ABSTRACT
Effect of cooking time and tenderizers on nutrients and anti-nutrient factors in African breadfruit seeds was investigated. African breadfruit seeds were separately cooked with plantain leaf ash, palm inflorescence and akanwa infusion in a separate pot. Thereafter, the cooking time of the cooked African breadfruit seeds was determined prior to evaluation of their proximate composition, mineral content, vitamin content, Antinutrient factors and sensory properties using standard analytical procedures. Data obtained were statistically analysed using SPSS version 22.0. The proximate analysis showed that African breadfruit cooked without tenderizers (ABF1) had the highest moisture, fat and carbohydrate content. The highest crude protein content was obtained in African breadfruit cooked with akanwa (ABF2) and plantain leaf ash infusion (ABF3) with African breadfruit seeds cooked with plantain leaf ash infusion having the highest dietary fibre. Highest value of ash was obtained in African breadfruit cooked with plant inflorescence ash infusion (ABF4). The mineral content of the cooked African breadfruit seeds showed that African breadfruit cooked without tenderizers had the highest phosphors content while African breadfruit cooked with akanwa had the highest potassium and iron content. African breadfruit cooked with plantain leaf ash infusion had the highest magnesium and calcium content whereas African breadfruit cooked palm inflorescence ash infusion had the highest value of sodium. The vitamin content of the African breadfruit seeds showed that the highest value of pro-vitamin A, vitamin B3, B6 and E was obtained in African breadfruit cooked with plant inflorescence ash infusion whereas the highest value of vitamin B1 and B3 were obtained in African breadfruit cooked without tenderizers and African breadfruit cooked with plantain leaf ash infusion, respectively. Antinutrient content of the cooked African breadfruit seeds revealed that the highest value of trypsin inhibitor and saponin was obtained in African breadfruit cooked with plant inflorescence ash infusion while highest value of phytate and tannin was obtained in African breadfruit cooked without tenderizer and African breadfruit cooked with plantain ash infusion respectively. African breadfruit cooked without tenderizer had the highest cooking time while African breadfruit cooked with plant inflorescence ash infusion recorded the least cooking time.
TABLE OF CONTENTS
TITLE PAGE i
CERTIFICATION ii
DEDICATION iii
ACKNOWLEDGEMENTS iv
TABLE OF CONTENTS v
LIST OF TABLES viii
LIST OF FIGURES ix
ABSTRACT x
CHAPTER 1
INTRODUCTION 1
1.2 Statement of the problem 3
1.3 Objective of the Study 4
1.3.1 General objective 4
1.3.2 Specific objectives 4
1.4.1 Significance of the study 5
CHAPTER 2
LITERATURE REVIEW 7
2.1 Relevance of legumes in human nutrition 7
2.2 African breadfruit 8
2.2.1 Nutritional value of African breadfruit seed 9
2.2.2 Anti-nutrients factors of African breadfruit seed 11
2.2.3 Processing and utilization of African breadfruit seed 15
2.3 Tenderizers 18
CHAPTER 3
MATERIAL AND METHODS 20
3.2 Sources of raw materials 20
3.3 Sample preparation 20
3.3.1 Production of ash from plantain leave 20
3.3.2 Production of ash from palm inflorescence 21
3.3.3 Preparation of African bread fruit meal 24
3.4 Method of analyses 26
3.4.1 Determination of cooking time 26
3.4.2 Proximate analysis 26
3.4.2.1 Determination of moisture content 27
3.4.2.2 Determination of ash content 27
3.4.2.3 Determination of fat content 28
3.4.2.4 Determination of dietary fibre 28
3.4.2.5 Determination of crude protein 29
3.4.2.6 Determination of carbohydrate content 30
3.4.2.7 Determination of energy value 30
3.4.3 Mineral analysis 30
3.4.3.1 Determination of phosphorus 30
3.4.3.2 Determination of calcium and magnesium 31
3.4.3.3 Determination of potassium 32
3.4.3.4 Determination of iron 33
3.4.3.5 Determination of sodium 34
3.4.4 Vitamin analysis 34
3.4.4.1 Determination of pro-vitamin A 34
3.4.4.2 Determination of vitamin B1 (thiamin) 35
3.4.4.3 Determination of vitamin B2 (Riboflavin) 36
3.4.4.4 Determination of vitamin B3 (Niacin) 37
3.4.4.5 Determination of vitamin B6 38
