ABSTRACT
The study is on the chemical, microbial, and sensory evaluation of selected indigenous condiments (ogiri) consumed in south eastern Nigeria. The aim of the study was to produce controlled ogiri condiments in dried form and compare with traditionally fermented ogiri and then evaluate them chemically, microbially and organoleptically. The seeds were boiled, manually dehulled, made into paste and fermented for 96hrs and their proximate, mineral, vitamins, anti-nutrient determined. Microbial load was determined by using the single microorganism isolated from the laboratory samples as starter culture. Sensory evaluation was conducted using 30 untrained panelists. The data obtained were subjected to analysis of variance (ANOVA) using SPSS version 20. The results of the Proximate analysis of the unfermented, controlled fermented and traditionally fermented showed that the moisture content of all unfermented ogiri samples ranged from 3.46%- 3.82 % and were significantly (p<0.05) similar to the moisture content of controlled and traditionally fermented samples. The controlled fermented samples ranged from 3.83-10.49% and were significantly (p<.0.05) higher than traditionally fermented ogiri samples which ranged from (3.96-7.68%). The crude protein of controlled fermented ogiri ranged from (17.19-20.37% while the traditionally fermented ranged from 20.17-22.04%; no significant difference(p<.0.05) existed between them. The mineral content of the controlled fermented (CFO) and traditionally fermented (TFO) samples increased as fermentation progressed. The controlled fermented ranged from Fe 2.97-3.0mg, Zn 2.02-2.43mg, Ca 4.49-4.50mg P 0.26-0.48mg; traditionally fermented ranged from Fe2.95-3.03%,Zn 2.04-2.31% Ca 0.44-0.49% P 0.29-0.38% respectively. The vitamin content of controlled fermented samples were significantly different (p<0.05). Beta carotene, thiamin, riboflavin, niacin and vitamin C ranged from 2020-10180mcg, 2.07-5.89mg, 0.20-0.37mg, 2.03-4.68mg and 3.7023.40mg respectively. However, the traditionally fermented ogiri samples ranged from 5210 -6410mcg, 3.10-6.28mg, 0.22-0.33mg, 2.03-3.75mg and 19.35-103.40mg respectively. The anti-nutrient of the controlled fermented samples are significantly different (p<0.05) oxalate , tannin, and phytate contents ranged from 0.07-0.45mg, 0.50-0.88mg and 0.01-0.02mg , meanwhile, traditionally fermented samples ranged from 0.18-0.65mg, 0.36-0.88mg and 0.00-0.02mg respectively. The microbial loads of all the controlled ogiri samples are within the acceptable limit of log104 and safe for consumption. Five microorganisms were isolated from each of the CFO samples and seven was the highest from TFO samples. No pathogenic contaminant was detected in all the samples. There was significant difference (p>0.05) in the sensory evaluation of color of controlled fermented ogiri samples. However, controlled fermented ogiri ugu (CFOUGU) (5.85%) was significantly higher in color and taste, while traditionally fermented ogiri okpehe (TFOOKPE) scored the least (3.43%). However TFOUGU was generally acceptable. The results of these studies showed that controlled fermented dried ogiri could last longer than the traditionally packaged ones and could be used to supplement our foods, especially the low income earners.
