ABSTRACT
This study investigated the effect of processing techniques on functional, phytochemical and nutrient properties of ukpo, ofor and achi. Ukpo, Ofor and Achi seed flours were analyzed using toasting and steeping technique at varying time intervals (5 and 10mins) as well as sprouting technique. The result obtained from the functional properties of the ukpo, ofor and achi flours showed that water absorption capacity, swelling index, emulsification capacity, gelatinization capacity and bulk density ranged from ranges from 2.61 to 5.65ml/g, 3.41 to 6.05%, 16.73 to 24.63%, 4.50% to 12.40% and 0.57g/ml to 0.66g/ml respectively. Also, the proximate composition showed that moisture content, dry matter, total ash, crude protein, crude fat, crude fiber and carbohydrate ranged from 8.14 to 11.53%, 29.72 to 92.70%, 1.68 to 2.75%, 4.56 to 7.39%, 1.85 to 3.03% and 20.88 to 26.46% respectively. The result of the mineral composition showed that calcium, potassium, phosphorus, zinc, iron and sodium values for ukpo, ofor and achi were 68.28mg/100g to 79.95mg/100g, 74.49mg/100g to 82.90mg/100g, 42.30mg/100g to 46.76mg/100g, 4.09mg/100g to 6.31mg/100g and 26.43mg/100g to 36.79mg/100g respectively. The Vitamins (A, B1, B2, B3, C and E) values ranged from 2.41 to 13.28 mg/100g, 0.46 to 0.71mg/100g, 0.22 to 0.50mg/100g, 0.31 to 0.61mg/100g, 4.61 to 6.10mg/100g and 2.61 to 3.85mg/100g respectively. The result of the phytochemical composition (mg/100g) such as tannin, alkaloid and phytate for ukpo, ofor and achi flour ranged from 2.56 to 3.95mg/100g, 1.27 to 1.94mg/100g and 0.62 to 0.91mg/100g respectively. Analysis showed that there were significant (p < 0.05) differences in the functional properties, phytochemical and nutrient values in ukpo, ofor and achi flours. Thus, the study affirms the presence of functional, phytochemical, mineral and nutrient values in ukpo, ofor and achi flours. The study also asserts that suitability of sprouting technique in ukpo, ofor and achi flour processing.
TABLE OF CONTENTS
Title Page i
Certification ii
Dedication iii
Acknowledgements iv
Table of contents v
List of Tables vii
List of Figures viii
List of Plates ix
Abstract x
CHAPTER 1: INTRODUCTION
1.1 Background of Study 1
1.2 Statement of Problem 7
1.3 Aim and Objectives of the Study 8
1.4 Scope of the Study 8
1.5 Justification of the Study 8
CHAPTER 2: LITERATURE REVIEW
2.1 Identification and Origin of Ukpo, Ofor and Achi 10
2.1.1 Mucuna Sloanei 10
2.1.2 Detarium Microcarpum 11
2.1.3 Brachystegia Eurycoma 12
2.2 Nutritional composition of Mucuna Sloanei, Detarium Microcarpum
and Brachystegia Eurycoma 14
2.2.1 Nutritional composition of Mucuna Sloanei 14
2.2.2 Nutritional composition of Detarium Microcarpum 15
2.2.3 Nutritional composition of Brachystegia Eurycoma 16
2.3 Importance and utilization of Mucuna Sloanei, Detarium Microcarpum
and Brachystegia Eurycoma 17
2.3.1 Importance and utilization of Mucuna Sloanei 17
2.3.2 Importance and utilization of Detarium Microcarpum 18
2.3.3 Importance and utilization of Brachystegia Eurycoma 19
2.4 Food Thickeners 19
2.5 Processing Techniques 22
2.5.1 Toasting 23
2.5.2 Steeping 23
2.5.3 Sprouting 23
CHAPTER 3: MATERIALS AND METHODS
3.1 Sources of Materials 25
3.2 Methods 25
3.2.1 Preparation of samples 25
3.2.2 Proximate composition analysis 32
3.2.2.1 Determination of moisture content 32
3.2.2.2 Determination of crude fat content 33
3.2.2.3 Determination of crude protein 34
3.2.2.4 Determination of total ash 34
3.2.2.5 Determination of crude fibre 35
3.2.2.6 Determination of carbohydrate content 35
3.2.3 Mineral content analysis 35
3.2.4 Vitamin analysis 36
3.2.5 Phytochemical analysis 40
3.2.6 Functional properties 41
3.3 Data Analysis 43
CHAPTER 4: RESULTS AND DISCUSSIONS
4.1 Results 44
4.1.1 Functional properties result 44
