The effects of earthworm concentration and extraction time on solubility of protein

Abstract

KEYWORDS ABSTRACT Earthworm Protein Extraction Optimisation Earthworm (Lumbricus rubellus) is known to contain proteins making it suitable for alternative high-protein resources for feed or animal food. Exctraction of proteins from earthworms is not an easy task and it requires multiple steps for purifying the protein extract. Furthermore, the extraction of earthworm protein is considered as uneconomical due to high operational cost. Therefore, altering the process is necesarry to enhance the extraction. The objective of this research is to optimize the solubility of protein from earthworm juice. The design used in this research is a completely randomized design consisting of two factors which are A (earthworm concentration) and B (extraction time). The results show that solubility of protein was 28.12% and the soluble solid was 67.63%. The optimum process includes earthworm concentration of 15% and extraction time of 90 minutes. Introduction Lumbricus rubellus worm has a high protein content accounted for 64-76% consisting of eight types of essential amino acids and five types of non-essential amino acids. Essential amino acids in worms are histidine, leucine, isoleucine, valine, methionine, phenylalanine, lysine, and threonine, while the non-essential amino acids are arginine, cystine, glycine, serine, and tyrosine. Beside protein, worms also contain 7-10% of fat, 0.55% of calcium, 1% of phosphorus, and 1.08% of crude fiber (Palungkun, 2010). The efficiency of the extraction process may affect the cost and the amount of extract obtained. Extraction using anaerobic process for 2 days was able to extract protein as many as 7% and dissolved material reached more than 50% (Hidayat et al., 2016). Extraction by boiling method has never been studied and used before. The purpose of this study was to determine the effect of boiling time on the soluble protein content of Lumbricus rubellus worm.