Over the years, interest in incorporating phytochemicals into bakeries like bread has grown rapidly because of consumers’ awareness of the need to eat high quality and healthy foods. Hence, this review sought to determine the phytochemical content, and the acceptability of bread fortified with dandelion leaves powder.
In this work, an online search was done on works from the period 1970 to 2020 in Google Scholar database, ScienceDirect database, Mendeley database, PubMed, African journal of food, agriculture, nutrition, and development online database (AJFAND). The online search included the use of keywords, bread fortification and dandelion bread fortification.
TABLE OF CONTENT
ABSTRACT
ACKNOWLEDGEMENT
TABLE OF CONTENT
CHAPTER ONE
INTRODUCTION
1.1 Background
1.2 Problem Statement and Justification
1.3 Hypothesis
1.4 Main objective
CHAPTER TWO
LITERATURE REVIEW
2.1 Composition of bread and physical characteristics
2.2 Uses and demand for bread
2.3 Bread fortification
2.3.1 Bread fortification with fennel seed powder
2.3.2 Bread fortification with soy flour
2.3.3 Bread fortification with leafy vegetable
2.3.4 Bread fortification with Moringa leaf powder
2.3.5 Bread fortification with rice bran
2.3.6 Bread fortification with Nettle leaves powder
2.4 Dandelion and its composition
2.5 Food products fortified with dandelion
2.6 Sensory evaluation of bread
2.8.1 Discriminatory Testing
2.9.3 Descriptive Testing
CHAPTER THREE
METHODOLOGY
CHAPTER FOUR
DISCUSSION
CHAPTER FIVE
CONCLUSION AND RECOMMENDATIONS
REFERENCES
ABSTRACT
Over the years, interest in incorporating phytochemicals into bakeries like bread has grown rapidly because of consumers’ awareness of the need to eat high quality and healthy foods. Hence, this review sought to determine the phytochemical content, and the acceptability of bread fortified with dandelion leaves powder. In this work, an online search was done on works from the period 1970 to 2020 in Google Scholar database, ScienceDirect database, Mendeley database, PubMed, African journal of food, agriculture, nutrition, and development online database (AJFAND). The online search included the use of keywords, “bread fortification” and “dandelion bread fortification”. The study revealed that bread fortified with dandelion leaf powder impacted the sensory properties of the final product with an increased phytochemical content. Fortification with 5 % dandelion leaf powder resulted in non-significant change in the sensory properties and acceptability of bread. However, fortification with 7.5 %, 10 %, or 20 % dandelion leaf powder resulted in a change in sensory properties (texture, colour, and aroma) that were not accepted by consumers showing that bread fortified with 10 % and 15 % will have poor acceptability. Further work needs to be done to determine how heating affects the phytochemical constituents of dandelion-enriched bread.
ACKNOWLEDGEMENT
I express my thanks and appreciation to my supervisor, Dr. Nazir Kizzie-Hayford, and my colleagues, Mr Michael Adu, and Mr. Renolph Casper, whose immense support and corrections contributed to the successful completion of this work.
CHAPTER ONE INTRODUCTION
1.1 Background
Bread may be described as a fermented confectionery product prepared from wheat flour, water, yeast, and salt via series of a process involving mixing, kneading, proofing, shaping, and baking (Dewettinck et al., 2008). Bread is one of the oldest staple food products which is made and eaten in most countries around the world. It can be taken as a full meal or as a supplement with drinks. Wheat flour is the main ingredient in bread making. Wheat belongs to the family;Poaceae, Genus, Tritium;and Species,Tritium aestivum(Pourafshar et al., 2015). Wheat flour contains all the amino acids including the essential amino acids with some limitations in lysine, arginine, aspartic acid, glycine, alanine, tyrosine, histidine, threonine, and valine (Shoup et al., 1996). Wheat is also rich in gluten content, a protein, which gives the bread a fine, tough, and elastic texture (Nwanekezi, 2013). Wheat consists of 72.51 g of carbohydrate, 12.2 g of dietary fiber, 13.70 g of protein, 1.87 g of fat, per 100 g with little vitamins and minerals (Adom et al., 2003).
Taraxacum Officinale, commonly called Dandelion, is a herbaceous perennial belonging to family Asteraceae. Dandelion is a good source of vitamins, fibers, carbohydrates, myristic acid, and minerals. It is richer in vitamins A and C, iron, and calcium than spinach (Schütz et al., 2006). The main phytochemicals of dandelion are sesquiterpene lactones, taraxacin, and taraxasterol (Schütz et al., 2006). Phytochemicals are non-nutritive chemical compounds derived from plants which play a significant role in human disease prevention. Traditional Chinese medicine combines dandelion with other herbs to treat hepatitis and enhance an immune response to upper respiratory tract infections such as bronchitis, and pneumonia (Modaresi & Resalatpour, 2012).
