Evaluation Of Hydrodistillation For The Extraction Of Orange Peel Essential Oil: Impact Of Parameters On Yield And Quality

Abstract

Objective: To evaluate hydrodistillation as a method for extracting essential oil from orange peel (Citrus sinensis) and to investigate the impact of key process parameters — temperature, extraction time, peel size, and water-to-peel ratio on the yield and quality of the extracted oil.

Study Design: Experimental laboratory study.

Place of Study: Department of Chemistry, The Superior University, Lahore, and Government College University, Lahore, Pakistan.

Methodology: Fresh Citrus sinensis peels (50 g) were subjected to hydrodistillation using a Clevenger-type apparatus. Extraction was performed at two temperatures (85°C and 100°C) over 200 minutes. The distillate was separated using n-hexane. Oil yield was calculated gravimetrically. Physical characterization (colour, odour, viscosity, solubility) was performed by sensory evaluation. Chemical composition was analyzed by UV-Visible spectroscopy (200–700 nm).

Results: At 85°C, the distillate yield was 12 mL/50 g (24%) after 200 minutes; no distillate was collected in the initial 80 minutes. At 100°C, the distillate yield was 15 mL/50 g (30%), with extraction commencing immediately. The essential oil yield after n-hexane separation was 5.5 mL/50 g (11%). The extracted oil was pale yellow in colour, with a fresh-to-tangy odour, low viscosity, and was soluble in organic solvents but insoluble in water. UV-Vis spectroscopy identified absorption peaks at 203, 208, 210, 234, 268, 278, 340, and 371 nm, corresponding to limonene, β-pinene, α-pinene, linalool, citral, coumarins, geranial, and carotenoids respectively.

Conclusion: Hydrodistillation successfully extracted essential oil from orange peel with 11% yield. Temperature (100°C), extraction time (200 minutes), fine peel grinding, and optimal water-to-peel ratio were identified as critical parameters for maximizing yield. The extracted oil exhibited a limonene-rich profile consistent with literature, confirming hydrodistillation as a viable, cost-effective, and eco-friendly method for orange peel essential oil extraction.