Optimization of potent mineral chelating peptides production from rapeseed meal proteins proteolysis and peptide characterizations

Preventing lipid oxidation and microbial spoilage are both major concerns in sectors such as food and cosmetic industries. Biopeptides, arouse great interest to substitute synthetic antioxidants. Some plant proteins, like 2S rapeseed albumins are known presenting antimicrobial properties. In this context, we aimed to valorize total rapeseed meal proteins with controlled enzymatic proteolysis to generate mineral chelating peptides from the 11S globulins fraction while keeping intact the albumins fraction. To do so, screening of proteases on total rapeseed protein isolate was implemented highlighting a globulin-selective hydrolysis with Prolyve®. Ultrafiltration was then used to purified albumins and enrich the peptide fraction. The fraction obtained showed a noteworthy metal chelating activity. Then, the selected proteolysis was optimized in order to maximize the albumins purity and yield. For that, enzymatic mechanism identification in a wide operating conditions area was led to define the DoE. Then, simulation of hydrolysis kinetics was driven to predict protein fractions concentration at any time and any set of operation conditions. The obtained models were implemented in a genetic-evolutionary algorithm to generate the Pareto Front and Domain, presenting the targeted economical compromises. One solution was chosen, and the identified corresponding operating conditions proved the metal chelating activity conservation (EC50 = 247 27 μg) for three times faster production at the same enzyme cost. Finally, peptide activity was investigated in oil-in-water emulsion systems and compared with EDTA. Results showed that peptides could be as effective as EDTA to avoid primary and secondary lipid oxidation products formation. This work demonstrates an original total valorization of both rapeseed meal proteins in food applications. First, antioxidant peptides produced from the globulin fraction, could be used as food preservative in oil-in-water emulsion systems, but also as preventing agents for micronutrient deficiencies. And, the purified albumin fraction could be used to prevent microbial spoilage. (Texte integral)