ABSTRACT
This study ascertained effects of processing methods on the quality and acceptability of Soybean milk. Three specific on objective and research questions were used for the study. The study adopted an experimental research design. Soybeans were subjected to 3 different processing methods which were the whole soybean seeds and were processed using modified methods of William and Akiko (2000), the soybean were weighed 75 g using 20 capacity weighing scale. Results indicated that the nutrient content of the three soy bean milk samples (SBM A, SBM B and SBM C) were significantly (p≤0.05) different. Sample SBM C ranges from moisture 12.3±0.25 and 41.7a±0.38 more crude protein; 20.3a±0.77 more crude fat ; 21.7a±0.86 more carbohydrates; 5.2±0.76 more total ash; and 5.8a±0.36 more crude fibre than samples SBM A and SBM B respectively. The mean values of the sensory characteristics were equally significantly (p≤0.05) different with the exception of appearance which showed no significant difference. Sample SMC was adjudged most preferable organoleptically, in terms of appearance, taste, aroma and acceptability followed by sample SBM A while sample SBM B received the least nod of organoleptic acceptability. The observed results suggested that steeping before hot extraction might be a better method for processing soymilk in order to improve its wider acceptability. The study recommends that food specialist extension workers should be sent to various towns and regions to continue with the education of rural people on how to process other soybean products such as soybean oil, soybean cake and soybean meal and Government should provide rural people with facilities such as processing machines (like grinding mill, manual bridge press, rain press, decorticators and expellers), at subsidized rates in order to encourage them and to enhance the use of different processing methods of these products that are not available in the rural areas.
TABLE OF
CONTENTS
Title Page i
Declaration ii
Certification iii
Dedication iv
Acknowledgement v
Table of Contents vi
List of tables ix
List of figures x
Abstract xi
CHAPTER ONE: INTRODUCTION
1.1
Background to the study 1
1.2 Problem
Statement 3
1.3 Objectives
of the Study 4
1.4 Research Question 4
1.5 Significance
of the study 5
1.6 Scope of the study 6
CHAPTER TWO: LITERATURE REVIEW
2.1 Conceptual frame work 7
2.1.1 Importance
of soybean 7
2.1.2 Food-type Soybeans 11
2.1.3 Constraints in processing and the use of
Soybeans products 12
2.1.4 Anti-nutritional factors 13
2.1.4.1 Tannin 13
2.1.4.2 Trypsin inhibitors 13
2.1.4.3 Hemagglutinins (Lectins) 14
2.1.4.4 Lipoxygenase enzymes 14
2.1.4.5 Phytates 15
2.2 Nutritional Quality in soybean 15
2.2.1 Isoflavones and its Content in Soybean and Soybean Related Foods 15
2.2.2 Proteins in Soybeans 17
2.2.3 Carbohydrates in Soybeans and related Foods 18
2.2.4 Lipids in Soybeans and related Foods 19
2.3 Meaning
of Processing/General Overview of Processing 21
2.3.1 Handling
Stages in Processing 22
2.3.2 Food
Processing 23
2.3.3 Methods
of food processing 23
2.3.4 Products
from Soybean Processing 27
2.3.5 Soybean
milk 28
2.3.6 Consumer Perception Studies on Attribute and
Benefits of Products 29
2.3.8 Effects of processing methods on soybean
products 31
2.3.8.1 Effects of
processing on soybean carbohydrates 32
2.3.8.2 Effects of
processing methods on soybean minerals 32
2.3.8.3
Effects of processing methods on soybean proteins 33
2.4 Theoretical framework 35
2.4.1 Effects of processing
methods on the quality and acceptability of
Soybean 39
2.5 Review of Related Empirical Studies 41
2.6 Summary
of literature review 43
CHAPTER
THREE: RESEARCH METHODOLOGY
3.0 Introduction 45
3.1 Design
of Study 45
3.2 Area
of the Study 45
3.4 Materials
for the Experiment 45
3.5 Method of Sample preparation 45
3.5.1 Method
1 (Hot Extraction Processing Method) 46
3.5.2 Method
2 (Cold Extraction Processing Method) 46
3.5.3 Method
3 (Steeping before Hot Extraction Processing Method 46
3.6 Proximate
composition analysis 52
3.7 Sensory
evaluation 55
3.8 Statistical analysis 56
CHAPTER
FOUR: RESULTS AND DISCUSSION
4.1 Proximate
composition 57
4.2 Sensory evaluation 59
