1.1 Introduction
Proximate composition is defined as the systematic determination of the basic nutritional constituents of food, including moisture, ash, crude protein, crude fat, crude fiber, and carbohydrates, which together provide essential information about the nutritional value and quality of food materials that are crucial for dietary evaluation and food science research (Abdullahi et al., 2025).
In the context of food science, proximate analysis is a foundational analytical procedure used to break down edible materials into their major macro nutrient components, offering a clear picture of how foods contribute to human nutrition and enabling comparisons between different food sources (Fiveable, 2026).
As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are significance of the study, scope of work, research questions, limitation of the study and definition of terms.
1.2 Background of Study
Proximate composition refers to the quantification of the major macro nutrient components in food such as moisture, ash (mineral content), crude protein, crude fat, crude fibre and carbohydrate. These components together provide vital information about food quality, energy value and potential health benefits (Ambo, Patience & Ayakeme, 2023). According to research in the field, assessment of proximate composition is essential to ascertain the nutrient density of foods and to develop food tables used by nutritionists and policy makers. Proximate analysis results assist in guiding consumers on their nutritional choices and in informing recommendations to improve dietary quality in populations with nutrient deficiencies or food insecurity (Ambo, Patience & Ayakeme, 2023).
Vegetables remain one of the most consumed sources of dietary nutrients worldwide due to their affordability, accessibility and versatility in meals. Green leafy vegetables and fruit vegetables are known to supply hydration, dietary fibre, essential macronutrients and various micronutrients that support growth, metabolism and immune function (Jibrin, Haruna & Babatunde, 2025). It was reported that spinach (Spinacia oleracea), a widely eaten leafy vegetable, contains significant levels of moisture, ash and crude fat relative to other vegetables, pointing to its important contribution to nutrient intake in many diets (Jibrin, Haruna & Babatunde, 2025). Similarly, studies have shown that cucumber (Cucumis sativus), while often consumed for its refreshing hydration and low caloric content, also has notable proximate and mineral components that make it nutritious beyond just water content (Ambo, Patience & Ayakeme, 2023).
Researchers assert that variations in soil fertility, climate, irrigation and post harvest handling influence the levels of proteins, fibres and carbohydrates measured in vegetable leaves (Jibrin, Haruna & Babatunde, 2025). This complicates efforts to generalize about the true nutritive potential of some vegetables when compared across regions. For example, one recent study reported that the moisture content of spinach samples ranged widely in proximate analysis, and that this had implications for shelf stability and storage potential (Ambo, Patience & Ayakeme, 2023). Other scholars have stated that proximate composition studies of leafy vegetables often focus on limited parameters or on whole fruits and rarely dedicate comprehensive analysis to leaves as edible parts, especially for vegetables like cucumber (Ambo et al., 2023).
Comprehensive analysis of both cucumber and spinach leaves is particularly important because these plant parts are eaten in some cultures as part of salads, soups or mixed dishes, yet their nutrient composition receives relatively less attention compared to more intensively studied vegetables such as kale or collard greens. One research contribution affirmed that leafy vegetables are rich sources of macronutrients and micronutrients, and that neglecting certain edible leafy parts in proximate studies limits nutritional data available to researchers and consumers (EPRA International Journal of Research & Development, 2024). In the case of spinach, proximate studies have shown that it is a significant source of proteins and micronutrients, and also may possess components with antimicrobial properties that contribute to its functional food value (EPRA International Journal of Research & Development, 2024).
Jibrin et al., (2025) contend that the inclusion of both cucumber and spinach leaves in comparative proximate studies would provide better context for nutrition planning, particularly for populations that depend on vegetable leaves as part of daily diets. Such research has practical implications for food security, malnutrition reduction and public health nutrition interventions in communities where leafy vegetables are key staples (Jibrin et al., 2025). For instance, a recent proximate composition study indicated that variations in crude fibre, protein and carbohydrate across vegetable samples highlight how different leaves contribute differently to nutrient intake, which has implications for dietary recommendations (Jibrin, Haruna & Babatunde, 2025). This study is set against the backdrop of these gaps and the need to enhance nutritional data on cucumber and spinach leaves through systematic proximate composition analysis.
1.3 Statement of Problems
Investigation revealed that leafy vegetables vary in their proximate and mineral contents depending on environmental conditions, cultivation practices, and sampling locations, leading to inconsistent information on their quality as food sources (Ambo, Patience, & Ayakeme, 2023). For example, proximate analysis of spinach from different towns in Nigeria revealed variability in moisture, protein, fiber, and ash content, which affected assessments of their nutritive value (Ambo, Patience, & Ayakeme, 2023).
