Monday, January 16, 2012
Molecules 2012, 17(1), 674-687
This study was conducted to evaluate the effects of evaporation, gamma irradiation and temperature on the total polyphenols, flavonoids and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activities of Tualang honey samples (n = 14) following storage over three, six or twelve months. The mean polyphenol concentrations of the six gamma irradiated honey samples at three, six and twelve months, respectively, were 96.13%, 98.01% and 102.03% higher than the corresponding values of the eight non-gamma irradiated samples. Similarly, the mean values for flavonoids at three, six and twelve months were 111.52%, 114.81% and 110.04% higher, respectively, for the gamma irradiated samples. The mean values for DPPH radical-scavenging activities at three, six and twelve months were also 67.09%, 65.26% and 44.65% higher, respectively, for the gamma irradiated samples. These data indicate that all gamma irradiated honey samples had higher antioxidant potential following gamma irradiation, while evaporation and temperature had minor effects on antioxidant potential…
Our study clearly demonstrates that over twelve months, different storage conditions had little effect on the polyphenol and flavonoid contents and DPPH radical-scavenging activities in Tualang honey samples. However, gamma irradiation had the potential to maintain these properties successfully. The most notable finding of our study was that evaporation, the type of container (dark or clear bottles) and temperature showed minor effects on the phenolic and flavonoid contents and DPPH radical-scavenging activities, while gamma irradiation played a major role in influencing the antioxidant properties of honey. Longer storage durations were associated with gradual decreases in the polyphenol and flavonoid contents and radical-scavenging activities of honey samples stored in different ways. Further research is now required to reveal the mechanism underlying the increase in polyphenol content and radical-scavenging activities of gamma irradiated Tualang honey samples.