Production and Quality Evaluation of Biscuit From Sweet Potato and Maize Flour Blends
Chapter One
Aims and Objectives of the Study
Therefore, the aims and objectives of this study include the following:
- To develop a locally available snack that can be easily access in our environment, now that there is problem on importation of goods
- To examine functional properties of flours produced from the blends of maize and sweet potato.
- To determine the proximate composition of the snacks produced from the blends of maize and sweet potato.
- To determine the sensory attributes of snacks produced from the blends of maize-sweet potato composite flour.
CHAPTER TWO
LITERATURE REVIEW
Maize (Zea may L.)
Maize (Zea mays L.) is the third most important cereal in the world after rice and wheat and ranks fourth after millet, sorghum and rice in Nigeria (FAO, 2009). Maize or corn is the most important cereal crop in sub Saharan Africa (Akingbala et al., 2007). It is mostly used and traded as a leading feed crop but is also an important food staple. In addition to food and feed, maize has a wide range of industrial applications ranging from food processing to manufacturing of ethanol (FAO, 2006).
Global statistics for cereal consumption indicate that the average total consumption in the African diet is 291.7g/person/day, including an average maize consumption of 106.2g/person/day (FAO, 2009). Maize is known and called by different vernacular names in Nigeria depending on locality like agbado, igbado or yangan (Yoruba); masara or dawarmasara (Hausa); ogbado or oka (Ibo); apaapa (Ibira); oka (Bini and Isha); ibokpot or ibokpot union (Efik) and igumapa (Yala) (FAO, 2002).
Origin of Maize
Maize is one of the oldest human-domesticated plants. Its origin is believed to date back to at least 7000 years ago when it was grown in the form of a wild grass called teosinte in Central Mexico. Recognizing its early potential as a major food crop, over time the Mesoamerican natives managed to improve the crop, by systematically selecting certain varieties for their desired traits. This process led to the gradual transformation of teosinte to its present day form known as maize, a name which is a likely derivative of “mahis”, meaning “source of life” for Tanio people, the natives known to have mastered its cultivation. Maize is also known as corn, which is the name that has come into common usage primarily because it is used in the United States, the world’s largest producer, consumer and exporter of maize.
Maize is an annual plant with high productivity which also enjoys exceptional geographic adaptability, an important property which has helped its cultivation to spread throughout the world. Its gradual expansion in the Americas by the Natives was rapidly propagated in the 16th century following the return of Columbus to Europe. Colonial conquests and trade played a central role in the spread of maize cultivation well beyond the European continent, to Africa and Far East Asia (FAO, 2006). There exist several hybrids of maize, each with their own specific properties and kernel characteristics; the most common ones include: dent (or field maize, used for livestock feeding and can be yellow or white), flint (or Indian maize, grown in Central and South America), and sweet (or green maize).
Depending on their colour and taste, maize grown around the world is generally categorized into two broad groups: yellow and white. Yellow maize constitutes the bulk of total world maize production and international trade (FAO, 2006). It is grown in most northern hemisphere countries where it is traditionally used for animal feed. White maize, which requires more favourable climatic conditions for growing, is produced in onlya handful of countries, the United States, Mexico and in southern Africa. White maize is generally considered a food crop. Market prices are usually higher for white maize compared to the yellow type but the premium can vary depending on local supply and demand conditions.
Chemical Composition of Maize
Generally, whole maize contains 362 Kcal/100g; 8.1% crude protein; 72% starch, 5% fat, 1.3% ash, 1.2% fiber; 60 ppm calcium, 35 ppm iron; 1.8 ppm Zinc; 3.9 ppm Thiamine; 2.0 ppm Riboflavin; 36ppm Niacin; 3.0ppm pyridoxine; 0.25 ppm folates; 241 mg/100g phosphrous; 0.16 ppm selenium (Bressani, 2002).
Starch
Is a major chemical component of the maize kernel, it provides up to 72 to 73% of the kernel weight. Other carbohydrates are simple sugars present as glucose, sucrose andfructose in amounts that vary from 1 to 3% of the kernel. The starch in maize is made up of two glucose polymers: amylose (an essentially linear molecule), and amylopectin (a branched form). The composition of maize starch is genetically controlled. In common maize, with either the dent or flint type of endosperm, amylose makes up 25 to 30% of the starch and amylopectin makes up 70 to 75%. Waxy maize contains a starch that is 100 % amylopectin. An endosperm mutant called amylose-extender (ae) induces an increase in the amylose proportion of the starch to 50% and higher. Other genes, alone or in combination, may also modify the amylose-to-amylopectin ratio in maize starch (Zarkadas et al., 2000; Boyer and Shannon, 2007).
Protein
After starch, protein is the next largest chemical component of the kernel. Protein content varies in common varieties from about 8 to 11% of the kernel weight, with most of it found in the endosperm. The protein in maize kernels is made up of at least five different fractions: albumin (7%), globulins (5%) and non-protein nitrogen (6%) amounting to about 18% of total nitrogen as well as the prolamine fraction (52%) and glutelin fraction (25%) of the total protein in the kernel. Usually a small amount, about 5%, is residual nitrogen (Afoakwa et al., 2002). The nutritional quality of maize as a food is determined by the amino acid make-up of its protein. In common maize, deficiencies in lysine and tryptophan are evident as confirmed with Quality Protein Maize (QPM) (Punita, 2006). An additional important feature of maize composition is the high leucine content in common maize and the lower value of this amino acid in QPM (Zarkadas et al., 2000; Mertz et al., 2005).
CHAPTER THREE
MATERIALS AND METHODS
Materials Source
The materials needed for snack production using maize-potato flour blend are:
- Maize(Zea may)
- Sweet potao (Ipomoea batatas)
- Skim powder milk
- Sugar, salt and baking powder
- Food grade flavor and
- Margarine
These materials were procured from the local market in Owo, Ondo State, Nigeria.
Methods
Production of Maize Flour
Maize The maize flour was prepared by the method reported by Asiedu (2009). Dried maize kernels were sorted to remove dirt’s and impurities, it was then washed in clean water to remove any attached dirt on the maize, after which it was dried under the sun for 48 hours, thereafter it was milled using attrition mill, sieved and packaged into high density polyethylene film (figure 1).
CHAPTER FOUR
RESULTS AND DISCUSSION
Results
Table 4.1: Results on the Functional Properties of Maize and Sweet potato Flour Blends
CHAPTER FIVE
CONCLUSION AND RECOMMENDATIONS
Conclusion
The present study has revealed that consumption of the maize-sweet potato based snack (biscuits) may improve nutrition in terms of the essential amino acid intakes in such a way that it may eventually contribute to the reduction of PEM, although an increase in the level of substitution of the maize flour with the sweet potato flour resulted in a reduction of the acceptance level in all the sensory attributes considered. Biscuits with a higher nutritional content can be made with composite blends of maize flour and sweet potato flour.
Recommendation
The comparative nutritional and sensorial credibility justify the need for further investigation into the use of various agricultural materials in the production of snacks that will promote both the nutritional and health needs of man. Attention should be paid towards attaining the fiber levels for digestion and health benefits without compromising the quality characteristics of products.
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