Optimization Using Response Surface Methodology (RSM) of NaCl, NaOH, and Activated Charcoal Concentration for the Purification Process of Crude Oil of Common Ponyfish

Abstract

Crude oil of common ponyfish (Leiognathus equulus) is a by-product of fish protein hydrolysate manufacturing at PT. Berikan Teknologi Indonesia. The quality of the crude fish oil produced falls below the International Fishmeal and Oil Manufacturers Association Standard. Therefore, to improve its quality, a purification process comprising of three stages was employed, degumming with NaCl (5-10%), neutralization with NaOH (10-18°Be), and bleaching with activated charcoal (6-10%). The purification process was optimized using RSM with the Box-Behnken Design. The 15 concentration formulations were obtained with response variables taken based on chemical test parameters (free fatty acids (FFA), acid value, peroxide value, and iodine value). The optimal point of NaCl, NaOH, and activated charcoal concentration was determined at 10%, 18°Be, and 9.4%, respectively with a desirability of 0.744. The purified common ponyfish oil exhibited FFA at 9.52±0.21%, acid value at 3.42±0.17 mg KOH/g, peroxide value at 1.25±0.03 mEq/Kg, and iodine value at 4.12±0.13 mEq/Kg. Pure common ponyfish oil resulting from the optimal conditions has been verified. All parameters indicate that the quality of common ponyfish oil is improved by the refining process. This indicates that the optimized process may be applied in real production in the field with a high degree of confidence.