Biochemical and Techno-Functional Investigation of Argan Press-Cake Proteins Foreseeing Food Application

Argan press-cake (APC) is reported to contain a significant content of proteins, comparable to conventional sources of protein isolates, such as soybean. In this regard, the present study evaluated the biochemical and techno-functional properties of major APC proteins fractions, foreseeing food application. Albumins and globulins represented approximately 41% and 50% of total extractable proteins, respectively. Globulins were prone to aggregation, potentially by hydrophobic interactions, resulting in limited solubility in water in the range of pH 3 to pH 11. Nevertheless, the limited solubility of globulins in water at pH ≤ 9 could be improved, up to 8-fold, by pH12-shifting treatment, that is, unfolding the proteins structure at pH 12, followed by refolding at pH 9 or lower. pH12-shifted albumins and globulins presented similar surface activity in the range of pH 3 to pH 11 and were able to form and stabilize foams and emulsions. Comprehensively, both fractions reduced the interfacial tension and surface tension up to 8 mN/m and 48 mN/m, respectively, and formed stable emulsions, with a mean droplet volume diameter (d4,3) of approximately 16 μm, using rotor-stator homogenization. These results indicate that albumins and globulins extracted from argan by-products could have potential applications as techno-functional food ingredients.