Quality Assessment of Sweet Roll Donut Sold in Makurdi Town Benue State
Chapter One
Objectives of study
The objectives of the study were to;
- evaluate the effects of supplementing wheat flour with pigeon pea and cassava flour on a sweet donut roll.
- evaluate the quality assessment of sweet donut rolls made from wheat-cassava-pigeon pea flour blends, and
CHAPTER TWO
LITERATURE REVIEW
Wheat
Wheat is the world’s third most important crop after maize and rice. Worldwide, wheat flour is used as the raw material for baking. The gluten protein in wheat makes it a unique substrate for breadmaking. The three main types of wheat are soft, hard, and durum. Unlike hard and durum wheats, which are used mainly for bread and pasta products, respectively, soft wheat has more than one major use, Including cookies, cakes, crackers and pretzels (Hoseney 1998).
The protein content varies significantly in wheat varieties and it ranges between 10 and 15% (Anjum and Walker, 2000). Wheat proteins contain albumins, globulins, gliadins and glutenins. While albumins and globulins are soluble in water and salt solution, respectively, gliadins and glutenins are collectively called gluten and are insoluble in water and salt solution.
It has been shown that the gluten proteins are responsible for the cohesive, viscoelastic property of wheat flour dough and the dough’s ability to retain gas during fermentation as well as dough setting during baking (Hoseney, 1998). To form cohesive and viscoelastic dough, gluten requires adequate hydration and kneading to promote cross linkages between glutenins and gliadins.
Gluten proteins
Among the cereal flours, only wheat flour has the ability to form gluten proteins when mixed with water to form a viscoelastic material that retains gas, resulting in high quality baked products. Hundreds of protein components which are present as either monomers or, linked by interchain disulfide bonds, as oligomers and polymers make up the gluten proteins (Wrigley and Beitz, 1998). They are unique because they are characterized by high contents of glutamine and proline, but are low in basic amino acids like lysine. The low content of basic amino acids implies that the level of electrical charges is very low. Thus, the low-charge density enhances interaction among the molecules forming the gluten, a condition that appears to be extremely necessary for dough formation (Hoseney, 1998).
The amino acid composition of gluten proteins also shows that about 35% of the total amino acids have hydrophobic side chains and hence the polar sides are not accommodated in the hydrophobic core of the protein (Hoseney, 1998). As a result, there is an increased hydrophobic interaction between gluten proteins. The hydrophobic interactions significantly contribute to the stabilization of gluten structure. In addition, the tendency of hydrophobic interactions to increase in energy with increasing temperature provides even more stability during the baking process.
Gliadin molecules have intra-molecular disulfide linkages resulting in a compact and globular shape. Compared to glutenins, gliadins have a low molecular weight of about 40,000 (Hoseney, 1998). The presence of disulfide bonds explains the need to knead the dough to break disulfide bonds between adjacent chains and realign them to form a continuous protein sheet (Stauffer 1998). When hydrated, gliadins have little or no resistance to extension, and are responsible for the dough’s cohesiveness.
Glutenin proteins are a heterogeneous group of proteins and multichained, linked by interchain disulfide bonds, with average molecular weights of about 3 million (Hoseney, 1998).
The high molecular weight of glutenins has been recognized as one of the main contributing factors to wheat’s desirable dough properties and baking performance. Physically, the protein is resilient and rubbery but not prone to rupture and gives the wheat dough its property of resistance to extension (Hoseney, 1998).
Cassava(Manihot esculenta, Crantz)
Cassava is an important source of food and income throughout the tropics, including Africa, Asia and Latin America. About 600 million people in Africa, Asia and Latin America depend on the plant for their survival, deriving calories and income from the roots and leaves (IFAD, 2008). Cassava production in Africa has more than tripled since 1961, from 33 million metric tons per year to 101 million metric tons, making the continent the largest producer in the world (IFAD, 2008). Advantages of cassava as a crop include flexibility in planting and harvesting time, drought tolerance, and ability of cassava to grow and produce in low nutrient soils, where cereals and other crops do not grow well (Onwueme, 1978; Nassar, 2005).
In Malawi, cassava is the most important root crop. Cassava plays an important role as a cash crop for smallholder farmers, middlemen, as well as sellers in various markets, and is gradually becoming an important industrial crop (Benesi et al., 2001). It is grown country wide and is a staple food crop for more than 30% of the population along the central and northern lake shore areas of Lake Malawi and the Shire highlands (Moyo et al., 1998). Country wide, cassava is used as a food supplement, a main part of breakfast, and snack food (Moyo et al., 1998). Cassava leaves are an excellent source of protein compared to legumes and are commonly consumed as vegetables in many parts of the country. The fresh cassava leaves contain 17-18% dry weight protein (FAO, 1993). The leaves are particularly important in the dry season when other green vegetables are in short supply.
CHAPTER THREE
MATERIALS AND METHODS
Introduction
Sweet donut roll used for this study was purchased at Makurdi town, while wheat flour and other ingredients were purchased from Ojuwoye market, Makurdi, both in Benue State, Nigeria.
