Alkaline Extraction of Protein from Spent Honey Bees

ABSTRACT Adult honey bees killed after honey harvest were analyzed and evaluated as a raw material for protein extraction. Bees collected were 49.8% crude protein, 7.54% total lipid, and 27.1% reducing sugar (moisture‐free basis). Whole bees were homogenized, body proteins solubilized in alkali, chitin removed by filtration, and protein recovered by acid precipitation. Amount of protein solubilized by NaOH addition varied from negligible without alkali (pH 6.1) to 93% of body crude protein with severest treatment at pH 11.2. With alkali extraction at pH 10.5 and acid precipitation at pH 5.5, 59% of total solids were found in the precipitate and 41% remained in the supernatant. The precipitate was 66.3% crude protein, 9.4% total lipid and 7.9% ash. Heads, thoraces and abdomens were separated and each separately extracted (pH 10.5) and precipitated (pH 5.5). Amino acid analyses of heads (70.1% protein), thoraces (54.9% protein) and abdomens (36.6% protein) permitted evaluation of protein quality. Thorax protein was most homogeneous for amino acids analyzed, and all were nutritionally limited by sulfur containing amino acids.