3.4.5 Antinutrient analysis 38
3.4.5.1 Determination of phytate 38
3.4.5.2 Determination of saponin 39
3.4.5.3 Determination of trypsin inhibitor 40
3.4.5.4 Determination of tannin 41
3.4.6 Sensory evaluation 41
3.4.7 Statistical analysis 42
CHAPTER 4
RESULTS AND DISCUSSIONS 43
4.1 Socio-economic characteristics of the respondents 43
4.2 Use of tenderizer by the respondents 45
4.3 Effect of tenderizers on cooking time of African breadfruit seeds 48
4.4 Proximate composition of African breadfruit seeds cooked with different tenderizers 50
4.5 Mineral content of African breadfruit seeds cooked with different tenderizers 55
4.6 Vitamin content of African breadfruit seeds cooked with different tenderizers 60
4.7 Antinutrient content of African breadfruit seeds cooked with different tenderizers 64
4.8 Sensory properties of African breadfruit seeds cooked with different tenderizers 67
CHAPTER 5
CONCLUSION AND RECOMMENDATIONS 72
5.1 Conclusion 72
5.2 Recommendations 73
References 75
LIST OF TABLES
Table 4.1: Socio-economic characteristics of the respondents 44
Table 4.2: Use of tenderizer by the respondents 47
Table 4.3: Effect of tenderizers on cooking time of African breadfruit seeds 49
Table 4.4: Proximate composition of African breadfruit seeds cooked with different tenderizers 51
Table 4.5: Mineral content of African breadfruit seeds cooked with different tenderizers 56
Table 4.6: Vitamin content of African breadfruit seeds cooked
with different tenderizers 61
Table 4.7: Antinutrient content of African breadfruit seeds cooked with different tenderizers 65
Table 4.8: Sensory properties of African breadfruit seeds cooked with different tenderizers 71
LIST OF FIGURES
Figure 3.1: Flow chart for production ash from plantain leaves 22
Figure 3.2: Flow chart for production ash from palm inflorescence 23
Figure 3.3: Flow chart for cooking African breadfruit seeds 25
CHAPTER I
INTRODUCTION
Legumes are important source of affordable alternative protein to most average families in many tropical countries (Agbogidi, 2010), and could compensate for the large proportion of carbohydrates often ingested in African diets (Oyeyinkan et al., 2013). They are also good sources of essential nutrients (Brigide et al., 2014; Kouris-Blazos and Belski, 2016). Legumes such as African breadfruit (Treculia africana) seeds are widely utilized in the Southern states of Nigeria where it serves as low cost meat substitute for poor families (Badifu and Akubor, 2011). African breadfruit is popularly known as ukwa by the Igbo, afon in Yoruba, ize in Benin, izea in Ijaw and ediang in Efik (Abodenyi et al., 2015). The seeds of African breadfruit are valuable food among the Igbos (Nzekwe et al., 2010).
Nutritional value of food crops are of utmost importance according to human health prospects because nutritionally sufficient food will provide proper growth and development in man (Soumya et al., 2016). African breadfruit seed is a rich source of high quality vegetable protein, oil and carbohydrates (Ayoade et al., 2015). Its crude protein serves as a cheap source of protein to the rural poor who cannot afford the luxury of buying meat or other sources of animal protein (Ugwu and Iwuchukwu, 2012; Uluocha et al., 2016). African breadfruit seeds possess 13.4 % protein, 0.31 % fat, 27.82 % carbohydrate, 1.5 % fibre and 1.23 % ash (Wang et al., 2011). They are rich dietary source of micronutrients such as zinc, manganese, iron, calcium, magnesium, potassium and sodium (Nnorom et al., 2015).
Earlier publication showed that whole African breadfruit seed contains glycine (6.45 g), alanine (3.79 g), serine (5.42 g), proline (3.42 g), valine (6.09 g) threonine (4.71 g), methionine (1.61 g), tryptophan (2.22 g) and histidine (2.55 g) (Adesina et al., 2016). The nutritional importance of any food crop depends not only on the nutrient composition but also on the presence of anti-nutritional factors. The higher the concentration of these metabolites the more dangerous they become to health. Their presence in food give rise to a genuine concern for human health in that they prevent digestion and absorption of essential nutrients (Mohamed et al., 2011; Offor et al., 2011).
