Enzymatic treatment of food samples

Rump round meat and lotus root were purchased from local markets and treated with an enzymatic process as follows. Briefly, frozen rump round meat was cut into 1.5 cm thick pieces and steamed for 10 min at 120℃, and then cooled down to room temperature for 30 min. Meat samples were placed into zippered bags with 250 mL 0.1% bromelain enzyme, and further treated for 4 h under 55 MPa of pressure at 55℃. Enzymes were inactivated by heating at 95℃ for 15 min, and the enzyme-treated meat samples were freeze-dried for downstream analysis.

Lotus roots cut into 1.5 cm thickness were steamed for 30 min at 120℃, cooled down to room temperature for 30 min, and then frozen at -18℃ for 24 h. Lotus roots were thawed for 3 h at room temperature, placed into zippered bags with 500 mL 0.5% Rohament CL enzyme (AB Enzymes, Germany), and placed under a vacuum for 5 min for efficient infusion of enzyme. The enzymatic reaction was then incubated for 1 h at 60℃. Enzymes were inactivated at 95℃ for 15 min, and the enzyme-treated lotus root samples were freeze-dried for downstream analysis.