As the population of the Earth is constantly growing it generates an unmet demand for protein, which is an urgent problem. The protein extraction process is a potential solution, which offers high-quality plant protein suitable for animal and human nutrition at a favorable price. The process used within our project produces green juice from the green alfalfa biomass through pressing. After the coagulation of protein from this green juice, the by-product is called DPJ (Deproteinized Plant Juices) or brown juice. Our preliminary results match the international literature, namely that brown juice take up as much as 50% of the fresh biomass in weight. To utilize this by-product is a crucial part of the process to make it environmental-friendly and financially viable as well. The examined brown juice samples came from a small-scale experiment of alfalfa varieties carried out in the experimental farm at the University of Debrecen. According to our preliminary results, brown juice has high macro- and micronutrient values, furthermore, it has a potentially high amount of antioxidant compounds. The study highlights that brown juice is suitable as an ingredient in microbiological media, in plant nutrition as a supplementary solution, for feedstock and for preparing human food supplements or functional foods. The potential utilization of all biorefinery products makes it a very appropriate technology for today’s challenges.