4.1.2 Proximate results 53
4.1.3 Mineral composition results 63
4.1.4 Vitamins composition results 72
4.1.5 Phytochemical composition results 81
CHAPTER 5: CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion 87
5.2 Recommendations 91
References 92
LIST OF TABLES
Table 4.1: Functional properties of ukpo 47
Table 4.2: Functional properties of ofor 49
Table 4.3: Functional properties of achi 51
Table 4.4: Proximate composition (%) of toasted, steeped and sprouted ukpo 57
Table 4.5: Proximate composition (%) of toasted, steeped and sprouted ofor 59
Table 4.6: Proximate composition (%) of toasted, steeped and sprouted achi 61
Table 4.7: Mineral composition of ukpo 66
Table 4.8: Mineral composition of ofor 68
Table 4.9: Mineral composition of achi 70
Table 4.10: Vitamin composition of ukpo 75
Table 4.11: Vitamin composition of ofor 77
Table 4.12: Vitamin composition of achi 79
Table 4.13: Phytochemical composition of ukpo, ofor and achi 83
LIST OF FIGURES
Figure 2.1. Mucuna Sloanei: Seeds and Fruits. 10
Figure 2.2: Detarium Microcarpum: Seeds and Fruits. 12
Figure 2.3: Brachystegia eurycoma: seeds and fruits. 13
Figure 3.1: Flow diagram of the processing treatments (steeping/sprouting and toasting) of Ukpo (Mucuna sloanei), Ofor (Detarium microcarpum) and Achi (Brachystegia eurycoma) 32
Figure 4.1: Graph of functional properties of toasted, steeped and sprouted Ukpo 48
Figure 4.2: Graph of functional properties of toasted, steeped and sprouted Ofor 50
Figure 4.3: Graph of functional properties of toasted, steeped and sprouted Ofor 52
Figure 4.4: Graph of proximate composition of toasted, steeped and sprouted Ukpo 58
Figure 4.5: Graph of proximate composition of toasted, steeped and sprouted Ofor 60
Figure 4.6: Graph of proximate composition of toasted, steeped and sprouted Achi 62
Figure 4.7: Graph of Mineral composition of toasted, steeped and sprouted Achi 67
Figure 4.8: Graph of Mineral composition of toasted, steeped and sprouted Ofor 69
Figure 4.9: Graph of Mineral composition of toasted, steeped and sprouted Achi 71
Figure 4.10: Graph of Vitamin composition of toasted, steeped and sprouted Ukpo 76
Figure 4.11: Graph of Vitamin composition of toasted, steeped and sprouted Ofor 78
Figure 4.12: Graph of Vitamin composition of toasted, steeped and sprouted Achi 80
Figure 4.13: Phytochemical composition of toasted, stepped and sprouted ukpo 84
Figure 4.14: Phytochemical composition of toasted, stepped and sprouted ofor 85
Figure 4.15: Phytochemical composition of toasted, stepped and sprouted achi 86
LIST OF PLATES
Plate 3.1: Toasted Ukpo (5minutes) 25
Plate 3.2: Toasted Ukpo (10minutes) 26
Plate 3.3: Toasted Ofor (5minutes) 26
Plate 3.4: Toasted Ofor (10minutes) 27
Plate 3.5: Toasted Achi (5minutes) 27
Plate 3.6: Toasted Achi (10minutes) 28
Plate 3.7: Steeped Ukpo (5minutes) 28
Plate 3.8: Steeped Ukpo (10minutes) 29
Plate 3.9: Steeped Ofor (5minutes) 29
Plate 3.10: Steeped Ofor (10minutes) 30
Plate 3.11: Steeped Achi (5minutes) 30
Plate 3.12: Steeped Achi (10minutes) 31
Plate 3.13: Sprouted Ukpo 31
CHAPTER 1
INTRODUCTION
1.1 BACKGROUND OF THE STUDY
Food thickeners or thickening agents are used in food to absorb the fluid of the food without altering its physical or chemical properties. These are the modified food starch, polysaccharide or certain vegetable gums, which are used in beverages, gravies, sauces and stews. Thickening agent is the term applied to substances which increase the viscosity of a solution or liquid/solid mixture without substantially modifying its other properties. It can be any ingredient or agent that is added to other food ingredients in order to create a stiffer or denser food mixture (Food Additive, 2011). Several food materials have been implicated over the years to have thickening potentials with the legumes the most utilized.
