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Cassava fermentation
Fermentation is the most common method of processing cassava foodstuffs in Africa.76 More than 90% of cassava for human consumption is processed using fermentation.77 Examples of fermented cassava foods worldwide are: gari, fufu and lafun (Nigeria); kumkum, myiodo and atangana bread (Cameroon); agbelima and akyeke (Ghana); foofoo (Congo); tapioca and puba (Brazil) and rale and karakata (Mozambique).22,25,78-81 One of the methods for effective fermentation of cassava products is by a lactic acid fermentation process.82 The method of fermentation varies from one location to another and is fermented using two processes, solid or submerged.
The solid fermentation process is characterized by the growth and/or cultivation of microorganisms under controlled conditions in the absence of free water for the production of the desired products.83-86 The typical microorganisms which grow during solid-state fermentation are yeasts and fungi. Aeration and agitation is used to remove carbon dioxide and for temperature control. Due to the small amount of water present, the biomass levels are lower and the heat generated per mass tends to be much greater than in submerged state fermentation.87
Submerged fermentation uses a dissolved or solid substrate, suspended in a large amount of water to form slurry.84 Bacterial and yeast cells are thus evenly distributed throughout the medium, but due to the high water content, bacterial cells are predominant and the process requires high oxygen concentrations.
Both spontaneous fermentation and starter culture fermentation can be used. However, spontaneous fermentation is neither predictable nor controllable, although it is typically utilised at household level, while starter culture is implemented during small scale or industrialized processing.
The microbial populations isolated during cassava fermentation, are mainly lactic acid bacteria (LAB) although yeast and moulds have also been identified. Lactic acid bacteria involved in cassava fermentation include: Leuconostoc spp., Bacillus spp., Corynebacterium spp.90,91 Lactobacillus plantarum, L. perolans, L. brevis.92 L. fermentum 93,94,95 L. casei, and L. delbrueckii.81
CHAPTER 1. GENERAL INTRODUCTION
1.1 Background
1.2. Problem statement
1.3. Aim and objectives
1.3.1. Aim
1.3.2. Objectives
1.4. Rationale
1.5. Study design
1.6. Thesis structure and outlin
1.7. References
CHAPTER 2 OVERVIEW OF PRODUCTION, CONSUMPTION AND NUTRITIONAL VALUE OF CASSAVA IN MOZAMBIQUE
2.1. Abstract.
2.2. Introduction
2.3. Cassava (Manihote esculenta, Crantz).
2.4. Mahewu
2.5. Micronutrients and anaemia
2.6. Iron and iron fortification of food.
2.7. Summary.
2.8. Limitations and possible constraints.
2.9. References.
CHAPTER 3 MINERAL CONTENT OF SWEET AND BITTER VARIETIES OF CASSAVA ROOTS AND SOILS FROM FOUR DISTRICTS OF MOZAMBIQUE
3.1. Abstract.
3.2. Introduction.
3.3. Materials and methods
3.4. Results and discussion.
3.5. Conclusions.
3.6. Limitation.
CHAPTER 4 CONTROLLED FERMENTATION OF TRADITIONAL CASSAVA MAHEWU IN MOZAMBIQUE TO DETERMINE THE STAGE FOR IRON FORTIFICATIO
4.1. Abstract.
4.2. Introduction.
4.3. Materials and methods.
4.4. Results and discussion.
4.5. Conclusions
4.6. Limitations.
4.7. References.
CHAPTER 5 IN VITRO BIOACCESSIBILITY OF IRON FORTIFIED CASSAVA MAHEWU: A NON-ALCOHOLIC FERMENTED BEVERAGE IN MOZAMBIQU
5.1. Abstrac
5.2. Introduction
5.3. Materials and methods
5.3.1. Mahewu iron fortification
5.3.2. Iron content and in vitro bioaccessibility
5.3.3. Statistical analysi
5.4. Results and discussion
5.5. Conclusions.
5.6. Limitations
5.7. References.
CHAPTER 6 GENERAL DISCUSSION AND CONCLUSIONS
APPENDICES
