Is now the time for a Rubiscuit or Ruburger? Increased interest in Rubisco as a food protein

Abstract

Much of the research on Rubisco (Ribulose-1,5-bisphosphate carboxylase/oxygenase) aims at increasing crop yields, with the aim of increasing plant production to feed an increasing global population. However, since the identification of Rubisco as the most abundant protein in leaf material, it has also been touted as a direct source of dietary protein. The nutritional and functional properties of Rubisco are on par with many animal proteins, and are superior to many other plant proteins. Purified Rubisco isolates are easily digestable, nutritionally complete, and have excellent foaming, gelling and emulsifying properties. Despite this potential, challenges in efficiently extracting and separating Rubisco have limited its use as a global foodstuff. Leaves are lower in protein than seeds, requiring large amounts of biomass to be processed. This material normally needs to be processed quickly to avoid degradation of the final product. Extraction of Rubisco from the plant material requires breaking down the cell walls and rupturing the chloroplast. In order to obtain high quality protein, Rubisco needs to be separated from chlorophyll, and then concentrated for final use. However, with increased consumer demand for plant protein, there is increased interest in the potential of leaf protein, and many commercial plants are now being established aimed at producing Rubisco as a food protein, with over $US60 million of funding invested in the past 5 years. Is now the time for increased use of Rubisco in food production as a nitrogen source, rather than just providing a carbon source?

RuBisCO: a sustainable protein ingredient for plant-based foods

“…The literature reported the essential amino acid composition of spinach (S. oleracea L.) RuBisCO seems to be comparable or even superior to that of animal proteins, especially beef and egg proteins (Figure 4). A larger subunit (LSU) of RuBisCO is highly conserved and because of this Rubisco protein isolated from different plants may have a similar nutritional profile (Liu et al, 2017;Pearce and Brunke, 2023). However, like other proteins, the nutritional value of RuBisCO is also affected by antinutritional compounds such as phenolics, phytic, and oxalic acids present in the plant tissues (Pérez-Vila et al, 2022).…”

“…Biochemical analysis linked symptoms of asphyxia and Essential amino acids composition of spinach (S. oleracea L.) RuBisCO and other commercial animal and plant proteins in comparison with the "ideal" protein according to FAO/WHO. Data adapted from FAO (2013) and Pearce and Brunke (2023). Nawaz et al 10.3389/fsufs.2024.1389309 Frontiers in Sustainable Food Systems 07 frontiersin.org…”

Protein Fractionation of Leafy Green Biomass at the Pilot Scale: Partitioning and Type of Nitrogen in the Fractions and Their Usefulness for Food and Feed

“…Several promising alternative protein sources for food and feed are suggested in the literature, e.g., insects, algae, and green leafy biomass, the latter is globally available in large quantities in the form of plant leaves. − This feedstock contains the protein ribulose-1,5-bisphospate-carboxylase/oxygenase (RuBisCO), which catalyzes carbon fixation in the photosynthetic cycle . Approximately 50% of the proteins in green biomass is RuBisCO and the protein is also the most abundant in the world .…”

In vitro protein digestibility of RuBisCO-enriched wheat dough: a comparative study with pea and gluten proteins

“…5,6 Research on leaf proteins was stimulated in the early 1940s, when Norman Pirie discussed the potential of leaf protein concentrates as a source of proteins for human consumption to overcome wartime food shortages. 5 The renewed interest, in the past 5-10 years, for RuBisCO from the scientific community is evidenced by the numerous recent reviews [7][8][9][10][11] and research articles exploring its extraction, [12][13][14] functional properties, 15,16 and digestibility. 17 In a previous work, we explored the use of RuBisCO, extracted from Cichorium endivia leaves, to fortify wheat-based food.…”