelf life of 6, 9 and 16 days respectively while canned Agidi maintained its quality throughout the 8 weeks of storage period.
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    Investigations into the Textural Characteristics of Agidi (A Fermented Corn Meal).
    (Obafemi Awolowo University, 1986) Osungbaro, Taiwo Olujide; Adeyemi, I. A.
    The effect of particle size, maize variety, fermentation periods and methods of milling on textural properties of 'agidi' was investigated. Textural properties were evaluated, using the Brabender Amylograph, Gel tester, and sensory evaluation. The data obtained showed that 'agidi' manufactured from wet-milled ogi of 4 425 pm particle sizes exhibited the highest gel strength while that from the dry-milled ogi of .0 600 pm particle size fractions recorded the highest gel strength. Of the five maize varieties investigated, FARZ-27 had the best gelling characteristics for 'agidi' manufacture, while FARZ-34, recorded the lowest gel strength and kewesoke recorded the lowest stability and setback values. 'Agidi' from wet-milled ogi fermented for 4 days recorded the highest gel strength, peak viscosity and index of gelatinisation values. While the dry-milled ogi soured for 2 days recorded the highest values for the above parameters. Gel tester results were highly correlated with sensory evaluation for 'agidi' samples of the same particle size manufactured either from different maize varieties or subjected to different days of fermentation.
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    Open Access
    Nutritional Evaluation of a Fortified Maize Weaning Food.
    (Obafemi Awolowo University, 1987) Komolafe, Abiola; Adeyemi, I. A.
    Nutritional evaluation was carried out on pregrelatinized maize flour blended with undefatted soy bean flour at 20, 32, 40 and 50% levels. The samples were evaluated for proximate composition, pepsin digestibility and mineral analysis for phosphorus, calcium and iron contents. The data were compared with values for Ogi, Soy-Ogi and Cerelac. Rat feeding experiments were also carried out on pregelatinidec maize flour fortified with soybean flour (at 30% Level), and cerelac. Protein content and pepsin digestibility Values: for fortified gelatinized maize flour samples found to range from 12 to 19% and 82 to 86% respectively. The corresponding values for Ogi, Soy-Ogi and cerelac were 7.06, 11.70 and 16.09% and 70.52, 78.73 and 91.55% respectively. Phosphorus contents of the pregrelatinized maize flour, 30% fortified maize flour, Ogi, Soy-ogi and cerelac were 280, 265, 200, 285 and 285mg/100g respectively. The corresponding values for calcium were 0.5, 56.5, 4.2, 205.3 and 352.5mg/100g respectively, while the values were 1.8, 3.1, 1.5, 5.6 and 6.8mg/100g respectively for iron. From rat feeding experiments, Protein Efficiency Ratio (PER), Net Protein Utilization (NPU) and Biological Value (BV) were1.14, 55.05% and 0.62 respectively for fortified maize flour while cerelac had corresponding values of 1.99, 71.09% and 0.83 respectively. It was apparent from the results obtained that pregelatinized maize flour fortified at 30% level with undefatted soybean flour could be nutritionally adequate as a weaning food.