Browsing by Subject "Rubisco"

In the world, the demand and consumption of protein are increasing all the time as the number of population is growing. One of the biggest challenges is to increase protein production while reducing emissions. In many countries, the demand for meat consumption has leveled off, and the demand for other, especially plant-based protein sources has increased. Soy is the most used plant-based protein. However, the majority of soy is imported to Europe. Finding another plant protein source that could be used both as human food and feed would increase Europe's protein self-sufficiency. The aim of this study was to isolate protein from two grass varieties for food use. In grass material, the protein is divided into two fractions: the green protein fraction and the white protein fraction. The green fraction contains membrane proteins and cell wall fibers and is not of interest in food use due to its sensory properties. The white fraction consists mainly of Rubisco (ribulose-1,5-bisphosphate carboxylase), which is a complete protein in its amino acid composition. Different methods can be used to isolate soluble proteins, such as thermal coagulation, precipitation based on pH adjustment, ultrafiltration, or fermentation. In this study, the isolation of the white protein fraction from grass material was achieved with a two-step isolation protocol, where first the green fraction is coagulated and then the white fraction is precipitated. The study also managed to determine the optimal parameters for protein isolation, the effects of antioxidant addition, and mass balance. Based on the research results, protein isolation from grass is possible, but studying other isolation methods might be useful so that a comparison of protein yield between methods would be possible.