ABSTRACT
This study investigated the glycemic index (GI) and nutrient composition of breakfast food produced from flour blends of whole wheat, cooking banana and pumpkin pulp. The flours were blended into five different proportions, sample 100: 0: 0 W-P-C, sample 90: 10: 0 W-P-C, sample 70: 20: 10 W-P-C, sample 35: 30: 35 W-P-C, sample 10: 20: 70 W-P-C, sample 0: 10: 90 W-P-C ad sample 0: 0: 100 W-P-C (W=whole wheat flour, P= Pumpkin pulp flour, C= cooking banana flour). The different flour samples were used to produce different breakfast foods. Seventy healthy, non-diabetic human subjects was used for the study. The anthropometric data of the human subjects was determined. The result revealed that their Body Mass Index (BMI) ranged between 21.62 and 23.63 kg/m2 which is within the normal range. The breakfast food samples were subjected to proximate composition, dietary fiber, carbohydrate characterization, and carotenoid content analysis. The results of the proximate composition revealed that the moisture content ranged from 7.88 to 8.85%, crude protein 2.87 to 14.67%, fat 0.87 to 2.86%, crude fibre 1.6 1 to 10.37%, ash 1.97 to 3.01%, carbohydrates 61.91 to 83.91%. The caloric value (energy) ranged from 330.76 to 353.32 Kcal. The result of the dietary fibre showed that the soluble fibre ranged from 2.10 to 3.07%, insoluble fibre 8.68 to12.24%, total fibre 11.75 to14.86%.The carbohydrate characterization results revealed that the digestible starch content of the breakfast food samples varied significantly (p < 0.05) and it ranged from 37.76 to 67.43%. The resistant starch content ranged from 3.20% to 4.91% and the total starch content ranged from 42.67 to 71.74%. The amylose and amylopectin contents ranged from 21.79 to 28.72 % and 71.29 to 78.22% respectively. The carotenoid content of the breakfast food ranged from 9.29 to 48.38mg/g. The blood glucose response of the subjects after consumption of the breakfast food samples, the glycemic index (GI) and glycemic load values (GL) were also determined. The results obtained revealed that the glycemic indices of the formulated breakfast food samples ranged from 28.9 to 63.68. The breakfast food formulated with sample 0: 0: 100 W-P-C had the lowest glycemic index value (28.9) followed by the breakfast food with sample 35: 30: 35 W-P-C (33.27%), they can therefore serve as good diabetic foods. This study also supports the consumption of cooking banana, whole wheat and pumpkin pulp as low glycemic index foods, they can as well serve as potential raw-materials in the formulation of diabetic foods.
TABLE OF CONTENTS
Tittle page i
Certification ii
Declaration iii
Dedication iv
Acknowledgement v
Table
of Contents vi
List
of Tables x
List
of Figures xi
List of Plates xii
Abstract xiii
CHAPTER 1: INTRODUCTION
1.1 Background of the Study 1
1.2 Statement of Problem 4
1.3 Research Objectives 5
1.4 Justification 6
CHAPTER 2: LITERATURE REVIEW
2.1 Glycemic Index (GI) 7
2.1.1 GI in the nutritional
management of diabetes 10
2.1.2 Effect of low GI diets on blood
pressure 11
2.1.3. Improved lipids by low GI
diets 11
2.1.4
Glycemic index in disease prevention 12
2.1.5
Glycemic index in obesity and weight control 13
2.1.6 GI in addressing individual
nutrition needs 14
2.1.7 Evidence-based nutrition advice
15
2.2 Glycemic Response 15
2.3
Glycemic Load (GL) 16
2.4
Factors affecting GIs and GLs of Foods 17
2.4.1
Carbohydrate contents of foods 18
2.4.2
Starch composition/properties 17
2.4.3
Amylose-amylopectin ratio 21
2.4.4
Gelatinization 21
2.4.5
Retrogradation 22
2.4.6
Dietary fiber 23
2.4.7
Sugars 25
2.4.8 Insulin response 25
2.4.9 Protein content 26
2.4.10
Processing techniques 27
2.4.11
Variety 27
2.4.12
Particle size 28
2.4.13 Fat 28
2.4.14 Acidity 29
2.4.15
Blood sugar level 29
2.5
Prospects of the Concept of GIs and GLs in the Management of
Diabetes Mellitus (Type 2 Diabetes
Mellitus) 29
2.6
Limitations/Controversies of the Concept of GI and GL 31
2.7 Pumpkin (Curcubita maxima) 34
2.7.1 Crop description 34
2.7.2 Importance of pumpkin in the