Flours from ‘achi’, and ‘ukpo’ have been found to be used in most States in Nigeria including Imo, Abia, Anambra, Akwa-Ibom and Ondo States. They are used as thickeners in traditional soups (for eating gari, pounded yam or cocoyam and fufu). They are equally used as emulsifiers and flavouring agents in traditional soups due to their gum content. Nutritionally, the seed proteins are rich in lysine but deficient in sulfur containing amino acids particularly cysteine and methionine (Okaka et al., 2006). Owing to their high protein content, they are used to supplement cocoyam (high carbohydrate) and melon (high oil) in soup making. According to Giwa et al. (2010), soup thickeners also help in tackling protein- energy deficiency (the most common form of malnutrition) in regions where the people depend mainly on starch-based diets.
The use of food thickeners depends upon the type of food and purpose, for instance, some are used to increase taste, flavor, nutritive value, etc. These are good sources of nutrients such as carbohydrate, protein and fats. The protein content of food thickeners can be compared to that of some important protein sources like oyster, pork and marine fishes (Lund et al., 2000; Ibironke et al., 2006).
There exist a wide range of thickening agents available in Nigeria, which are mainly Brachystegia eurycoma also known as “Achi”, Afzelia africana (Akpalata), Detarium microcarpum (Ofor) and Mucuna solannie (Ukpo) and are commonly used by millions of Nigerians (Enwere, 1998).
Mucuna solannie which is popularly known as “ukpo” by the Igbo-speaking people of South-eastern Nigeria is a legume belonging to the subfamily papilonacea. It comprises pods covered with brownish dense whisker – like hairs called trichomes that are irritating when they come in contact with the skin or eyes. Each pod may contain 1 to 3 seeds with a hard coating which is white when immature and turns black when mature and dry. (Enwere, 1998). Mucuna species generally have high protein content of 24% to 1.44%, lipids ranging from 2.86% to 9.8%, crude fibre (5.3 – 11.5%), ash (2.9 – 5.5%), and carbohydrate ranging from 59.2% to 64.88% (Arianthan et al., 2003, Vadivel and Janardhanan 2000; Adebowale et al., 2005; Ezeagu et al., 2003). The anti-nutritional factors found in Mucuna species include L-dopa, phenolics, tamin, haemagglutinins, trypsin and chymotrypsin inhibitors, phytic acid, saponins and cyanogenic compounds. (Vadivel and Janardhanan, 2000). However, most of these anti-nutritional factors are eliminated to low levels during processing. Ukachukwu and Obioha (1997) reported detoxification by cooking for 90min or toasting for 60min. In Eastern Nigeria, Mucuna seeds are usually toasted for 5 – 10 minutes before grinding and flouring to supplement as thickener in sauce or soup. Mucuna solannie is used as a soup thickener in traditional soups preparation. Here the seeds are cracked, boiled, dehulled, ground to powder and added to the soup. In some localities, it is prepared as a choice dish. In this case the Mucuna solannie is cracked, boiled overnight and dehulled. All parts of Mucuna plant are reported to possess phytochemicals of high medicinal value of human and veterinary importance and also constitute as an important raw material in Ayurvedic and folk medicines. Mucuna seeds constitute as a good source of several alkaloids, antioxidants, anti-tumor and anti-bacterial compounds. Seeds are the major source of L-DOPA, which serve as a potential drug in providing symptomatic relief for Parkinson’s disease (Siddhuraju et al, 1996).