TABLE OF CONTENTS
Title page i
Declaration ii
Certification iii
Dedication iv
Acknowledgements v
Table of Contents vi
List of Tables ix
List of Figures x
List of Plate xi
Abstract xii
CHAPTER 1
INTRODUCTION
1.1 Background of the Study 1
1.2 Statement of Problem 6
1.3 Objectives of the Study 7
1.4 Significance of the Study 8
CHAPTER 2
LITERATURE REVIEW
2.1 Origin of Condiments 9
2.2 Preservation of Foods 11
2.2.1 Drying 12
2.2.2 Refrigeration 13
2.3 Fermentation as a Processing Method for Ogiri Condiments 14
2.3.1 Types of fermentation 16
2.3.2 Microflora in fermented foods 19
2.3.3 Starter development 20
2.3.4 Effect of fermentation on anti-nutrients 20
2.3.5 Toxins and toxin producing organisms in fermented foods 23
2.3.6 Classification of fermented foods 24
2.4 Anti-Nutrient Factors 24
2.4.1 Phytic acid 25
2.4.2 Oxalic acid 25
2.4.3 Polyphenolic compounds 26
2.4.4 Hydrolysable tannin 27
2.4.5 Ricin 27
2.6 Sensory Evaluation of Food 28
2.6.1 Sensory environment 29
2.7 Legume-Based Fermented Foods 30
2.7.1 Effect of flavour on legume-based fermented foods 31
2.8 Castor Oil Plant (Ricinus communis) 33
2.8.1 Toxicity of castor oil bean (Ricinus communis) 33
2.9 Fluted Pumpkin Seed (Telfairia occidentalis Hook) 35
2.9.1 Nutritional value of fluted pumpkin 36
2.9.2 Uses of fluted pumpkin 37
2.10 African Oil Bean Seed (Pentacle thramacrophyla) ”Ugba’ 38
2.10.1 Preparation of ’’ ugba’’ 39
2.10.2 Consumption pattern/uses of “ugba” 41
2.10.3 Preservation and storage of ugba 42
2.10.4 Microorganisms in “ugba” fermentation 44
2.10.5 Chemical changes during ugbaproduction 45
2.10.6 Proximate composition of oil bean seed (“ugba’) 47
2.10.7 Toxicology of African oil bean seed 48
2.11. Prosopis africana mesquite (“Ogiri Okpehe”) 50
CHAPTER 3
MATERIALS AND METHODS
3.1 Raw Material Collection 54
3.2 Sample Preparation 54
3.2.1 Pilot study 54
3.2.2 Castor oil seed processing of ogiri igbo (ogiri isi) for fermentation 55
3.2.3 Processing of fluted pumpkin seed (Telfairia occidentalis) into ogiri 58
3.2.4 African oil bean seed processing 61
3.2.5 Prosopis africana seed processing of ogiri okpehe 64
3.3.0 Chemical analysis 67
3.3.1 Proximate composition 67
3.3.2 Determination of crude protein content 67
3.3.3 Determination of carbohydrate content 69
3.3.4 Determination of ash content 69
3.3.5 Determination of crude fat content (Soxhlet Method) 70
3.3.6 Determination of crude fiber content 70
3.3.7 Determination of food energy 71
3.3.8 Mineral determination 72
3.3.9 Determination of phosphorus 72
3.4.1 Determination of calcium and magnesium 73
3.4.2 Determination of potassium and sodium 74
3.4.3 Determination of vitamins 75
3.4.4 Vitamin A determination 75
3.4.5 Vitamin C determination 76
3.4.6 Niacin determination 77
3.4.7 Riboflavin determination 77
3.4.8 Thiamine determination 77
3.5 Anti-Nutrient Determination 77
3.5.1 Determination of phytate content 77
3.5.2 Determination of oxalate content 78
3.5.3 Determination of tannin content 80
3.6 Microbial Analysis of Samples 81
3.6.1 Isolation and identification of microorganisms from ogiri samples 81
3.6.2 Total viable count (Microbial load) 85
3.6.3 Control fermentation 87
3.7 Sensory Evaluation 87
3.7.1 Preparation of uha soup for sensory evaluation of different ogiri samples 88
3.7.2 Recipe for uha soup preparation 88
3.7.3 Sensory environment 88
3.8 Statistical Analysis 89
CHAPTER 4
RESULTS AND DISCUSSION
4.1 Proximate Composition of Ogiri Samples 90
4.2 Mineral Composition of Ogiri Samples 93
4.3 Vitamin Composition of Ogiri Samples 98
4.4 Anti Nutrient Composition of Ogiri Samples 101
4.5 Viable Count 105
4.6 Microorganisms Isolated from the Ogiri Samples 107
4.7 Sensory Characteristics of Ogiri Samples 111
CHAPTER 5
5.0 CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion 115
5.2 Recommendations 116
REFERENCES 118
APPENDICES 132
LIST OF TABLES
Table 2: Fermented Vegetable Protein used in Nigeria 31
Table 3: Nutritive value of Telfairia Seeds and Leaves 36
Table 4.1: Proximate Composition of the Ogiri Types 91
Table 4.2: Mineral Composition of the Ogiri Types 96
Table 4.3: Vitamin Composition of the Ogiri Types 100
Table 4.4: Anti nutrient Composition of the Ogiri Types 104
Table 4.5: Total Viable Counts of the Ogiri Types 106
Table 4.6: Microorganism Isolated from the Ogiri Types 109
Table 4.7: Sensory Properties of the Ogiri Types 113
LIST OF FIGURES
Figure 1: Flow Chart for the Production of Ogiri-isi 56
