CHAPTER ONE
INTRODUCTION
1.1
Background to the Study
Food spreads generally includes fat-based spreads of edible vegetable oils or animal fat such as
margarine, cheese and butter, or spreads obtained from fruits and vegetables such as jams, jellies
and purees. Spreads are added to food in order to enhance the flavor, texture and nutritional
properties of the food. Salads, sandwiches and many other home recipes will be bland and
unattractive without food spreads. (Owusu, 2012).
Nuts are recognized as a source of high energy food and good nutrients due to high content of fats,
carbohydrates, proteins, vitamins and minerals (Souza, 2015; Cardoso, 2017 and Taş, 2017).
Several epidemiological studies have revealed that people who consume nuts regularly are less
likely to suffer from coronary heart disease (Souza, 2015, Jackson, 2014). Cashew (Anacardium
occidentale) is a also a source of dietary trace minerals copper, iron, manganese, magnesium and
phosphorus etc (Mah, 2017) known by many local names such as earthnuts, peanuts, goober peas,
monkey nuts, pygmy nuts and pig nuts. Nuts generally have been shown to possess a good number
of electrolytes and mineral contents and these have been shown to have a lot of health benefits (
Ros, 2010 and Fischer, 2013) Sodium is the major cation in extracellular fluid and essential
element for normal life cycle and metabolism of both plants and animals. Sodium makes some
93% of the total cation content in blood plasma (Leeson, 2011) Potassium is an essential mineral
and a major electrolyte found in the human body. It plays an important role in electrolyte
regulation, nerve function, muscle control, and blood pressure. Potassium is found within all cells
of the body, and its levels are controlled by the kidneys. Primarily, potassium functions to regulate
water and mineral balance throughout the body (Mahan, 2012 and Martin, 2015).
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Peanuts can be utilized in production of cheap and wholesome foods like peanut butter, peanut
bars, nimko, peanut milk etc. which can alleviate the situation of protein calorie malnutrition and
iron deficiency in the country especially among women and children (Khalil and Chughtai, 2013;
Ali and Nigam, 2013). Peanut butter is the most important product made from peanuts in the world
as it is utilized as extremely nutritious spread as well as delicacy in porridge, cookies, cakes and
ice cream. It became popular in developed countries due to its wholesomeness, longer shelf life,
microbial stability and ease of consumption (Woodroof et al., 2013). Peanut butter is made by
grinding dry roasted groundnuts into a paste (Mutegi et al., 2013). Peanuts are also used as major
ingredients in the formulation of weaning food with other cereals such as sorghum, corn, and
millets because of their high protein and omega 6 fatty acid contents (Mutegi et al., 2013). In
Nigeria, the use of marketed peanut butter in the confection of sauce is very popular among the
urban population . Although, the primary purpose of spices is to impart flavor and piquancy to
food, the medicinal, antimicrobial and antioxidant properties of spices are also exploited.
Groundnut or peanut (Arachis hypogea) is a plant which belongs to the family of plants called
Fabaceae (Eke-Ejiofor et al., 2012). Botanically, groundnut is a legume although it is widely
identified as a nut and has similar nutrient profile with tree nuts (Grosso et al., 2010). This annual
plant is generally distributed in the tropical, sub-tropical and warm temperate areas and represents
the second most important legume in the world based on total production after soybean (USDA,
2014). Peanuts make an important contribution to the diet in many countries. Peanut seeds are a
good source of protein, lipid and fatty acids for human nutrition (Grosso et al., 2010). Peanutcontaining foods have high consumer acceptance because of their unique roasted peanut flavour.
Peanuts are continually applied for the preparation of new and improved food products. A large
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proportion of peanut production in the world is destined to domestic foods such as peanut butter,
snack products, confections and roasted peanut products. Peanut constitutes a major annual oilseed
crop and a good source of protein containing high lysine content which makes it a good
complement for cereal. The proximate composition of mature groundnut seeds in per 100 g edible
portion is reported to be; moisture (6.5 g), protein (25.8 g), lipids (49.2 g), carbohydrate (16.1 g),
dietary fibre (8.5 g), calcium (92 mg), magnesium (168 mg), phosphorus (376 mg) and iron (4.6
mg) (USDA, 2014). However, peanut contains some anti-nutritional factors such as phytic acid,
condensed tannins, trypsin and amylase inhibitor, that may limit its usage and nutritional value.
Peanuts and its derivatives are often classified as street food which satisfies essential need of the
urban population by being affordable and available. Peanut seeds are eaten raw, boiled or roasted,
made into butter or paste and are used for thickening soups (Campos-mondragon et al., 2019)
Groundnut has diverse uses owing to its valuable nutritional composition. It consists of 47-50%
oil content which has greater percentage of unsaturated fatty acids that makes it an edible oil of
choice for human nutrition and good health (Pattee, 2015). Groundnut comprise of 25-30% protein
content which enables its seeds and oilseed cake to be utilized as good source of dietary protein
with digestibility comparable to animal proteins (Singh and Singh, 2011). Peanuts are rich in
vitamins, minerals and bioactive compounds that contribute towards its protective effects against
cardiovascular ailments, cancer, diabetes, osteoporosis and other degenerative diseases (Isanga
and Zhang, 2017).
Groundnuts are rich in nutrients and phytonutrient Groundnuts are good source of niacin, folate,
vitamin E, magnesium and phosphorus. They also are naturally free of trans-fats and sodium, and
contain about 25% protein. Some studies have assessed associations between peanut consumption
and postprandial blood glucose, nutrient intake, elevated fat oxidation rate and increased satiety
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(Reis 2011; Wien, 2014; Alves, 2014 and Reis, 2013). They stated that there are no positive
associations between peanut consumption and body fat and that the consumption of large portions
did not result in changes in body composition (Wien 2014 and Barbour, 2015). Chloride also plays
a role in helping the body maintain a normal balance of fluids. It is mostly seen as an anion
accompanying sodium and hardly exists alone. It also acts as a buffer in the exchange of oxygen
and carbon dioxide in red blood cells (Yunos, 2010). Extracellular bicarbonate levels are regulated
by the kidneys which regenerate and reabsorb bicarbonate ions. Unlike other electrolytes that must
be consumed in the diet, adequate amounts of bicarbonate are produced through metabolic
processes to meet the body’s needs (Yucha, 2014). Many processes in the body, especially in the
brain, nervous system, and muscles, require electrical signals for communication. The movement
of sodium is critical in generation of these electrical signals. Therefore, too much or too little
sodium can cause cells to malfunction, and extremes in the blood sodium levels, too much or too
little can be fatal (Wessling-Resnick, 2014). Iron (Fe) is a mineral that is naturally present in many
foods, added to some food products, and available as a dietary supplement. Iron is an essential
component of hemoglobin, an erythrocyte protein that transfers oxygen from the lungs to the
tissues (Wessling-Resnick, 2014).
Cashew (Anacardium occidentale) has been cultured essentially, and whole fruit is used for
medicinal and food purposes, e.g., apple and kernel. Cashew gained its importance during World
War II due to the utilization of its significant by-product, the cashew nut shell liquid (Cordeiro
2016). The Cashew nut has nutritious properties with a pleasant flavor. Cashew kernels have
shown lowdensity lipoprotein cholesterol levels and coronary risk diseases. Cashew part contains
proteins and fats. The proteins include lysine, cysteine, arginine tyrosine, valine, and many
vitamins like vitamin C, E, D (Bes‐Rastrollo and Sabaté, 2017). Cashew gum has been used widely
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for many health-related issues. These are less in saturated fatty acids and more in unsaturated fatty
acids. Its health benefits have been used to decrease the risk of cardiovascular diseases, oxidative
stress, inflammation, high cholesterol, and diabetes (Cardoso and Duarte, 2017). Cashew nuts are
used for several medicinal purposes and have great importance related to health, as evidenced by
research (Cordeiro 2016). These are used for obesity, diabetes, heart disease, urinary disorders,
digestive disorders, and many other clinical applications like bone relaxation, cold and flow, etc.
