Production of Biscuits From Malted Sorghum and Wheat
Chapter One
Objectives of the Study
The objectives of this study were:
- Utilization of sorghum and wheat flour in biscuits making.
- To study the acceptability of biscuits produce from malted wheat-sorghum flour
- To evaluate the quality of biscuits made from composite flours (wheat and sorghum).
CHAPTER TWO
LITERATURE REVIEW
General Structure and Chemical Composition of Cereal Grain
Botanically the cereal seed grain or kernel is covered by fibrous outer layer (bran or seed coat) to protect the grain from attack by insects. This protection is quite effective if there are no cracks on the surface (Kordylas, 2001). Therefore the kernel structure is important with respect to minimizing damage during grain harvest, drying, handling, storage, milling, and germination and in enhancing nutritional value (Pomeranze and Bechtel, 2008). The seed coat surrounds the endosperm and embryo (germ). The endosperm is the main part of the kernel, which contains a large part of the food material- starch and protein. That is the part, which generally makes food grains important as food for both humans and animals. It provides food for the developing seed if it is plant, and food for the seed during storage.
Wheats and sorghums grain contains the outer translucent and inner opaque endosperm, the proportion of which determines the endosperm texture. The peripheral endosperm is almost completely filled with protein bodies resulting in a tightly packed structure. The corneous hard or translucent endosperm protein of sorghum grain is similar; with starch granules packed in cages of protein that completely fill the cell. The soft or opaque endosperm is characterized by large inter-granular air spaces. Starch granules in this region of the endosperm are found covered with a thin layer of protein. Air spaces in the soft endosperm result in a less dense material, thus kernels with predominantly soft endosperm are less dense than hard kernels. The round loosely packed, starches granules and weakly adhering protein matrix, are responsible for the kernels soft character. The tightly packed, hard endosperm on the other hand, has strong protein- starch adhesion that results in a hard endosperm (Hoseney et al., 2004; Rooney and Sullins, 2007; Mazhar, 2003).
The embryo contains the life of the seed, and it is the part that develops into a new plant when the seed is planted. It contains most of the proteins present in the seed with some fat, vitamins, and minerals. (Kordylas, 2001) and starch, there is generally a gradient increasing protein and decreasing starch per cell from the inner to the outer region of the endosperm (FAO, 2009).
Anos, (2007) reported that the wheat kernel consist of endosperm, bran and germ. The endosperm constitutes about 83% of the kernel weight and it is the source of white flour and contains the greatest share of proteins in the whole kernel, as well as carbohydrates, iron and many B-complex vitamins, such as riboflavin, niacin and thiamin. Bran constitutes about 14.5% of kernel weight and it’s included in whole-wheat flour, and is also available separately from nutrients in the whole wheat. The bran contains small amount of protein, larger quantities of Bcomplex vitamins trace minerals and indigestible cellulose material, (dietary fiber). The germ constitutes about 2.5% of kernel weight, usually separated because of the fats, which limit the keeping quality of flour. Wheat germ can be purchased separately and included in whole-wheat flour. Hoseney, (2006) reported that the germ comprises 2.5-3.5% of the kernel, relatively high in protein sugar mainly sucrose and raffinose, oil and ash. It contains no starch but rather high in B and E vitamins and contains many enzymes.
Egan et al (2001) found that the wheat grain has the following composition: Endosperm 85%, bran 12.5% and germ 2.5%, while Kent-Jones and Anos (2007) reported that the average composition of wheat grain is approximately 85% endosperm, 2% embryo or germ and 13% husk. Wheat cultivation in the Sudan dates back to more than 2000 years, but until 1940’s production was confined to the northern region (16-22°N) where all inhabitants are traditionally wheat consumers. During the Second World War (1942/43) and because of the difficulties of importing wheat from abroad, great need had been felt for additional wheat to be produced from local resources. Hence 20,000 feddens of irrigated clays of central state (Gezira Scheme) were cultivated and the trial was considerably successful.
The varieties grown were Giza 155 and Mexican. However, in-spite of success no wheat was produced in Gezira scheme after the war was over. This was partly because it was possible to import wheat besides the Gezira tenants who have already developed a taste for their subsistence sorghum crop found it difficult to grow wheat. In addition to the above reasons land and irrigation water formerly allocated to wheat production were needed for other crops within the rotation. But after 2000’s wheat growing area has been extended Southwards to warmer regions, to the irrigated scheme of central Sudan such as those in Gezira, New Halfa and White Nile (1215°N)(Ali, 2007; Ishag and Ageep, 2001, Mohamed, 2005).