Figure 2: Flow Chart for the Production of Ogiri-ugu 59
Figure 3: flow Chart for the Production Process of Ogiri Ugba 62
Figure 4: Flow Chart for the Preparation of Ogiri Okpehe 65
LIST OF PLATES
Plate 1: Unfermented Castor Seed Bean 57
Plate 2: Controlled Fermented Castor Seed Bean. 57
Plate 3: Unfermented Ugu Seed 60
Plate 4: Controlled Fermented Ugu Seed 60
Plate 5: Unfermented African Oil Bean Seed 63
Plate 6: Controlled Fermented African Oil Bean Seed 63
Plate 3: Unfermented Okpehe Seed 66
Plate 4: Controlled Fermented Okpehe Seed 66
Appendix Plate 1 133
Appendix Plate 2 133
CHAPTER 1
INTRODUCTION
1.1 Background of the study bean is a poisonous seed of the castor bean plant
“Ogiri” is a fermented condiment of plant origin consisting of parts of trees, seeds, shrubs and grass which exist in large number in the tropical rainforest and savannah grass land zones. They are often referred to as food accessories because of their ability to stimulate appetite and increase the flow of gastric juice. Some common examples that are found in south eastern Nigeria are ogiri Igbo (castor oil seed-Ricinus communis), Ogiri ugu (Fluted pumpkin-Telfairia occidentalis) seed, Ogiri ugba (African oil bean seed-Pentaclethra macrophylla), Ogiri okpehe (Prosopis africana) seed etc. They are used principally to add flavour to foods as fermented products (Nwiruka and Ekeke, 2005).
Fermented foods are defined as palatable products prepared from raw or heated materials which acquire their characteristic properties by a process that involves microorganisms (Buckenhusk, 1993).They are essential parts of food in all parts of the world, particularly in Africa that is grappling with the problem of feeding its teeming population. Fermented foods and beverages constitute a major portion of people’s diet (Achi, 2005). Fermented condiments give pleasant aroma to soups and sauces in many countries (Sarkar et al., 1993). They also have great potential as key protein and fatty acid sources, and are good sources of gross energy. This implies that condiments are basic ingredients for food supplementation and their socio-economic importance can not be over emphasized. In Africa, many proteineous oily seeds are fermented to produce food condiments called ’ogiri’. (Sanni and Ogbonna, 1991; Leejerajumnean et al., 2000; Azokpota et al., 2006; Ogunshe et al., 2006., Ogunshe et al., 2007; Ogunshe et al., 2008).
These fermented proteinous oily seeds called ‘ogiri’ are produced from fluted pumpkin (Telfairia occidentalis) seeds, which has a strong-smelling ammoniacal odour consumed particularly in Imo state south eastern Nigeria. ‘ugba’ is a Nigerian fermented vegetable protein from the African oil bean (Pentaclethra macrophyla) popularly consumed by Umunneochi people in Abia State, eastern part of the country, while okpehe, also known as afiyo, is a strong-smelling fermented condiment from Prosopis africana highly popular in Nsukka and the middle-belt of Nigeria (Ogunshe et al., 2006). ‘ogiri’ Igbo (castor oil seed-Ricinus communis), is popularly consumed in Anambra State as traditional food condiment.
Traditional foods in south eastern Nigeria often lack variety and consist of large quantities of the staple food (cassava,yam, maize) with supplements of plantain, cocoyam, rice ,and beans, depending on availability and season (Achi, 1999). Soups and sauces eaten with the staples are an essential component of the foods and may contain a variety of seeds, nuts, pulses, and leaves.The staple foods provide the kilocalories but are very poor in other nutrients. Soups are the main sources of proteins and minerals and one of the ways to enrich the foods is to improve the nutrient content of soups.Seeds of these legumes account for up to 80% of dietary protein and is the only source of protein for some groups. Their cooked forms are eaten as meals, for example, seeds of fluted pumpkin and are commonly used in fermented form as condiment to enhance the flavor of foods (Oniofiok et al., 1996).
Although, Nigerians have exhibited mixed feelings in terms of consumer tastes and preferences for such foods (Achi, 2005), the introduction of foreign high technology products, especially processed ones because of globalization and liberalization of the economy, radically changed the Nigerian food culture into a mixed grill of both foreign and local dishes (Ojo, 1991).
