Optimizing the use of Sinapis alba seed meal extracts as a source of thiocyanate (SCN−) for the lactoperoxidase system

• An antimicrobial system generated with thiocyanate derived from Sinapis alba seed meal.
• Production of the antimicrobial agent (OSCN−) was optimized.
• The developed antimicrobial system has potential to be Generally Recognized As Safe.

The multi-component lactoperoxidase system (LPSys) is used for improving food safety and requires thiocyanate (SCN−) as a substrate for the generation of antimicrobial hypothiocyanite (OSCN−). Production of OSCN− is usually limited by intrinsic concentrations of SCN− or else SCN− must be supplied from a synthetic source. Our objective was to optimize the production of OSCN− in the LPSys using SCN− derived from glucosinolates present in yellow mustard (Sinapis alba) seed meal. Thiocyanate was produced from S. alba seed meal by shaking a 1:20 (w:w) meal:H2O mixture at 70 °C for 10 min. Increasing the exogenous H2O2 to an equimolar concentration (500 μM) of SCN− further increased OSCN− production, whereas H2O2 concentrations in excess of SCN− enhanced OSCN− decay. Glucose and glucose oxidase (GOx) were substituted for H2O2 to sustain OSCN− production resulting in an optimized LPSys containing 4.92 U/mL lactoperoxidase, 64 mM glucose, 342 U/L GOx, and 500 μM SCN−. Maximum OSCN− in the optimized system was 40 μM, a concentration that is predicted to have antimicrobial effects, thus demonstrating the potential of the low value S. alba seed meal as source of SCN− for preparing a generally recognized as safe LPSys.