Detarium microcarpum belongs to the family caesalpiniceae, phylum spermatophyte and the order fabacea. The various ethic names in Nigeria are: ofor in (Igbo), taura (Hausa), gatapo (kanuri), gkungorochi (Nupe) and aikperlarimi (Etsako) etc. It is particularly associated with dry savannah countries. It is known to flower throughout the wet season and fruits between November and January. Detarium microcarpum has diuretic and anti-inflammatory effects and reduces blood glucose levels weighed and subjected to dry ashing in a well-cleaned in diabetic patients. The functional properties are quite similar to those of Brachystegia eurycoma, hence it is equally classified as a food gum (Fatope et al., 1993).
Brachystegia spp. is locally known as “Achi” by the Ibos, “Akolodo or Eku” by Yoruba, “Akpakpo or Apaupan” by Ijaw, “Dewen” by Benin, “Okwen” by Edo, ‘oyam’ by the Kwales and “Okung” by Efik (Adewale and Mozie, 2010; Ikeagwuet al., 2009; Nwosu et al., 2011; Nwosu, 2012). Brachystegia spp. an underutilized legume crop consumed in Nigeria is a seasonal woody plant mainly found along river banks or swamps in Western and Eastern Nigeria, as well as well drained soils. In Nigeria, there are three major species of Brachystegia which include Brachystegia nigerica, Brachystegia eurycoma and Brachystegia kennedyi. B. nigerica seed or leaf, (specify) is broad in size, round in shape, dark red in colour; has gummy husk which makes dehulling hard and is commonly found in Katsina, Adamawa in Northern Nigeria. B. eurycoma is medium in size, round in shape, dark brown in colour with less sticky husk which makes dehulling very easy. It is commonly found along river banks of the Southern Nigeria. Achi seed is classified as legume with its pod containing seeds, an economic tree crop that grows in the tropical rainforest of West Africa, and contains 56% carbohydrate, 15% crude fat, 9% protein, 4.5% ash and 2.9% crude fiber (Uhegbu et al., 2009). Processing of Achi to obtain the inner edible seeds (cotyledonous kernels) normally involves such operations as parboiling, soaking or roasting prior to dehulling. The finely ground seeds of Achi have been used in the treatment of sewage sludge and were found to improve sludge filterability and compare favourably with the traditional ferric chloride conditioner and the optimum value for Achi for this treatment is 21.5% (0.4 g/cm3) and for ferric chloride is 25% (0.5 g/cm3) (Eze, 2002). According to some researchers, Achi contains 10.52% protein, 2.50% ash, 8.70 crude fibre, 8.50% moisture content, 8.48% edible fat and 61.30% carbohydrate. These nutrients are required for proper functioning of the human body system. Crude fibre is very effective in reducing blood cholesterol levels and moderating glucose response in diabetics. Enjoying achi as a thickener daily is highly nutritious. The local soup thickeners are the most nutritive part of the plant, well known to contain a significant source of vitamin C, magnesium, protein, vitamin B6 and provitamin A as beta-carotene.
