Effects of storage temperatures, vacuum packaging, and high hydrostatic pressure treatment on the formation of biogenic amines in Gwamegi

This study investigated the effects of storage temperatures, vacuum packaging, and high hydrostatic pressure (HHP) on the formation of biogenic amines (BAs) in Gwamegi. The Gwamegi samples were subjected to 400 MPa pressure for 10 min at 20 degrees C or vacuum packaging, and then stored at -16, 5, or 25 degrees C for 28 days. The amounts of six BAs (histamine, tyramine, cadaverine, putrescine, spermine, and spermidine) and the total plate counts were checked weekly. Compared with the control at 5 degrees C, the total plate counts were 2-3 log CFU lower for the HHP-treated samples and 1-3 log lower for the vacuum-packaged samples. Tyramine, spermine, and spermidine were found in Gwamegi stored at -16 degrees C and tyramine, cadaverine, spermine, and spermidine at 5 degrees C, whereas all six BAs were found at 25 degrees C. Histamine was relatively low in amount in all the treated samples. The BAs reached a high level during storage at 25 degrees C, with the total concentration reaching 1099 ppm in 28 days. After HHP treatment or vacuum packaging, the concentration of cadaverine and spermidine decreased, whereas that of tyramine and spermine increased. Tyramine was the dominant BA in all the samples and during storage at 5 degrees C in the control (0-56.67 ppm), HHP-treated (0-105 ppm), and vacuum-packaged (0-90 ppm) samples. Both HHP treatment and vacuum packaging effectively reduced the formation of some types of BAs and improved the microbial quality in Gwamegi. However, simultaneously, they also promoted the formation of others types of BAs such as tyramine and spermine.