Application of irradiation techniques to food and foodstuffs

In a comparative research on the decontaminating effects of ginseng leaf tea, ethylene oxide (EO) and 5 kGy gamma-irradiated groups could reduce microorganisms below the detectable level. And there is no growth of microoganisms after three months of storage at 30 deg C. The decimal reduction dose (D10 value) for microorganisms contaminated were 0.70 - 0.95 kGy. EO fumigation and irradiation at 5 kGy had little effects on soluble matters, sugar, amino acid, polyphenols and pigments. However, EO fumigation caused a significant change in the amount of ascorbic acid, free amino acid, moisture, pH and acidity of the sample. In the sensory evaluation, irradiated samples showed no significant difference from the non-treated control in overall flavor, taste, color and acceptability. The extracts of EO-fumigated samples, however, were significantly different in color and taste from other groups even after three months of storage. On the other hand, GC analysis tendency with storage time, resulting in the formation of significant amounts of the secondary products such as ethylene chlorohydrin and ethylene glycol. Based on the above results, it can be concluded that an optimum dose range (5kGy) of gamma irradiation effectively improves the microbiological quality of ginseng leaf tea, suggesting that irradiation techniques are a potential alternative to chemical fumigant, ethylene oxide. (author)