Diverse foods could be produced from the seeds of African breadfruit on the basis of custom, tradition and ethnic group (Nwabueze and Nwokenna, 2010). In Nigeria, African breadfruit seed provide an important food source which is consumed as main dish (Nwabueze and Nwokenna, 2010). Cooking of legumes such as African breadfruit seeds is the most common method used to obtain a palatable product with improved nutritional value (Alessandra et al., 2014). However, the cooking time of certain varieties of African breadfruit seeds contribute to the constraint of their utilization. They actually take considerable period of time before they are properly cooked for eating (Nwakalor, 2014). This prompted the need for cooking African breadfruit seeds with tenderizers.
In most parts of Nigeria, African breadfruit seeds are normally processed for consumption by boiling with tenderizers such as trona (Oyetayo and Omenwa, 2016). Use of tenderizers in processing of African breadfruit seeds cannot be put to an end, especially in developing countries with low income earners. This is because they are believed to reduce cooking time, reduce expenditure (Nasiru et al., 2011), keeps the cotyledons of African breadfruit seeds intact without breaking, enhance the appeal of the resultant meal (Egbuonu and Nzewi, 2014), and increase their micronutrients (Okwunodulu et al., 2018).
This study investigated the effect of cooking time and tenderizers on nutrients and anti-nutrient factors in African breadfruit seeds.
1.2 STATEMENT OF THE PROBLEM
Nutrient deficiency is a serious health issues globally, especially in rural parts of Nigeria, where the affordability of protein rich foods such as meat are difficult. Legumes such as African breadfruit seeds that possess the potential to contribute in eradicating nutrient deficiency are so hardened that it requires cooking for a long time to soften the cotyledons (Nwakalor, 2014). Earlier publication by Okaka et al. (2006) noted that cooking results to reduction in nutrients. Furthermore, most households in Nigeria consistently use trona as tenderizer in cooking African breadfruit seed, thus resulting to underutilization of palm bunch, palm inflorescence, plantain peels, banana leaves cocoa pods and maize cobs that are a good source of potash ash (Okwunodulu et al., 2018).
Aside these, food poisoning arising from plant secondary metabolites, otherwise known as anti-nutritional factors has not been properly addressed in Nigeria, and indeed in most parts of the developing world/countries that depend mostly on plant-based diets (Onwuka, 2014). Major drawback to consumption of African breadfruit seeds is the presence of antinutrients such as saponin, tannin, trypsin inhibitor, oxalate and phytate (Olapade and Umeonuorah, 2013). These compounds interfere with processes such as digestion, absorption and utilization of nutrients (Gemede and Ratta, 2014). More so, possible health problems associated with toxicity of these antinutrients includes but not limited to gastrointestinal and neurological disorders, pancreatic enlargement, growth dispersion, neuropathy and even death (Gemede and Ratta, 2014). This study focuses on investigating the effect of cooking time and tenderizers on nutrients and anti-nutrient factors in African breadfruit seeds.
1.3 OBJECTIVE OF THE STUDY
1.3.1 General objective
The general objective was to determine the effect of cooking time and tenderizers on nutrients and anti-nutrient factors in African breadfruit seeds.
1.3.2 Specific objectives
The specific objectives of the study were to:
i. identify the various types of tenderizers used for cooking African breadfruit seed.
ii. prepare African breadfruit meal using various tenderizers.
iii. determine the proximate composition of meal prepared using various tenderizers.
iv. determine the vitamin and mineral content of meal prepared using various tenderizers.
v. determine the anti-nutrients in the meals prepared using various tenderizers.
vi. assess the sensory attributes of meal prepared using different types of tenderizers.
1.5 SIGNIFICANCE OF THE STUDY
1. Considering nutrient deficiency that is prevalent in most rural parts of developing countries such as Nigeria, health hazards associated with antinutritional factors and that African breadfruit seeds are hard to cook in nature, this study is expected to provide information on effect of tenderizers and cooking time on nutrients and antinutrients in African breadfruit seeds. This would form a basis for absorption of nutrients in African breadfruit seeds by its consumers.
2. The findings from this study will reveal tenderizers that have potential to increase the nutrient composition of African breadfruit seeds meal and in turn increase their utilization in food systems. This will in turn discourage the use of chemical based tenderizers that possess detrimental effects in cooking of African breadfruit seeds.
3. The findings from this study will be reflected in the country-specific food composition database so that provision of dietary guidance using such food composition database as a reference material will be more effective.
4. Data obtained in this study will be of immense benefits to consumers of African breadfruits seeds, dietitians and food professionals.
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