Food flavouring condiments are prepared by traditional methods of uncontrolled solid substrate fermentation resulting in extensive hydrolysis of the protein and carbohydrate components (Achi, 2005). Production of these condiments is by spontaneous fermentation carried out in people’s homes using rudimentary utensils under varying unhygienic conditions (Oguntoyinbo et al., 2010). The methods employed in the production of fermented condiments differ from one region to another, depending on existing traditional systems.
The castor oil bean, Ricinus communis is a major oil seed and has been known since ancient time. It grows into a tree in the subtropical zones attaining heights of between 11-13 meters. Ricinus communis is a plant commonly found in both tropical and temperate climates of the world (Lakshmamma and Prayaga, 2006). Ricinus communis is of the family Eurphorbiacae (Ogunniyi and Nkikang, 2000). The castor plant grows in the wild in large quantities. It is available at low cost and the plant is known to tolerate varying weather conditions. Specifically, the castor bean plant requires a temperature of between 20 and 260C with low humidity throughout the growing season in order to obtain maximum yields. The weather conditions for its growth limit its cultivation to tropical areas of the developing world (Ogunniyi and Njikang, 2000). Castor bean is a poisonous seed of the castor bean plant, ordinarily, the castor bean is inedible because the seed contains a toxic protein, recin, and other toxic constituents; recinine and recinoleic acid, but this was removed by fermentation (Lakshmamma et al., 2006).
Fluted pumpkin ( Telfairia occidentalis Hook. F., Family: Curcubitaceae) probably originated from south eastern Nigeria, and is widely distributed among the Igbo speaking people, particularly around Imo State, Nigeria (Akoroda, 1990a), where it has the widest diversity (variation in pod and seed colour, seed and plant vigour, anthocyanin content of leaves and petioles or shoots, leaf size and their succulence, dioecious or monoecious plants) (Chewya and Eyzaguirre, 1999; Chinhande et al., 1997).The Leaves are spirally arranged, with 3-5.5 cm long, while female flowers are solitary in leaf axils; they are cream coloured; fruit is drooping, ellipsoid berry 40- 95cm by 20-50cm and weighs about 10kg; seeds are compressed ovoid about 4.5 cm long, black or brown–red (Grubben and Denton, 2004; Pursglove, 1991). It is a herb, climbing by coiled, often branched tendrils to a height of over 20m. The root system ratify the top surface of the soil, stem is angular glabrous and fibrous when old. There are two main varieties in Nigeria: Ugu-ala (succulent, broad leaves, small black seeds about 12g, a thick vine and slow growth); Ugu-elu (high growth rate, large brown coloured seeds of 20 g or more, fast emergence, thin stems and small leaves) (Omidiji, 1997; Chweya and Eyzaguirre, 1999; Odiaka et al., 2008). A third cultivar, Nsukka local was selected from local land races and is tolerant to root knot nematodes. It is widely cultivated in the West and Central Africa (Benin Republic, Cameroon, Nigeria, Sierra Leone to Angola, and up to Uganda in East Africa). It is called ‘ugu’ by the Igbos, ‘ugwu’ by the Yorubas and ‘ekobon’ by the Cameroonians (Schippers, 2002; Grubben and Denton, 2004)
The seeds are used as propagating materials, eaten roasted, boiled or ground to paste as soup condiment. Telfairia leaves are rich in Mg, Fe and fibres and are used as food supplements. The seed is used for cooking (Horsefall and Spiff, 2005), marmalade manufacturing (Egbekun et al., 1998) and cookie formulations (Giami and Barber, 2004). Several workers have reported the nutritional composition, chemical characterization and functional properties of fluted pumpkin seeds (Badifu et al., 1991; Fagbemi et al., 2005; Ganiyu, 2005; Fasuyi, 2006). The nutritional value of the fluted pumpkin seeds of (45% fat and 20.5% crude protein, according to Akintayo (1997) justifies the wide consumption as reported by Ifon and Bassir (1980). The seed has an excellent pattern of amino acids (93.7%) which contains higher levels of most essential amino acids (except lysine) than soybean meal with 94.9%. Even the K and Na availability are higher in Telfairia seed (58.8%) than that of soybean seed cake (54.9%) (Esuoso et al., 1998).
