CHAPTER ONE

GENERAL INTRODUCTION

For the past decades, increasing population, urbanization and changing food habits has led to an increased demand for Wheat-based convenient foods in many developing countries. However, as wheat is not grown in countries with tropical climate, they have to rely on expensive wheat imports paid with foreign exchange.

With rising wheat prices on the global markets, there is an interest to promote utilization of local sources of flour for partial substitution of wheat flours in food products in order to lower the dependency to wheat imports and also to increase livelihoods of local farmers.

Sweet potato and pumpkin seeds are crops which are rich in starch and are widely grown and consumed as staple food in tropical countries. It requires low inputs of water, fertilizers and labour.

In Cameroon, soybeans, sweet potato and pumpkin seeds are one of the most important crops in terms of production, energy intake, and contribution on Growth Domestic Product (GDP), soybeans, sweet potato and pumpkin flour has been examined as a local alternative to wheat flour.

The possibility of using starchy tubers instead of wheat flour in foods depends on their chemical and physical properties.

Amlylose and amlopectin ratio for examples influences the flour’s behaviour in foods systems such as viscosity, gelatinization and setback which affect texture of the end product. To be widely accepted, soybeans, sweet potato and pumpkin seeds flour needs to meet the high quality requirements base on the physio-chemical characteristics of the end product.

 Background to the study

The world today is characterized by a rise in health consciousness and growing interest in the role of food for maintaining human well-being and consumer health. In addition to their nutritional and sensory properties, foods are presently recognized as active and protective agents and flour is conventionally a food based-product that has become a major component of human food and snacks in most part of the world.

Flour is one of the most nutritious plant foods available, offering an array of minerals and critical nutrients; it forms the foundation for bread, cakes, and pastries. It may be described as the skeleton, which supports the other ingredients in a baked product.

In addition to being the most nutritious plant food, it is a major source of starch and energy which provides substantial amounts of vitamins B, photochemical, and dietary fibre. Globally, wheat is being produced of about 680 million tonnes over five years from 2008 to 2012, with almost 700mt being produced in 2011 (FAOStat).

This makes it the third most important crop in terms of global production. Unfortunately, wheat production is low in Cameroon due to the climatic condition which is unfavourably to the crop, leading to the importation of wheat.

Cameroon is endowed with many legume crops like soybeans which is cheap and used mostly in the production of milk in most homes. Soybeans are a leguminous vegetable of the pea family that grows in tropical, sub-tropical and temperate climates. Soybeans were domesticated in the 11^thcentury BC around North East of China (FAO, 2005).

It is believed that it might have been introduced to Africa in the 19^th century by Chinese traders along the east coast of Africa. It consists of more than 36% protein, 30% carbohydrate and excellent amounts of dietary fibres, vitamins and minerals.

It also consists of 20% oil which makes it the most important crop for producing edible oil (Gibson and Benson, 2005). The use of soybeans is increasing because of its functional properties and being an economic source of dietary protein and important bio-active components such as isoflavones. 

Soybeans are considered an inexpensive source of high-quality protein (38% – 55%) that are abundantly rich in most cereal grains (Shorgen et al., 2006) but low in sulphur amino acids, lutein and xanthenes.

Pumpkin fruit (Cucurbita pepo) is a squash-like gourd in the Cucurbitaceae family of vegetables native to Mexico (Atuonwu and Akobundu, 2010). Pumpkin seeds (pepita) are edible kernels of fruit pumpkin. Pumpkin seeds are flat, dark green seeds, with some encased in a yellow-white husk.

They have a malleable, chewy texture, and have a subtly sweet, pleasantly nutty flavour (Campbell and Gold, 2009).

They are also a rich source of essential fatty acids, which have numerous health benefits like providing protection against serious health diseases such as high blood pressure, arthritis, cancer, promoting healthy skin and improving brain power (Pongjanta et al., 2006).

The unique nutritional and health benefits of pumpkin seeds has contributed to increasing their popularity in recent years.

Sweet potato is a crop grown in the savannahs of western Cameroon precisely in the Santchou locality in about 334km from the city of Douala because of its hardy nature and broad adaptability; it provides a sustainable food supply when other crops fail (Ndunguru and Rajabu, 2000).

It is rich in beta-carotene, a vitamin A and it is also extremely rich in bioavailable betacarotene, which the body converts into vitamin A (retinol) at a ratio of 12 to 1(Reaching Agent for Change (RAC), 2012).

According to Waized et al. (2015), about 125g of most SP varieties can supply the recommended daily allowance of vitamin A for children of 300µg and 700µg non-lactating mothers. On top of beta carotene, SP also contains other vitamins like C, E, K and B (International Potato Centre (IPC), 2010).

Therefore, the use of these nutrients base foods with improvement of processing methods will raise their production and consumption and hence improve the health status of every individual, as well as generating income to small farmer’s holders.

1.2 Statement of the problem

The consumption of cereal snack foods such as biscuits, cookies, cakes, wafers and short bread has become very popular in Africa particularly in Cameroon, especially among children (Abayomi et al., 2013). They are ready-to-eat, convenient and inexpensive food product containing digestive and dietary principle of vital importance.

In Cameroon, the consumption of ready-to-eat baked products is continually growing and there has been an increase in reliance of imported wheat (Adeyeye and Akingbala, 2015). Moreover, Cameroon grows staple crops other than wheat such as maize, sweet potato, pumpkin seed, cassava, soya bean etc that can be used for baked foods.

It would therefore be of economic advantage if wheat flour can be replaced with flour from cereals, tubers, and legumes, hence reducing the reliance on its importation and thus enhance the industrial utilization of local crops (Obabanjo and Ighere, 2014).

Malnutrition, particularly protein deficiency, is prevalent in many parts of Africa as animal protein is too expensive for most people in Africa. Many leguminous crops provide some protein, but soya bean is the only available crop that provides an inexpensive and high quality source of protein comparable to meat, poultry and egg (Edema et al., 2005).

The key benefits of soya are its high protein content, vitamins, minerals and insoluble fibre. The high fibre content makes soya beans and other soya containing foods valuable in case of constipation, high cholesterol and type-2 diabetes (Gibson and Benson, 2005).

As cereals are the staple diet of developing nations and since they mostly rely on plant-based food sources, so the utilization of pulses to supplement pumpkin flour can be an effectual approach to combat protein energy malnutrition.

Soya bean is rich in protein with well balanced amino acid profile, so in search for nutritious food products, it provides an opportunity to be used in baked products such as cookies, bread, pasta and snack foods (Kaduna et al., 2012).

This has pushed the researcher to work on the assessment of quality and sensory properties of biscuits made from complementary flour, thus encouraging the use of under-utilized food crops like sweet potato, pumpkin seed and soybeans in producing value added products with nutraceutical potentials.

1.3 Research questions

• How can soybeans, sweet potatoes and pumpkin seeds (Cucurbita maxima) be converted to complementary food to produce biscuits?
• How can complementary flour be used to formulate biscuit?
• To what extend does the formulated biscuit be acceptable?

 1.3.1Research objectives

The overall objective of this work is to production of biscuits using complementary flour made of soybeans, sweet potato, and pumpkin seeds. 

 1.3.2 Specific objectives

 The specific objectives of this study are;

• To transform soybeans, sweet potato and pumpkin seeds into flour.
• To produce biscuit using complementary flour.
• To assess the sensory properties and consumer acceptability of the formulated biscuit.