Determination of Vitamin C Content in Fresh and Stored Fruit Juices

CHAPTER ONE

1.0 Background of the Study

Vitamins are essential micronutrients required in small quantities for the proper functioning of the human body. Among them, vitamin C (ascorbic acid) plays a vital role in maintaining health. It acts as a strong antioxidant, supports the immune system, and promotes wound healing. It also enhances iron absorption and protects cells from oxidative stress (Naidu, 2003).

Humans cannot synthesize vitamin C naturally, so it must be obtained from dietary sources such as fruits and vegetables. Citrus fruits like oranges, lemons, and grapefruits are particularly rich in ascorbic acid. Many people consume fruit juices as a convenient way to meet their daily vitamin C requirements.

However, vitamin C is a heat-sensitive and easily oxidized compound. Factors such as exposure to air, light, high temperature, and prolonged storage can reduce its concentration in fruit juices (Lee & Kader, 2000). Pasteurization and packaging, though important for preserving shelf life, may also lead to significant vitamin C loss.

Determining the vitamin C content in both fresh and stored fruit juices is essential to evaluate the nutritional quality of these beverages. This information helps consumers make informed choices and allows producers to improve processing and storage methods to retain nutrient value.

This study therefore focuses on determining and comparing the vitamin C content in freshly prepared and stored fruit juices using standard analytical methods.

1.1 Statement of the Problem

Fruit juices are often consumed as healthy alternatives to carbonated drinks. However, the vitamin C content may decrease during storage or processing, reducing their nutritional benefit. Many consumers are unaware of this degradation and assume that stored or packaged juices have the same vitamin levels as fresh ones.

There is limited local data comparing vitamin C concentrations in freshly prepared and stored fruit juices. Understanding these differences will help determine the actual nutritional value of these beverages and guide both consumers and manufacturers.

1.2 Aim and Objectives of the Study

Aim:
To determine the vitamin C content in fresh and stored fruit juices.

Objectives:

1. To prepare fresh fruit juice samples from selected fruits such as orange and pineapple.

2. To analyze vitamin C concentration in fresh and stored fruit juice samples.

3. To compare the ascorbic acid levels between freshly prepared and stored juices.

4. To evaluate the effect of storage duration on vitamin C stability.

5. To recommend better storage and processing practices for preserving vitamin C content.

1.3 Significance of the Study

The study will provide valuable information on how storage affects vitamin C levels in fruit juices. It will help consumers understand the nutritional differences between fresh and processed products.

The results will also guide food manufacturers on how to improve processing and packaging methods to minimize vitamin C loss. In addition, the findings will contribute to food science research on the stability of water-soluble vitamins during storage.

1.4 Scope of the Study

This study will focus on commonly consumed fruit juices such as orange and pineapple. Both fresh and stored samples will be analyzed for vitamin C content using titrimetric and spectrophotometric methods. The research will be limited to vitamin C determination and will not include other nutrients or microbial studies.

1.5 Definition of Terms

Vitamin C (Ascorbic Acid): A water-soluble vitamin and antioxidant essential for immune function and tissue repair.
Antioxidant: A substance that prevents oxidation and protects cells from free radical damage.
Oxidation: A chemical process that results in the loss of electrons, often causing nutrient degradation.
Storage: The process of keeping fruit juice over time under specific conditions such as temperature and light exposure.
Fresh Juice: Juice extracted directly from fruits without any form of processing or preservation.
Stored Juice: Juice kept for a specific period, often processed or packaged to extend shelf life.