Physicochemical and Sensory Qualities of Tiger-nut Chocolate Bread
Justification of the Study
Wheat-tiger-nut fortified with chocolate is not widely used in the production of bread therefore has been poorly investigated. Thus the commercial potentials of tiger-nut which has not been exploited sparked a keen interest in its flour selection for production of cookies and snacks. The success of this research work will provide information on the nutritional composition of bread made from wheat-tiger-nut and chocolate flour; also encourage the commercial/industrial application of the tiger-nut flour as an alternative to other most used flour and for better utilization of the crop.
Objectives of the Study
The main objectives of the study are to determine the functional properties of wheat and tiger nut flour blends and sensory properties of bread produced with wheat-tiger nut flour blends.
WHEAT (Triticum spp)
Distribution Origin of Wheat
Wheat is evolved from wild grasses. The centre of origin is South Asia. Tegri- Euphatis drainage basin. Large genetic variability is observed in Iran, Isreal, and Bordering countires. Wheat can be crossed with Aegilops and Agropyron species successfully. Manmade hybrid, Triticale is the cross between wheat (Triticum monococum) and Rye (Cecale Cereals) (Shewry and Jones, 2005).
Common wheat, sp.
Kingdom: Plantae – Plants
Subkingdom: Tracheobionta – Vascular plants
Superdivision: Spermatophyta – Seed plants
Division: Magnoliophyta – Flowering plants
Class: Liliopsida – Monocotyledons
Family: Poaceae – Grass family
Genus: Triticum – wheat
Species: Triticum aestivum – common wheat
Other Species: T. aestivum, T. aethiopicum, T. araraticum, T. boeoticum, T. carthlicum, T. compactum, T. dicoccoides, T. dicoccon, T. durum, T. ispahanicum, T. karamyschevii, T. macha, T. militinae, T. monococcum, T. polonicum, T. spelta, T. sphaerococcum, T. timopheevii, T. turanicum, T. turgidum, T. Urartu, T. vavilovii, and T. zhukovskyi.
Importance of Wheat
Wheat is a grass widely cultivated for its seed, a cereal grain which is a worldwide staple food. The many species of wheat together make up the genus Triticum; the most widely grown is common wheat (T. aestivum). The archaeological record suggests that wheat was first cultivated in the regions of the Fertile Crescent around 9600 BCE. Botanically, the wheat kernel is a type of fruit called a caryopsis (Adams et al., 2002).
Wheat is grown on more land area than any other food crop (220.4 million hectares, 2014). World trade in wheat is greater than for all other crops combined. In 2016, world production of wheat was 749 million tonnes, making it the second most-produced cereal after maize. Since 1960, world production of wheat and other grain crops has tripled and is expected to grow further through the middle of the 21st century. Global demand for wheat is increasing due to the unique viscoelastic and adhesive properties of gluten proteins, which facilitate the production of processed foods, whose consumption is increasing as a result of the worldwide industrialization process and the westernization of the diet (Fraley, 2003).
Wheat is an important source of carbohydrates. Globally, it is the leading source of vegetal protein in human food, having a protein content of about 13%, which is relatively high compared to other major cereals but relatively low in protein quality for supplying essential amino acids (Shewry et al., 2006).
Nutritional Content of Wheat
Globally, there is no doubt that the number of people who rely on wheat for a substantial part of their diet amounts to several billions. Therefore, the nutritional importance of wheat proteins should not be underestimated, particularly in less developed countries where bread, noodles and other products (e.g. bulgar, couscous) may provide a substantial proportion of the diet(Adams et al., 2002). Wheat provides nearly 55% of carbohydrate and 20% of the food calories. It contains carbohydrate 78.10%, protein 14.70%, fat 2.10%, minerals 2.10% and considerable proportions of vitamins (thiamine and vitamin-B) and minerals (zinc, iron). Wheat is also a good source of traces minerals like selenium and magnesium, nutrients essential to good health (Topping, 2007).
