Protein nanofibrils (PNFs) from plant-based protein sources have great potential for use in new sustainable food applications or biobased materials. Plant-based proteins from seven different sources (fava bean, mung bean, lupin, oat, rapeseed, soybean, and potato) were evaluated here for their ability for forming PNFs and compared with whey protein PNFs. Formation of PNFs was studied under incubation at acidic conditions (pH 2) and heat (85–90 °C) for 24–96 h. Presence of PNFs was detected using thioflavin T, circular dichroism spectroscopy, Fourier-transform infrared spectroscopy, and atomic force microscopy. The results showed that all plant-based proteins were able to form PNFs. For some of the plant protein isolates in this study, nanofibril formation is reported for the first time. We also describe and compare the distinct features associated with each protein source and the morphological alterations of the nanoscale structures. Finally, we describe how PNF production can be enhanced by purifying the fibril-forming protein component. Taken together, our study suggests that the structural and functional variation within plant protein nanofibrils can be exploited in future scaled-up food or material applications.

Protein nanofibrils (PNFs) have potential for use in food applications as texture inducers. This study investigated the formation of PNFs from protein extracted from whole fava bean and from its two major storage proteins, globulin fractions 11S and 7S. PNFs were formed by heating (85 °C) the proteins under acidic conditions (pH 2) for 24 h. Thioflavin T fluorescence and atomic force microscopy techniques were used to investigate PNF formation. The foaming properties (capacity, stability, and half-life) were explored for non-fibrillated and fibrillated protein from fava bean, 11S, and 7S to investigate the texturing ability of PNFs at concentrations of 1 and 10 mg/mL and pH 7. The results showed that all three heat-incubated proteins (fava bean, 11S, and 7S) formed straight semi-flexible PNFs. Some differences in the capacity to form PNFs were observed between the two globulin fractions, with the smaller 7S protein being superior to 11S. The fibrillated protein from fava bean, 11S, and 7S generated more voluminous and more stable foams at 10 mg/mL than the corresponding non-fibrillated protein. However, this ability for fibrillated proteins to improve the foam properties seemed to be concentration-dependent, as at 1 mg/mL, the foams were less stable than those made from the non-fibrillated protein.

Soy (Glycine max) is used in a wide range of products and plays a major role in replacing animal-based products. Since the cultivation of soy is limited by cold climates, this review assessed the nutritional, sensory, and functional properties of three alternative cold-tolerant crops (faba bean (Vicia faba), yellow pea (Pisum sativum), and oat (Avena sativa)). Lower protein quality compared with soy and the presence of anti-nutrients are nutritional problems with all three crops, but different methods to adjust for these problems are available. Off-flavors in all pulses, including soy, and in cereals impair the sensory properties of the resulting food products, and few mitigation methods are successful. The functional properties of faba bean, pea, and oat are comparable to those of soy, which makes them usable for 3D printing, gelation, emulsification, and extrusion. Enzymatic treatment, fermentation, and fibrillation can be applied to improve the nutritional value, sensory attributes, and functional properties of all the three crops assessed, making them suitable for replacing soy in a broad range of products, although more research is needed on all attributes.