ASSESSMENT OF ROASTING EFFECTS ON VITAMIN B6 STABILITY AND BIOAVAILABILITY IN DEH.YDRATED FOOD SYSTEMS

Abstract

ABSTRACTDehydrated food systems were employed to study the stability and bioavailability of vitamin B6 as affected by roasting at 180°C for 25 min. The roasting conditions were selected to permit estimation of the maximum effects of the roasting process on the B6 vitamers and are above those which would be normally used for commercial processing. The relative degradation of pyridoxine, pyridoxamine, and pyridoxal phosphate was found to be 50‐70% by both microbiological and semi‐automated fluorometric assay methods. Estimates of biologically available vitamin B6 in the roasted model systems, as determined by rat bioassay correlated closely with microbiological results. Thus, vitamin B, remaining after roasting at 180°C for 25 min was biologically available and active. Semiautomated fluorometric values for total vitamin B6 in untreated and roasted systems were 1.65‐3.63 times higher than corresponding microbiological assay data. Fluorescence spectra studies of samples prepared for the semiautomated assay revealed no detectable interfering compounds. Microbiological assay provided an accurate evaluation of available vitamin B6 in the roasted model food system as shown by the rat bioassay. The consistently high results from the semiautomated fluorometric method indicate that further work is required before this method can be accurately used to quantitatively determine the level of vitamin B6 in foods.