Project – Development and Sensory Evaluation of Fortified Cassava-Based Snack Products Using Soybean and Moringa Leaf Powder

CHAPTER ONE

INTRODUCTION

1.1 Background to the Study

Food plays a fundamental role in human growth, development, health and general well-being. However, the nutritional quality of foods consumed by many households is influenced by affordability, availability, cultural preference and the nutrient composition of locally available food materials. In many developing countries, there is increasing interest in the development of affordable food products that can provide improved nutritional value while retaining acceptable sensory characteristics. Food product development through fortification and composite formulation provides an opportunity to combine locally available staples with nutrient-dense plant materials. Cassava is particularly important in this regard because it is widely cultivated and consumed in Nigeria, but its root is predominantly a carbohydrate source and contains relatively low protein. The Food and Agriculture Organization (FAO) has noted that cassava products can be nutritionally improved through the incorporation of protein-rich crops such as legumes, including soybean, thereby increasing their nutritional value and potential for wider food utilization (FAO, 1990).

Cassava is one of the important root crops used extensively for food production in Nigeria because of its adaptability to different ecological conditions and its versatility in food processing. Cassava flour can be incorporated into several products, including snacks, biscuits, baked products and other convenience foods. Nevertheless, the nutritional limitation of cassava flour, particularly its low protein content, creates a need for complementary ingredients capable of improving its nutrient density. Maziya-Dixon et al. (2017) demonstrated the potential of combining high-quality cassava flour with soybean and other legumes in snack production, reporting that the soybean-containing snack had substantially improved protein characteristics while remaining acceptable to sensory panellists. Their findings indicate that cassava-based snacks can serve not merely as energy-providing products but also as vehicles for improving dietary quality when appropriately formulated.

Soybean is an important leguminous crop with considerable potential for improving the nutritional quality of cereal- and root-based foods. Unlike cassava, which is relatively poor in protein, soybean provides substantial amounts of protein and other nutrients, making it suitable for composite flour formulation and food fortification. The incorporation of soybean into cassava-based products can therefore help to address the nutritional imbalance associated with cassava-dominated foods. Research on cassava-soybean snack products has demonstrated that blending the two materials can improve proximate nutritional characteristics and produce products with acceptable sensory qualities. Onwuzuruike et al. (2021) found that different soybean-cassava flour blends produced measurable differences in protein, fat, carbohydrate and sensory characteristics, demonstrating the importance of selecting appropriate blending proportions during product development.

Beyond soybean, Moringa oleifera leaf powder has attracted considerable attention as a plant-based food fortificant because of its nutrient-rich composition. Moringa leaves contain various micronutrients and bioactive compounds and have been incorporated into different food products, including traditional foods, bakery products, beverages and complementary foods. Oyeyinka and Oyeyinka (2018), in their review of Moringa oleifera as a food fortificant, reported that Moringa leaves, seeds and flowers have been investigated for use in several food products because of their nutritional potential. The incorporation of Moringa leaf powder into cassava-based snacks may therefore provide an additional means of increasing the micronutrient and functional value of the product while making use of an indigenous plant resource.

The nutritional advantages of Moringa leaf powder, however, must be considered alongside its influence on the sensory properties of food. Food fortification does not automatically guarantee consumer acceptance because changes in colour, flavour, aroma, taste and texture can occur as the proportion of a fortifying ingredient increases. Research has shown that Moringa leaf powder possesses distinctive sensory characteristics that may affect the acceptability of fortified foods. Studies of Moringa-fortified foods have consequently emphasized the importance of identifying an appropriate level of incorporation that balances nutritional improvement with consumer preference. For example, a study on the sensory attributes and acceptability of complementary foods fortified with Moringa leaf powder observed that the sensory characteristics of Moringa-containing products were important considerations in determining acceptable fortification levels (Nutrition & Food Science, 2019). Similarly, research on Moringa-based snacks found that appropriate processing and substitution levels could produce products with acceptable texture and improved nutritional characteristics (Sengev et al., 2016).

Sensory evaluation is therefore an essential component of the development of fortified snack products because nutritional improvement must be accompanied by consumer acceptability. Sensory evaluation commonly considers attributes such as colour, appearance, taste, aroma, texture and overall acceptability. A product may have improved nutritional composition but fail to achieve practical usefulness if consumers reject its sensory characteristics. Maziya-Dixon et al. (2017) demonstrated this relationship in their evaluation of cassava-legume snack products, where sensory responses differed according to the type and processing of the legume incorporated. Similarly, Torkuma et al. (2023) reported that cassava-soybean-based ready-to-eat snack formulations could achieve acceptable sensory characteristics, illustrating the potential of composite formulations to produce nutritionally improved and consumer-acceptable snacks.

