1.1 Introduction
Starch can be obtained from cassava, sorghum, maize, sago and potatoes. But this project focused on the production of starch from cassava. Starch can be cross-linked a product that will be suitable for noodle, salad cream custard making. Normally it is easier to make this product from corn and potatoe starch, but cassava which is readily available and cheap can be employed to meet the demand of the people. Other synthetic starch produced from cassava includes; carboxymethyl starch (which is produced when one of the hydrogen atom of the starch is replaced by carboxymethyl groups, starch acetate, starch xanthate and hydroxyl alkyl starch. These are used as thickening agents, sterbilizer and emulsifier in products. Cassava starch when treated with phosphate is used in frozen products when they are defrosted to prevent them from dripping. This study investigated the production of starch from cassava and preparation of cross-link derivatives.
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, Limitations of the Study and Definition of technical terms.
1.2 Background of Study
Cassava flour production till date is carried out at local levels mostly by local women who do so to enhance household food security (Fapojuwe, 2008), and according to Nweke et al. (2002), production of cassava flour remains labour-intensive. Large scale production of cassava flour in Nigeria failed probably due to the limited information on processing variables that promote detoxification in cassava, and fermentation to produce unique flavor characteristics associated with cassava flour (Achinewu and Owuamanam, 2001; Nweke et al., 2002).
Hydrolysis, either enzymatic or acidic, is the breaking down of cellulose and hemicellulose polymers in lignocellulosic biomass to form individual monomers (Jacobsen & Wyman, 2000). Acid hydrolysis is preferred over enzymatic, as it is a faster process and highly efficient (Lenihan et al., 2010). Onyelucheya et al. (2016) and Abidin et al. (2014) employed acid hydrolysis for CP and obtained RSC of 2.22 mg/ml and 5.75%, respectively. These yields are, however, low, hence the need to study the kinetics and thermodynamics of the process.
Kinetics modelling of lignocellulosic biomass hydrolysis describes the relationship between the principal state variables and the behaviour of the process (Luoa et al., 2012). Its thermodynamic parameters play a crucial role in determining the extent of reaction and position of equilibrium, where the reaction rate is catalyst and temperature-dependent (Sarma et al., 2014). Discovering the kinetic models that wholly describe the hydrolysis process is an essential step in the successful conversion of CP to useful products (Onyelucheya et al., 2016). The models are based on the acid-catalysed breakdown of long and straight chains of cellulose to shorter oligomers (Jacobsen & Wyman, 2000). It is therefore important to investigate the kinetics and thermodynamic aspects of CP hydrolysis in terms of Ea, A, ∆H, ∆G, and ∆S.
Fresh cassava root contains a toxic compound (hydrogen cyanide), which is harmful for human consumption and apparently detrimental for the use of cassava in food industries (Iglesias et al., 2002). However, research have shown that processing techniques such as peeling, fermentation, soaking and drying can detoxify and reduce the cyanide content, improve palatability and add value to the root (Cardoso et al., 2005; Burns et al., 2012). Converting cassava root into food forms and raw materials such as fufu, cassava flour, tapioca, flour, chips and pellets can extend the shelf-life, facilitate trade and promote industrial use (Taiwo, 2006; Fadeyibi, 2012). Therefore, in Nigeria where the research was carried out, the activities that was conducted is to know the Kinetic Study of Acid Hydrolysis of Manihot Esculentus (Cassava Starch).
1.3 Statement of Problems
Traditional processing of cassava by fermentation is centered on reduction of cyanide in the resultant product through extended period of fermentation for up to 7days as important strategy for the safety of product (Sanni, 2005). However, the traditionally processed cassava flour contain varied amount of residual cyanide because of the tendency by local processors to shorten the duration of fermentation in order to meet growing market demand (Nweke et al., 2002).
It is difficult to understand how cassava and cassava products such as cassava flour can be promoted without giving proper consideration to the fact that it contains cyanogens (linamarin) that liberates poisonous cyanide in the body. Consumption of cassava and its products containing amounts of cyanide can cause acute intoxication, with symptoms of dizziness, headache, nausea, vomiting, stomach pains, diarrhea and sometimes death (Oluwole et al., 2003).
1.4 Aim and Objectives of Study
The main aim of the study is to scrutinize the Kinetic Study of Acid Hydrolysis of Manihot Esculentus (Cassava Starch). In achieving this aim, the following specific objectives were laid out as follows:
- To investigate the acid hydrolysis of cassava starch
- To investigate how different fermentation times influence the quality characteristics of Starch.
- To produce Starch from cassava at controlled conditions of temperature, relative humidity and time.
- To monitor the fermentation time for breakdown and removal of cyanogenic compounds and cyanide.
1.5 Significance / Justification of Study
This present study considered the variability in the environment and fermentation conditions (temperature, relative humidity and duration of fermentation) during fermentation of cassava mash as they affect quality characteristics of Starch. There is need to optimize the local cassava flour processing methods as well as its industrialization especially by reducing the fermentation time and achieving the elimination of cyanide while maintaining cassava flour quality.
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.
1.6 Scope of Study
The study focuses on the determination of the Kinetic Study of Acid Hydrolysis of Manihot Esculentus (Cassava Starch).
1.7 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).
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