Conventional solid-state fermentation impacts the white lupin proteome reducing the abundance of allergenic peptides.

The demand for high-quality and sustainable protein sources is on the rise. Lupin is an emerging plant-based source of protein with health-enhancing properties; however, the allergenic potential of lupins limits their widespread adoption in food products. A combination of discovery and targeted quantitative proteome measurements was used to investigate the impact of solid-state fermentation induced by Rhizopus oligosporus on the proteome composition and allergenic protein abundances of white lupin seed. In total, 1,241 proteins were uniquely identified in the fermented sample. Moreover, the effectiveness of the solid-state fermentation in reducing the abundance of the tryptic peptides derived from white lupin allergens was demonstrated. Comparably, a greater decrease was noted for the major white lupin allergen based on ß-conglutin peptide abundances. Hence, conventional solid-state fermentation processing can be beneficial for reducing the potential allergenicity of lupin-based foods. This finding will open new avenues for unlocking the potential of this under-utilised legume.

Evaluation of the Major Seed Storage Proteins, the Conglutins, Across Genetically Diverse Narrow-Leafed Lupin Varieties.

Lupin seeds have an excellent nutritional profile, including a high proportion of protein and dietary fiber. These qualities make lupin seeds an ideal candidate to help meet the growing global demand for complementary sources of protein. Of consequence to this application, there are nutritional and antinutritional properties assigned to the major lupin seed storage proteins-referred to as α-, ß-, δ- and γ-conglutins The variation in the abundance of these protein families can impact the nutritional and bioactive properties of different lupin varieties. Hence, exploring the conglutin protein profiles across a diverse range of lupin varieties will yield knowledge that can facilitate the selection of superior genotypes for food applications or lupin crop improvement. To support this knowledge generation, discovery proteomics was applied for the identification of the 16 known conglutin subfamilies from 46 domestic and wild narrow-leafed lupin (NLL) genotypes. Consequently, the diversity of abundance of these proteins was evaluated using liquid chromatography-multiple reaction monitoring-mass spectrometry (LC-MRM-MS). This comparative study revealed a larger variability for the ß- and δ-conglutin content across the lines under study. The absence/lower abundance of the ß2- to ß6-conglutin subfamilies in a subset of the domesticated cultivars led to substantially lower overall levels of the allergenic ß-conglutin content in these NLLs, for which the elevation of the other conglutin families were observed. The diversity of the conglutin profiles revealed through this study-and the identification of potential hypoallergenic genotypes-will have great significance for lupin allergic consumers, food manufactures as well as grain breeders through the future development of lupin varieties with higher levels of desirable bioactive proteins and lower allergen content.

Evaluation of protein extraction methods for in-depth proteome analysis of narrow-leafed lupin (Lupinus angustifolius) seeds.

Lupin is slated as a potential contributor towards future food security. Lupin possesses several nutritional and nutraceutical attributes, many linked to seed proteins. For in-depth characterisation of the lupin proteome, liquid chromatography-tandem mass spectrometry was used to evaluate four protein extraction procedures. The proteomes of three narrow-leafed lupin were qualitatively evaluated using protein/peptide identifications and further quantitatively assessed by data-independent proteome measurement. Each extraction buffer led to unique protein identifications; altogether yielding 2,760 protein identifications from lupin varieties. The analysis of protein abundance data highlighted distinct differences between Tris-HCl and urea extracted proteomes, while also revealing variation amongst the cultivar proteomes with the wild accession (P27255) distinctly different from the domesticated cultivars (Tanjil, Unicrop). The extraction buffer used influenced the proteome coverage, downstream functional annotation results and consequently the biological interpretation demonstrating the need to optimise and understand the impact of protein extraction conditions.