It also has importance in Cancer, and protects from aging ( Davis, 2013).
Avocado (Persea americana Mill) is one of the oldest flowering plants in history, and the genus
Persea belongs to the family Lauraceae (Popenoe and Zentmyer, 2013). The cultivars of cultivated
Avocados can be grouped into three distinct races, namely, West Indian, Guatemalan, and
Mexican, based on their characteristics and ecological adaptations (Rendón-Anaya et al., 2019).
Avocados are typically regarded as vegetables because they are frequently used in salads and have
a savoury rather than sweet flavour. Fruits are with a tough outer layer, a fleshy centre, and a shell
around a seed. Fruits can be with pale yellow-green flesh, which is smooth and buttery, with a
faintly nutty flavour and texture like a firm, mature banana. Avocado fruits contain Vitamin K,
which is 26% of the daily value (DV), Folate is 20% of the DV, Vitamin C is 17% of the DV,
Potassium is 14% of the DV, Vitamin B5 is 14% of the DV, Vitamin B6 is 13% of the DV, and
Vitamin E is 10% of the DV in a single 3.5 ounce (100 gram) serving. It also contains small
amounts of magnesium (Mg), manganese (Mn), copper (Cu), iron (Fe), zinc (Zn), phosphorus (P),
and niacin (vitamin B3) (Dreher and Davenport, 2013). Avocados have a lot of potassium in them.
Compared to bananas, which are a typical high-potassium food, a 3.5-ounce (100-gram) portion
contains 14% of the recommended daily intake (RDA) (Dreher and Davenport, 2013).
Monounsaturated fatty acids are proven good for heart health. Avocados are heavy in fat. It
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contains 77% fat calories, making it one of the fattiest plant foods on the planet. They don’t,
however, contain just any fat. Avocados are high in oleic acid, a monounsaturated fatty acid, which
is known for some of its health advantages ( Méndez-Zúñiga et al., 2019)
1.2
Statement of the Problem
Peanut butter is considered healthier alternative to butter and margarine because it mostly consists
of plant based unsaturated fats with negligible amount of trans-fats (Sanders, 2011). Its
consumption has also been suggested to be preventive in diseases like hypercholesterolemia,
diabetes, obesity, gallstones and constipation due to high percentage of unsaturated fats, fiber and
phytonutrient contents. Peanut butter has been utilized successfully for treatment of
malnourishment in impoverished countries by World Health Organization (Kane et al., 2010).
Emphasis on groundnut, cashew and avocado crop in Nigeria can solve complex problems of
edible oil deficiency and malnutrition in the country. But lack of government focus, little
awareness among farmers, low input usage, non-availability of short duration cultivars and
certified seeds restricts the production of these nuts in the country. Large number of these nuts
cultivars has been developed in Nigeria to meet the needs of country’s agricultural system,
however little work has been done on their proximate composition for differentiation on the basis
of their end use.
1.3
Justification of the Study
Based on the nutritional qualities of these nuts the consumers would use these products to improve
their nutritional status. Also from the nutritional content, if they find it acceptable, they can use
the product to replace many other such products that their nutritional properties are not acceptable.
The results of the mineral analysis if favorable will help to produce cheap and affordable peanut
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butter whose nutritive values could be compared with those of the real butter made from animal
fat as well as promote the planting of cashew, avocado and groundnut plant in Nigeria.
1.4
Aim of the Study
The main objective of this study is to evaluate the mineral content and anti-nutritional factors of
peanut butter prepared with groundnut, cashew nut and avocado nut in south west area of Nigeria.
Specific Objectives
The specific objectives of the study are to:
 To evaluate the mineral composition of the peanut butter
 To produce peanut butter using different blends of cashew nuts, groundnut and avocado
nuts.
 To evaluate the nutritional compositions of the various “peanut butter” blends
 To analyse the anti-nutritional factors of the peanut butter
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CHAPTER TWO
LITERATURE REVIEW
2.1
Nuts and Seeds
Edible nuts include tree nuts, seeds and certain legumes. Botanically, the term "nut" refers to an
indehiscent fruit that is usually shed as a one seeded unit. The pericarp is usually lignified (McNeil,
Jackson, and Morley-Bunker, 2017). They are valued for their sensory, nutritional, and health
attributes (Ventachalam and Sathe, 2016). Nuts that are consumed include; tree nuts such as
hazelnuts (Corylus avellana), macadamias (Macadamia integrifolia) and pecans (Carya
illinionensis). Seeds include Brazil nuts (Bertholletia excelsa), almonds (Prunus amigidalis),
pistachios (Pistachia vera), oyster nuts (Telfairia pedata) and cashew nuts (Anacardium
occidentale). Legumes in the nut category are represented by groundnuts (Arachis hypogea) and
bambara nuts (Vigna subterranean). In Uganda groundnuts, shea nuts, oyster nuts are popular
sources of oil (Okullo et al., 2010; Mugisha, Lwasa, and Mausch, 2014).
2.1.1 Production and Consumption of Nuts and Seeds
Production and consumption data vary according to particular nut. World production of tree nuts
is highest in the United States, India, Iran, Turkey, and China. Major producers of groundnuts are
China, India, and the United States (Varshney, Pandey, and Puppala, 2017). In 2017, almond were
the most produced and consumed nuts globally at 2,161,199 and 2,032,227 metric tons respectively
(McNeil, Jackson, and Morley-Bunker, 2017). This was followed by walnuts and pistachios with
respective production levels of 1,214,990 and 508,270 metric tons (McNeil et al., 2017). World
over, the per capita consumption of nuts is low but is improving due to inclusion of nuts in
guidelines for healthy eating in some Western countries (Ros, 2010). Nuts are part of the healthy
Mediterranean diet but their per capita consumption is as low as 2 to 9 kg (Brufau et al., 2016).
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The largest consumers of nuts in Africa include; South Africa, Morocco, Nigeria and Egypt where
macadamias, cashew nuts and shea nuts are the most popularly consumed nuts. Groundnuts are
important oil seed grown and consumed world-wide with annual production levels in excess of 45
million metric tons (FAOSTAT, 2018). Groundnuts make a significant contribution to nutrition
and livelihood improvement in sub-Saharan Africa (Okello, Biruma, and Deom, 2010).
2.1.2 Nutrient Composition of Nuts and Seeds
In developing countries, nuts and groundnuts are the primary source of digestible protein with
amounts varying between 25 and 34%, cooking oil with yield ranging from 44 to 56%, and then
vitamins in relatively high proportions. Importantly, nuts constitute complex matrices rich in
unsaturated FA and bio-active compounds such as tocopherols, phytosterols and phenolic
compounds. They contain proteins, carbohydrates and fibre (Brufau et al., 2006; Ros and Mataix,
2006; Carughi et al., 2015). Total fat content of nuts ranges from 46% in cashew nuts and
pistachios to 76% in macadamia nuts (Carughi et al., 2015; Table 1). Oil from nuts are constituted
of low levels of saturated fatty acids (SFA) and rich in monounsaturated fatty acids (MUFA) and
polyunsaturated fatty acids (PUFA) (Kris-Etherton et al., 1999; Ros and Mataix, 2006).
Groundnuts are particularly rich in MUFA (Mckevith, 2005). These properties of the nuts make
them reliable raw material for enhancing nutrients in mainly cereal diets of maize, millet and
sorghum in product development.
Nuts are cholesterol free but contain sizable amounts of phytosterols that are essential in membrane
structure (Yang, Liu, and Halim, 2009). When present in sufficient amounts in the intestinal lumen,
phytosterols interfere with cholesterol absorption and hence lower blood cholesterol (Ros, 2010).
