Thermal Stability of Vitamin B6 Compounds in Liquid Model Food Systems


  • Florida Agricultural Experiment Stations Journal Series No. 4334. This research was supported in part by Grant No. 564 from the Nutrition Foundation, Inc., and Grant No. 5901–0410–9–0305–0 from the Competitive Research Grants Office, USDA-SEA. The assistance of Dr. J.A. Cornell and Dr. J.P. Adams is gratefully acknowledged.


The degradation of pyridoxine (PN), pyridoxal (PL), and pyridoxamine (PM) during thermal processing was evaluated in casein-based liquid model food systems. Limited evaluation of various potentially reactive ingredients suggested that vitamin B6 stability is not strongly a function of food system composition. Rapid interconversion of PL and PM was observed. Kinetic analysis of B6 vitamer degradation revealed approximately 2.5- to 3.5-fold greater stability of PN than the other nonphosphorylated vitamers, with activation energies of 27.3, 23.7, and 20.8 kcal/mol for the loss of total vitamin B6 after initial fortification with PN, PM, and PL, respectively. Limited studies with pyridoxal 5′-phosphate indicated that it is approximately 1.5- to 2-fold less stable than PL.