Effect of Bloodmeal Hydrolysate and Hydrolysate Modified Clay Bloodmeal-Based Thermoplastic Mechanical Properties

Abstract

Novotein thermoplastic (NTP) is a bloodmeal based plastic developed by the University of Waikato by mixing bloodmeal with water, additives and tri-ethylene glycol (TEG - a plasticiser and petroleum based product) so it can be extruded and injection moulded. In this research, bloodmeal was hydrolysed with alcalase, trypsin and pepsin. The hydrolysates were used in NTP as a substitute for TEG at four different concentrations. Tensile strength, modulus and glass transition temperature decreased with increasing hydrolysate, and also decreased with each subsequent hydrolysis step (Alcalase, then trypsin, then pepsin), consistent with a “plasticising” effect and the shorter chain lengths of the hydrolysate. While these trends were promising, the resulting material required a higher specific mechanical energy to extrude at higher hydrolysate contents and was very brittle. The effect of salt content in the hydrolysate and order of operations in preparing the material for extruding on specific mechanical energy would need to be explored further. Future work could look at fractionating the hydrolysate to recover the lower molecular weight peptides, or to increase extent of hydrolysis without increasing salt content in the hydrolysate.