Nuts contain substantial amounts of calcium, potassium and magnesium but their sodium content
is low (Carughi et al., 2015).
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2.2
Groundnuts
Groundnut, Arachis hypogea, is the 6th most important crop in the world valued by both small
holders and commercial traders (Usman, Taiwo, Haratu, and Abubakar, 2013). Groundnut is an
annual self-pollinating herbaceous legume that grows to a maximum height of 60 cm (Okello et
al., 2015). This annual herbaceous legume is also known as groundnut, monkey nut, earthnut,
gobber, gobber pea, groundnut vine, potato bean, wild bean, earth-ball, Chang Sheng Guo (Longlife nuts), pygmy nut and pig nut (Özcan, 2010). Groundnuts are distinguished from other plants
by flowering above the ground but producing fruits below the surface (Okello et al., 2014).
Groundnut cultivation was also active in Ecuador, Bolivia, Brazil, and the Caribbean.
In Uganda, groundnut is among the main staple crops because it contains high amounts of oil
widely used in food preparation. It is becoming a cash crop with notable increase in both
production area and productivity. This is evident by the significant expansion of the industry in
Uganda and with spillovers in the neighboring countries (Okello, Monyo, Deom, Ininda, and
Oloka, 2013). The National Groundnuts Improvement Programme has developed groundnuts
varieties to meet the challenge of persistent pests and diseases (Okello, Biruma, and Deom, 2010).
2.2.1 Agronomy
Groundnuts are divided into two subspecies, hypogaea and fastigiata. Arachis hypogaea subspecies
hypogaea has two varieties hypogaea and hirsuta while Arachis hypogaea subspecies fastigiata has
four varieties i.e. fastigiata, vulgaris, peruviana and aequatonaria. These differ in plant, seed and
pod characteristics (Okello et al., 2016). Commercial varieties include Virginia or runner
(subspecies hypogea), Valencia (subspecies fastigiata) and Spanish (subspecies vulgaris).
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2.2.2 Production of Groundnuts
Groundnut is the 6th most important oil seed crop in the world (Usman et al., 2013). The World
production of groundnuts in 2018 was estimated at 45.95 million metric tons (FAOSTAT, 2018)
China is the largest producer accounting for 37.85% of World production. This is followed by
India with 14.57% of the total production.
2.2.3 Nutrient composition of groundnuts
Groundnuts are an important source of nourishment providing several longterm health benefits
due to the presence of essential nutrients and antioxidants (Bishi et al., 2013). As shown in Table
5, groundnuts are rich in macro and micro nutrients. Groundnut composition may vary depending
on cultivar, maturity, growing location, stress factors, herbicides, pesticides, infection and
atmospheric factors (Rodrigues et al., 2013).
2.2.3.1 Fatty Acids
Groundnut kernels contain 40 to 50% oil (Mukri et al., 2012). The oil contains 80% unsaturated
FA particularly oleic (C18.1) and linoleic acid (C18.2ω6) that are beneficial to cardiovascular
health. The ratio of oleic to linoleic acid is an important indicator of nutritional quality and stability
of groundnuts and their products (Gulluoglu et al., 2016). Groundnut oil contains both saturated
and unsaturated FA (Gunstone and Sanders, 2002). Levels of these FA vary with variety, maturity
of seed and environmental conditions (Singh and Singh,1991).
Dominant FA in groundnut oil are; oleic (C18.1), linoleic (C18.2ω6) and palmitic (C16.0)
constituting about 80% of the total FA composition. Stearic (C18.0) , arachidic (20.0), behenic
(C22.0), lignoceric (C24.0) acids occur in less amounts (Zahran, and Tawfeuk, 2019). Arachidic
acid (C20.0) is the characteristic FA in groundnuts. However, levels beyond 4.8 mg/100 g are
indicative of adulteration (Carrín and Carelli, 2010).
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In addition, C20.0 and C22.0 are useful in the stabilisation and emulsification of peanut butter but
are reported to be atherogenic (Savage, and Keenan, 1994). Total FA in groundnut oil vary with
variety and other factors. Groundnut oil comprises 80% unsaturated FA and 20% saturated FA
(Shasidhar, Vishwakarma, and Pandey, 2017). Typical proportions of oleic acids vary between 21
and 85% while linoleic acid ranges from 2 to 43% in groundnut oil. Linolenic acid (C18.3ω3)
content in groundnut oil has been reported to be as low as <1% (Souza, 2011; Wang et al., 2012).
Linoleic acid and Alpha-linolenic acids are essential for humans while docosahexaenoic and
gamma-linolenic acids are conditionally essential under some developmental or disease conditions
(Whitney and Rolfes, 2018).
Essential fatty acids (EFA) are beneficial to cardiovascular health, cognitive health (proper
impulse transmission), pregnancy, lactation and infancy to ensure proper development of the brain
and nervous system (Jumbe et al., 2016). Different EFA pose varying effects in the body for
instance; omega-6 FA encourage blood clot formation whereas omega-3 FA reduce clotting. The
ideal is to achieve a balance between omega-6 and omega-3 FA (Arbex et al., 2015). According
to Simopoulos (2010), the ratio of omega-6 to omega-3 should be 4:1 for good health.
2.2.3.2 Vitamins
According to Krautgartner et al., (2016), groundnuts consists of varying amounts of vitamins A,
E, thiamine, riboflavin, niacin, pantothenic, folate, B6 and C (Inuwa et al., 2011; Reddy ;Wang,
2018). However, Reddy (1988) described vitamins A, C and D as limiting vitamins in groundnut.
Beta-carotene is the most prevalent carotenoid in groundnut oil and can be detected at a level of
60 μg/l in oil from immature groundnuts. Literature about actual amounts of beta-carotene in
mature nuts is scanty, however, the levels are reported to decrease with maturity (Gunstone and
Sanders, 2012; Nautiyal, 2012). Other carotenoids including alpha and beta are present in lower
12
amounts (Cobb and Johnson, 2013). Groundnuts also contain tocopherols that act as anti-oxidants
in groundnut oil (Wasowicz et al., 2014). Vitamin E occurs in four main isomers in foods α-, β-,
γ-, and δ-tocopherols. Average amounts of the above tocopherols in groundnut oil were reported
as 6.1 mg/100 g alpha tocopherol, 8.1 mg/100 g β and γ- tocopherol and 1.8 mg/100 g δ-tocopherol
(Kornsteiner, Wagner, and Elmadfa, 2016). According to Grilo et al. (2014), α-tocopherol has the
highest biological potency. Alpha tocopherol improves immunity, delays ageing, reduces risk of
cardiovascular disease and enhances stability of groundnut oil (Wang, 2018).
2.2.3.3 Minerals
Groundnuts contain a wide range of minerals that contribute to health and well-being (Rodrigues
et al., 2013; Savage, 2014). The above scholars reported high levels of potassium (600 to 1,693
mg/100 g), magnesium (250 to 308 mg/100 g) and moderate levels of calcium (65 to 134 mg/100
g) in whole groundnut kernels. The amounts of iron, zinc, manganese, selenium and copper were
<10 mg /100 g of groundnut kernels. Asibuo et al. (2018) asserted that cultivar and genotype may
affect mineral content of groundnuts. Savage (2014) noted that despite the substantial levels of
minerals in groundnuts, there can be losses during handling and processing. Processing on the
other hand may add to the mineral content due to tear and wear of machinery. Groundnuts are an
excellent source of phosphorous providing about 50% of our daily needs. Minerals maintain
healthy fluid and electrolyte balance in the human body while others work as precursors for
enzymes, blood and bones. Zinc is a co-factor in many body processes (FAO/WHO, 2010; Jumbe
et al., 2016). Raw groundnuts provide 4.53 mg/100 g of zinc (Mustapha et al., 2015). Although
appreciable amounts of mineral elements in whole kernels, Mckevith (2015) asserted that
vegetable oil does not contain the same amount of macronutrients, vitamins and minerals as whole
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oil seeds. Detailed information about mineral content of groundnut oil is limited, however, levels
of metal ions should be low to minimize chances of oil oxidation (Frankel, 1980).
