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DETERMINING THE ACTIVITIES AND SPECIFICITY OF ENZYMNES IN FERMENTATION OF STARCH FROM MAIZE.


Project topic for Biology department

CHAPTER   ONE

INTRODUCTION

1.1 Background of the Study

 The primary aim of this project is centered on the determination of the catalytic and specific activities of enzymes in fermentation of starch from maize.  These enzymes are DIASTASE, MALTASE and ZYMASE.  This determination study is made possible through certain unique properties which these collection of enzymes posses. 

Speaking in concrete terms, ENZYMES serve as biocatalysts, speeding up chemical reactions.  Like those involved with fermentation of starch.  Enzyme molecules accelerate the rate of reactions, often by many orders of magnitude, thereby allowing the substance involved undergo a chemical breakdown.

Enzymes in fermentation of starch go about their work in an ASSEMBLY-LINE fashion, each enzyme performing a specific task at a particular stage of the fermentation process.  For instance, the enzyme – MALTASE, breaks down MALTOSE into two isomeric fermentable sugars namely  -  Glucose and Fructose; thereby preparing another stage for another enzyme to act during the fermentation process.  Enzymes in fermentation process, especially in starch; perform their work at blinding speed.

A single molecule of enzyme can catalyze thousands of chemical reactions per second.  This is because enzymes in fermentation reaction particularly in starch have a marked ability to accelerate the reaction and also to promote the specific processes involved under the chemically mild conditions, which prevails in the fermentation process.

In all ways, these enzymes readily make essential physiochemical contributions to the fermentation process by virtue of their organized and involved three-dimensional structure, which reveals certain regions on the enzyme surface where small solute molecules or ions can bind reversibly.  Such solutes are called LIGANDS; a term borrowed from ORGANOMETALLIC CHEMISTRY.

There may be many ligard-binding sites on the surface of an enzyme.  But each site usually possesses the power to bind only a limited range of ligards, by virtue of the character of the site.  The term “CHARACTER” is here used to cover not only the three-dimensional shape of the site but also its charge characteristics and to what degree it is hydrophobic or hydrophitic. 

The character of a binding site is clearly a function of the amino acid side chains that are brought together there by the folding of the polypeptide chain.  Enzymes are distinguished from other protein molecules by having ACTIVE SITES.  The substrate binds at the active site of its enzyme in much the same way as other ligards might do, but once bound there, a chemical reaction ensures because of the special nature of the enzyme active site in respect to their catalysis and specificity in fermentation bio-process.

Maize is the most widely grown grain crop in the Americas, with 332 million metric tons grown annually in the United States alone. The kernel of maize has a pericarp of the fruit fused with the seed coat referred to as “caryopsis”, typical of the grasses, and the entire kernel is often referred to as the “seed”. The grains are about the size of peas, and adhere in regular rows round a white, pithy substance, which forms the ear.

Cereal crops are rich sources of hydrolytic enzymes. Among the cereals, barley and maize have been found to produce high levels of amylase enzymes during germination which is naturally produced to digest starch in the endosperm. Barley is grown in the temperate regions and cannot survive high temperatures. Maize crop requires considerable moisture and warmth and is grown all over Nigeria where it is well adapted.

Maize production in Nigeria can be accelerated as the crop has great potentials and can be cultivated in most parts of Nigeria, North and South. An overriding concern would be the need to streamline breeding objectives for greater effectiveness. In this respect, the emphasis is on cultivation of special strains of maize that produce high levels of amylases. These varieties have been developed by International Institute of Tropical Agriculture (IITA), Ibadan and are in cultivation in Nigeria but the demand for them has not been there

1.2 Statement of the Problem

Maize is the most important and widely consumed cereal in Kenya and a staple food crop for 96 percent of Kenya‟s population with 125kg per capita consumption and provides 40 percent of the calories (WEMA, KARI and AAFT, 2010). Yields per hectares and production volumes still remain well below the projected consumption level of 36.0million bags in 2009 thus necessitates imports to cover deficits(Economic Review of Agriculture, 2010). Sorghum, maize and millet beverages possess similar features which involve the lactic acid bacteria fermentation which plays a key role in safety acceptability of the products. They are popularly consumed by adults because of the social, religious, therapeutic values and to some extent used for weaning children under five years old (Nwachukwu et al., 2010). However, the extent of fermented maize based products use by children under five and their contributing to nutritional status is not yet established. On the other hand, the contribution of fermented maize based products to4morbidity is not known, given that modes of preparation and handling are mainly traditional that may lead to contamination. The current project sought to establish and document the role of fermented maize-based products on nutritional status and morbidity of children 6-59 months old in Homa bay and Kakamega counties.

1.3       Aim and Objectives of Research

The research is aimed at determining the activities and specificity of enzymnes in fermentation of starch from maize.

1.4       Research Questions

1. Which fermented maize based products are available at household level, to what extent are they wed ns complementary foods and under what household conditions, for children 6-59 months in Nigeria?

2          What are the nutrition properties, microbial contaminants and aflatoxin levels in fermented maize products utilized at household levels in Nigeria?


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