1.1 Introduction
Potato (Solanum tuberosum L.) is well-known vegetable grown all over the world. It is regarded as valuable supply of nutrients because it provides nearly all necessary nutrients needed for human body ranging from macronutrients that are considered as high level of energy to micronutrients like minerals and vitamins (Vreugdenhil let al, 2007). The root of Sweet potato is the major source of energy due to its high carbohydrate content. In addition to these nutrients, sweet potato is well known for its β-carotene content and other minor components such as vitamins B, C, E and phenolic acid, as well as potassium, calcium, iron, zinc and phosphorus (Burri et al., 2011).
As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Research hypothesis and questions, Limitations of the Study and Definition of technical terms.
1.2 Background of Study
Potato has an important role to play in preventing malnutrition, especially in impoverished areas of the world. Although potato has a relatively low energy density, it has negligible fat, contains quality protein, fiber, and vitamins, minerals, especially potassium, and important phytochemicals, many of which have antioxidant properties. Potato is important to global nutrition and health.
Sweet potato is one of the major roots and tubers and it was reported to be the 7th most important food crop in the world (Kays, 2004). The importance of sweet potato as a food crop is growing rapidly in some parts of the world and in sub-Saharan Africa, it is outpacing the growth rate of other staples. Sweet potato is used for human consumption and as a healthy cheap source of animal feed. It is considered an excellent food security crop in sub-Saharan Africa. It requires less agro- chemical inputs and survives/grows in diverse conditions (CIP, 2013).
Sweet potatoes are rich in complex carbohydrates, dietary fiber, beta carotenela vitamin A equivalent nutritional, vitamin c and vitamin B6. In 1992, the center for science in the public interest compared the nutritional value of sweet potatoes to other vegetables, considering fiber content, complex carbohydrate, protein, vitamin A and C, iron and calcium, the sweet potato ranked highest in nutritional value.
Sweet potato varieties with dark orange flesh have more beta carotene than those with light encouraged in Africa where vitamin A deficiency is a serious health problem. Despite the name preliminary studies on animals have revealed that it insulin resistance. Sweet potato yields an important starch which is used commercially in laundries in sizing textile and papers and in manufacturing adhesives.
The crop is sensitive to drought at the tuber initiation stage 50-60 days after planting and is not tolerant to water-logging, as it may cause tuber rots and reduce growth of storage roots if aeration is poor. Depending on the cultivars and conditions, tuberous roots mature in two to nine months. Early-maturing cultivars can be grown as an annual summer crop in temperate areas, such as the northern United States. They are mostly propagated by stem or root cuttings or by adventitious roots called slips that grow out form the tuberous roots during storage.
The plants (sweet potatoes) are now cultivated throughout tropical and warm temperate regions wherever there is sufficient water to support their growth. The plant does not tolerate frost. It grows best at an average temperature of 240c (750f), abundant sunshine and warm nights. Annual rainfalls of 750-1000mm are considered most suitable with a minimum of 500mm in growing season. Sweet potato like the other roots and tubers is mainly made of carbohydrates. Total carbohydrates, which are mainly starch (FAO, 2002), make up about 19% to 28% of the root. While the 86% (on dry basis) of total soluble sugars are glucose, the remainder are fructose and sucrose (Zhang et al., 2002), besides the fact of having a significant fiber content. Protein content is 1% to 2% and it has high biological value due to its high lysine content, whereas lipid level is low (FAO, 2002).
Therefore, in Nigeria where the research was carried out, the activities that was conducted is to know the Formulation of Microbial Growth Medium from Sweet Potato.
1.3 Statement of Problems
Investigation revealed that the sweet potato or sweetpotato (Ipomoea batatas) is a dicotyledonous plant that belongs to the bindweed or morning glory family, Convolvulaceae. Its large, starchy, sweet-tasting, tuberous roots are a root vegetable (Alkasrawi et al., 2003). The young leaves and shoots are sometimes eaten as greens.
The sweet potato is commonly thought to be a type of potato (Solanum tuberosum) but does not belong to the nightshade family, Solanaceae, but both families belong to the same taxonomic order, the Solanales. The sweet potato, especially the orange variety, is often called a "yam" in parts of North America, but is botanically very distinct from true yams.
The plant is a herbaceous perennial vine, bearing alternate heart-shaped or palmately lobed leaves and medium-sized sympetalous flowers. The edible tuberous root is long and tapered, with a smooth skin whose color ranges between yellow, orange, red, brown, purple, and beige. Its flesh ranges from beige through white, red, pink, violet, yellow, orange, and purple. Sweet potato cultivars with white or pale yellow flesh are less sweet and moist than those with red, pink or orange flesh (Alkasrawi et al., 2003).
1.4 Aim and Objectives of Study
The aim of the study is to examine the Formulation of Microbial Growth Medium from Sweet Potato. In achieving this aim, the following specific objectives were laid out as follows:
- To determine the growth of Aspergillus spp on the formulated Sweet potato glucose agar;
- To examine the growth of Rhizopus spp on the formulated Sweet potato glucose agar;
- To assess the growth of Escherichia coli on the formulated Sweet potato agar;
- To identify the growth of Staphylococcus aureus on the formulated Sweet potato agar;
- To determine the physical properties of the formulated media and commercially available media.
1.5 Research Questions
The study came up with research questions so as to be able to ascertain the above stated objectives. The specific research questions for the study are stated below as follows:
- What is the growth of Aspergillus spp on the formulated Sweet potato glucose agar?
- What is the growth of Rhizopus spp on the formulated Sweet potato glucose agar?
- What is the growth of Escherichia coli on the formulated Sweet potato agar?
- What is the growth of Staphylococcus aureus on the formulated Sweet potato agar?
- What are the physical properties of the formulated media and commercially available media?
1.6 Significance of Study
This study will be of immense benefit to other researchers who intend to know more on this study and can also be used by non-researchers to build more on their research work. This study contributes to knowledge and could serve as a guide for other study.
1.7 Scope of Study
The scope of the research is focused on the Formulation of Microbial Growth Medium from Sweet Potato.
1.8 Limitations of the Study
During the course of this study, many things militated against its completion, some of which are:
- Time Constraint: The time frame given to accomplish this project was very short due to school academic calendar and it was carried out under pressure which made the researcher not to implement some necessary features.
- Research material: availability of research material is a major setback to the scope of the study.
- Frequent power failure: This made the researcher append more money on fuel to ensure sustainable power.
- Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection (internet).
