Abstract:
The purpose of this research work is to study a permanent viscosity reduction process of certain processed vegetable oils and lard using gamma ray from Cobalt-60. Six main factors were studied. The first were oil types, which were palm oil, coconut oil and lard. The second were solvent types, which were ethyl alcohol and diesel oil. The third were oil:solvent ratios of 4:1 and 3:2. The forth was gamma ray dose at 30 and 50 kGy. The fifth was adding or not adding air during irradiation. The sixth was temperature of 40 and 75 oC during irradiation. For the cases that the solvent was not diesel gasoline, the solvent was extracted by a simple fractional distillation technique. Subsequently, the samples were tested for the change in viscosity using ASTM D445 standard. Finally, the quality and significance of the data obtained were statistically analyzed using General Linear Model (GLM). Results indicate that gamma irradiation by controlling the six factors result in permanent viscosity reduction in the range of 7.63 - 46.92 %. Samples exhibiting the largest viscosity reduction were controlled the following way: coconut oil, ethyl alcohol, 3:2 ratio, 30 kGy dose, air bubbling during irradiation, temperature of 75oC. Statistical analysis revealed that at the 96.83 % confidence level, the following two factors contribute the most: gamma ray dose and adding/not adding air during irradiation. The following five factors also contribute, but to a lesser extent: oil types and solvent types, oil types and oil:solvent ratios, oil types and gamma ray dose, solvent types and oil:solvent ratios, and oil:solvent ratios and gamma ray dose.