However, Mucunna spp, Detarium microcarpum and Brachystegia spp. are considered to be good thickening agents. The processing of the cereals and starch roots into a form of paste and eaten with soups is the general practice. Among the legumes used in soups for emulsification and stabilization are Mucuna sloanei (ukpo) and Brachystegia eurycoma (achi) and Detarium microcarpum (ofor). Each of the soup thickeners differs in species from the others and so have their individual characteristic flavor which they impart to soups. At present, most of the indigenous edible plants which could be used as food thickeners in Nigeria and other West African countries have been neglected and have remained relatively unknown and under-utilized. Mucuna sloanei, Brachystegia eurycoma and Detarium microcarpumare naturally found in tropical and sub-tropical areas respectively (Ayozie, 2010). Soup is a primary liquid food general served warm that is made by combining ingredients such as meat and vegetables with stock, juice, water or another liquid, it is a tasty popular food that is nutritious, wholesome and stimulates the appetites. Thickening usually improves the taste, but most important is the nutritional value of foods. Thickeners are substances, which when added to a mixture, increase its viscosity without substantially modifying other properties such as taste and aroma (Okwu et al., 2010). Flours from these soup thickeners have been found to be used in most state in Nigeria with varying processing methods. They are used as thickeners in traditional soups (for eating of garri, pounded yam or cocoyam and fufu), equally used as emulsifiers and flavoring agents in traditional soups due to their ability to swell in water and influence the viscosity of liquid in addition to their low cost, which is an advantage to most customers as little quantity of this thickeners creates great viscosity as against other thickeners like melon and ogbono (Ezeoke, 2010).
Nutritionally, ukpo, achi and ofor are important and good economic sources of protein and carbohydrates, these nutrients are essential to human nutrition but the composition of these nutrients in them differs. The protein of these foods is rich in lysine but deficient in sulfur containing amino acids particularly cysteine and methionine. Specifically, Mucuna sloanei (Ukpo) contains between 6-19% crude protein; 39.8- 61.49% carbohydrate; 1.84- 5.9% fat and 11.24-17.10% vitamins. ‘Achi’ contains between 10-32% crude protein and 18.67% carbohydrate; while ‘ofo’ contains 12.0- 15.6% protein; 0.79g/ml vitamins; 6.0% fat and 35.4- 68.2% carbohydrate (Ajayi etal., 2006), (Ene – bong, 1992). Several issues are associated with available soup thickeners used in this region due to improper processing, as the soup thickeners are usually exposed to the environment, leading to moisture uptake, contamination by dust and black soot which affects their thickening ability. There is little or no information on improved methods that are suitable for processing of soup thickeners in order to increase their thickening ability as well as safety. The study is therefore aimed at determining the effect of boiling and soaking on the physicochemical, functional and pasting properties of three commonly consumed soup thickeners.
Flours from ‘ukpo’, ‘ofor’ and ‘achi’ have been found to be used in most states in Nigeria including Imo, Anambra, Akwa Ibom and Ondo States. They are used as thickeners in traditional soups (for eating gari, pounded yam or cocoyam and fufu). They are equally used as emulsifiers and flavouring agents in traditional soups due to their gum content. These gums are called the seed gum and food gum (hydrocolliods). These are not true gums but are of simpler structures. These seeds gums are extracted from the seeds when crushed to flour and when in powder form have the ability to swell in water and thus are able to influence the viscosity of the liquid. Apart from this culinary use, it is possible for these gums when used as additives in other foods to impact desirable textural and functional properties to the finished food product particularly the “convenience foods” (Ajayi et al, 2006., Adebowale and Lawal, 1986).
Processing of agricultural products remains the most important food and nutrition security aspect in the modern world. Due to urbanization, food is produced in remote areas and transported into towns or cities to feed the ever-growing population. The seasonality of agricultural produce al so necessitates processing of products so that they are available throughout the year. Processing of agricultural products is done to improve consumer acceptability while retaining its nutritional value. Different techniques are used for processing cereals and legumes that include fermentation and germination. Most processing techniques are localized to a certain region, while others are practiced across the world.