The sorghum kernel is flattened sphere grain approximately 4.0mm long, 3.5mm wide and 2.5mm in thickness. The kernel weight varies from 8-50mg (average 28mg) (Rooney and Clark (2008) and Kordylas (2001)). It involves four main parts, the bran (pericarp or outer cover), testa, the endosperm (storage tissue) and germ (embryo). Rooney and Sullins (2007) stated that the pericarp is composed of epicarp, mesocarp and endocarp, has low protein content and mainly composed of cellulose and starch. It includes wax and small starch granules in the mesocarp (Sanders, 2005 and Collier, 2003). Testa, the pigmented cells beneath the pericarp cells is generally attributed to the presence of polyphenols (Tannins); the endosperm consists of the aleurone layer, the peripheral, corneous and floury endosperms. The aleurone layer cells have spherical bodies that vary in size, containing no starch granules, but it contains proteins, minerals, water- soluble vitamins, enzymes and oil (Hoseney et al. 2004; Rooney and Sullins, 2007). Germ or embryo is surrounded by soft endosperm, rich in protein and oil (Rooney and Sullins, 2007).
The size, pigmentation, and other characteristics of the grains vary widely among varieties. The color of the grains varies from white, yellow and orange to red and brown. Their size and shape may be large, small, round or flattened. The husk differs in size, color texture and shape.
Hubbard et al. (2000) reported that, the relative proportion for medium- sized sorghum kernels; the bran, germ and endosperm were found to be 7.9, 9.8 and 82.3% respectively. Hulse et al. (2000) reported 7.3 to 9.3%, 7.8 to 12.1 and 81.1 to 84.6% for bran, germ and endosperm respectively. Endosperm, the largest part of the kernel, is relatively rich in mineral matter, ash and oil content it is however, a major contributor to the kernel’s protein, starch and B-complex vitamins (FAO, 2005). The grains of many sorghum varieties have a dark layer in the central part containing the embryo sac, which gives a sour, bitter taste, and a dark unattractive color to flour produced from them. Yellow grains without the dark layer, however, give good quality flour, although the flour is sometimes coarse (Kordylas, 2001).
Proximate analysis provides a good initial impression of the relative value and utility impression of an agriculture commodity, and allows a basis of comparison between different species, plant parts and cultivation conditions (FAO, 2001). Compositionally, a cereal consists of 12-14 % water, 65-75% carbohydrates, 2-6% lipids and 7-12% protein. Cereals are quite similar in gross composition being low in protein and high in carbohydrates (Eliasson and Larsson, 2003).
CHAPTER THREE
MATERIALS AND METHODS
Collections of Materials
The wheat (Triticum aestivum) and sorghum (Sorghum bicolar) grains were obtained from Oja Oba market in Owo, Ondo State, Nigeria. The wheat and sorghum grains were sorted manually and milled using the commercial disc attrition mill. Sorghum flour was sieved by using mesh size of 250 μm opening. Other Materials/ingredients such as sugar, fat common salt and sodium bicarbonate used in this study were also bought at Oja Oba market.
Preparation of Flour
Production of Malted Sorghum
Malted-sorghum flour was produced using the procedure described by Mohamed (2002). The sorghum grains (2 kg) were sorted to remove stones, dirt and other extraneous materials. The cleaned grains were thoroughly washed and steep in water for 12 hrs so as to attain a 42-46% moisture level. The hydrated grains were spread on a moist jute bag which had been previously sterilized by boiling for 30 minutes and the grains were allowed to germinate for four days. Non-germinated grains were discarded and the germinated seeds were dried at 60°C in a cabinet dryer to a moisture content of 10-12%. The withered rootless grains were gently brushed off, and the malted grains were dry milled, sieved and packed in a seal lock cellophane bag until ready for used.
CHAPTER FOUR
RESULTS AND DISCUSSION
Results
Table 4.1: Results for Proximate Analysis of Biscuits Produced from Malted Sorghum and Wheat
CHAPTER FIVE
CONCLUSION AND RECOMMENDATION
Conclusion
From the study, it can be concluded that sorghum and wheat flour combination for biscuits production is very good, from the results it is shown that the combinations of both flour for biscuits making prove to be a good source of mineral in moderate amount, good source of protein (SWB), fat (SWA) and carbohydrates (all samples).
Recommendation
Based on the study above it is therefore recommended that the use of wheat and sorghum in perfects combination ratio should be encourage in food industries this can contributes in the control of micronutrient malnutrition, though in low amount and its easily available in market in low price.
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