Preparation of sweet donut roll flour
Bambara groundnut flour was prepared as described by Enwere (1998) and Ade-Omowaye et al. (2008), Figure 1. Two kilogram (2 kg) of clean whole- some sweet donut roll seeds were soaked with deionized water for 4 hours. The seeds were thereafter drained and dried in a tray drier (Model No SED-12, Shivang Furnaces and Oven PVT LTD, India) at 60°C for 12 h. The dried seeds were dehulled manually, boiled at 100°C for 30 min and further dried in the tray dryer at 65°C for 6 h. During drying, the seeds were stirred at intervals of 20 mins to ensure uniform drying. After that, the seeds were immediately cooled and milled using attrition mill (Model No SK-30-SS, PAAB Metal Works, Ikotun, Benue, Nigeria) and sieved with 500μm mesh sieve followed by packaging in polyethylene bags.
Preparation of doughnut
Prior to the production of doughnut, sweet donut roll flour was blended with wheat flour as shown in Table 1. The doughnut samples were produced with slight modification to the method of Paraggon Book Service (2013) as shown in Figure 2. The basic formulation consists of 100% blended flour, 30% fat, 1 egg, 10% sugar, 10% yeast, and 20% milk. The wheat–sweet donut roll flour used was poured into a clean bowl and baking fat gradually incorporated and mixed together vigorously. Yeast was dissolved with the already diluted milk and poured into the flour and mixed together with the salt, sugar, and egg. After mixing and proper kneading, dough formed was carefully kept in a warm environment prior to proofing (intermediate proofing). Deep frying of the dough in hot vegetable oil followed to obtain doughnuts. This method was repeated for each flour blend to obtain different samples of doughnut.
CHAPTER FOUR
RESULTS AND DISCUSSION
Proximate composition of flour obtained from wheat/sweet donut roll flour blends are shown in Table 2. The moisture content (%) of the flour samples ranged between 12.78 ± 0.05–12.88 ± 0.05. The moisture content of ALE (100% wheat flour), DEL (90:10, wheat: sweet donut roll), PIE (80:20 wheat: sweet donut roll) and ROW (70:30 wheat: sweet donut roll) were 12.78 ± 0.05, 12.66 ± 0.1, 12.75 ± 0.05 and 12.88 ± 0.05, respectively. These values agreed with the findings of Adeyeye and Akingbala (2015) for acceptable moisture for flour for baking. There was direct relationship between protein content of the flour blends and sweet donut roll flour addition, as protein increased steadily with increase in enrichment with sweet donut roll flour from 10.25 ± 0.01%−11.78 ± 0.02% amongst samples.
It has also been reported that when legume proteins were supplemented with those of cereals, there was synergistic effect of the protein quality, i.e., the protein quality is better than those obtained from single plant origin (Mensah & Tomkins, 2003). This synergistic effect was also observed for fat, ash, and fiber contents, which increased as the proportion of sweet donut roll flour increased ranging from 1.63 ± 0.01–2.23 ± 0.00%, 0.79 ± 0.02– 1.88 ± 0.01%, and 3.58 ± 0.01–4.02 ± 0.01%, respectively. The fat, ash, and fiber contents of the flour were observed to increase with an increase in the level of addition of wheat flour with sweet donut roll flour.
CHAPTER FIVE
CONCLUSION
In conclusion, this study showed that replacement of wheat flour with sweet donut roll flour promotes production of doughnuts with considerable improvement in the protein content and other mineral contents of the flour. Doughnuts produced with addition of sweet donut roll flour with up to 10% substitution in wheat flour will produce a more nutritionally balanced and acceptable product at no significant added cost and as well as promote utilization of bambara groundnut, an under-utilized crop.
The water absorption capacity (WAC) of CF was significantly higher than WAC values of control (WF) and flour blends. WAC of CF was approximately six times higher than that of the control flour. Supplementation with CF resulted in a slight increase in WAC of the flour blends. In the same line, the oil absorption capacity (OAC) of CF was higher than of control and blended flours. In addition, the swelling power (SP) of CF was significantly higher than those of control and flour blends. The behavior exhibited by flour samples on WAC and OAC reveal their molecular structure.
At each of the temperatures studied (70 and 80 degrees C); the flour viscosities among samples were statistically different. CF exhibited the greatest flour viscosity at both temperatures compared to control and flour blends. As the levels of supplementation were increased, the viscosity of flour blends slightly increased. This was due to addition of CF at increased levels. The low viscosities of WF and PPF are related to the cohesiveness of the starch molecules of the flours.
Among the physical properties of bread, loaf volume was negatively affected due to the dilution of gluten as CF and PPF were added at high levels. Conversely, bread loaf weight increased with the supplementation of non-wheat flours and became denser as the proportion of CF and PPF were increased in the formulation. In general, wheat bread had superior baking quality attributes compared to blended flour breads. More studies on the use of non-wheat flours alongside wheat flour (WF) are suggested to explore alternatives on how best to improve the baking quality of blended flour bread. On the other hand, supplementation of WF with non- wheat flours greatly improved the physical properties of cookies, including weight, diameter, height, and spread ratio. The greatest cookie weight, diameter and spread ratio were found for cookies with the highest amounts of CF and PPF, whereas the control cookies had the lowest values for all parameters.
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