Protein Isolation from Cricket (Gryllusmitratus)

Abstract

The aim of this study is to isolate protein from cricket or Gryllusmitratus, determine
the effect of pH to protein solubility and the amino acid composition of the isolate. Proximate
analyses of cricket powder were done and resulted in (54.09 ± 7.65)% crude protein, (5.35 ±
0.14)% ash, (24.93 ± 1.47)% fat and (9.00 ± 0.64)% other components. Cricket powder was
extracted with two different solvents: water and sodium hydroxide at extraction temperature
from 30 to 50 oC for 30, 60 and 90 minutes. Extraction using water at 30 oC for 30 minutes was
chosen with 51.98 mg/ml protein content. The extracted protein was isolated using three
precipitation methods (ammonium sulfate, isoelectric point and acetone precipitation). The
result found that acetone precipitation gave the highest purity of protein content as much as
99.19% and the protein recovery up to 64.94%. Amino acids of the protein isolate both essential
and non-essential have been determined, where essential amino acid was lower compared to its
non-essential amino acid. The solubility of the isolate was determined and showed the highest
solubility at pH 8 and the isoelectric point at pH 5. In conclusion, acetone precipitation was able
to isolate protein from cricket with high purity and recovery containing all of the essential
amino acids.