Optimization of the Hermetia illucens Larvae Extraction Process with Response Surface Modelling and Its Amino Acid Profile and Antibacterial Activity

Abstract

Hermetia illucens Larvae (HiL) is a protein source that can replace soybean meal and act as functional feed in the poultry industry. This study aims to optimize the HiL extraction process and evaluate the amino acid profile and antibacterial activity. Response surface modelling (RSM) was used to optimize the HiL extraction process and yield assessment. RSM followed by three levels and three variables based on Box-Behnken design. The extraction method used alkali extraction procedure with three variables, e.g., X1: NaOH solvent, X2: HCl solvent, and X3: precipitation volume. Inhibitory zone assay used Staphylococcus aureus, Bacillus subtilis, Salmonella typhimurium and Escherichia coli. Model build by RSM has R2 = 0.9949 with significant value (P<0.01). The correlation plot of experimental yield versus predicted yield has R2 = 0.9974. Validation of the model has a lack of fit value (P>0.05) which indicate that the model is valid. The EAAI and BV value of HiL extract are 16.51 and 5.30%, respectively. HiL extract did not show antibacterial activity to inhibit gram-positive and gram-negative bacteria. The optimum yield (23.03%) was obtained by performing with NaOH 2.35 M, HCl 2.76 M, and precipitation volume 25.28 mL. EAAI of HiL extracts is slightly higher than that of dried HiL but lower than that of soybean meal.