Characterisation of a starch extrudate coated with an aqueous solution of pea protein isolate.

Research on the use of protein films as barriers against water have not oft en found industrial applications. In the present work, a pea protein coatin g was applied on an extruded starch. The quality of the coating at the labo ratory scale was quantified by determination of the specific mass, bulk tex ture and humidity absorption. The semi-industrial scale was assessed, based on the balance of material entering and leaving the apparatus. Results by surface response methodology show the importance of the water contained in the solution on the transformation of the extruded starch. Thus a large amo unt of coating retains a large quantity of water and increases product spec ific mass and mechanical resistance, whilst a high protein concentration is necessary to make a humidity proof film. The matter balance, in the indust rial application, showed the necessity for the machine to be run for some t ime before real production was started.