Optimization of the decanter process in terms of the protein yield for the manufacture of an oat-based milk substitute

Abstract

Even though oat-based milk substitutes offer numerous nutritional benefits, one of their major disadvantages is the low protein content. To overcome this issue, the impact of the decanter process on the protein yield was investigated. A design of experiments with 30 experimental runs was performed to determine the influence of acceleration, feed, feed temperature, inner weir diameter, and differential speed on the separation process. The results were used to calculate the ideal parameters. Accordingly, an acceleration of 4,000 g, a feed of 20 kg/h, a temperature of 20 °C, an inner weir diameter of 68 mm, and a differential speed of 180 min⁻¹ resulted in the highest theoretical protein in dry matter content (14.22 % w/w) corresponding to a protein yield of 98.2 %. The validation experiments with the calculated parameters led to a centrate with a protein in dry matter content of 11.63 ± 0.14 % (w/w), an absolute protein content of 1.00 ± 0.01 % (w/w), and a protein yield of 81.3 ± 1.70 %. The centrate was free of dark particles confirming an adequate separation of undesired solids. SDS-PAGE further proved that no protein fraction was completely separated. In conclusion, the parameters of the decanter process should be set carefully in order to achieve a high protein yield.