2.2.3.4 Protein
Groundnuts contain up to 24% protein and they make a significant contribution to nutrition when
consumed (Ayoola and Adeyeye, 2012; Bishi, et al., 2013). Groundnuts contain eleven essential
amino acids (Latif, Pfannstiel, Makkar, and Becker, 2013; Table 6), These include; leucine, isoleucine, tryptophan, lysine, phenylalanine, cysteine, threonine, methionine, tyrosine, histidine and
valine. Although it is non-essential, groundnuts contain significant amounts of arginine which is a
precursor to nitric oxide that helps to keep arteries relaxed, improving blood flow. Arginine also
improves healing time in tissues in the body (Gornik and Creager, 2014).
2.2.3.5 Anti-nutritional Factors
Anti-nutritional factors present in human or animal foods tend to reduce nutrient utilization or food
intake, thereby contributing to impaired gastrointestinal and metabolic performance. Antinutritional factors in groundnuts include; trypsin inhibitors, agglutinin, phytates, condensed
tannins and α-amylase inhibitors (Qiang et al., 2016). Phytates act as chelating agents that combine
with minerals in groundnut oil and reduce chances of its oxidation. A distinguishing factor between
tannins and other anti-nutrients is their high molecular weight and ability to function as antioxidants (Okuda and Ito, 2011). Tannins like the above mentioned compounds form cross links
with proteins and other molecules (West, Hill, and Utley, 2013). Tannins are widespread in foods
of plant origin, particularly in legume seeds, cereal grains, fruits, vegetables, and different
beverages such as wine, tea, cocoa, as well as cider (Kunyanga et al., 2011). Research has shown
that groundnut skin contain high levels of tannins (Isanga and Zhang, 2017). Given their
astringency, tannins in peanut skin may have an influence on the sensory properties of peanut and
14
its products (Ashok and Upadhyaya, 2012). Groundnut skins contain catechol tannins which
influence testa colour (Nautiyal, 2012). Tannins content in groundnut skin vary from 20.5 to 23.8%
(West et al., 2013). Amounts of tannins tend to decrease with de-hulling and normal cooking
procedures of boiling and roasting (Anuradha et al., 2017).
2.2.4 Health Benefits of Groundnuts
Groundnut consumption is associated with several health benefits, such as antioxidant,
hypocholesterolemic, cardio-protective, anti-cancer, anti-inflammatory and anti-diabetic benefits
(Justyna and Waldemar-Wardencki, 2011; Vadivel et al., 2012). They are good sources of
manganese, copper, zinc and phosphorous. Most nuts are rich in magnesium providing 8 to 20%
of daily recommended in take of 400 mg in a serving of 28 g (Kris-Etherton et al., 2019). Nuts are
excellent sources of vitamin E (King et al., 2018).
Research by Reis et al. (2011) demonstrated that ingestion of 63 g of roasted peanuts per day at
breakfast lowered carbohydrate intake and ultimately reduced postprandial glycemic response,
which might help improve glycemic control and reduce the diabetes risk. According to the above
mentioned scholar, roasting resulted into cleavage of the cell walls after that released the fat
content of the peanuts, resulting in the lower glycemic response observed. It is therefore implied
that peanut consumption (42.5 to 75 g/day) in a period of three weeks, independent of body
composition alteration, improves glycemic control, induces satiety, and attenuates non-esterified
fatty acids (NEFA) concentration. On the whole, inclusion of peanuts in the diet does not only
improves the quality of the diet, but stimulates satiety and reduces glycemic response (Reis et al.,
2011; Wien, Oda, and Sabaté, 2014). Further observations suggest that regular consumption of
peanuts in adequate portions may result in weight control (Wien et al., 2014).
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2.2.5 Forms of Utilization
2.2.5.1 Seeds
Groundnuts seeds are consumed directly either raw or roasted. Young pods may be consumed as
a vegetable (Martin and Ruberte, 2015). Roasted groundnuts make good accompaniment to coffee
and tea and eaten alone even without any beverage. The roasted groundnuts are becoming common
in large supermarkets packed in polyethene materials usually in 250 g and in small plastic cups in
measures of 250 to 500 g. Raw groundnuts are also sold in its primary forms for further processing.
The consumption of raw groundnuts is nowadays rare.
2.2.5.2 Flour
Edible-grade groundnuts with low oil content may be milled into flour and boiled with onions,
tomatoes, salt, mushrooms, dried fish, meat or chicken and hot water. It may also be mixed with
green vegetables such as cowpea leaves, amaranthus or beans, mushrooms to make a stew. Stew
may be vegetarian or prepared with meat.
2.2.5.3. Paste
Groundnut butter sauces are made in Uganda and eaten as a side dish to a starchy staple food e.g.
Matooke (green bananas), rice, sweet potatoes, cassava, millet/maize bread (kalo/kawunga) and
yams (Mugisha, Lwasa, and Mausch, 2014). The paste popularly known as odii or kipooli, is used
as a sauce mixed with fish, meat or vegetables to accompany the main dish. It is important in
children’s diet especially in East, North and North Eastern Uganda. It is also popular with children
in boarding schools where it is termed as an appetizer for meals and as a spread.
2.2.5.4 Ingredient
Groundnuts are used as ingredients in various bakery products such as cakes, cookies and
confectionaries. Groundnuts used in confectionary are large-seeded, have high sucrose and protein
16
content. They are low in oil and raffinose family oligosaccharides which are known for causing
flatulence, bloating and abdominal discomfort (Bishi et al., 2013).
2.2.5.5 Oil
World over, the biggest percentage of groundnuts is used for oil production. Oil may be used in
domestic culinary operations or in industry. China and India are the largest producers and
consumers of groundnut oil (Arya, Salve, and Chauhan, 2016; Kaiser and Ernst, 2012; Nautiyal,
2002; Salve and Arya, 2018). Oil from groundnuts is considered a premium cooking and frying
oil due to its excellent oxidative stability (Varshney, Pandey, and Puppala, 2017). Groundnut oil
is considered to be superior to soybean oil during frying because it develops fewer flavour
2.3
Cashew Nut
Cashew is an evergreen perennial plant belonging to the family Anacardiaceae. This family
consists of 400-600 species. Among the eight species in the genus Anacardium, the only cashew
is valuable due to its nutritious kernel. Cashew is a tropical tree present in South America and
Brazil. Plant height varies from 5 to 14 m. The trunk is usually short and irregular, starting branches
close to the ground. Leaves are green that are placed in a spiral pattern towards the end of the stem.
Leaves become mature after 20-25 days. Flowering can occur at any time; individual flowers are
short in size consisting of five yellowish-green sepals and five white to reddish petals. In 2011,
about 4.7million tons of raw nuts were produced worldwide, which were distributed between Asia
and Africa, where 1.8 million cashew apples were produced [1].
2.3.1 Cashew Composition
The nuts of Cashew are present in the regions of north-eastern Brazil, similar to kidney seed shape
appearance that holds the lower part of this, the product of the tree. It is a favorite dried organic
product that has excellent and brilliant taste. During the 16th century, the Portuguese familiarized
17
cashew with India and Africa. The Cashew tree has great importance, as its valuable wood has
analgesic effect, the cashew itself didn’t acquire notoriety in the start of the twentieth century.
Now India is the biggest country in making, processing, and exporting cashew bits on the earth. It
is used as a mixed drink or in foods to distribute bread rolls, frozen yogurts, and chocolates. It can
also be utilized for natural products, juice, liquor, desserts. The cashew nutshell fluid is extracted
from shell comprises as destructive astringent oil valuable in brake coating, paints, and plastics
[6].
