EXTRACTION, CHARACTERIZATION AND APPLICATIONS OF CASTOR SEED OIL FROM WILD Ricinus communis

Abstract

The extraction of Castor oil was accomplished by mechanical cold pressing of the seeds of wild castor plant (Ricinus communis) found in Ini Local Government, Area Akwa Ibom State, Nigeria. Oil yield was 38.69%. The virgin oil (obtained as clear, viscous, pale-yellow liquid) was further purified by filtration through sintered glass (fine mesh screen). This was to eliminate any dust, gum, or other particulates present. Physicochemical characterization of the purified oil revealed low acid value (2.07), low iodine value (84.18), low peroxide value (38.00), but relatively high specific gravity (0.959), hydroxyl (163.64) and saponification (175.31) values. These values compare favourably with ASTM standards and general specifications for industrial grade castor oil (WHC, 2012), suggesting that the oil has good industrial potential. Fourier transform infra-red (FTIR) spectroscopic analysis has confirmed the presence of major functional groups in the oil, notably hydroxyl l (3414.12cm-1), carbonyl (1739.85cm-1), olefinic (1659.80cm- ) and methylenic (2925.15cm-1 ). Determined fatty acid composition of the oil by gas chromatography-mass spectrometry (GC-MS) shows ricinoleic acid (74.10%) as the major constituent fatty acid. Other fatty acids were linoleic (10.32%), oleic (7.55%), stearic (2.81%), palmitic (2.59%), erucic (1.70%) and eicosadienoic (0.93%). The appreciable oil yield (39.43%) from this castor seed variety, the quality, unique physicochemical characteristics of the extracted oil, and the renewable nature of castor oil as a natural resource justify the oil’s commercialization and full exploitation in traditional, as well as novel areas (e.g. biopolymer and biofuel production) of industrial application.