human diet 35
2.7.2.1 Starch content in the fruit 35
2.7.2.2 Carotenoid 36
2.7.2.3 Minerals 39
2.7.3 Pumpkins as Anti-diabetic
Functional Medicines 39
2.7.4 Technology for Processing Fruit
Vegetable into Powder 40
2.8 Cooking Banana (Musa paradisiaca) 41
2.8.1 Plant growth and structure 42
2.8.2 Nutritional composition of
cooking banana 42
2.8.3 Production of flour from
cooking bananas 44
2.9 Wheat (Triticum aestivum) 46
2.9.1
Nutritional content of wheat 48
2.9.2
Medicinal properties of wheat 49
2.9.3
Types of wheat flours and their uses 50
2.9.3.1
All-purpose flour 50
2.9.3.2
Bread flour 50
2.9.3.3
Self raising flour 50
2.9.3.4
Whole wheat flour 51
2.10
Breakfast Foods 51
2.10.1
History of breakfast foods 53
2.10.2 Formulation of ready-to-eat breakfast foods 56
CHAPTER
3:
MATERIALS AND METHODS
3.1
Sources of Materials 57
3.2
Preparation of Samples 57
3.2.1
Production of cooking banana flour 57
3.2.2 Production of pumpkin pulp flour 59
3.2.3
Production of whole wheat flour 61
3.3
Formulation of Composite Flour Samples from Whole wheat, Cooking banana
and Pumpkin pulp Flour (%) 63
3.4 Production of Breakfast Food 63
3.5 Determination of the Proximate Composition
and Caloric Value of the
Breakfast Food Samples 66
3.5.1 Moisture
determination 66
3.5.2 Total ash determination 66
3.5.3 Crude protein
determination 67
3.5.4 Crude fat determination 67
3.5.5 Crude fibre
determination 68
3.5.6
Carbohydrate
determination 68
3.5.7 Determination of
total energy or caloric value (CV) 69
3.6 Carbohydrate Characterization of
the Breakfast Food Samples 69
3.6.1
Determination of total starch 69
3.6.2
Determination of resistant starch 69
3.6.3
Amylose content determination 70
3.7
Determination of the Dietary Fibre Fraction of the Breakfast Food Samples 70
3.8
Carotenoid Determination of the Breakfast Food Samples 71 3.8.1 Extraction 71
3.8.2
Partition to petroleum ether 72
3.9
Glycemic Index Determination 72
3.9.1
Subject characteristics 72
3.9.2
Test foods/ samples 73
3.9.3
Study design 73
3.10 Method
of Data Analysis 74
3.10.1
Glycemic index calculation 74
3.10.2
Glycemic load (GL)
calculation 75
3.10.3 Statistical analysis 75
CHAPTER 4: RESULTS AND DISCUSSION
4.1 Anthropometric Characteristics of the Healthy
Volunteers/ Subjects 76
4.2 Proximate
Composition and Caloric Value of the Breakfast Food Samples 77
4.3 Dietary Fiber Fraction of the
Breakfast Food Samples 82
4.4 Characterization of Carbohydrate in
the Breakfast Food Samples 84
4.5 Carotenoid Content of the Breakfast Food Samples 86
4.6 Glycemic
Responses of the Standard Food and Breakfast Food Samples 87
4.7 Glycemic Indices (GIs) and Glycemic
loads (GLs) of the breakfast food
Samples 89
CHAPTER 5: CONCLUSION AND RECOMMENDATION
5.1 Conclusion 91
5.2
Recommendation 9
References
Appendices
LIST OF TABLES
2.1: Substituting high GI foods for
low GI alternatives 14
3.1: Formulation of composite flours from cooking
banana, pumpkin pulp
and
whole wheat flour (%) 63
4.1: Anthropometric data of the healthy volunteers 76
4.2: Proximate composition of the breakfast foods 77
4.3:
Dietary fiber fraction of the breakfast foods 82
4.4: Characterization of carbohydrate in
the breakfast food samples 84
4.5: Carotenoid content of the
breakfast food samples 86
4.6: Glycemic
responses (mg/dl) of the standard food (glucose) and
breakfast foods at various time
intervals 87
4.7:
Glycemic indices (GIs) and glycemic loads (GLs) of the breakfast food
samples (%) 89
LIST OF FIGURES
3.1: Flowchart for the production cooking banana flour
3.2: Flowchart for the production of pumpkin pulp
flour
60
3.3: Flowchart
for the production of whole wheat flour 62
3.4: Flowchart for the production
of breakfast food from the
composite flour breakfast food
64
LIST OF PLATES
1: 100: 0: 0 W-P-C 65
2: 0: 0: 100 W-P-C 65
3: 90: 10: 0
W-P-C 65
4: 0: 10: 90 W-P-C 65
5:
70: 20: 10 W-P-C 65
6: 10: 20: 70 W-P-C 65
CHAPTER
1
INTRODUCTION
1.1 BACKGROUND OF THE
STUDY
Glycemic
index (GI) is a ranking related to how carbohydrates in food affect blood
glucose levels.