In the case of cucumber, proximate studies often focus on fruits or specific anatomical parts, leaving gaps in the understanding of whole leaves despite their use in some diets and as by-products in agriculture (Oluwagbenle, Adesina, & Aremu, 2019). In addition, factors such as soil conditions, agricultural practices, post-harvest handling, and analytical methods are known to influence proximate composition results, which makes comparison across different studies challenging.
Furthermore, few recent studies integrate both cucumber and spinach leaves in a single analysis to provide a direct comparison, which limits the ability to make informed recommendations for consumers and policymakers about their relative nutritional benefits. It is against this backdrop that this study seeks to explore the proximate composition and analysis of cucumber and spinach leaves to address these gaps in nutritional data for these vegetable leaves.
1.4 Aim and Objectives of Study
The aim of this study is to analyse the proximate composition of cucumber and spinach leaves and evaluate their contribution to daily nutrient intake. In achieving this aim, the following specific objectives were laid out as follows:
- To evaluate the crude fat and crude fibre content of cucumber and spinach leaves.
- To determine the ash and carbohydrate content of cucumber and spinach leaves.
- To assess the crude protein content of cucumber and spinach leaves.
- To determine the moisture content of cucumber and spinach leaves.
- To compare the proximate composition between cucumber and spinach leaves and assess their nutritional significance.
1.5 Research Questions
The study came up with research questions so as to be able to ascertain the above stated objectives. The specific research questions for the study are stated below as follows:
- What is the moisture content of cucumber and spinach leaves?
- What is the crude protein content of cucumber and spinach leaves?
- What are the crude fat and crude fibre contents of cucumber and spinach leaves?
- What are the ash and carbohydrate contents of cucumber and spinach leaves?
- How do the proximate compositions of cucumber and spinach leaves compare nutritionally?
1.6 Significance of Study
It is believed that at the completion of the study, the research will inform farmers and agricultural extension officers about the nutritive potential of these leaves, supporting better utilization. Also, the findings will inform agricultural extension workers and farmers about the nutrient retention in leaves under different cultivation and post-harvest conditions, supporting improved crop utilization.
Furthermore, food composition tables and policy recommendations by government agencies will be updated with this current data. In addition, this research will provide accurate data on the moisture, protein, fat, fibre, ash, and carbohydrate content of cucumber and spinach leaves, which are widely consumed vegetables in Nigeria.
Lastly, the study will provide baseline data for future research on the nutritional value of leafy vegetables, particularly in assessing their role in combating protein-energy malnutrition and micronutrient deficiencies.
1.7 Scope of Study
This study focuses on cucumber and spinach leaves obtained from farms and local markets in Rivers State, Nigeria. The analysis will be conducted in laboratory facilities in Port Harcourt, Rivers State. The study covers the proximate composition, including moisture, crude protein, crude fat, crude fibre, ash, and carbohydrate content, of fresh leaves collected within the study period.
1.8 Limitations of the Study
During the course of this study, there were some problems encountered which stood as limitations to the research work. Some of the limitations include:
- Time Constraint: The time frame given to accomplish this project was very short due to school academic calendar and it was carried out under pressure which made the researcher not to implement some necessary features.
- Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection.
1.9 Definition of Terms
Proximate Composition: The measurement of the basic nutrient components of a food item, including moisture, ash, crude protein, crude fat, crude fibre, and carbohydrate, which determine its nutritional value (Ambo, Patience & Ayakeme, 2023).
Cucumber Leaves: The edible leaves of Cucumis sativus, used in traditional diets and salads (Oluwagbenle, Adesina & Aremu, 2019).
Spinach Leaves: The edible leaves of Spinacia oleracea, consumed globally for their nutrient content, including protein, fibre, and minerals (Jibrin, Haruna & Babatunde, 2025).
Moisture Content: The amount of water present in a food sample, usually expressed as a percentage of the total weight (EPRA International Journal of Research & Development, 2024).
Crude Protein: The total protein content of a food, usually determined by nitrogen analysis (Ambo, Patience & Ayakeme, 2023).
Crude Fat: The total lipid content of a food sample (Oluwagbenle, Adesina & Aremu, 2019).
Crude Fibre: The indigestible portion of plant foods, representing cellulose and lignin (Jibrin, Haruna & Babatunde, 2025).
Ash Content: The total mineral content left after complete burning of organic matter (EPRA International Journal of Research & Development, 2024).
Carbohydrate Content: The amount of carbohydrate in a food sample, usually calculated by difference (Ambo, Patience & Ayakeme, 2023).
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