The African oil bean tree (Pentaclethra macrophylla Benth) is a large leguminous woody plant that belongs to the sub-family Mimosoidae. It is frequently cultivated in forest areas, with about eight (8) flat glossy brown edible seeds per pod. The plant grows both as wild and cultivated types. The raw seed is a potential source of edible protein and calories, containing the twenty (20) essential amino acids and essential fatty acids that make up more than 80% of fatty acids in the oil (Enujiugha and Agbede, 2000). The fermentation of the African oil bean seed effects better nutrient availability and digestibility with significant softening of the cotyledons (Enujiugha and Akanbi, 2002). With successive processing steps during the fermentation, there is progressive softening of the cotyledons; reduced astringency and increased palatability; and enhanced meaty flavour. However, the fermented product ugba has a high rate of deterioration and susceptibility to microbial spoilage within 2 weeks of production.
Prosopis (mesquite) is a genus of about 45 species of leguminous spiny pod-bearing trees and shrubs found in subtropical and tropical regions of America, Africa and southwest Asia (Anon, 2009). The trees of P. africana can be found growing wild in the Middle belt, North and some parts of Eastern and Southern parts of Nigeria. The indehiscent pods are palatable to man and animals .The seeds are fermented into a traditional condiment, ‘’okpehe’’ which can serve as a low-cost source of protein, especially for the rural populace. This study is intended to improve the utilization of our indigenous condiments through increased awareness on the nutritional content.
1.2 STATEMENT OF PROBLEM
Traditional diets in West Africa often lack variety and consist of large quantities of the staple food (cassava, yam, maize) with supplements of plantain, cocoyam, rice, and beans, depending on availability and season (Achi,1999). Soups eaten with the staples are an essential component of the diet and may contain a variety of seeds, nuts, pulses, and leaves. The staple foods provide the calories but are poor in other nutrients. Soups are the main sources of proteins and minerals and one of the ways to improve the diet has been to improve the nutrient content of soups. The traditional condiments have not attained commercial status due to the very short shelf life, objectionable packaging materials, stickiness and the characteristic putrid odour (Arogba et al., 1995). Fermented condiments often have a stigma attached to them; they are often considered as food for the poor.
The production of fermented vegetable proteins for use as food condiments is craft-based. Remarkably, in many areas of Nigeria today they are still made in traditional ways with success, depending upon observance of good manufacturing practices and control of environmental conditions during the manufacturing phase as starter cultures are not normally used and therefore variations in the quality and stability of the products are often observed. As with any other fermentation process, the understanding of the microbial ecology of vegetable fermentations requires the knowledge of the fermentation substrates, i.e. the seeds of the various plants as well as the products obtained thereof. Therefore, the use of these condiments, it is suggested, could be extended as a food ingredient included in most fabricated foods in order to further increase their versatility and utility (Giami and Bekebain, 1992; Achi, 1999).
1.3 OBJECTIVES OF THE STUDY
1.3.1 The general objective of this work was to produce controlled ogiri condiment in dried form and compare with traditionally fermented ogiri and then evaluate them chemically, microbially and organoleptically.
1.3.2 The specific objectives of the study were to:
1. Produce and determine the proximate composition of varieties of ogiri and compare them with the traditionally fermented samples.
2. determine the mineral composition
3. determine the vitamin composition
4. assess some anti- nutritional contents of the samples
5. determine their microbial loads
6. conduct sensory evaluation on soups cooked with the ogiri samples to determine their consumer acceptability.
1.4 SIGNIFCANCE OF THE STUDY
Due to increasing problems in the economic situation in Nigeria there is need to urgently find ways to ameliorate the problem of malnutrition. Among such ways is a deeper research into some unutilized or underutilized legume based products called ‘ogiri’.
This study will give indepth knowledge about the microbial, physiochemical, and nutritional profile of varieties of ogiri condiments. Those that will benefit from this study are food manufacturing companies such as Cadbury, Nestle Foods, Erisco Foods, Dangote Foods and many others, so that ogiri could be made into fabricated seasonings and in order to further increase their versatility and utility. The knowledge gained by Nurses, community health workers and Dietitians will be of benefit to the populace through nutrition education. They will advocate the use of these condiments to the masses which will contribute to daily intake of essential nutrients and reduce the rate of malnutrition and nutrition related diseases among poor Nigerians. It will also reduce the cost of importing synthetic seasonings and condiments, thereby boosting the Nigerian economy. Farmers will also find planting the crops more lucrative which in turn boost their income. Others will gain through buying and selling the raw and/or the products.
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