ABSTRACT
Jam is a product made from whole fruit cut into pieces or crushed which varies in their nutritional and sensory properties due to different process technology and types of fruit used. Jam is an effective method of product conversion as it retains health and nutritional benefits of the raw material, especially of seasonal products. The aim of this study was to prepare an acceptable jam, to evaluate the nutrient and sensory properties of jam produced from blends of pineapple and pawpaw pulp. Ripened pineapple and pawpaw fruits were purchased from Ubani and Ahiaeke markets Umuahia, Abia State. The proximate, mineral and vitamin composition of the jam samples were determined using standard laboratory procedures. Jams were produced from a blend of pineapple and pawpaw in the ratio 100:0:0, 0:100, 60:40, 40:60 and 50:50 respectively. The sensory properties of the jam were determined on the basis of 9 point Hedonic scale by 20 panellists. All tests were carried out in triplicates; means and standard deviation obtained from chemical analyses were calculated. The proximate composition result of the jam produced indicated energy value between 228.90kcal-273.64kcal, moisture content of 30.43%-40.47%, crude protein content of 0.26-1.29%, fat content of 0.12-0.28%, crude fibre content of 0.44%-2.14%, ash content of 0.27-0.63%, and carbohydrate content of 56.65-67.81%.Ca(89.55mg/100g), Mg(141.77mg/100g), P(190.08mg/100g) and K(60.41mg/100g) were significantly higher in sample PWJ (100% pawpaw jam) while Fe(3.25mg/100g) was significantly higher in sample control SBJ (strawberry commercial jam). Vitamin A (201.54mg/100g) was significantly higher in sample PWJ (100% pawpaw jam) while Vitamin C (125.22mg/100g) was significantly higher in sample PIJ (100% pineapple jam). Sample blends show the proportion of raw materials influences the nutritional value of the final product. The sensory properties of the jam showed that there is no significant (P>0.05) difference in the appearances of the samples except sample SBJ which is the control. The result showed that sample PWJ (100% pawpaw) taste was highly accepted with the mean score of (7.25) following sample SBJ which is the control. The result showed that there is no significant (P>0.05) difference between the general acceptability of sample PWJ, PIJ, PWPI, PIPW1 and PIPW2, respectively. This study has revealed pawpaw and pineapple blends could be used in production of quality jam without adverse effect on the nutritional quality contents and provide essential nutritional benefits needed for good body growth and body functions.
TABLE
OF CONTENTS
Title
Page i
Certification
ii
Dedication iii
Acknowledgement iv
Table
of Contents
v
List
of Table
viii
List
of Figures
ix
Abstract x
CHAPTER 1
INTRODUCTION 1
1.1 Statement of
Problem 4
1.2 Objective of Study 6
1.4 Significance of
study 7
CHAPTER 2
LITERATURE REVIEW 8
2.1 Definition of key
terms 8
2.2 Jam production 9
2.2.1 Formulation of
jam 10
2.2.2 Reasons for jam production 12
2.2.3 Uses of jam 13
2.2.4 Recipes involved
in jam making 13
2.3. Nutrient
Analysis
22
2.3.1 Determination of
proximate content 22
2.3.2 Determination of
mineral content
24
2.3.3 Determination of
vitamins content 24
2.4 Sensory
Evaluation
25
2.4.1 Definition of
sensory evaluation
25
2.4.2. Types of sensory analysis
26
CHAPTER 3
MATERIALS AND METHOD 29 Experimental Design 29
3.2. Sample Material Collection
29
3.3 Sample
Preparation
29
3.4 Packaging
and storage of samples 33
3.5 Chemical
Analysis 33
3.5.1 Proximate composition
33
3.5.2 Mineral
Analysis
37
3.5.3 Vitamin
Analysis 40
3.6 Sensory
Analysis
42
3.7. Statistical
Analysis
42
CHAPTER 4
RESULTS AND DISCUSSION 4.1 Proximate Composition
of Jam
43
4.2
Mineral Composition of Jam 54
4.3
Vitamin Composition of Jam
60
4.4
Sensory Evaluation
64
CHAPTER 5
CONCLUSION
AND RECOMMENDATIONS
5.1 Conclusion 69
5.2 Recommendations 71
REFERENCES 72
APPENDIX
I 80
APPENDIX
II 81
LIST
OF TABLES
Table 2.1 The nutritive value of pawpaw and pineapple fruit 17
Table 2.2 The nutritive value of strawberry fruit 18
Table 3.1 Formulation of Fruits for Jam Production 32
Table 3.2 Recipe for Production of
Jam
32
Table 4.1 Proximate composition of jam produced from
pawpaw and pineapple 53
Table 4.2 Mineral
composition of jam produced pawpaw and pineapple pulp 59
Table 4.3 Vitamin
composition of jam produced from pawpaw and pineapple
pulp 63
Table 4.4 Sensory evaluation of jam
produced from pawpaw and pineapple
pulp
68
LIST
OF FIGURES
Figure 3.1 Flow Chart
for Jam Production
31
CHAPTER 1
INTRODUCTION
Nowadays, fruits and vegetables are increasingly vital for healthy
food consumption. Not only are they highly recommended aspects of
health-promoting diets, but they also contain minerals and vitamins (Babajide et al., 2013; Hoejskov, 2014; Timothy et al., 2019). Public awareness of the
beneficial properties of fruits and vegetables continues to increase due to
recommendations of dieticians and physicians, educational programmed media
(Timothy et al., 2019; Silva et al., 2017).