Glycemic index describes the blood sugar level after the consumption of a
carbohydrate-containing test food relative to a carbohydrate-containing
reference food, typically glucose or white bread (Jenkins et al., 2008). High glycemic index is observed in carbohydrates
that breaks down rapidly during digestion due to their blood glucose response
is high and fast. Carbohydrates that breaks down gradually have a low glycemic
index (Jenkins et al., 2004). Diets
established on carbohydrate foods that are more gradually absorbed, digested
and metabolized have been related to a reduced risk of Type 2 diabetes mellitus
and cardiovascular disease. Improved glycemic control by the use of diet could reduce the
intake of medications, decrease the chances of diabetic complications, increase
life expectancy, and improve the quality of life (Thomas and Elliott, 2009).
Also, intervention studies has shown enhancement
in the hemoglobin concentration and insulin sensitivity in people living with
diabetes as a result of a low GI diet. Research also suggests that low glycemic
index foods may aid weight control by having effects on fuel partitioning and satiety.
These
findings shows that low GI foods have no negative effect and thus, suggest that
the GI should be a vital consideration in the dietary management and prevention
of diabetes mellitus (Marsh et al.,
2011).
Pumpkins
(Cucurbita maxima) are fruit
vegetables, which belong to the family of Cucurbitaceae. It is one of such
plants that are frequently used as a food as well as traditional medicine for
long days. Pumpkin fruit could be consumed as a staple, supplying notable
amounts of carbohydrates to the human diet. The fruit pulp, seeds, leaves, and
marrow are usually utilized. Pumpkin
flour is recently the main processed product of pumpkin fruit, this is because
it can be easily stored for a long time and conveniently used in manufacturing
formulated foods. Meals made from pumpkin flour could have nutritional
advantage in terms of dietary fibre, minerals, and vitamins (Noor Aziah and
Komathi, 2009). The pumpkin fruit contains fibre and acetylated pectin present
as thirthy percent of the weight dry matter (Morris et al., 1998). Pectin, when consumed, is assumed to control
glycemic levels and decrease the need for insulin by patients living with
diabetes (Guillon and Champ, 2000). Pumpkin is commonly believed to have active
hypoglycemic attributes. The hypoglycemic chemical of pumpkin includes
polysaccharides from the fruit pulp, oil from ungerminated seeds, and protein
from germinated seeds (Xiong, 2000; Cai et
al., 2003). The hypoglycemic attributes of pumpkins have been observed to
be active in the fruit pulp and seeds in humans, who are Type 1 Diabetes
Mellitus (Riccardi et al., 1999) and
Type 2 Diabetes Mellitus (Shi et al.,
2003) patients as well as in normal animals, for instance, alloxan-induced diabetic rats and rabbits (Fu
et al., 2006). The protein-bound
polysaccharides found in pumpkin fruit has viable potentials to be used as an
anti-diabetic agents, due to its ability to improve glucose tolerance by bringing down the blood
glucose levels and raising the levels of serum glucose tolerance (Adams et al., 2011; Carvalho-De et al., 2012).
Cooking banana (Musa paradisiaca) is a starchy crop that serves as a major staple
food for many people in developing countries and it is extensively grown in the
tropical and sub-tropical regions. It belongs to the family "Musaceae."
According to Aurore et al., (2009),
plantain and cooking banana are consumed both in their ripe and unripe stages,
unlike dessert bananas, which are usually consumed in their ripe stages. Cooking banana is a vital source of
many vitamins and minerals, particularly, vitamin A, B6, C, and
potassium. It is a known source of carbohydrate and fibre. Gaster (1993)
recommended cooking banana for use in the management of obesity maintaining
that with their high satiety value, palatability and relatively low energy
content, they are suitable for encouraging weight loss and preparation of
low-calorie diets. The processing of cooking bananas
into flour, beer, wine, and weaning food products is a means of adding value to
the fruits as well as increasing the durability of the derived products
(Echibiri, 1996; Chukwu et al., 1998;
Adeniji and Empere, 2001). The increased rate of consumption of plantain/cooking
banana is associated with traditional folklore and medical benefits which includes
the management of diabetes mellitus (Odenigbo et al., 2013).
Wheat
(Triticum aestivum) is an important staple food crop for
more than one-third of the world population and it accounts for more proteins
and calories to the world diet than any other cereal crops (Abd-El-Haleem et al., 1998; Adams et al., 2002). Wheat is an essential
source of carbohydrate in a majority of countries (Lannce and Garran,
2002). It is easy to store and transport,
nutritious and can be processed into several forms of food products. With a
small quantity of animal or legume protein added, a wheat-based meal is highly
nutritious (Victor, 2011).
