Thesis Abstract

Abstract
Vitamin C, also known as ascorbic acid, is an essential nutrient for human health due to its antioxidant properties and its role in collagen synthesis. The determination of ascorbic acid content in vegetables is crucial as they are a major dietary source of this vitamin. In this study, we aimed to assess and compare the ascorbic acid levels in selected vegetables commonly consumed in daily diets. A total of five vegetables, namely broccoli, bell peppers, tomatoes, spinach, and kale, were chosen for analysis based on their popularity, availability, and varying vitamin C content. The vegetables were obtained from local markets and processed to extract the ascorbic acid for analysis. The extraction process involved homogenizing the vegetable samples, followed by the addition of a suitable solvent to extract the vitamin C. The ascorbic acid content was then determined using a standardized titration method with 2,6-dichlorophenol indophenol (DCPIP) as the titrant. The titration process involved adding DCPIP solution to the vegetable extract until a color change was observed, indicating the endpoint of the reaction. The volume of DCPIP solution required for the color change was used to calculate the ascorbic acid content in the vegetable samples. The results of the analysis revealed varying levels of ascorbic acid in the selected vegetables. Among the vegetables tested, bell peppers exhibited the highest concentration of ascorbic acid, followed by broccoli and kale. Tomatoes and spinach showed relatively lower levels of vitamin C compared to the other vegetables. These findings provide valuable information on the vitamin C content of commonly consumed vegetables and can aid in dietary planning for individuals seeking to meet their daily vitamin C requirements. In conclusion, the determination of ascorbic acid content in selected vegetables is essential for assessing their nutritional value and contribution to daily vitamin C intake. The results of this study highlight the importance of including a variety of vegetables in the diet to ensure an adequate supply of essential nutrients, including vitamin C. Further research can focus on exploring factors influencing the variability of vitamin C content in vegetables and optimizing extraction and analysis methods for accurate quantification.

Thesis Overview

1. 1.0INTRODUCTION

Vitamin C is a water-soluble compound that is essential for life. It is involved in many processes in the human body, including: the production of collagen in the connective tissue; the synthesis of dopamine, non-adrenaline and adrenaline in the nervous system; and the synthesis of carnitine, which is important in the transfer of energy to the cell mitochondria. A deficiency in vitamin C causes scurvy, a disease that affected sailors in the 16th – 18th Centuries. It was discovered that fresh fruit, e.g. limes and oranges, or sauerkraut (preserved cabbage) provided the sailors with protection from scurvy.

In Australia and New Zealand, the recommended daily intake (RDI) of Vitamin C is 60 mg. The Nobel-prize winning scientist, Linus Pauling (1901 — 1994), believed in regular mega doses of vitamin C, but this is still regarded as unorthodox in conventional medicine.

Vitamin C is often used as an antimicrobial and antioxidant in foodstuffs. It was first isolated in 1928 and in 1932 it was proved to be the agent which prevented scurvy (hence its scientific name of “ascorbic acid”, which literally translates as “anti-scurvy acid”). Its structure was determined in 1933 and confirmed by total synthesis soon after.

Ascorbic acid is a stable solid that does not react with air, however, it is rapidly oxidized on exposure to air and light when in aqueous solution.

Ascorbic acid needed for buoyant health, vitality and endurance. It ensures clear skin, a fresh complexion and healthy gums and teeth. This can be achieved, only if individual and animals adhere to soft summer fruits, like black currents, lemon, oranges to mention a few often times. Its mild deficiency results in gums and teeth easily infected. Also poor growth scurvy, in chromic cases and very slow healing of wounds and fractures (Goldsmith, 2001).

1. 1.1Structure of Vitamin C

CHEMICAL DATA

Formula
C6H806

Mol. Mass
176.12g/mole

Physical data

Density
1.694g/cm3

Melt. point
1900c (3740F)

Boiling point
5530C (10270F)

1.2 Vitamin C the Antioxidant

In biological systems, reactive oxidants are often produced from metabolic processes. They have the ability to react with other molecules (e.g. DNA), thus damaging the cell. The body protects its cells by utilizing another group of molecules called antioxidants (to which vitamin C belongs) to reduce (and hence detoxify) the oxid ants.

1.3 Volumetric Analysis

Volumetric analysis is a technique that employs the measurement of volumes to determine quantitatively the amount of a substance in solution. In any reaction between two or more species, the reaction equation shows the stoichiometric ratio of reacting species. Take, for example, the reaction being investigated today, that between solutions of ascorbic acid and 12.

1.4 Indicators

12 forms a blue complex in the presence of starch (Vitex) and hence can act as its own indicator. Whilst the ascorbic acid is in excess, 12 which is being added from the burette is being reduced and is decolourising. As soon as all the ascorbic acid present has been oxidised, the added 12 will no longer be reduced and, due to the Vitex that has been added, the solution becomes pale blue.

1.5 The Aim of Study

Cabbage widely contains a reasonable percent of vitamin C (Ascorbic Acid). From the findings made so far, most people take vegetables for pleasure purpose, seldom give a thought about the value and importance of Ascorbic acid in them. This project and research is carried out to determine the vale of vitamin C contains in the selected vegetables.

Consequently, this study will show and stress the need and desire for consumption of vegetables. Similarly, to elucidate, the need and importance of vegetable and vitamin C, and best possible ways of using and preserving it, ascorbic acid oxidize that would otherwise attack the vitamin C.

1.6 The Objectives of the Study

The objectives of this study are:

1. Determine the concentration of vitamin C in selected vegetables
2. Ascertain the nutritional status of our vegetable;
3. Compare the vitamin C level in vegetables.