2.3.2 Cashew Refining
These nuts are to be prepared to remove palatable bit which is profoundly nourishing. In India, it
is collected during long periods of April and May and promoted rapidly from that point. The
external surface of cashew is thick and slightly thin internal surface. The pieces that are obtained
during preparation are of various evaluation like wholes, parts, and bits, etc.
2.3.3 Role of Cashew Nuts in Heart Diseases
As nuts have been selected that they are not suitable food due to their high-fat substance. But recent
studies suggest that nuts might be beneficial for the heart. About 66% of cholesterol comes from
the liver, not from food, its creation being animated by soaked fat. Soaked fat itself can be
dangerous for the heart. Soaked fats are discovered prevalently in synthetic items, including dairy
items. However, people can reduce their cholesterol level by using food containing low-soaked
food and more unsaturated fats. Recently, tree nuts have been developing a great medical
advantage. For example, previous studies from epidemiological and clinical examinations have
shown that tree-nut is helpful for the heart diseases.
Cashew part that is less in soaked fat and more in monounsaturated fat lessens the general degrees
of cholesterol and low-density lipoproteins (LDL) - the claimed "bad cholesterol" that prompts
18
coronary disease and builds high-density lipoproteins (HDL), hence assisting in making the heart
more sound [7]. The Cashew part contains fiber, carrying more fiber into the diet brings down the
level of cholesterol and the danger of heart disease prominently, which is known as heart nibble.
The fiber in the digestive tract lessens the assimilation of cholesterol from food consumption.
Ordinary use of these nuts, as a feature of a low-soaked fat eating routine, can bring down the
danger of coronary disease overall by advantageously influencing the cholesterol levels in blood
and can reduce the risk of having a subsequent respiratory & cardiovascular failure[8].
2.3.4 Cashew Nuts for Diabetes
Daily utilization of food that is rapidly increasing the sugar level in the blood leads to developing
heart diseases and diabetes as Cashew nuts contain high mono saturated fat that is beneficial for
decreasing the blood glucose level and increase insulin production. Thus, diabetes can be managed
by cashew pieces. They are essential for type 2 diabetes. They are lower in sugar and higher in
fiber; when these factors are combined, they decreased the blood glucose level and prevent the
development of type 2 diabetes [9].
2.3.5
Cashew Nuts for Rhinitis
As Cashew parts are rich in vitamin B, an ordinarily occurring cell strengthening which has
invulnerability high power. Consequently, burning through cashew parts during winter and cold
season will improve an individual’s insusceptibility [10].
2.3.6 Cashew Nuts for Obesity
Harvard University declared that a healthy food contains copious fat from the nuts of tree and olive
oil has a strong agent for weight reduction as a small calorie, kept for a low eating regimen and a
great benefit for weight reduction [11]. These nuts are rich in supplements and fiber that they will,
19
in general, fulfill appetite on less energy than other snacks [12]. Cashew extract causes significant
reduction in total cholesterol, triglycerides, LDL and VLDL cholesterol [13].
2.3.7 Protection from Cancer
This disease can likewise get destroyed from nuts. Selenium - rich cashew bits are helpful for lung,
liver, skin, cerebrum, and gastrointestinal malignancy. Due to significant fiber content likewise
assists with fighting malignancy. They act as an antioxidant and prevent the growth of cancer cells
by removing the free radicals from the body. A class of flavonoids called Proanthocyanidins fight
tumor cells and prevents them from further division. High copper content and proanthocyanidins
in cashew nut fight copper content in cashew helping to prevent colon cancer [14].
2.3.8 Eye Protection
Today’s women are selecting to work at home by using mobile phones and laptops continuously,
which damage their eyes. Zeaxanthin is a pigment that is present in Cashew, by the consumption
of Cashew, will protect the retina from damaging the UV rays and hence protects the eye.
2.3.9
For Skin
We all want fresh, flawless, and glowing skin and avoid cosmetic products for damaged skin. By
eating a few Cashews daily, we can be protected from acne and damaged skin. This is the most
beneficial effect of Cashew nut for charming and glowing skin[15].
2.3.10 Helpful for Ageing
Vitamin E has extra ordinary boosting power. A new investigation conducted on 65 years old
people found that Vitamin E supplementation appeared to stop the decrease in insusceptibility
related to aging. 100g of cashew pieces contain 46mg of Vitamin E, in this way protecting from
aging as cashew contains free radicals that keep the body free from wrinkles and lines in the face.
Cashew is used in skin remineralization and in the treatment of premature aging [16].
20
2.3.11
Renal Role
Potassium is an essential element to protect the human renal system. As it contains sodium and
potassium, so, it can be used to treat dehydration and essential minerals, which are suitable for the
kidneys. 28.35gm of cashew portion gives 0.00015kg of potassium. Potassium is a common
mineral is acquire on a regular basis excepts from delicate coconuts and cashew nuts.
2.3.12 Role in Digestive Disorders
Cashew contains 1.30% fiber. Dietary fiber is beneficial for stomach-related issues. It maintains
water, soothes the stool, and removes the blockage. Thus, it is beneficial for hemorrhoids, varicose
veins, hiatal hernias, and diverticulosis.
2.3.13 Copper as an Antioxidant, Energy Building & Bones
Copper plays a vital role in physiological aspects of life like iron use, bone and connective tissue
improvement and essential for skin and hair colors. Copper is a basic fundamental part of the
protein, superoxide dismutase, which plays a key role in providing energy and cancer prevention.
It is essential for the action of lysyl oxidase, a special protein associated with cross-linked collagen
and elastin, which provides support to bones, joints and flexibility to bones. They act as an
antioxidant and reduce inflammation as they contain free radicals and keeps the body healthy.
2.3.14 Cashew For Bones And Neuralgia
About 22.3% of magnesium is present in one-fourth cup of cashews. It contains calcium,
magnesium which are essential for nerve and muscle tone. It acts like a natural calcium channel
blocker that keeps calcium from rushing into the nerve cell and enacting the nerve. By regulating
the calcium entrance, that will keep the nerves loose.
21
Recent studies have shown that magnesium decreases the recurrent attack of headache, lowers the
circulatory strains, cardiovascular failures, manages hormonal influences in women during
menopause, and lowers the seriousness of Asthma [17].
2.3.15 Role of Cashew Kernel
Cashew kernels are purified from raw cashew. These are soft, white, and meaty but change the
color and taste upon roasting. They are attached with shells and classify them carefully by food
companies around the world. These are dried to lose the skin and then peeled off [18]. Cashew part
contains protein (18.22g), carbohydrates (27.13g), and fat (46.92g) per 100g. These have lower fat
content than other nuts containing oleic acid, which is essential for the cardiovascular system [19].
The lipid parts of Cashew are rich in unsaturated fats, which include oleic acid and polyunsaturated
fats. As this is free from cholesterol and contains a fixed amount of monosaturated fat, which is
best for lowering the cholesterol level [20]. However, cashew has the most powerful benefits for
health, including heart, nerve functioning, and muscle, maintain bone strength and oral health.
These are good source of vitamins and dietary fats, which are good for our health to absorb fatsoluble vitamins [21].
These are classified into three types; white/scorched wholes, pieces, and splits. They are low in
sugar and rich in proteins, fibers, and healthy fats. They also contain important minerals and
vitamins like calcium, magnesium, and copper, which are essential for the production of energy,
brain health, immunity, and strengthen the bone. In addition, it contains calcium, phosphorus,
copper, zinc, iron, magnesium, and sodium. As Cashew parts give the energy of 611KCals/100g,
and this is an equal amount that of almond (612Kcal/100g). In addition, it contains minerals like
Calcium, Phosphorus, Sodium, Potassium, Magnesium, Iron, Copper, Zinc, and Manganese. It is
highly rich in starch. Oligosaccharides of cashew part are, for the most part, galactosyl sucrose.