CHAPTER
FIVE: SUMMARY, CONCLUSION AND RECOMMENDATION
5.1 Summary 62
5.2 Conclusions 62
5.3 Recommendations 63
5.4 Restatement of problem 63
5.5 Description
of procedures used 64
5.6 Contribution to knowledge and suggestion
for further 64
REFERENCES
65
APPENDIX I 68
LIST
OF TABLES
Table
4.1.1: Proximate composition of soybean milk samples
57
Table 4.2.2: Mean sensory scores of soybean milk
samples from 3 different
processing
methods of soybean milk 59
LIST
OF FIGURES
Figure 1: Hot extraction processing technique 48
Figure 2: Cold
extraction processing technique 49
Figure 3: Steeping before hot extraction processing technique 50
Figure 4: Samples A, B and C
of soybean milk 51
CHAPTER ONE
INTRODUCTION
1.1 Background
to the study
Soybean
is a farm crop that belongs to the family of legumes. It is scientifically
called (Glycine Max (L) Merrill).
It is an annual herbaceous plant which is bushy, erect and with
leafy plant structure. Its height is 40 – 100 cm. It is believed that soybean
has been part of the history of China for about 5,000 years, but now the production
of soybean is circulating to different parts of the world. The beans grow in
pods that develop in clusters of 3 to 5 cm with each pod usually containing 2
or 3 beans. These beans are sometimes big or small, long, round or oval. The
colour can also vary. Some are yellow, others are green but can also be brown
and some are even black or with spots (Mullen 2003).
According
to Fennel, (1996) soybeans were first introduced into Nigeria in 1908, but the
first successful cultivation was in 1973 with the Malayan variety, which was
found suitable for commercial production in Benue state in Central Nigeria. Iwe,
(2003) revealed that soybeans have been used as food for centuries and its
exceptionally good nutritional value is well known. They noted that soybean
contains 40% high quality protein, 20% edible vegetable oil and a good balance
of amino-acid and has therefore tremendous potential to improve nutritional
status and welfare of the families of resource - poor farmers.
According
to Mpepereki, Makonese, and Giller, (1996), benefits of soybean over other
grain legumes commonly grown by small-holders, such as groundnut (Arachis
hypogea), cowpea (Vigna unguiculata) and common bean (Phaseolus vulgaris)
include lower susceptibility to pests and diseases, better grains storage
quality, a large leaf biomass, which gives a soil fertility benefit to
subsequent crops and a secure commercial market for the crop.
Nigeria
is the largest producer of soybeans for food in West and Central Africa. Osho
(2003), though still largely regarded as a relatively new crop, soybean has
made a successful incursion into the diet of many Nigerians, particularly children
and nursing mothers. Soybean derivatives such as soy-gari, soy-milk, soy-ogi,
soy-ebiripo and soy-lafun have been developed and found to be good substitutes for
more conventional food ingredient like melon, cowmilk and cowpea.
According to Ugwu and Nwoke, (2011), in a survey
carried out on the acceptability and quality of Soybean processing method in
Orumba South L.G.A of Anambra state posited that soybean products are widely
accepted and consumed. According to them, Soybean products are widely accepted
by over 50% of adults, 60% of house wives, and over 90% of growing children.
Therefore,
the value of soybean both for satisfying human dietary needs and for
compounding livestock feeds cannot be overlooked. There is need to stimulate
and encourage the production of soybeans.
Meanwhile,
Africa’s serious malnutritional problem is especially acute in terms of protein
deficiency. Livestock constitute the major source of protein for human consumption
but a combination of factors including the fall in foreign exchange earnings,
the recent persistent drought and the poor performance of indigenous animals have
led to situation where the prices of such conventional livestock products such
as meat, eggs and milk have risen beyond the reach of the ordinary man.
There
is, therefore, an urgent need to seek for alternative source of high quality
cheap protein. Soybean has the potential to meet part of this need.