Food security is a global issue that has been lingering till date.
There has been great clamouring for adequate agricultural food production and
utilization to sustain the world’s estimated 7.6 billion people (as of June
2017 United Nations estimation). However, the problem of getting enough food at
all times is not limited to agricultural production only, Khatoon et al. (2015), as a lot of foods still
get lost along the food value chain (Usman, 2017), despite the overwhelming
degree of hunger that bedevils a great number of poverty-stricken population of
poor nations. This loss of food is either due to deliberate action of food
wastage by affluent people, evitable handling/processing operation losses, Jedermann
et al. (2014), or losses incurred as
a result of the perish ability, Khatoon et
al. (2015) of many agricultural foods. Fresh fruits and vegetables top the
list of most perishable agricultural food commodities as a result of their high
moisture content in conjunction with various readily available nutrients/growth
factors (Singh, 2007; Arah et al.,
2016). Timothy et al. (2019) reported
that poor availability and considerable post-harvest losses challenge both
consumption and processing of fruits and vegetables. Fruits and vegetables are
not always accessible at the same time due to peculiarities of location and
seasonality.
Fruits are the fleshy seed-associated composition of a plant which
has either sweet or sour taste and are edible in the raw state. The most
cultivated ones include; pineapple, pawpaw, apple, cashew, orange, grape,
strawberry, banana, mango and lemon. Vitamins, minerals and fibre, Pomper and
Layne, (2005) are common beneficial uses when fruits are consumed.
Pineapple fruit is a great source of fibre and is mostly consumed
in countries including India, Philippines and Taiwan (Usman, 2009). The fruit
has an internal juicy flesh with a mix of sweet and tart taste. The area closer
to the base of the fruit has more sugar content and therefore a sweeter taste
and more tender texture. The pineapple fruit contains some amount of sugar,
pectin and acid. However, the amount and proportion present is not sufficient
for a successful gel formation (Afoakwa et
al., 2006).
Pawpaw, Carica papaya
plant bears the fruit papaya with other known names as papaw in other
countries. It is indigenous to the tropics of the Americas, possibly from
southern Mexico and bordering Central America. Pawpaw plant grows in three
sexes; male (does not bear fruit), female (bears inedible fruits) and
hermaphrodite/ dioecious (bears edible fruits) (Timothy et al., 2019). The hermaphrodites are widely grown for commercial
purposes. Pawpaw fruit may be classified as ripe when it is soft when felt and
the skin colour changes to amber and it has best qualities when it ripens on
the tree. There are numerous kinds of fruits which all have their unique
benefits and uses including being used in preparation of or as food products
(Timothy et al., 2019).
For long-term consumer benefits, robust harvesting of fruits and
vegetables requires effective and efficient storage facilities and techniques.
To preserve their freshness for a long period of time, they have to be
transformed into a more stable product able to retain the initial nutritional
and mineral contents (Timothy et al.,
2019).
Jam is an effective method of product conversion as it retains
health and nutritional benefits of the raw material, especially of seasonal
products (Timothy et al., 2019). Jams
exist in diverse forms, e.g. chutney, fruit butter, jelly, marmalade, fruit
spread, etc. (Shen et al., 2012). Jam
is a product made from whole fruit, cut into pieces or crushed. Fruit extract, sugar, pectin and acid are the
four ingredients that are needed in their right proportions for a successful
fruit jam. Sugar imparts sweetness, activates pectin and has the ability to
prolong the shelf life of the jam while pectin is used as a thickening agent
and citric acid used to balance the sweetness of the sugar as well as bring the
pH to optimum level to ensure jell formation. They ensure a good gel formation,
which is an important quality characteristic of a good jam (Afoakwa et al., 2006). Jam varies in their nutritional and organoleptic properties
as a result of different process technology and types of fruit and vegetable
used (Usman, 2009). Jam making includes the following major steps: cutting,
crushing/grounding to required consistency, thermal processing, adding sugar
for pectin activation, mix formation, and packaging. Pectin helps to preserve
the raw material as it substantiates the gelling agent, sugar or honey (Afoakwa
et al., 2016).