22
These kernels give an oil that can be used as a mechanical and chemical antidote for irritant poison
[22].
2.4
Avocado Nut
Avocado is a fruit with a history of about 10,000 years, produced from tropical trees characterized
by a pear shape and blackish-green colour with high nutritional value, creamy texture, and unique
taste [1, 2]. Avocado is considered as ‘Green Gold’ and has a great value because of its commercial
importance [3].
2.4.1 The Nutritional Worth of Avocado
2.4.1.1 Avocados are Nutrient-Rich Fruits
Avocado fruits contain Vitamin K, which is 26% of the daily value (DV), Folate is 20% of the
DV, Vitamin C is 17% of the DV, Potassium is 14% of the DV, Vitamin B5 is 14% of the DV,
Vitamin B6 is 13% of the DV, and Vitamin E is 10% of the DV in a single 3.5 ounce (100 gram)
serving. It also contains small amounts of magnesium (Mg), manganese (Mn), copper (Cu), iron
(Fe), zinc (Zn), phosphorus (P), and niacin (vitamin B3) [35, 36, 37].
2.4.1.2 Avocados Have a Higher Potassium Content Than Bananas
Avocados have a lot of potassium in them. Compared to bananas, which are a typical highpotassium food, a 3.5-ounce (100-gram) portion contains 14% of the recommended daily intake
(RDA) [37].
2.4.1.3. Avocado Is High in Monounsaturated Fatty Acids
Monounsaturated fatty acids are proven good for heart health. Avocados are heavy in fat. It
contains 77% fat calories, making it one of the fattiest plant foods on the planet. They don’t,
however, contain just any fat. Avocados are high in oleic acid, a monounsaturated fatty acid, which
is known for some of its health advantages [37, 38].
23
2.4.1.4 Avocados Are a Great Source of Fibre
Avocados are high in fibre, with roughly 7% by weight, which is a lot compared to other foods.
Fibre may provide significant weight-loss and metabolic-health effects [37, 39].
2.4.1.5. Avocado Eaters Are Often Healthier
Avocado eaters were found to be significantly healthy compared to those who did not consume
this fruit. Avocado eaters consumed far more nutrients and were half as likely to suffer from
metabolic syndrome, a group of symptoms that is a key risk factor for heart disease and diabetes
[40]. Avocado eaters were also lighter, had a lower BMI, and had much less abdominal fat. They
also had greater levels of HDL cholesterol (the ‘good’ kind) [37].
2.4.1.6. Avocados May Assist with Weight Loss
Avocados have some indication of being a weight-loss-friendly food [41]. In one study, those who
ate Avocado with their meal felt 23% more full and had a 28% reduced desire to eat over the next
5 hours than people who did not eat Avocado. If this holds true over time, incorporating Avocados
in your diet may automatically help you eat less calories and make it simpler to maintain good
eating habits [37].
2.4.2 Avocado Varieties
Avocados come in a variety of shapes and sizes. Even though the fruit is mostly pearshaped, some
types are virtually round. They also come in a variety of sizes, depending on the kind. Bacon,
Fuerte, Gwen, Hass, Pinkerton, Reed, and Zutano Avocados are the most prevalent varieties, with
many chefs favouring the Hass kind [35]. Due to the pebbly, rough skin of one of the most popular
kinds, the Hass Avocado is also known as the Avocado pear or alligator pear in some locations.
You can learn to differentiate them by their appearance and feel even if they don’t have a label.
Avocados are available year-round in the market, even though their optimum season is late winter
24
or early spring. Avocados, which were formerly a rare treat, are now widely available, even on
fast food sandwiches [42].
2.4.3 Medicinal Properties
Although the Avocado fruit is mainly used as a meal, it also has many therapeutic properties. The
medicinal properties of Avocado are as follows:
2.4.3.1 A Cure for High Cholesterol
In a small-scale scientific trial, 16 men ranging in age from 27 to 72 were given varying amounts
of Avocado (12 to 112 fruits per day). Half of them had a significant drop in cholesterol, whereas
none of the others had an increase. Avocados may not be a bad option for folks with excessive
choleserol or triglyceride levels [37, 55]. atherosclerosis [55]. Avocado consumption may also
help those with atherosclerosis-related angina pectoris. Antioxidant levels in the blood may have
a role in Alzheimer’s disease progression [56]. According to studies, folks who have this disease
have much lower alpha-carotene levels in their blood than healthy people [37, 55, 57].
2.4.3.2 . Aid In Digestion and Blood Sugar Balance
Because of its alkaline qualities and the softening and protecting actions of the fat on the mucous
membranes, the Avocado fruit is regarded to be beneficial for patients with ulcers or gastritis.
Studies have demonstrated that avocado-eating assists diabetics in maintaining their optimal blood
sugar levels, suggesting that the fruit may be helpful to diabetics [58].
2.4.3.3 Skincare Using the Pulp of Avocado
The mashed pulp of Avocado fruits can be used directly as a soothing cure for the skin and
protection for sunburns [58]. It is also used to protect skin from irritations and suppurating wounds.
It can also be applied (massaged) onto the scalp to relieve itching and promote hair growth. Using
25
mashed Avocados, egg white, egg yolk, or honey, you may make a soothing and cooling face mask
for dry or aged skin [35].
2.4.3. 4
Avocado Oil in Aromatherapy, Cosmetics and Skincare
Avocado oil has gained popularity as a natural carrier oil, and it is used as a base oil in cosmetics
and aromatherapy in a variety of combinations. Natural skincare lotions, liniments, hair treatments,
massage creams, muscle oils, soaps, and shampoos all include it. Avocado oil is a mild, vitaminrich oil that moisturizes and protects the skin [56]. Avocado oil disperses well on the skin and is
well absorbed. The oil is particularly beneficial to dry, ageing skin, dermatitis, and sun-damaged
skin. Avocado oil has been discovered to be helpful as a treatment for psoriasis when combined
with vitamin B12. Some dermatologists believe it can help with eczema [59].
2.5
Food spreads
Margarines and other spreads excluding butter are however, important sources of vitamin E and
they supply14 % of total vitamin E intake in adults, 17 % in boys and 16 % in girls in the United
Kingdom (British Nutrition Foundation, 2004). For example, there are diverse types of spread
varying from cheese, butter, margarine to fruit spreads on the Ghanaian market (Mpere, 2018).
Owing to drawbacks accompanying consumption of such as cheeses and margarines, substitutes
which may be able to supply the functionalities required in conventional spreads with fewer
nutritional predicaments are being pursued (Johnson, 2014).
Several efforts are being made to expand the utilization of some local food sources in the
manufacture of variety of breadspreads, which are becoming increasingly pursued because of the
nutritional benefits of some of the local foods that are readily available however underexploited.
The Persea americana fruit also known as avocado pear now proves convenient. Avocado pear is
a seasonal fruit and native to the tropics and sub-tropics such as tropical America, Far Asia and
26
Cuba (Pamplona-Roger, 2017). Peanuts are a good source of minerals such as calcium,
phosphorus, magnesium and potassium and some vitamins such as vitamin E, K and B and contains
44 to 56% oil and 22 to 30% protein on dry matter basis (Bonku et al., 2020, Guo, 2020).
Tocopherol present in peanut oil in an amount of about 0.05 percent is a good sign of the highest
stability of the peanut oil (Aoyagi, 2015). Due to its low moisture content and high oil stability,
the peanut plant is becoming widely utilized in the production of peanut paste to be consumed as
foodspread and in soups in Nigeria and several parts of the world (Abdulrahama, 2014). A variety
of food spreads is now consumed worldwide, ranging from spreads of dairy origin, plant-based
spreads, and more recently, composite food spreads. Common spreads include dairy spreads such
as cheeses, creams, and butters; plant derived spreads such as jams, jellies and hummus. Food
spreads are mostly used with baked foods and other moistened baked foods like bread; biscuits
that are consumed instantly. In Nigeria, the most popular food spreads include both spreads of
dairy and plant origins, with the most common including dairy butters, mayonnaise, margarine,
jams, peanut-butter and chocolate spreads (de Brauw, 2021; Steyn, 2016).
