Evaluation of Proximate and Sensory Properties of Cocoyam-Wheat Composite Bread
Chapter One
Objectives of the study
The main objective of the study is to carry out an evaluation of proximate and sensory properties of cocoyam-wheat composite bread. The following are the specific objectives of the study:
- To examine the proximate composition of whole-wheat (WWB) and cocoyam-wheat composite bread (CCBs) samples
- To examine the sensory attributes of whole-wheat and cocoyam-wheat composite breads samples.
- To determine the bread characteristics.
CHAPTER TWO
LITERATURE REVIEW
Concept of Bread
Bread is a staple food stuff and is eaten in most countries around the world. It may be described as a fermented confectionery product produced mainly from wheat flour, water, yeast and salt by a series of processes involving mixing, kneading, proofing, shaping and baking (Dewettinket al., 2008). Composite flour had advantage for developing countries as it reduces the importation of wheat flour and encourage the use of domestic agricultural product as flour.
The use of white flour derived from the processing of whole wheat grain by eliminating the outer bran and the components which was aimed at improving the aesthetic value of white bread has also led to drastic reduction in the nutritional quality when compared to bread made from whole grain cereals (Dewettinctet al 2008, Manguet al., 2011). Recently consumer‟s awareness of the need to eat foods that have positive impact on health (functional foods) is increasing. Therefore the trend is to produce special bread made from whole ground flour and other functional ingredients known as health bread or functional foods. The development and consumption of such functional foods that contain whole wheat grains not only improve the nutritional status of the general population but also have been shown to have beneficial effects in the prevention of several diseases, such as cardiovascular diseases, constipation, irritable colon, colon cancer, obesity and diabetes (Rodriquez et al., 2006, Schatzkinet al., 2001, Jideani and Onwubali 2009). Wheat is a good source of calories and other nutrients but its protein is of lower nutritional quality when compared to milk, soyabean, pea and lupin proteins as its protein is deficient in essential amino acids such as lysine and threonine (Bakke and Vickers, 2007; Dewettinket al., 2008; Jideani and Onwubali 2009).
Recently consumers awareness of the need to eat high quality and healthy foods known as functional foods, that is foods which contains ingredients that provide additional health benefits beyond the basic nutritional requirements is increasing (Ndife and Abbo 2009). Therefore, the trend is to produce specially breads made from whole grain flour and other functional ingredients known as health breads or functional foods (Denettincket al., 2011).
Jideani and Onwubali (2009) reported that the development and consumption of such functional foods not only improves the nutritional status of the general population but also help those suffering from degenerative diseases associated with today‟s changing life style and environment. The whole wheat flour has been shown by many researchers to be a rich source of these functional ingredient such as fibre, phytochemicals, minerals, essential amino acids that are located in the bran and fat soluble vitamins contained in the germ of the whole wheat grain (Dewettinck et al, 2011).
The enrichment of bread and other cereal based confections with legumes flours particularly in regions where protein utilization is inadequate has long been recognized. This is because legume, nutritionally proteins are high in minerals, vitamin B and lysine, an essential limiting amino acid in most cereals. (Jideani and Onwubali 2009). High protein soy breads form a popular carrier of nutrition to vulnerable groups like pregnant and nursing mothers, young and school children in reducing the incidence of malnutrition and at the same time encourage the farmers to grow more soybeans due to the increased utilization (Islam et al., 2012).
Cocoyam
Overview
Cocoyam is a common name for more than one tropical root crop and vegetable crop belonging to the Arum family (also known as Aroids and by the family name Araceae) and may refer to:
Taro (Colocasia esculenta) – old cocoyam
Malanga (Xanthosoma spp.) – new cocoyam
Cocoyams are herbaceous perennial plants belonging to the family Araceae and are grown primarily for their edible roots, although all parts of the plant are edible. Cocoyams that are cultivated as food crops belong to either the genus Colocasia or the genus Xanthosoma and are generally comprised of a large spherical corm (swollen underground storage stem), from which a few large leaves emerge. The petioles of the leaves stand erect and can reach lengths in excess of 1 m (3.3 ft). The leaf blades are large and heart-shaped and can reach 50 cm (15.8 in) in length. The corm produces lateral buds which give rise to tubers or cormels and suckers or stolons.
CHAPTER THREE
MATERIALS AND METHODS
The study was carried at the Department of Food Science and Technology, University of Uyo, Uyo, Akwa Ibom state.
