IOSR Journal of Applied Chemistry (IOSR-JAC) e-ISSN: 2278-5736.Volume 7, Issue 9 Ver. I. (Sep. 2014), PP 01-03 www.iosrjournals.org www.iosrjournals.org 1 | Page Titrimetric Determination of Ascorbic Acid Levels in Some Citrus Fruits of Kurgwi, Plateau State Nigeria J. G. Nangbes 1 *, D. T. Lawam 2 , J. B. Nvau 1 , N. A. Zukdimma 1 and N. N. Dawam 3 1 Department of Chemistry, Plateau State University, Bokkos, PMB 2012, Jos. 2 Department of Chemistry, Collage of Arts Science and Technology, Kurgwi, Plateau State. 3 Department of Microbiology, Plateau State University, Bokkos, PMB 2012, Jos. *Correspondence: E-mail: nangbesjg@gmail.com ; nangbesj@yahoo.com Abstract: Citrus samples of three different fruits, sweet orange (Citrus sinensis) lime (Citrus aurantifolia) and lemon (Citrus lemon) were picked fresh from the trees at intervals of seven days, from September to November at different locations in Kurgwi, washed and kept in the refrigerator at 4 o C pending analysis. Two stages of fruit development, Ripe and Unripe, were considered during sampling. The bark of these fruits were peeled off with sterile knife and sliced into half, then manually compressed into a 250cm 3 beaker and filtered off with glass wool in to a 100cm 3 beaker to remove the pulps which could block pipette jets. The Standard Methods of the Association of Official Analytical Chemists, AOAC methods, 939.13 and 966.18 were used for the determination of ascorbic acid in the fruit juice. Results of these determinations showed that sweet orange (Citrus sinensis) lemon (Citrus lemon) and lime (Citrus aurantifolia) have concentration range of 50.23mg/100mL – 56. 26mg/100mL, 51.33 mg/100mL – 53.47 mg/100mL and 34.12mg/100mL – 35.62mg/100mL, respectively. The unripe species of all the fruits tend to have higher ascorbic acid content as shown in the results obtained, with sweet orange and lemon having almost twice the level of ascorbic acid than lime. Patients with diabetes, stroke, heart diseases and cancer etc could take more of sweet orange and lemon, which have higher levels of ascorbic acid than lime as revealed by this research. Keywords: Ascorbic acid, Lemon, Lime, Sweet Orange. I. Introduction Ascorbic acid also known as vitamin C is the most important vitamin for human nutrition that is supplied by fruits and vegetables. It is a valuable nutritional component because of its antioxidant and therapeutic properties. It helps the body in forming connective tissues, bones, teeth, blood vessels and plays a major role as an antioxidant that forms part of the body defense system against reactive oxygen species and free radicals, thereby preventing tissue damage. [1,2,3] Ascorbic acid is widely distributed in plant cells, which plays many crucial roles in growth and metabolism. It is also a potential antioxidant having the capacity to eliminate several different oxygen species keeping the membrane-bound antioxidant, α-tocopherol (vitamin E) in the reduced state and so acts as a cofactor to maintain the activities of a number of enzymes by keeping metal ions in the reduced state which appears to be the substrate for oxalate and tartrate biosynthesis [4,5,6] . It is widely used in the treatment of certain diseases such as scurvy, common cold, hemorrhagic disorder, wound healings as well as infertility. [7] Ascorbic acid is also reported to be an important ingredient for the synthesis of dopamine, noradrenaline and adrenaline in the nervous system or in the adrenaline glands . [8] Ascorbic acid is also reported to be an essential antioxidant that helps protect against cancers, heart disease and stress. It is also part of cellular chemistry that provides energy, it is essential for sperm production and for making the collagen protein involved in the building and health of cartilage, joints, skin and blood vessels. Ascorbic acid helps in maintaining a healthy immune system, it aids in neutralizing pollutants, is needed for antibody production, acts to increase the absorption of nutrients (including iron) in guts, and thins the blood. [9] Citrus fruits such as lime, lemon, orange, grape fruit and tomato are common sources of vitamin C or ascorbic acid. Other sources include papaya, broccoli, Brussels, sprouts, black berries, cauliflower, spinach, cantaloupe and blue berries. Most plants and animals have the ability to synthesize ascorbic acid for their needs. The only mammals that are unable to synthesize ascorbic acids are primates including man and guinea pigs. Therefore, humans depend on exogenous sources of ascorbic acid which include fruits and vegetables as well as food supplements and pharmaceutical preparations. [3]