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Title: Variability in the biological, physical and chemical properties of ting, a maize meal fermented product of southern Africa
Author: Mpuchane, Sisai Felicity
Awarding Body: University of Surrey
Current Institution: University of Surrey
Date of Award: 1983
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The microbial content of ting fermented at 15°, 20°, 25°, 30° and 37°C is investigated. At the lower temperatures, there is a predominance of Gram negative rods, namely, Enterobacter cloacae, Enterobacter aerogenes and Klebsiella aerogenes The appearance of Gram positive bacteria and yeasts and the disappearance of moulds, is more gradual at this temperature range. The product is characterized by a slow fermentation and low viable count. Between 20° and 25°C, there is a mixed culture beginning on the second day of fermentation, and by the third day, only Gram positive bacteria and yeasts are isolated. Flavobacterium spp. are isolated at these temperatures in addition to the above Gram negative rods. The rate of fermentation and viable count are higher than at 15°C. At 30° and 37°C, most Gram negative organisms disappear after the first day and the fermentation is then dominated by 1actobacilli, streptococci, pediococci, leuconostocs and yeasts. The fermentation at this temperature is characterized by a vigorous reaction and a high viable count. Isolates from a natural fermentation (maize meal fermenting by addition of water and nothing else) of meal are used to prepare starters. Individual isolates are assessed for their ability to grow in maize meal, to produce acidity and a characteristic aroma. On the basis of all these characteristics, various recombinations of isolates are made. Ting thus prepared is given to a taste panel for analysis. It is generally noted that temperature and brand of meal have a greater effect on the variability of ting than the type of starter used. A comparative study is made' of ting prepared from irradiated, autoclaved and normal untreated meal. The untreated meal receives a higher rating than the two. However the considerable variability found throughout the work in apparently identically prepared tings indicates the difficulty in controlling fermentation experiments with the substance.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Microbiology