2.5.1
Classification of Food Spreads
The general classification of spreads include, but not limited to, spreads made from edible
vegetable oil (plant-based spreads) or animal fat (diary spreads) or a combination of both such as
margarine, cheese and butter, and those obtained from fruits and vegetables such as jams, preserves
and marmalades. Food spreads are classified based on the following factors, the source of the
spread, the ratio of ingredients and the technique used in the preparation of the spread. The two
most common categories are the dairy and plant-based spreads, while a third less common category
comprises meat-based spreads (Young et al., 2019).
27
2.5.1.1
Spreads of animal origin
Food spreads of animal origin can also be called dairy spreads. These typically consist of edible
oils of fat source (as they are mainly fat-based). Edible fats and oils mean foodstuffs constitute of
glycerides of fatty acids. They are of vegetable or animal (including milk) or marine origin and
may contain a continuous oil phase for preparation of emulsifier-free, structured without
emulsions, a homogenous mixture of plant fiber-containing material, edible oil, water, and an
efficient amount of an emulsifier to prevent oil separating out from the plant fiber and other
mixture solids, which would otherwise take place in the absence of an emulsifier and in the
condition of when the edible spread composition is discharged while held under pressure
(O'Dwyerd, 2013: Macias-Rodriguez, 2020). Lastly, is the use of packaging containing the edible
spread composition held inside a pressurized container and dispensed without experiencing oil
separation is possible.
2.5.1.2 Spreads of Plant origin
Plant derived spreads are typically thick and gelatinous. This state is reached by a combination of
fruit with three ingredients: pectin, acid and sugar. They are all produced by preserving the fruit
with sugar, and are thickened or jellied to some degree. Most fruit jellies and jams contain about
one percent pectin. It is naturally occurring and found in many fruits, some containing enough
natural pectin to make finished product (Wells-Moses, 2016). These products have the following
characteristics:

Jams: high sugar foods prepared by crushing fruits (including flesh and juice) with sugar
and water, and heating till pectin is activated. The pectin thickens the final product via
cross-linking of the large polymer chains until form sets. Jams are usually thick and sweet
28
but not as firm as jelly. They are rich in vitamin C, minerals, iron, phytonutrients and even
fibre.

Jellies (gelatin): made from cooking fruits, and then straining to extract the juice which is
combined with pectin and sugar for the final product, a clear, gelatinous, and sparkling
spread of thin consistency. Typically, they contain more pectin than jams, which gives their
firm texture and holds its shape. Only selected kinds of fruits are used in jellies.

Purees: this is the raw pulp obtained from the boiling of whole fruits or vegetables, flesh
and juice. Due to the absence of sugar or acids to serve as preservative, purees have a
relatively low shelf-life.

Marmalade: made from the juice of fruits boiled with sugar and water (just as in jelly),
but usually containing sliced, ground, or diced peels (of a single or a combination) of citrus
fruits evenly dispersed through the clear gel, incorporating a slightly bitter taste. Just like
jelly, it contains more water compared to jam, but unlike jelly, the fruit pulp is not strained
out of the liquid.

Fruit spreads: generally, fruit juices or whole fruits processed, concentrated along with
sugar and pectin (and may sometimes contain no added sugar). The major difference
between fruit spreads is their consistency and the type and proportions of fruits used.

Fruit conserves: also known as a whole fruit jam, conserves are made either from
simmering fruits in a hot sugar mixture long enough for all the flavor to be extracted and
sugar to penetrate the fruit without dissolving it or sprinkling dry sugar over raw fruit in
layers and leaving to steep before boiling slightly to achieve setting point. This is the
chunkiest fruit spread.
29

Fruit preserves: made from whole or cut up fruit in clear, slightly jelled syrup this fruit
preparations have sugar as their main preserving agent (and sometimes acid). Dried fruits
may be added (but not nuts). There are many varieties of fruit preserves globally,
distinguished by method of preparation, type of fruit used, and place in a meal. Can be used
like a jam.

Fruit compote: These are 100% fruit with no sugar added. If needed, a sweet fruit juice
such as white grape juice or apple juice may be added.

Fruit curd: mostly used as a dessert topping, it‘s usually made with fruit juice (lemon,
lime, orange or raspberry). Other basic ingredients include beaten egg yolks, sugar, and
zest cooked together and the cooled to give a soft, smooth, intensely flavored spread.

Fruit butters: made by forcing the whole fruit through a sieve after cooking to softness.
The pulp is cooked with sugar and stirred rapidly or blended to give a smooth consistency.
Usually, spices and herbs are added and a limited amount of sweeteners and pectin. Fruit
butters are thicker and have less sugar than jam. Only certain fruits is used.

Hummus: this is a smooth blend of chickpeas (or other similarly leguminous foods)
usually eaten with bread or vegetables.

Nut spreads: this consists a series of products, which are likened to butter, containing less
cholesterolat least 40% nut ingredients, which can be combined in various forms, e.g., as
nuts, a paste and/or a slurry. They are rich in vitamins and some phytochemicals such as
tocopherols and phenolic compounds.

Chocolate spreads: made from chocolate paste and flavour and does not solidify under
room temperature. It is suitable for eating bread, waffles, pancakes, muffins, and pies.
30

Syrups: a highly viscous blend of boiled fruit juice, sugar, lemon juice (optionally) and
further thickened by powdered pectin (if desired).
2.5.2 Ingredients used in food spread production
Each ingredient used in the formulation of the composite foodspread is employed for the
specifically characteristics it has and/or the result it has on the finished product, the nutritional
benefits it contributes, and it aesthetic qualities. If these effects are understood, the ingredients
may be selected with the assurance that the products produced will be good (Ishinwu, 2011).
2.5.2.1 Peanut
Peanuts (Arachis hypogea) are agreat source of minerals such as calcium, phosphorus, magnesium
and potassium and some vitamins such as vitamin E, K and B and holds 44 to 56% oil and 22 to
30% protein on dry matter basis, freshly harvested peanut contains 5-7% moisture on average and
about 3% ash (Rodrigues, 2013). Tocopherol present in peanut oil in an amount of about 0.05
percent is a good sign of the highest stability of the peanut oil (Aoyagi, 2015). Due to its low
moisture content high oil stability, the peanut plant offers better processing characteristics and
keeping quality. Peanuts‘ protein nature provides better water binding and emulsifying abilities.
Due to its‘ high fibre content, peanut has a digestibility index of 89%. Of the various amino acids
present in peanut, sixteen are responsible for the reaction it undergoes during roasting which leads
to browning, due to high amount of sucrose, extreme temperature of roasting and high fiber content
(Settaluri, 2012). Peanuts are a good source of minerals such as calcium, phosphorus, magnesium
and potassium and some vitamins such as vitamin E, K and B and contains 44 to 56% oil and 22
to 30% protein on dry matter basis. It also has high amount of oleic and linoleic fatty acid profile
that accounts for about 75 to 80% of the total oil it contains (Syed, 2021). Peanut seeds are a good
31
source of protein, lipid and fatty acids for human nutrition. Peanutcontaining foods have high
consumer acceptance because of their unique roasted peanut flavour. Peanut constitutes a major
annual oilseed crop and a good source of protein containing high lysine content which makes it a
good complement for cereal. Roasted peanuts are processed by heating the peanuts up to 180 °C
for around 12–15 min or at 160 °C for 40–60 min depending on the moisture content. The
processing methods like roasting and boiling have shown increase in the concentration of these
bioactive compounds. These bioactive compounds have been recognized for having disease
preventive properties and are thought to promote longevity (Adeyeye, 2010).
