Upscaling of alkaline pea protein extraction from dry milled and pre-treated peas from laboratory to pilot scale: Optimization of process parameters for higher protein yields

Abstract

The upscaling of pea protein extraction from laboratory scale with a centrifuge to pilot scale with a decanter centrifuge was investigated, and the pea protein extraction efficiency from dry milled and pre-treated peas was compared. Upscaling from laboratory to pilot scale is possible since starch was under the limit of detection (< 0.5%). The protein banding pattern of a sodium-dodecyl-sulfate polyacrylamide gel electrophoresis confirmed that albumins and globulins were extracted by alkali extraction. Protein yield increased from 59.5% to 67.1% for dry milled peas due to constant and quick discharge of dry matter in the decanter centrifuge. For pre-treated peas, the protein yield increased from 60.3% to 94.3%, which is explained by an improved cutting and improved separation in pilot scale compared to laboratory scale. The impact of acceleration, mass flow, differential speed and their respective interactions in the decanting process was determined with a design of experiments. For dry milled peas, only the mass flow exceeded the significance level. However, a mass flow of 5 kg h−1, an acceleration of 1000 gtimes and a differential speed of 50 min−1 led to the highest protein yield of 75.6%. The obtained protein yields for the pre-treated peas were in the range of 83 to 96% and therefore did not show significant differences in protein yield.