Due to the increasing demand from the growing Nigerian Populace, the functionality of these local foods needs to be investigated to increase their utilization. The various traditional and foreign methods of processing Ukpo, Ofor and Achi seems to alter or vary the functional, phytochemical, nutritional and viscosity properties of these seeds Therefore, this study tends to investigate the effects of processing techniques (sprouting/steeping and toasting) on the nutrient, functional, phytochemical and viscosity properties of these three food thickeners (Ukpo, Ofor and Achi). It is hoped that a good result from this research will help increase their utilization and also reduce post-harvest losses.
1.2 STATEMENT OF PROBLEM
In West Africa, dietary pattern varies and is influenced by the vegetation belt. For example, in the northern parts of Nigeria, cereals dominate, while in the south, legumes, nuts, seeds and starchy roots or tubers are the main food components (Ene-Obong and Carnovalue, 1982). The processing of the cereals and starch roots into a form of paste and eaten with soups is the general practice. Among the legumes used in soups (mainly for emulsification and stabilization of soups) are Brachystegia eurycoma (achi), Detarium microcapum (ofor), Mucuna solannie (ukpo) and Irvingia gabonensis (ogbono). Each of the soup thickeners differ in species from the others and so have their individual characteristic flavours, which they impart to soups. Often, choice depends on individuals, but Brachystegia eurycoma and Detarium microcarpum are favourite soup thickeners in South Eastern Nigeria. These food thickeners, mainly found in the legume family, are usually processed into flour and used as soup thickener and stabilizer. The functional properties, phytochemical properties, nutritional properties and viscosity properties of food additives and thickeners are factors to be considered before their choice. These properties are often affected by the conditions under which the ingredient is applied or processed. The method of processing these thickners can alter/improve the nutritional, phytochemical, functional and viscosity properties, hence to need to examine the processing techniques employed in their processing.
1.3 JUSTIFICATION OF THE STUDY
The use of thickening agents in food industry has come to stay. The functional properties of seed flour assume importance in the development of food product. Proteins and starch are the main contributors for changes in functional properties such as Bulk density, oil and water absorption and least gelation concentration. Therefore, adequate information on the chemical composition of these seed flours is a prerequisite for its effective utilization. Given its remarkable nutritional potential, there is need for nutritional and anti-nutritional factor evaluation as this would form the basis on which they will be constantly utilized as soup thickeners or formulation of new diets or used in the fabrication of new food product in the food industry. The anti-nutritional factor present in seed flours confers come health benefits e.g. the phytic acid of the seeds possesses antioxidant, anti-carcinogenic and hypoglycemic activities (Aremu et al, 2015). This study will help increase knowledge as regarding these benefits. Also, they can impair nutrient utilization e.g. polyphenols decrease digestibility by forming a complex with dietary proteins. Thickening agents are often used as food additives and in cosmetics and personal hygiene products (Igwenyi, and Azoro, 2014). The food use and consumption of these soup thickeners calls for more research to provide information on their mineral, pharmacological, phytochemical compositions and properties of their constituents so as to ascertain their actual nutritional values, health and other medicinal importance. However, this requires prior information and understanding of desirable functional properties and the behavior of the material in systems during processing, manufacturing, storage, preparation as well as consumption (Sai-Ut et al., 2009).
Therefore, there is a need to exploit the food and industrial potentials of Brachystegia spp. and Mucuna spp. seeds using different processing techniques.
1.4 OBJECTIVES OF THE STUDY
The main objective of this study was to determine the effect of processing techniques on the functional, phytochemical and nutrient properties of Ukpo, Ofor and Achi. The specific objectives are to:
i. process Ukpo, Ofor and Achi into flour using toasting, steeping and sprouting techniques
ii. determine the functional, phytochemical and nutrient properties of the flours and
iii. carry out a comparative analysis of the results.
1.5 SCOPE OF THE STUDY
The scope of this study covered Ukpo, Ofo and Achi seeds sourced locally from Afor Ebi Market, Ututu in Arochukwu Local Government Area of Abia State. The Ukpo, Ofor and Achi were processed using steeping, sprouting and toasting technique. Hence their functional, phytochemical and nutritional properties were investigated.
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