2.5.2.2 Avocado pears
Persea Americana commonly known as Avocado pears or alligator pears. Avocados are very
nutritious, high in unsaturated fat and at their buttery best when used in raw preparations (Brooks,
2020). Avocado has several medicinal and health benefits (Pamplona-Roger, 2007 and Duarte,
2016). The pulp of the avocado fruit is added to the diet it helps to reduce cholesterol levels
(Pamplona-Roger, 2014). Various studies have confirmed that apart from being a source of energy
and vitamins, avocado also delivers specific non-nutritive physiological benefits that may enhance
health. It can thus be considered as a "functional food", based on the definition of (VelderrainRodríguez et al., 2021). Among the nutraceutical ingredients found in avocado pulp are
antioxidants, such as vitamin E or tocopherols (4.31 UI/100 g) and glutathione (17.7 mg/100 g),
more than three times the amount in any other fruit. As a source of antioxidants, the vitamin E and
glutathione neutralize free radicals that may damage aging cells, the heart (Adaramola, 2016), and
contribute to the development of some types of cancer, such as cancer of the mouth and pharynx
(O'Toole, 2000; Heber, 2001; Pamplona-Roger, 2007). Lutein, a carotenoid, helps to protect the
eye from diseases such as cataracts and reducing the risk of age related macular eye disorders.
32
Avocados contain a high amount (248 mg/100 g) of lutein (Johnson et al., 2015). The level of βsitosterol in avocado is similar to that in soy and olives. It has been demonstrated through animal
studies that β-sitosterol is related to the inhibition of cancerous tumors (Lambri et al., 2013). β sitosterol has been shown to improve men's prostate function (Lu, 2015). As a good source of
vitamin D, it is beneficial for those at risk from osteoporosis. Oleic acids and folate prevents stroke,
breast cancer and lowers cholesterol levels in blood. The avocado (Persea americana) is known for
its pleasing taste and predominance of monounsaturated fatty acids (Dreher & Davenpot 2013). It
is also recognized as a functional food that contains health‐ promoting phytochemicals such as
glutathione and beta‐ sitosterol (Ferreira da Vinha et al., 2013). It has been used as a fruit, mashed
as a sandwich spread, and cubed as a topping for baked potatoes and soups, but its feasibility as a
fat replacer has not yet been studied.
2.5.2.3 Flavouring Ingredients
Salt: This provides the salt content of the food spread (about 1.5%). It balances sweetness and
contributes to flavour, as well as highlighting the natural flavours of other ingredients. Salt
contains the element sodium, which is an essential nutrient needed by the body in small amountsto
balance fluids in the blood and maintain a healthy blood pressure Adding salt to the formulation
restructures the proteins, which then act as a binding and emulsifying agent.
2.5.2.4 Miscellaneous ingredients
Hydrogenated vegetable oil (0.125 %): is generally added to improve oil stability. While acting as
a stabilizer to prevent the oil from collecting at the top of the jar, vegetable oil also enhances
smoothness, spreadability. Other ingredients include dextrose (2%), sweetener, xanthan gum,
33
vinegar and corn syrup (2%), and protein sources whichare added as prescribed by the specific
recipe being usedto produce particular flavors and textures
34
CHAPTER THREE
MATERIALS AND METHODS
3.1
Materials:
Samples of groundnut, Avocado nut and Cashew nut, culture media, autoclave and incubator, petridish
3.2
Source and collection of nut samples:
Peanut butter samples incorporated with groundnut, cashewnut and avocadonut will be purchased
from different markets in Abeokuta viz: Panseke, Lafenwa, Olomore, Kuto and Onikolobo. The
samples will be taken to the laboratory immediately after purchased.
3.3
Sample Analysis
3.3.1 Production of Cashew Nut, Avocado Nut And Groundnut Slurries
The cashew nuts, avocado nuts as well as the groundnuts will be sorted manually to remove spoilt
ones and then cleaned with water and weighed with a weighing balance. They will be manually
cracked and dehulled into separate stainless steel bowls. From the bowls, they will be ground
separately with the aid of single disc attrition mill (NEWIN JM-130) into slurries. The slurries will
be weighed again to determine their percentage yield before being packaged and stored in airtight
plastic containers for further analysis.
3.3.2 Production of Spread Samples
3.3.2.1 Preparation of the Different Sample Blends
The cashewnut slurry, avocadonut slurry and the groundnut slurry will be blended in the ratio of
90:10, 80:20,70:30,60:40,50:50, and vice versa with each samples weighed out into three places
using a weighing balance and a plastic spoon. One hundred percent each of cashew nut slurry,
Avocado nut slurry and groundnut slurry weighing 100g each will also be weighed out into three
places which will be used as control sample. The entire blends above were each separately with
35
2g of gelatin, 0.32g of ascorbic acid, 4.9g of sugar, 0.2g of salt and 30ml of soybean oil (laser).
The different blends will be placed in plastic containers.
3.3.3 Production of spread Samples from Different Blends of Cashewnut, Avocadonut and
Groundnut Slurries
The “butter” samples will be produced in batches by weighing out 100g of each of the blends with
the aid of a weighing balance and then mixing them with the other ingredients already weighed
out as stated. Then, each will be blended or mixed thoroughly with the aid of a blending machine
before being pasteurized at 60°C for 3 minutes. After cooling, they will be packaged and stored in
airtight plastic containers for nutritional evaluation and proximate analysis
3.3.4 Mineral Composition
The mineral contents of the samples will be determined by the procedure of AOAC (2000).
Manganese, copper, phosphorus, potassium, magnesium, calcium, iron, selenium, zinc, copper
elements were measured with Atomic Absorption Spectrophotometer (Thermo scientific S Series
Model GE 712354) after digesting with a perchloric – nitric acid mixture (AOAC, 2000). Prior to
digestion, 0.50 g of the samples were weighed into a 125 ml Erlenmeyer flask with the addition of
perchloric acid (4 ml), concentrated HNO3 (25.00 ml) and concentrated sulphuric acid (2.00 ml)
under a fume hood. The contents were mixed and heated gently in a digester (Buchi Digestion unit
K-424) at low to medium heat on a hot plate under perchloric acid fume hood and heating was
continued until dense white fume appeared. Heating was continued strongly for half a minute and
then allowed to cool followed by the addition of 50 ml distilled water. The solution was allowed
to cool and filtered completely with a wash bottle into a Pyrex volumetric flask and then made up
with distilled water. The solution was then read on the Atomic absorption Spectrophotometer.
3.3.5 Anti –Nutritional Factors
36
The anti nutritional contents of the samples will be determined by the procedure of AOAC (2000).
Tannin, Saponin, Oxlate, Phytate, Flavonoid, Alkaloid elements were measured with Atomic
Absorption Spectrophotometer (Thermo scientific S Series Model GE 712354) after digesting with
a perchloric – nitric acid mixture (AOAC, 2000). Prior to digestion, 0.50 g of the samples were
weighed into a 125 ml Erlenmeyer flask with the addition of perchloric acid (4 ml), concentrated
HNO3 (25.00 ml) and concentrated sulphuric acid (2.00 ml) under a fume hood. The contents were
mixed and heated gently in a digester (Buchi Digestion unit K-424) at low to medium heat on a
hot plate under perchloric acid fume hood and heating was continued until dense white fume
appeared. Heating was continued strongly for half a minute and then allowed to cool followed by
the addition of 50 ml distilled water. The solution was allowed to cool and filtered completely with
a wash bottle into a Pyrex volumetric flask and then made up with distilled water. The solution
was then read on the Atomic absorption Spectrophotometer.
37
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