The development of fortified cassava-based snack products using soybean and Moringa leaf powder is therefore relevant to food and nutrition research in Nigeria because it brings together an abundant carbohydrate-rich local crop, a protein-rich legume and a nutrient-dense leafy plant. Previous studies have established the potential of cassava-soybean combinations and Moringa-based fortification independently, but the combined incorporation of soybean and Moringa leaf powder into cassava-based snack products requires further evaluation, particularly with respect to formulation, nutritional enhancement and sensory acceptability. This creates an opportunity to develop snack products that utilize locally available agricultural materials while potentially improving the nutritional quality and diversity of commonly consumed snack foods. The present study is consequently designed to develop fortified cassava-based snack products using soybean and Moringa leaf powder and to evaluate their sensory characteristics in terms of colour, taste, aroma, texture and overall acceptability (Oyeyinka & Oyeyinka, 2018; Maziya-Dixon et al., 2017).

1.2 Statement of the Problem

Cassava is widely used as a food crop and as a raw material for numerous processed foods in Nigeria, but its nutritional composition presents a limitation when it constitutes a major component of the diet. Cassava root is predominantly carbohydrate-based and contains relatively little protein compared with legumes such as soybean. Consequently, snacks produced mainly from cassava flour may provide substantial energy without providing proportionate amounts of protein and selected micronutrients. The FAO has recognized that cassava products can be nutritionally improved through combination with protein-rich crops such as legumes. The challenge, therefore, is to develop cassava-based snack products that retain the functional and economic advantages of cassava while addressing some of its nutritional limitations through appropriate fortification (FAO, 1990).

A second problem concerns the nutritional quality of commonly consumed snack products and the need for affordable alternatives that can contribute more nutrients to the diet. Snacks are increasingly incorporated into daily eating patterns, particularly because of convenience, availability and ease of consumption. However, the nutritional quality of snacks varies considerably according to their ingredients and formulation. Research on cassava-soybean snack products has shown that incorporation of soybean can substantially improve the protein characteristics of cassava-based products. Maziya-Dixon et al. (2017) found that soybean-containing cassava snacks provided a nutritional advantage while still demonstrating acceptable sensory characteristics. Despite this evidence, there remains a need to investigate additional combinations involving other nutrient-dense indigenous ingredients such as Moringa leaf powder in order to broaden the nutritional possibilities of cassava-based snack development.

Another problem is the possible conflict between nutritional fortification and sensory acceptability. Increasing the level of a nutrient-rich ingredient in a food product may alter its colour, flavour, taste, aroma or texture, potentially reducing consumer acceptance. This is particularly relevant to Moringa leaf powder because its distinctive colour and flavour may become more noticeable at higher incorporation levels. Studies have therefore emphasized the importance of determining fortification levels that provide nutritional benefits without producing undesirable sensory characteristics. Oyeyinka and Oyeyinka (2018) identified sensory acceptability as an important consideration in the development of Moringa-fortified foods, while Sengev et al. (2016) demonstrated that processing and substitution levels influence the sensory quality of Moringa-containing snack products.

There is also a research gap concerning the combined use of cassava, soybean and Moringa leaf powder in snack product development. Existing research has examined cassava-soybean composite snacks and Moringa-fortified food products, but fewer studies have focused specifically on the simultaneous utilization of cassava as the principal base, soybean as a protein-rich fortificant and Moringa leaf powder as a nutrient-dense leafy fortificant in the development of snack products. Onwuzuruike et al. (2021) demonstrated that soybean-cassava flour proportions influence nutritional and organoleptic characteristics, while Torkuma et al. (2023) established the feasibility of producing acceptable ready-to-eat snacks from cassava-soybean composite flour. These findings provide a basis for further investigation into combined fortification with soybean and Moringa leaf powder. It is against this background that this study seeks to develop fortified cassava-based snack products and evaluate their sensory characteristics in order to determine formulations that may provide improved nutritional potential without compromising consumer acceptability.

1.3 Purpose of the Study

The general purpose of this study is to develop and carry out sensory evaluation of fortified cassava-based snack products using soybean and Moringa leaf powder.

