La RuBisCO ˸ un ingrédient protéique pour enrichir les aliments à base de blé ? : Etude de la structure, des interactions protéine-protéine et de la digestibilité in vitro des protéines de la pâte de blé enrichie en RuBisCO

Dietary proteins from plants often display an unbalanced amino acid profile in comparison to animal proteins. A way to overcome this problem is to combine plant proteins from different sources with complementary amino acid compositions. RuBisCO is the main protein of leaf protein concentrates. Because of its high content in lysine, RuBisCO could improve the amino acid profile of wheat-based products. However, the introduction of non-wheat proteins in wheat-based foods often dilutes the gluten network or even impede its proper formation. This leads to poorer textural and culinary properties of the food. In this context, we have studied the possible consequences of RuBisCO enrichment on the quality of wheat-based products. The study was performed on a model system, a wheat dough. For comparison, enrichments with gluten and pea proteins were also studied. The main output of this work is that RuBisCO behaviour differs from that of legume proteins when introduced in dough. RuBisCO subunits establish weak bonds and form disulphide bridges when introduced in wheat dough. In addition, RuBisCO enrichment enhances the formation of disulphide bonded large size polymers during the dough thermal treatment. This may be related to its high content of cysteines and free thiols. This could prevent the negative consequences of gluten network weakening in wheat-based food. The enrichment of dough with RuBisCO modifies the kinetics of proteolysis during in vitro digestion. However, the global in vitro digestibility of proteins remains unchanged. These promising results confirm the potential of RuBisCO to be used for enriching wheat-based foods.