Development and characterisation of a vacuum flash evaporator for concentrating a heat sensitive aqueous peptide stream

Canesis Network Limited, in conjunction with Keratec Limited, has developed a patented process for the chemical extraction of soluble keratin proteins from wool. This extraction process results in the generation of several proteinrich streams, including a dilute aqueous based peptide stream. This peptide stream requires concentration, and evaporation has been found to be a convenient method for achieving this. The peptide-containing stream is sensitive to heat damage. The existing evaporator has been found to be far from ideal for the application, with the harsh evaporation conditions resulting in damage to the peptides and undesirable darkening of the peptide solution. To overcome this, and increase product throughput, a new evaporator has been designed and built for this application. This study discusses the design and construction of this new, purpose built, flash type evaporator to evaporate the peptide stream in a vacuum. The study also details investigations undertaken to assess the performance of the evaporator and characterise the evaporation peptide stream. The overall outcome of this study has shown that the peptide stream can be successfully concentrated by evaporation using a flash evaporator operating under vacuum. Damage to the peptide stream can be minimised by controlling the evaporation conditions. Optimal operating conditions for processing the peptide stream have been identified. Investigations into the heat damage of keratin peptides and the effects of heat damage on the peptide offer an exciting opportunity for future research work.

A vacuum flash evaporator was designed and built for the concentration of heat sensitive protein solutions. This development and characterisation study has shown that the heat sensitive protein solution can be successfully concentrated by evaporation using a vacuum flash evaporator. Damage to the heat sensitive solution, resulting in a darker than desired concentrated protein stream, can be minimised by controlling the evaporation conditions. Maintaining an evaporation temperature of 70°C or less was found to produce a concentrated protein stream of acceptable colour. The evaporation rate was found to be affected by the flow rate through the evaporator and the temperature of evaporation. Further research is required to investigate the factors contributing to the heat damage of keratin protein solutions and the effects of heat damage on the proteins.