Breakfast is the first meal
(food) of a day, usually eaten in the early hours of the day before undertaking
the day's activity. Breakfast is considered an important meal because it breaks
the overnight fasting period and refill the supply of glucose to the blood
stream. The consumption of breakfast cereals and other related products has
increased lately because of the lack of time for making food in modern times
(Takeuchi et al., 2005). Eating a
healthy breakfast reduces the risk of enhancing Type 2 diabetes. Low GI
breakfast foods prepared from whole grain legumes and cereals, plant protein
and bioactive components have been reported to be linked with lower postprandial
glucose excursion and the reduction of oxidative stress (David et al., 2005).
From the archeological evidence at Neolithic sites, breakfast foods are usually
made from many kinds of cereals which were manufactured with devices like
extruder and oven toaster (George, 2003).
1.2 STATEMENT OF PROBLEM
Although
different types of oral hypoglycemic drugs and insulin are available for
diabetic treatment, there is still an increasing demand by diabetic patients
for natural dietary products that have hypoglycemic activity. According to
Halim (2003), the disadvantages of presently available drugs are that they are
to be given throughout life and they produce side effects (such as frequent
urinating, drowsiness, constipation and stomach discomfort). Diabetes is
expensive both in terms of modern medical health care, and quality of life
(which is beyond the reach of people in the low-income group) has led to a growing
interest in alternative therapies for diabetes management. Alternatives are,
therefore, required and this includes dietary plants and herbal preparations
which have recently received substantial attention and have been observed to be
a promising choice over modern synthetic medicines, in a number of studies. In developing countries, all over the world, 80% of the
population continues to use traditional medicine in primary medical problems (Grover and Yadav, 2004).
Recent
research carried out has validated several such claims of the use of
traditional medicinal plants (Zafar et al., 2002; Tatiya et al., 2011). Currently, the determination of the glycemic
index of different foods has been on the increase globally because of increased
awareness of their nutritional implication on individuals. From literature,
pumpkin (Cucurbita maxima) pulp and
cooking banana ((Musa paradisiaca)
have shown potent anti-diabetic activity and thus have been used as food for
diabetic patients without the knowledge of their glycemic index and responses.
This present study, therefore, is carried out to produce and determine the
glycemic index and nutrient composition of breakfast food produce from whole
wheat, cooking banana and pumpkin pulp flour blends.
1.3 RESEARCH OBJECTIVES
The
major objective of this study is to determine the glycemic index and nutrient
composition of a breakfast food produced from wheat (Triticum aestivum), cooking banana (Musa
paradisiaca) and
pumpkin (Cucurbita maxima) pulp flour
blends.
The
specific objectives are to:
I.
Produce composite flour
from whole wheat, cooking banana and pumpkin pulp flours
II.
Formulate breakfast food
using different composite ratios of the flour blends
III.
Determine the chemical
composition of the breakfast food
IV.
Determine the
carbohydrate characterization of the breakfast food
V.
Determine the dietary fibre
fraction of the breakfast food
VI.
Determine the carotenoid
content of the breakfast food
VII.
Determine the glucose
response, glycemic index and loads of the formulated breakfast food using human
subjects.
1.4 JUSTIFICATION
Many
specific interventions can be carried out in the management and perhaps the
avoidance of diabetes mellitus and the most integral component is medical
nutrition (Franz et al., 2002).
Medical Nutrition Therapy (MNT) plays a vital role in the management of
existing diabetes (Type 1, Type 2 and gestational diabetes) and in avoiding or
limiting the increase of impaired glucose tolerance and diabetes-related
complications (ADA, 2008). The American Diabetes Association (ADA, 2008)
recommendations states that the utilization of glycemic load (GL) and glycemic
index (GI) may provide a modest additional advantage of carbohydrate over that
observed, when only total carbohydrate is considered. This is because glycemic
index explains how different carbohydrate containing rich foods directly affect
blood sugar level and it is considered a better way of categorizing
carbohydrates. The therapeutic value of a low-GI diet in diabetes has been shown
in both Type 1 and Type 2 patients (Brand-Millerr, 1994). Dietary interventions
with low-GI foods thus appear to lower the glycosylated hemoglobin fraction and
the incidence of hypoglycemic episodes in juvenile and maturity-onset diabetes
(Gilbertsson et al., 2001; Giacco et al., 2000). These findings, coupled
with the fact that there are no existing negative effects of a low GI diet on
humans suggests, that the GI should be a vital consideration in the management
and prevention of diabetes mellitus. Dietary therapy has been and will remain a
mainstay for diabetic treatment. There
is therefore the need to study the glycemic index and nutritional composition
of breakfast food produced from whole wheat (Triticum aestivum), cooking banana (Musa
paradisiaca) and
pumpkin (Cucurbita maxima) pulp flour
blends so as to increase the utilization of these plant crops and also to
assist diabetic patients in making informed dietary choices.
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