MICROORGANISMS ASSOCIATED WITH CASSAVA FERMENTATION

MICROORGANISMS ASSOCIATED WITH CASSAVA FERMENTATION

CHAPTER ONE

• Introduction

Cassava is a popular West African granular starchy food traditionally made from fermented fresh cassava tubers which is of the important stable food crops grown in tropical Africa. The starchy roots are the main food source and the processed leaves are use as a proteins-rich food in Africa and elsewhere (Bradbury, 2006).

The tubers are usually processed into a variety of products such as garri, fufu, chips, and can be processed into flour for breads and biscuits (Cardoso et al, 2005). Cassava has the ability to grow in poor and acidic soils which are often not suitable for other crops and yield a harvest in time of drought when all other crops have failed for lack water. These are low energy density, low protein content, rapid postharvest determination and potential cyanide toxicity (Mlingi, 1995).

Garri has been noted as one of the major product popular form in which cassava is consumed in Nigeria, better varieties which contain higher amount of cyanogenic glucoside, have to be processed to remove the toxic compounds before consumption, whereas, sweet varieties which have low level of cyanogenic glucosides can be eaten fresh (Rosling, 1990). Cyanide is very poisonous because is bind to an enzymes cytochrome oxide and stop it action in respiration, which is a key energy conversion process in the body. Hydrolysis of linamain is initiated during maceration or grating whereby linamarese canes into intimate contact with the substrate leading to the liberation of the volatile poisonous hydrogen cyanide (Sokari et al., 1992).

Since being introduced by Portuguese traders from Brazil in the 16^th century, it is known that Nigeria is the largest producer of cassava in the world with about 45 million metric tons. Essentially a carbohydrate food with low protein and fat, the edible part of fresh cassava root contains 32-35% of carbohydrate, 2-3% of protein, 75-80% of moisture, 0.1% of fat, 1.0% of fibre and 0.70-2.50% of ash. Fermentation not only enhances detoxification, but may also improves the quality and hygiene safety of the food (Ogunsua, 1980).

Processing cassava into garri requires equipment such as graters