Comparative study of essential oil composition of fresh and dry peel and seed of Citrus sinensis (L) Osbeck var shamuti and Citrus Paradise Macfadyen var Marsh

Abstract

Citrus essential oils have an impressive range of food and medicinal uses. In this study investigation has been conducted on the variation in the yield, chemical composition and their identities in oils isolated  from fresh and air-dried peel and seed of orange (Citrus sinensis) and grape(Citrus paradisi) planted in a  cocoa farm. The yield of solvent-extracted essential oils from the fresh peel and seed ranged between  0.31 and 1.01%, while the yield in the air-dried peel and seed of the two different citrus samples ranged between 0.98 and 2.30%. The four major compounds present in all the oils are limonene, myrcene, alpha terpinene and camphene which ranged between 74.97 - 90.58%, 5.19 - 10.41%, 0.14 - 4.00% and 0.05 - 3.87%, respectively in fresh peel and seed. In the air-dried peel and seed their values ranged between 58.64 - 77.30%, 0.08 - 5.04%, 0.05 - 3.68% and 0.02-4.88%, respectively for the four compounds. The fresh peel and seed have lower yield but contain higher percentage concentrations of major compounds that serve as compound identification for the citrus family. Air-dried peel and seed have alcohol components like spathulenol (9.78 - 15.13%), linalool (5.05 - 9.27%), nerol (7.98 - 8.60), alpha terpeniol (1.06 - 1.15%) and farnesol (1.54 - 1.66%) which were not present in fresh samples of the two different citrus samples. Apart from concentration differences, the results of this study are similar to other research work in other regions of the world on citrus; the only difference was the identification of  camphene in this study but which was not found in citrus located in other regions of the world under  consideration.

Keywords: Citrus peel, Seed, Fresh, Air-dried, Essential Oil.