Wheat grain precisely known as caryopsis consists of the pericarp or fruit and the true seed. In the endosperm of the seed, about 72% of the protein is stored, which forms 8-15% of total protein per grain weight. Wheat grains are also rich in pantothenic acid, riboflavin and some minerals, sugars etc. The barn, which consists of pericarp testa and aleurone, is also a dietary source for fiber, potassium, phosphorus, magnesium, calcium, and niacin in small quantities (Topping, 2007).
The kernel of wheat is a storehouse of nutrients essential to the human diet. Endosperm is about 83% of the kernel weight; it is the source of white flour. The endosperm contains the greatest share of the protein in the whole kernel, carbohydrates, iron as well as many B-complex vitamins, such as riboflavin, niacin, and thiamine. Bran is about 14.5% of the kernel weight (Uauy et al., 2006). Bran is included in whole-wheat flour and is available separately. Of the nutrients in whole wheat, the bran contains a small amount of protein, larger quantities of the B-complex vitamins listed above, trace minerals, and indigestible cellulose material called dietary flour (Blechl et al., 2007). Wheat germ is the embryo of the wheat kernel. The germ or embryo of the wheat is relatively rich in protein, fat and several of the B-vitamins (Adams et al., 2002). The outer layers of the endosperm and the aleurone contain a higher concentration of protein, vitamins and phytic acid than the inner endosperm. The inner endosperm contains most of the starch and protein in the grain. It is separated from wheat being milled for flour (Drankham et al., 2003).
Wheat germ is sodium and cholesterol free, and dense in nutrients. It is rich in vitamin E, magnesium, pantothenic acid, phosphorus, thiamin, niacin and zinc. It is also a source of coenzyme Q10 (ubiquinone) and PABA (para-aminobenzoic acid) (Shewry, 2007). Wheat germ is also high in fiber, and contains approximately 1 gram of fiber per tablespoon. A diet high in fiber can be useful in regulating bowel function (i.e. reducing constipation), and may be recommended for patients at risk for colon disease, heart disease, and diabetes (Shewry, 2009).
MATERIALS AND METHODS
The major materials used such as Wheat (Triticum aestivum), Tigernut (Cyperus esculentus var. sativus) and chocolate were purchased from the local market in Owo, Ondo State Nigeria, and other ingredients used for this study were also purchased at Ikoko market Owo. This research work was carried out in Department of Food Science and Technology, Rufus Giwa Polytechnic Owo, Ondo State, Nigeria.
Preparation of wheat flour
For the production of wheat flour, 2kg of wheat was measured after which foreign materials such as dirt’s, stone, cobs, damaged and colored seeds were removed manually by hand picking. The sorted wheat was milled using laboratory attrition mill to produce wheat flour (WF) and was stored in an air tight polythene bag until needed further analysis as shown in figure I.
RESULTS AND DISCUSSION
Table 4.1: Proximate composition of Whole wheat-Tigernut- chocolate
CONCLUSION AND RECOMMENDATIONS
In terms of overall acceptability sample TCB5 has the highest sensory score, butit does not have any significant different with other sample inclusion of tigernut flour and chocolate in wheat flour at different levels resulted in notable increase in fat contents, fibre and ash. In the production of bread from wheat flour blended with tiger nut and chocolate as natural sweetener. The moisture content of all the samples is lower than that of other researchers. This guaranteed good quality and shelf -life of the cookies. And there was no growth both in nutrient agar plates for bacteria count and in potato dextrose agar fungi. The product is more stable when store under freezing condition for weeks. From respondent assessment, sensory attribute such as colour, appearance, aroma, taste and overall acceptability of bread were rated high between like slightly and like extremely. This is an indication apart from additional nutritional benefit, the characteristic eating quality and suitable of the food satisfied consumer’s perception.
This product, most especially at 15% tigernut flour and 5% chocolate level of substitution is recommended for human consumption. Further studies in these area include selection of improvise varieties of tigernut and protein supplement such as tigernut as well as optimization of processing conditions for the production of tigernut breads and functional quality acceptability of the blends could be carried out.
Also, Nigerians should be encouraged to cultivate tigernut based diet to meet their daily nutritional requirements.
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