Paper Title
Determination of Vitamin C (Ascorbic Acid) Concentration by Redox Titration in Some Fruits Cultivated and Sold in Enugu Metropolis of Nigeria
Author
E.N. Owoh, C.C. Nnonah, J.N. Ezeh & H.C. Ezeh
Section
Engineering, Health, Pure and Applied Sciences
Abstract

This work was done to determine the concentration of VitaminC in some mature ripped fruits and canned fruit juice sold in some selected areas within Enugu metropolis in order to sensitize the public on the importance and the needed correct quantity of Vitamin C which the body needs for proper well-being. Some ripe raw fruits and packaged fruit juice were bought from Topland and Garriki markets in Enugu State of Nigeria and the determination of Vitamin C concentration by Redox titration was carried out on them. Aliquot of each sample (20ml) solution were prepared and transferred into a conical flask (250ml). Distilled water (150ml) was added and starch indicator solution (1ml) was also added. Each sample solution was titrated with iodine solution (0.005M). The endpoint of the titration was identified as the first distinct trace of a dark blue-black colour due to the starch-iodine complex. Titration was repeated with further aliquots of sample solution until concordant results (titres agreeing within 0.1 ml) were obtained and the results of the analysis given as: Pineapple Fruit 122.0mg/100ml; Orange Fruit 102.5mg/100ml; Vitamin C tablet 100.73mg/100ml; Ribena Juice 52.98mg/100ml; Cucumber Fruit 37.21mg/100ml; Happy Hour Juice 29.0mg/100ml; Orange Juice 20.1mg/100ml; Lucozade Boost Juice 18.60mg/100ml; Pineapple Juice 12.67mg/100ml. The result of the analysis can help anyone who wishes to take Ascorbic acid (Vitamin C), in making a proper decision in order to meet up with the World Health Organization recommendation of atleast 45 milligrams per day; 300 milligrams per week for healthy living.

Keywords
Ascorbic acid, Redox titration, concentration, World Health Organization

Introduction

Vitamins are a group of small molecular compounds that are essential nutrients in many multi-cellular organisms, and humans in particular. L-Ascorbic acid, first isolated as a pure substance by Albert Azent-Gyorgi and Charles Kingin (Romero, et al., 1992), is an anti-oxidant and free radical scavenger found ubiquitously in fruit and vegetables, such as citrus fruits (oranges, lemons, limes, tangerines, etc.), melons, tomatoes, peppers, broccoli, and green leafy vegetables such as spinach, potatoes and turnips.Its quantitative determination is especially important in the production of wine, beer, milk, soft drinks and fruit juices, where it can be a quality indicator(Gerrior& Zizza,1994). It plays essential roles in the human diet and its importance to growth and repair of tissues in all parts of human body cannot be over-emphasised. It is necessary in collagen formation, an important skin proteins, scar tissue, tendons, ligaments, and blood vessels (Wilson, Baguley, Wall, Jameson, & Findlay, 2014). Vitamin C is essential for the healing of wounds, and for the repair and maintenance of cartilage, bones and teeth 13. Since Vitamin C is easily oxidized, storage and cooking in air leads to the eventual oxidation of Vitamin C by oxygen in the atmosphere(Sidibé, et al, 1996).

Vitamin C is the most familiar of all the nutrients because of its widespread use as a dietary supplement. Vitamin C is very critical to human beings, and all mammals can use their own cells to make Vitamin C. Vitamin C is needed for the growth and repair of tissues in our body and because the body does not store Vitamin C in its tissue, we need to consume it on regular basis (Combs,2001).Vitamin C improves the absorption of iron from plant based foods and helps to strengthen our immune system to work properly protecting us from diseases (WHO, 2004).

 

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