The
bean is said to have more protein than beef, more calcium than milk and more of
a fatty substance called Lecithin than eggs. The soybeans protein have been developed
for use in hospital diets, particularly for post –operative diets and soybean
flour protein concentrates and isolates have been incorporated into infant
foods, such as rice-and – wheat based foods, in order to increase protein
content. The soy flour is used to make bread, pudding, pancakes, soup thickener
and other foods.
There
are many procedures that food raw materials go through before they are finally
available as edible food products. In food processing, these procedures are
commonly referred to as unit operations.
Soybean
can be processed into different products such as soybean oil, soybean
meal/cake, soymilk, soybean fortified ‘gari’ and tapioca, soy- ebiripo,
soy-tortilla and cereal-based traditional weaning food etc. Variations in
processing methods also yield a host of co-product.
However,
Nigerian food scientists have discovered the high nutritional content or value
of this crop and they are now creating awareness and advertising to people on
the uses of these crop soybeans. Also, Adjebeng-Asem and Osho (2002) said that
numerous efforts have been undertaken by research institutes, NGO and
industries to promote the production of the crop in Nigeria to bridge the gap
of limited adoption and production in Nontraditional areas.
1.2 Statement of the Problem
Soybean has been used as food for centuries
because of its good nutritive value. Some processing methods can enhance the
nutritional value of soybean by increasing the availability of amino acid,
vitamins and also protein digestibility (Prodanov, Vierra,
and Vidal-Valverde, 2004). In
addition, the bean extract is rich in vitamins, minerals and acids.
Meanwhile,
Africa’s serious malnutrition problem is especially acute in terms of protein
deficiency. Livestock constitute the major source of protein for human body,
but a combination of factors including the recent persistent drought and the
poor performance of indigenous animals have led to the situation where the
prices of such conventional livestock products such as meat, eggs and milk have
risen beyond the reach of ordinary man. In view of this problem an alternative
source of high quality cheap protein was sought for and soybean was found to
have the potential to meet part of this need.
Soy-protein
has been developed for use in hospital diets particularly for post-operative
diets and soy flour protein concentrates and isolates have been incorporated
into infant food as rice to increase their protein contents.
The
realization of the good nutritive value of soybean by the Nigerian food
scientists necessitated the awareness campaign mounted by the various arms of
government in recent times to educate the populace on the processing and
production of the soybean products.
1.3 Objectives of the Study
The
major objective of this research was to assess the effects of processing
methods on the quality and acceptability of Soybean.
The
specific objectives are to:
1. Identify
different methods of processing soybean
2. Identify
problems and constraints in processing of soybean products.
3. Determine
the level of acceptability of soybean products.
1.4 Research Question
This
notwithstanding, it was deemed necessary to answer the following research
questions:
1. What
are the different methods of processing soybean?
2. What
are the problems and constraints in processing of soybean products?
3. What
is the extent of the level of acceptability of soybean products?
1.5 Significance of the study
The findings of this study, hopefully, will create
awareness on the appropriate authorities (educators/educationists and other
stakeholders in Home Economics) on the effects of processing methods of
Soybean.
The
findings of this study may also educate the general public on the need for
quality and acceptability of the effects processing methods of soybean. This research will be useful to food
specialist, especially in educating the society on how to process other soybean
products such as soybean oil, soybean cake and soybean meal.
The
study will serve as a benchmark to the Government as they provide soybean
producers and processors with facilities such as processing machines (like
grinding mill, manual bridge press, rain press, decorticators and expellers),
at subsidized rates in order to encourage them and to enhance processing of
these products that are not available in the locality.
It
will be advantageous to the marketers if they can commercialize these processed
soybean products, in the society.
The
study is also aimed at educating families to exploit locally produced foods to
produce nutritionally adequate products for the use of the family this will
also aid in combating malnutrition.
Finally,
this research works if put into practice will help farmers to cultivate soybean
in a larger quantity.
1.6
Scope of the
study
The scope of this research work examines effects of
processing methods on the quality and acceptability of Soybean. It looked at
the proximate analysis and sensory evaluation of the products.
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