Dandelion leaves are rich source of ß-carotene and inulin. ß-carotene is responsible for protecting cells from oxidation and cellular damage. Inulin is a complex carbohydrate in dandelion leaves responsible for the elimination of pathogens in the gastrointestinal tract, as well as the repression of cancer and osteoporosis (Simandi et al., 2002).
Incorporating phytochemicals into popular foods such as bread can benefit human health by supplying specific bioactive compounds that have a preventive role in several diseases. The process is termed bread fortification. Bread fortification is a health strategy and can impact more people without requiring them to change their existing consumption patterns (Calendar, 2018).
1.2 Problem Statement and Justification
Wheat bread is known to be a good source of calories, fibers, and protein. However, wheat has a low content of phytochemicals. Wheat bread is usually fortified with herbs to improve its nutritional and health value.
1.3 Hypothesis
Fortifying bread with dandelion leaf powder will improve its phytochemical content, and affect its overall acceptability as compared to unfortified bread.
1.4 Main objective
To determine the phytochemical content and sensory properties of bread baked with blends of different proportions of wheat flour and dandelion leaf powder so as to investigate the levels of fortification that are most acceptable by consumers.
1.5 Specific Objectives
- To determine the acceptability of wheat bread products fortified with dandelion leaf powder.
- To determine the phytochemical quality and quantity of wheat bread products fortified with dandelion leaf powder.
CHAPTER TWO LITERATURE REVIEW
2.1 Composition of bread and physical characteristics
The Code of Food, Beverage, and Shared Objects defines bread as a product prepared by baking in special furnaces and under defined conditions of mass consisting of wheat flour, water, yeast, and salt. Bread is produced by baking the dough after the processes of scaling, mixing, primary fermentation, folding, dividing, rounding, resting, shaping, proofing, baking, cooling, and storage (Chang et al., 2015). Bread is popular around the world and one of the oldest foods (Ijah et al., 2014).
Wheat flour is the main material in making bread. The chemical composition of the flour depends on the degree of milling. Increasing the degree of milling reduces the percentage of starch and increases the components present in the bark such as inorganic ingredients and insoluble fiber (Giannou et al., 2003). Milling and refining of wheat flour may also lead to loss of nutrients in the flour (Pourafshar et al., 2015). Wheat flour is high in gluten, which makes it superior to other types of flour including maize and barley. Proteins in wheat, gliadins and glutenins, interact with each other when mixed with water creating the gluten grid. The grid can bind the gases produced during fermentation and swells causing the bloating of the dough. The amount of proteins contained in the flour determines the amount of gluten to be formed, which, in turn, determines the strength, shape, and structure of the dough. As a result, flour has an exclusive property of shaping the structure and appearance of bakery products (Giannou et al., 2003).
2.2 Uses and demand for bread
Bread is believed to be the most complete, cheap, and basic food in times of extreme food poverty. It is a popular food consumed by almost one-third of the world’s population daily (Nwanekezi, 2013). Bread also has high fiber content, which reduces the risk of cardiovascular diseases, type II diabetes, and obesity (EHa, 2010). It can be taken as a full meal or as a supplement with drinks. Bread is also used as a vehicle for fortification (Dewettinck et al., 2008). The quality of bread depends on the nutritional value of the raw materials used and the effect of the processing (Bhol et al., 2016)
2.3 Bread fortification
There has been an explosion of consumer interest in incorporating active ingredients into popular foods like bread that can benefit human health by supplying specific bioactive compounds which have a preventive role in several diseases. Bread fortification is a health strategy and can impact more people without requiring them to change their existing consumption patterns (Calendar, 2018).
2.3.1 Bread fortification with fennel seed powder
Several research reports on bread fortification have been documented. Exemplarily, Das et al., (2013) evaluated the effects of fennel seed powder on the sensory properties and antioxidant activity of the fennel fortified bread. Fennel is an edible herb commonly used for confectionery. Bread fortified with fennel seed powder showed high antioxidant activity and good consumer acceptability when up to 7.0 % of fennel seed powder was added. The antioxidant activity of fennel seeds is attributed to the presence of flavonoids. These flavonoids scavenge reactive oxygen species in the human body thereby preventing cancer and degenerative neurological diseases in the body. White bread has a typical yeasty aroma. In the sensory analysis, the loaves of bread supplemented with 7.0 % and 10.0 % fennel seed powder scored significantly higher than the white bread, suggesting that the panel preferred the sweet aroma of fennel to the yeasty aroma of white bread. Loaves of bread with 3.0 % and 5.0 % fennel had a faint aroma of fennel, which was not sufficient to mask the yeasty aroma. On the other hand, bread with 15.0 % powder of the fennel seeds was rejected by the panel since the aroma of the fennel was very strong.
