Leaf Protein Concentrate of Rye ( Secale cereale L.): A Green Innovation for Future Food and Feed

Abstract The concept of a green biorefinery offers promising pathways for the sustainable production of alternative protein sources for food and feed, utilizing green biomass derived from protein-rich plants and grasses. A central challenge in this approach is the reliable provision of high-quality protein. To address global protein shortages, various plant sources such as alfalfa, broccoli, green pea, and triticale have been investigated. In the present study, we evaluated the potential of rye ( Secale cereale L.) as a source for leaf protein concentrate (LPC) production, employing two isolation methods, i.e., microwave coagulation (MW) and lactic acid fermentation (LA) of green juice (GJ) after wet-fractionation. The green juice powder (P-GJ) was used as a control. The results revealed that different amounts and compositions of LPC are generated by the methods applied. The P-GJ resulted in lower protein content (14.06%) and higher levels of most antioxidant capacity, i.e., total phenolic contents (TPC) 182.51 mg GAE/g and water-soluble antioxidant capacity (ACW) 8.038 μg/mg ascorbic acid. The LA method resulted in a lower yield and protein content in comparison to the MW method. On the other hand, the MW method increased the protein content by 35.55% compared to LA-LPC and 106.47% compared to P-GJ. LA and MW LPC showed no significant differences (p