Simultaneous extraction and enzymatic hydrolysis of mustard bran for the recovery of sinapic acid

[Display omitted] •The bioconversion of a mustard by-product was studied for the recovery of sinapic acid.•Several commercial enzymatic cocktails were identified with a sinapoyl esterase activity.•Extraction and hydrolysis of sinapine in sinapic acid was carried out simultaneously.•The sinapic acid yield with Depol 740 L (68%) was similar to that of a pure rumen FAE.•The sinapoyl esterase activity was found not tolerant to ethanol from 10 vol%. The simultaneous extraction and enzymatic hydrolysis of sinapine from a mustard residue was designed for the recovery of sinapic acid, a high value-added phenolic acid. An initial screening allowed the identification of sinapoyl esterase activities in commercial enzymatic cocktails (Depol 740 L, Ultraflo XL, Deltazym VR AC-100, Pectinase-PL “Amano”) and in a mono-enzymatic solution of rumen feruloyl esterase. These enzymatic cocktails were not very tolerant to ethanol with a diminution of 70–90% of the activity in presence of 10% (v/v) of ethanol. Different extraction processes on mustard bran were designed depending on the solvent compositions (ethanol 70% (v/v), water with or without sinapoyl esterase), pH (4.3, 7 or 12) and temperatures (50, 75 or 100 °C). Their respective efficiencies were discussed. The implementation of Depol 740 L in water allowed to recover 68% of the accessible sinapic acid (25.4 ± 0.1 μmol/g of bran dry matter) in 2h40 min under mild conditions (pH 7, 50 °C). This efficient biocatalytic production of sinapic acid from mustard feedstock using an enzymatic cocktail paves the way for new developments for the design of an industrial process.