2.3.2 Bread fortification with soy flour
Soybean crops are rich is in oil and protein (Serrem et al., 2011). The incorporation of soy flour in bread increases the nutritional quality but with reduced general acceptability. This was confirmed by Ndife et al., (2011) who evaluated the nutritional, sensory quality, and consumer overall acceptability of bread fortified with soy flour. The incorporation of soybean flour into whole-wheat bread resulted in poor flavour scores. Most of the panelists complained of beany flavour from the soy flour in the composite bread. Serrem et al., (2011) reported that substitutions of defatted-soy-flour into wheat bread and biscuits were associated with the roasted soybean flavour and after taste. In soybeans, enzymatic break down by lipoxygenases or autoxidation of linoleic and linolenic acid produces hydroperoxides such as ketones and aldehydes that may be responsible for the beany-flavour which discourages soy consumption. The brownish bread appearance could occur due to caramelization and Maillard reactions, as the protein contributed by the soybean flour must have reacted with sugar during the baking process (Ndife et al., 2011).
2.3.3 Bread fortification with leafy vegetable
Vegetables largely contain phytochemicals, protein, and minerals. Bread enriched with vegetables was acceptable at low inclusion levels (1-2%) by consumers. This was confirmed by Odunlade et al., (2017) who evaluated the effect of the leaf powders of eggplant on the physical and sensory properties of bread. The volume of the bread decreased significantly. This was attributed to the reduction in gluten content as a result of the supplementation. The supplementation of wheat flour with non-glutinous flour results in lower bread volumes. Results of the sensory evaluation revealed that in terms of overall acceptability, the bread enriched with 1 % or 2 % vegetable leaf powder was acceptable to the consumers while the samples with 3 % inclusion level were neither liked nor disliked. This was because of the newness of such inclusion in the bread as most people are not accustomed to the consumption of green bread in the country.
2.3.4 Bread fortification with Moringa leaf powder
Sengev et al., (2013) determined the effect ofMoringa oleiferaleaf powder supplementation on some physico-chemical and sensory properties of wheat bread. Bread was prepared from varying proportions of 100 %, 99 %, 98 %, 97 %, 96 % and 95 % wheat flour supplemented with 0 %, 1 %, 2 %, 3 %, 4 % and 5 %Moringa oleiferaleaf powder respectively. The moisture content decreased significantly (p< 0.05.) from 35.20 % in 100% WF to 27.65 % in 95 WF:5 Moringa leaf powder composite bread. This could be due to the low moisture content of Moringa leaf powder used in the blends and might have implications in terms of the texture and microbiological quality of bread processed with added Moringa leaf powder.
Furthermore, the loaf volume and specific volume decreased significantly (p < 0.05) from 796.70 to 495.73 cm[3] and 4.70 to 2.65cm[3]/g respectively. This could be due to the reduction in gluten content as a result of supplementation. An increase in yeast dosage and longer fermentation time could help improve these physical characteristics.
There was also a significant (p < 0.05) decrease in preference in all the attributes evaluated as the percentage of Moringa leaf powder. The significant (p < 0.05) decrease in likeness for crust and crumb as the level of supplementation increased could be ascribed to the green colour of the bread imparted by the chlorophyll content of the leaves which was also alien to consumers. The decrease in likeness for flavour of the bread samples could be attributed to the herbal flavour of the leaf powder. The decrease in general acceptability with an increase in the percentages of Moringa leaf powder implies that panelists did not accept bread supplemented with Moringa leaf powder. The use of flavouring agents to mask the unacceptable herbal flavour ofMoringa oleiferapowder could help improve the acceptability of these products.
2.3.5 Bread fortification with rice bran
Rice bran is a good source of proteins, lipids, vitamins, and minerals. Ameh et al., (2013) evaluated the effects of rice bran supplementation on the physico-chemical and sensory properties of wheat bread. The result showed that 100% of wheat bread had better acceptability scores compared to composite bread however, all the composite bread samples had significantly higher values for nutritional parameters with a decreased volume. The average dough volume of the composite flours decreased significantly with an increasing proportion of rice bran. This may be attributed to the higher level of gluten present in wheat flour compared to composite blends which could not be properly stretched by carbon dioxide gas during fermentation and proofing.
2.3.6 Bread fortification with Nettle leaves powder
Nettles are of considerable interest as preservatives in foods for both human and animal consumption. Supplementation with 4% nettle powder could be adopted in wheat bread manufacturing without affecting quality adversely. The moisture content of nettle fortified bread is, however, high. This was proved by Man et al., (2019). Moisture content for bread increased on fortification with increasing nettle powder. This is attributed to the high water-binding capacity of the nettle powder. It may stale faster than the normal bread. The highest acceptability was 2% however considering high nutritional value, 4% nettle was optima.
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- Quote paper
- Esther Owusu Acheampong (Author), 2020, Sensory evaluation and phytochemical analysis of bread fortified with dandelion leaf powder, Munich, GRIN Verlag, https://www.hausarbeiten.de/document/1216374