Specifically, the study seeks to:

1. determine the effect of different levels of soybean incorporation on the sensory characteristics of cassava-based snack products;
2. determine the effect of different levels of Moringa leaf powder incorporation on the sensory characteristics of cassava-based snack products;
3. evaluate the combined effect of soybean and Moringa leaf powder fortification on the sensory attributes of cassava-based snack products; and
4. determine the overall acceptability of the developed fortified cassava-based snack products among sensory panellists.

1.4 Research Questions

The following research questions will guide the study:

1. What effect do different levels of soybean incorporation have on the sensory characteristics of cassava-based snack products?
2. What effect do different levels of Moringa leaf powder incorporation have on the sensory characteristics of cassava-based snack products?
3. What is the combined effect of soybean and Moringa leaf powder fortification on the sensory attributes of cassava-based snack products?
4. Which of the developed fortified cassava-based snack products has the highest overall acceptability among sensory panellists?

1.5 Research Hypothesis

The following null hypothesis will be tested at the 0.05 level of significance:

H₀: There is no significant difference in the sensory acceptability of cassava-based snack products fortified with different levels and combinations of soybean and Moringa leaf powder.

1.6 Significance of the Study

The study will be significant to consumers because it may provide information on the sensory acceptability of snack products developed from locally available food materials. The development of nutritionally improved cassava-based snacks may provide consumers with additional food choices that combine cassava with protein-rich soybean and nutrient-dense Moringa leaf powder.

The study will also be significant to food scientists and product developers because it will provide information on the formulation and sensory performance of cassava, soybean and Moringa-based snack products. The findings may serve as a basis for further studies involving nutrient analysis, shelf-life assessment, functional properties and optimization of composite flour ratios.

The study will be useful to farmers and agricultural processors because the utilization of cassava, soybean and Moringa in value-added food products may contribute to increased demand for these agricultural commodities. The development of such products may support diversification of the uses of locally produced crops and potentially create additional opportunities for small-scale food processing.

The study will further benefit nutritionists and dietitians by providing information on the sensory response to food products fortified with plant-based ingredients. Although sensory evaluation does not by itself establish nutritional adequacy, it is an important preliminary consideration in the development of food products intended for regular consumption.

Finally, the study will be useful to students and researchers as reference material for future research on food fortification, composite flour technology, cassava utilization, soybean-based food products, Moringa leaf powder and sensory evaluation.

1.7 Scope of the Study

The study focuses on the development and sensory evaluation of fortified cassava-based snack products using soybean and Moringa leaf powder. The study will involve the processing of cassava into flour and the preparation of soybean flour and Moringa leaf powder for incorporation into the snack formulations.

The study will focus primarily on the formulation of different samples using varying proportions of soybean and Moringa leaf powder. The sensory properties of the developed products will be evaluated using selected sensory attributes, including colour, appearance, aroma, taste, texture and overall acceptability.

The study is limited to sensory evaluation and product development. Where laboratory proximate or physicochemical analyses are included in the research design, they will be restricted to the parameters specified in the methodology. The study will not attempt to establish clinical nutritional outcomes among consumers.

1.8 Operational Definition of Terms

Cassava: A root crop scientifically known as Manihot esculenta that serves as a major source of carbohydrate and is used as the principal base material for the snack products developed in this study.

Cassava-based snack: A ready-to-eat or conveniently consumed food product formulated principally from cassava flour and processed into a snack form.

Composite flour: A flour produced by blending two or more different flour materials in predetermined proportions for the purpose of improving the functional or nutritional characteristics of a food product.

Fortification: The deliberate addition of nutrient-rich food ingredients to a food product to improve its nutritional characteristics.

Soybean: A leguminous crop rich in protein and other nutrients, processed into flour and incorporated into the cassava-based snack formulations in this study.

Moringa leaf powder: Powder obtained from appropriately processed and dried leaves of Moringa oleifera and used as a plant-based fortifying ingredient in the snack formulations.

Sensory evaluation: A systematic assessment of food products using human sensory responses to attributes such as appearance, colour, aroma, taste, texture and overall acceptability.

Sensory acceptability: The extent to which sensory panellists find a developed food product pleasant or satisfactory based on its evaluated sensory characteristics.

Snack product: A food item prepared for convenient consumption between or alongside regular meals.

Overall acceptability: The general degree to which sensory panellists accept or prefer a developed snack product after considering its combined sensory characteristics.

Project – Development and Sensory Evaluation of Fortified Cassava-Based Snack Products Using Soybean and Moringa Leaf Powder