Determination of the Shelf Life and Nutritional Quality of Tomato Paste under Different Storage Conditions (Kano, Nigeria)

CHAPTER ONE

1.0 Background of the Study

Tomato (Solanum lycopersicum) is one of the most widely consumed vegetables in the world. It is a major ingredient in many traditional and industrially processed foods. Tomatoes are valued for their bright color, pleasant flavor, and rich nutritional content. They contain essential vitamins such as vitamin C and vitamin A, minerals like potassium and calcium, and powerful antioxidants such as lycopene and β-carotene (Agarwal & Rao, 2000).

However, fresh tomatoes are highly perishable. They have a high moisture content, which makes them prone to microbial spoilage and nutrient loss. To extend their shelf life, tomatoes are often processed into paste, puree, or sauce. Tomato paste, in particular, is one of the most popular and stable tomato products used in households and food industries.

Despite being processed, tomato paste is still sensitive to storage conditions. Factors such as temperature, light, and packaging can significantly influence its quality during storage. High temperatures can accelerate vitamin degradation and lipid oxidation, while exposure to light may cause color fading and flavor deterioration (Sørensen et al., 2002). Over time, these changes can reduce both the nutritional and sensory quality of the product.

In developing countries like Nigeria, storage facilities are often inadequate, and ambient conditions vary widely across regions. In Kano, where the climate is hot and dry, maintaining the stability of tomato-based products poses a challenge. Consumers and retailers may store tomato paste at room temperature without proper consideration of its effect on quality. Therefore, it is important to determine how different storage conditions influence the nutritional quality and shelf life of tomato paste.

By studying the changes in key nutrients such as vitamin C, lycopene, and total solids during storage, it becomes possible to establish optimal conditions that maintain product quality. This research will also provide useful information for producers, retailers, and consumers regarding safe storage practices and the expected shelf life of tomato paste under various conditions.

1.1 Statement of the Problem

Tomato paste is widely consumed in Kano and across Nigeria. However, improper storage often leads to loss of nutrients, changes in color, and flavor deterioration. High temperature and poor packaging accelerate these changes, making the product less nutritious and less appealing.

Many consumers are unaware of how storage temperature and duration affect the quality of tomato paste. As a result, they may use products that have already lost significant nutritional value. This study seeks to identify the effect of different storage conditions on the shelf life and nutritional composition of tomato paste sold in Kano, Nigeria.

1.2 Aim and Objectives of the Study

Aim:
To determine the shelf life and nutritional quality of tomato paste stored under different conditions in Kano, Nigeria.

Objectives:

1. To analyze the initial nutritional composition of freshly processed tomato paste.

2. To store the paste under different temperature and light conditions for a set period.

3. To monitor changes in vitamin C, lycopene, moisture content, and total solids during storage.

4. To assess the shelf stability and identify the most suitable storage condition.

5. To make recommendations for consumers and producers on proper storage practices.

1.3 Significance of the Study

This study is significant because it provides practical information about how storage affects the quality and shelf life of tomato paste. The findings will help manufacturers improve packaging and recommend appropriate storage conditions.

For consumers, the research will increase awareness about the impact of temperature and light on food quality. It will also promote better storage habits at home and in retail outlets. Moreover, the study supports efforts to reduce post-processing food losses, which remain a major issue in Nigeria’s food system.

1.4 Scope of the Study

The study focuses on the effect of storage temperature and duration on the nutritional quality of tomato paste. It will be conducted using paste samples stored at refrigeration temperature (4°C), moderate temperature (20°C), and ambient temperature (30°C). Analyses will include the determination of vitamin C, lycopene, and total solids. Microbial and sensory evaluations will not be covered.

1.5 Definition of Terms

Tomato Paste: A concentrated tomato product obtained by cooking and reducing tomato pulp.
Shelf Life: The period during which a product remains safe and retains its desired quality under defined conditions.
Storage Conditions: Environmental factors such as temperature, humidity, and light that influence product stability.
Lycopene: A natural red pigment and antioxidant found in tomatoes.
Vitamin C: A water-soluble vitamin that helps in immune function and acts as an antioxidant.
Nutritional Quality: The measure of essential nutrients retained in food after processing or storage.