Degradation and Binding to Food Proteins of Vitamin B‐6 Compounds During Thermal Processing

摘要

ABSTRACTThermal degradation and interconversion of B‐6 vitamers and extent of their covalent binding to food proteins during processing at 121°C was evaluated. In solutions of potassium caseinate, radiolabelled forms of pyridoxal (PL) and pyridoxal phosphate (PLP) underwent partial conversion to pyridoxamine (PM) and pyridoxamine phosphate (PMP), respectively. Labelled pyridoxine (PN) underwent only slight oxidation to PL. Processing of evaporated milk, chicken liver and muscle containing tritiated B‐6 vitamers yielded similar results. The extent of covalent binding to protein and net retention of vitamin B‐6 varied among the food systems examined. Pyridoxyllysine and several unidentified bound forms of the vitamin formed during thermal processing were found in hydrolysates of casein, liver and muscle proteins. Bis‐4‐pyridoxyl disulfide was no