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dc.contributor.supervisorBeal, Jane
dc.contributor.authorObinna-Echem, Patience Chisa
dc.contributor.otherFaculty of Science and Engineeringen_US
dc.date.accessioned2014-04-11T09:47:48Z
dc.date.available2014-04-11T09:47:48Z
dc.date.issued2014
dc.date.issued2014
dc.identifier375568en_US
dc.identifier.urihttp://hdl.handle.net/10026.1/2983
dc.descriptionFull version unavailable due to 3rd party copyright restrictions.
dc.description.abstract

Akamu is a lactic acid bacteria fermented cereal-based food that complements infant diets in most African countries. Uncontrolled fermentation increases the variability in quality and safety of akamu. This study was aimed at the controlled fermentation of akamu with selected lactic acid bacteria (LAB), investigation of the probiotic potential of the LAB and the effect of variation in production method on the product quality and sensory properties. PCR-DGGE analysis of traditional akamu samples revealed LAB community dominated by Lactobacillus fermentum, L. plantarum, L. delbrueckii subsp. bulgaricus and L. helveticus. Isolated yeasts were Candida tropicalis, C. albicans, Clavispora lusitaniae and Saccharomyces paradoxus. The isolated Lactobacillus plantarum strains (NGL5 and NGL7) fermented irradiated ground maize slurries and produced significant levels of lactic acid (>73 mmol L-1) and low pH ≤3.63 displaying inhibitory activity against Salmonella enterica serovar Enteritidis NCTC 5188, Escherichia coli 1077 (NCTC 11560), Bacillus cereus NCIMB 11925, Staphylococcus aureus NCTC 3750 and Listeria monocytogenes NCTC 7973 in MRS agar and E. coli 1077 in maize slurry fermentation. Viability of both strains of L. plantarum at pH 2 after 3 h was reduced from ≥8.26±0.05 to ≤4.94±0.49 Log10 CFU mL-1 while incubation in 0.3% bile allowed growth to 5.73±0.13 and 7.93±0.12 Log10 CFU mL-1 after 6 h for NGL5 and NGL7 respectively. Auto-aggregation of the L. plantarum strains at 37oC (≥25 after 5 h) correlated with adhesion to hydrocarbons (<15, 26, 33 and 64% for Hexane, Hexadecane, Ethyl acetate and Chloroform respectively). The strains failed to exhibit gelatinase or haemolytic activity but adhered to porcine mucin (OD403 nm ≥0.63 with viability ≥6.52 Log10 CFU mL-1) and Caco-2 cells (≥5.13 Log10 CFU mL-1). The ash, mineral (Ca, K, Mg, Na, S and Zn), IDF, SDFP and TDF content of the L. plantarum fermented ground maize slurries were significantly (p≤0.05) higher than that of the traditional akamu but the peak and final viscosities (139.5 and 68.5 cP respectively) were significantly (p≤0.05) the least. The aroma, appearance, colour, flavour and texture of the resultant porridges were liked moderately by 75% of the assessors. This study demonstrated that fermentation with the L. plantarum strains would contribute towards product safety and the L. plantarum strains possessed some probiotic potential that could be beneficial to the consumers particularly in those developing countries were the main staple foods are fermented cereals.

en_US
dc.description.sponsorshipRivers State Scholarship Board, Rivers State, Nigeriaen_US
dc.language.isoenen_US
dc.publisherUniversity of Plymouthen_US
dc.subjectAkamuen_US
dc.subjectLactic acid bacteriaen_US
dc.subjectYeasten_US
dc.subjectGround maize slurryen_US
dc.subjectLactobacillus plantarumen_US
dc.subjectProbiotic potentialen_US
dc.subjectProduct quality, safety and sensory propertiesen_US
dc.titleDevelopment of a Nigerian fermented maize food “Akamu” as a functional fooden_US
dc.typeThesisen_US
plymouth.versionEdited versionen_US
dc.identifier.doihttp://dx.doi.org/10.24382/1413


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