Materials
Cocoyam (X. Sagittifolium) samples were collected randomly from farmers along Nwaniba. A 100% hard wheat flour, yeast (instant dry yeast), fat, baking powder, sugar and salt were purchased from local shops in Morogoro, Nigeria. Reagents and chemicals for proximate analysis were obtained from Sigma-Aldrich chemical suppliers, and are of analytical grade.
Research design
Completely randomized design (CRD) was used in the study and principal factor was bread types (WWB, CCB 1, CCB 2, and CCB 3). The samples were analyzed for proximate composition, baking characteristics and sensory attributes. The effects of the principal factor on these parameters were determined
Preparation of cocoyam flour
Fresh corms were thoroughly washed with tap water, peeled using a stainless-steel knife, rewashed and cut into 0.5 cm thick slices. The slices were dried to a constant weight in an oven set at 105°C for 24 hours before milling into flour using a grinder fitted with a 500-µm mesh sieve. Flour obtained was packed in polyethylene bags and stored at 4° C ready for preparation of composite flours.
CHAPTER FOUR
RESULTS AND DISCUSSION
Chemical composition
Table 4.1 shows the result of the proximate composition of the cocoyam-wheat composite bread samples. The analysis of variance on all proximate analysis data showed significant differences between the bread samples at p<0.05. The moisture content values were 20.99% and 17.31% for the 100% wheat bread (WWB) and 30% cocoyam-wheat composite bread (CCB 3), respectively. This result implies that, the moisture content of the samples decreased with increase in the levels of cocoyam flour. Crude protein values were 12.54% and 9.04% for the 100% wheat bread (WWB) and30% cocoyam-wheat composite bread (CCB 3) respectively while fat contents values were 2.02% and 0.54% for 100% wheat bread (WWB) and30% cocoyam-wheat composite bread (CCB 3), respectively. This means that, the protein and fat content significantly decreased as the amount cocoyam flour substitution increased. It is therefore suggested that, consumption of this bread with other protein rich diet is of greater nutritional importance in order to compensate the reported reduction. Furthermore, fibre contents values were 0.29%and 1.54% for 100% wheat bread and 30% cocoyam-wheat composite bread, respectively implying a significant increase in fibre content with increasing the amount cocoyam flour substitution levels.
CHAPTER FIVE
CONCLUSION AND RECOMMENDATIONS
Conclusion
This study evaluated the proximate and sensory properties of cocoyam-wheat composite bread. In the view of the results, a similar proximate, sensory and baking quality comparable to 100% wheat bread was observed in 10% cocoyam-composite bread. This suggests that bread of good nutritional and sensory qualities could be produced from up to 10% cocoyam flour substitution in wheat flour. Findings of this study have potential to promote the production and diversification of cocoyam consumption in Nigeria and other African countries.
Cocoyam flour has been shown to possess ample amounts of proteins, minerals, and fat, which makes it an important source of these nutrients when used to partially replace wheat flour for culinary applications. Its physico-chemical and functional properties were also found to be desirable for use in composite flour blends.
Recommendations
The following recommendations are necessary based on the results obtained:
- Further studies should be done to improve the color and texture of bread to make it more appealing and palatable.
- Shelf-life, packaging and storage studies should be done because no preservative was added to the bread and they spoilt within few days of production.
- Farmers of cocoyam will be encouraged as they will be making more sales since a conversion of product from their produce has been developed.
- Globally, convenience is the main focus, producing a snack with local raw material which can compete with the conventional, will be a welcome development.
REFERENCES
- AACC. Approved Methods of American Association of Cereal Chemists. 10th Edn., AACC International, St. Paul, MN. 2000
- Akobundu ENT, Ubbaonu CN, Ndupuh CE (1988) Studies on the baking potentials on non-wheat composite flours. J Food Sci Technol 41: 211–214
- Akubor, P. I. (2013). Effect of ascorbic acid and citric acid treatments on the functional and sensory properties of yam flour. International Journal of Agricultural Policy and Research, 1, 103–108.
- AOAC.“Official Methods of Analysis,”Association of Official Analytical Chemists methods, AOAC 16th Edition. Washington DC. 1995.
- Araki E, Ikeda MT, Ashida K, Tanaka K, Yanaka M and S Iida Effects of rice flour properties on specific loaf volume of one-loaf bread made from rice flour with wheat vital gluten. Journal of Food Science and Technology Research 2009: 15 (4): 439 – 448.
- Chauhan GS, Zillman RR and NAM Eskin Dough mixing and bread making properties of quinoa-wheat flour blends. International Journal of Food Science and Technology. 1992; 27: 701–705.
