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Sorghum protein ingredients show promising applications, given that sorghum is a resilient grain with high protein content and bioactive components, such as tannins, in certain genotypes. This study aimed to investigate the production and characterization of sorghum protein ingredients extracted from both tannin-free and tannin-rich cultivars, along with an examination of their behavior in aqueous suspensions. The use of high-pressure homogenization to improve ingredient dispersibility was also assessed. Protein extracts exhibited protein contents ranging from 50 to 67 g/100 g (wet basis), with the highest values obtained in tannin-free samples. Total lipid contents were between 18 and 26 g/100 g (wet basis), with a high contribution of free fatty acids (68–76 g/100 g lipids), and tocopherol contents ranged from 1080 to 2039 µg/g total lipids. This is substantially higher than the lipid content in flours, implying an accumulation of lipids during the protein extraction process. While the dispersibility of the protein extracts in aqueous media was initially limited, high-pressure homogenization proved effective in reducing the average size of the particles in suspension, from 9–66 µm to 1.8–2.5 µm. This processing step significantly enhanced protein dispersibility by up to 288 %, especially for the tannin-rich samples.

The food transition towards an increased consumption of plant proteins aimed at limiting environmental impacts requires a diversification of plant protein sources. In this study, we explored the potentialities of the sustainable oilseed crop camelina to provide dietary proteins and to prepare oil-in-water emulsions. An innovative green refinery process, including the removal by ultrasound of the mucilage attached at the surface of the seeds and extraction by grinding in water at pH 8, was used to recover aqueous extracts containing camelina seed proteins. These proteins, mainly composed of the 11S globulin cruciferins and the 2S albumin napins, contained the nine essential amino acids of nutritional interest. Camelina seed proteins exhibited low solubility in the range of pH 5.5–2, attributed to the cruciferins. Oil-in-water emulsions stabilized by camelina seed proteins revealed the preferential adsorption of napin at the oil/water interface and exhibited physical instability below pH 7. Homogenization of the whole aqueous extracts containing oil bodies (OBs) induced the adsorption of cruciferins and napins together with oleosins at the surface of homogenized OBs, and their sedimentation below pH 6.5. Camelina seed proteins adsorbed at the oil/water interface governed the surface properties of the oil droplets and homogenized OBs as well as the physical stability of the emulsions as a function of pH. This work brings new insights into the potentialities of camelina seed proteins recovered by aqueous extraction that may serve as natural plant-based functional ingredients in the food industry and that will contribute to the development of innovative and sustainable plant-based food emulsions.