Biorefinery of Green Biomass─How to Extract and Evaluate High Quality Leaf Protein for Food?

Abstract

There is a growing need for protein for both feed and food in order to meet future demands. It is imperative to explore and utilize novel protein sources such as protein from leafy plant material, which contains high amounts of the enzyme ribulose-1,5-biphosphate carboxylase/oxygenase (RuBisCo). Leafy crops such as grasses and legumes can in humid climate produce high protein yields in a sustainable way when compared with many traditional seed protein crops. Despite this, very little RuBisCo is utilized for foods because proteins in the leaf material has a low accessibility to monogastrics. In order to utilize the leaf protein for food purposes, the protein needs to be extracted from the fiber rich leaf matrix. This conversion of green biomass to valuable products has been labeled green biorefinery. The green biorefinery may be tailored to produce different products, but in this Review, the focus is on production of food-grade protein. The existing knowledge on the extraction, purification, and concentration of protein from green biomass is reviewed. Additionally, the quality and potential application of the leaf protein in food products and side streams from the green biorefinery will be discussed along with possible uses of side streams from the protein production.

Perspective on the Effect of Protein Extraction Method on the Antinutritional Factor (ANF) Content in Seeds

“…Therefore, strategies are needed to sophisticate the protein extraction, filtration, and fractionation to improve the quality and usability of protein fractions. Recently, a green leaf biorefinery utilizes a promising membrane filtration technology that includes several fractionation steps and avoids usage of chemicals resulting in higher protein quality with potential for food applications. , However, so far the method has been focused on optimizing protein quality and concentration, and the effect on ANFs has not been investigated.…”

Plant leaf proteins for food applications: Opportunities and challenges

“…When compared with ovalbumin, alfalfa leaf protein showed higher foam capacity but foam stability tends to be lower (Wang & Kinsella, 1976). In contrast, another study conducted by Knuckles reported higher foam stability for alfalfa LPC compared to egg white protein, and better foam stability might have resulted because the LPC was a more purified white fraction (Knuckles & Kohler, 1982;Møller et al, 2021). For alfalfa protein, it was reported that the presence of lipids (∼12%) in their composition has some negative effects on their foam stability (Wang & Kinsella, 1976).…”

Coupling the benefits of grassland crops and green biorefining to produce protein, materials and services for the green transition

“…Different anti-nutritional factors are present in different plant species and they need to be quantified in each specific case as they may concentrate in the protein fraction and affect nutrient bioavailability. Any new protein product produced from alfalfa, clover or grass needs an EFSA approval before the protein can be used in food products in the EU (Møller et al, 2021).…”