Each ingredient imparts different types of sensory attributes
including taste, texture, odour and appearance (Pomper and Layne, 2005). The
difference in the sensory quality affects the level of demand and the market
value. Sensory evaluation deals with the use of the five senses of sight,
smell, taste, touch and hearing to bring to mind, assess, evaluate and infer
responses to the characteristics of foods and materials as they are perceived.
It is used in food industries to aid in understanding consumers’ behaviour and
exploiting new markets (Martínez, 2007). It has three main testing or
techniques for assessment namely descriptive, discriminative and affective
testing (Carpenter et al., 2012).
Descriptive testing deals with perceiving the characteristics of the product,
discriminative testing also deals with determining if there are differences
among the products and affective testing deals with knowing how well a product
is accepted or preferred.
1.1. STATEMENT OF THE PROBLEM
Fruits are widely grown and consumed, especially freshly, in the
raw state by most people. Fresh fruits and vegetables top the
list of most perishable agricultural food commodities as a result of their high
moisture content in conjunction with various readily available nutrients/growth
factors (Singh, 2007; Arah et al.,
2016). The challenge with fruit is its easy
perishable nature and it being a seasonal crop or plant. Due to this reason
fruits are not available throughout the year and for one to consume fruit, one
must wait for another seasonal time. Nigeria today is faced with the challenge
of meeting the needs of its population also, the problem of ignorance arising
from the exclusion of fruits and vegetable to diets which could result to a
wide range of disease and micronutrient deficiency (United Nations Children
Emergency Fund, UNICEF, 2004). Different fruits which are grown in Nigeria fail
to reach market due to spoilage, over ripening and mechanical damages which
occur to the harvested fruits. Thus, the necessity for its proper utilization
so as to make it available always even during off seasons by processing them
into food products. Also, the less awareness of the nutritional value of most
fruits leading to its utilization in the production of products like jam,
jellies which has resulted to its wastage (Arah et al., 2016).
With this challenge in the mind of food processors, there is an
increase in the development of food products to serve as preserves for these
fruits in order to have them available throughout the year. Some of these fruit
products are jams, jellies, marmalades, juices, fruit powders and others alike
(Khatoon et al., 2015).
Jam preparation is considered for this study, to promote long-term
consumers benefits, as robust harvesting of fruits and vegetables requires
effective and efficient storage facilities and techniques to preserve their
freshness for a long period of time, transformed into a more stable product
able to retain the initial nutritional and mineral content (Timothy et al., 2019).
Jam is an effective method of product conversion as it retains health and
nutritional benefits of the raw material, especially of seasonal products.
Jam processors have different methods which they use to prepare
their jam as well as having different ingredients composition, resulting to
different results. As poorly formulated
fruit products particularly jams, could easily be rejected by consumers (Usman,
2009). In view of this, jam should be properly prepared in a manner acceptable
by consumers thereby reducing great loss in food industry and country. Jam production
will help to curtail post harvest losses, scarcity of fruits throughout the
year and cost in industries and reduce micronutrient deficiencies in
individuals (Khatoon et al., 2015).
1.2 OBJECTIVES OF THE STUDY
The general objective of this study is to evaluate the nutrient
and sensory properties of jam produced from blends of pawpaw and pineapple
pulp.
The specific objectives
include:
1. To produce jam from blending Pawpaw and pineapple
2. To determine the proximate content of the jam.
3. To determine the mineral content of the jam.
4. To evaluate the vitamin content of the jam.
5. To assess sensory attributes of the jam.
1.3. SIGNIFICANCE OF STUDY
Jam production from blends of pineapple and pawpaw and several
fruits will reduce post-harvest losses due to spoilage, wastage from improper
storage which will prevent reduction in their nutritive values, make them
accessible and available out of season and reduce micronutrient deficiencies in
individuals. In developing countries like Nigeria, it will help curb
importations and encourage production for commercial and home use, which will
improve food security making it available even out of season in its preserve as
jam. It will also confer health benefits to the consumers and provide part of
their daily micronutrients as needed. Findings of this study could be
incorporated into the Nigeria food composition table which will be beneficial
to the food industries, Nutritionist, Dietitians and other related health
practitioners as a dietary guide in reference to standard.
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