Antimicrobial Activity of ε-Polylysine Mixtures against Food-borne Pathogens

This study was conducted to investigate the difference of antimicrobial activity between $\varepsilon$-polylysine/grapefruit seed extract mixture and $\varepsilon$-polylysine/glyceride mixture against food-borne pathogens. The minimum inhibitory concentration (MIC) of the $\varepsilon$-polylysine/grapefruit seed extract mixture was 100 times lower than that of the $\varepsilon$-polylysine/glyceride mixture. In case of the $\varepsilon$-polylysine/glyceride mixture the MIC of Bacillus cereus (0.1 $\mu$L/mL) and Pseudomonas aeruginosa (0.1 $\mu$L/mL) were lower than that of Escherishia coli (15 $\mu$L/mL). When rices were cooked with the $\varepsilon$-polylysine/glyceride mixture the number of total microbial cell was decreased during storage at 2$0^{\circ}C$ as concentration of the $\varepsilon$-polylysine/glyceride mixture increased. The antimicrobial activity was the highest against Escherishia coli as the concentration of the $\varepsilon$-polylysine/glyceride mixture increased. Sensory terms such as taste, flavor and texture were not significantly different in cooked rices prepared with 0.5% $\varepsilon$-polylysine/glyceride mixture, but there was significantly different in cooked rices prepared with 1% (p＜0.05) in the overall acceptability, indicating that the cooked rice with 0.5% $\varepsilon$-polylysine/glyceride mixture was recommended.

ε-Polylysine 혼합제제들의 식품부패균에 대한 항균효과

$\varepsilon$-Polylysine에 grapefruit seed extract와 glyceride를 각각 혼합한 항균보존제의 식품부패균에 대한 항균효과를 MIC test와 실제 쌀밥에 적용하였다. 두 혼합 항균제 모두 clear zone을 나타내었으나, $\varepsilon$-polylysine과 grapefruit seed extract 혼합물이 $\varepsilon$-polylysine과 monoglyceride 혼합물보다 약 100배정도 낮은 minimum inhibitory concentration을 보였다. Glyceride 첨가제의 실험에서 Bacilius cereus와 Pseudomonas aerugines의 경우 0.1 $\mu$L/mL에서 생육이 저해된 것에 반해 Escherishia coli의 경우 15 $\mu$L/mL에 저해되어 E. coli가 이 항균제에 대하여 강한 저항성을 보이는 것으로 나타났다. 취반 시 glyceride 흔합항균제를 여러 농도별 (0.3%, 0.5%, 1%)로 첨가시킨 쌀밥을 72시간동안 저장하였을 때 총균수는 항균제의 농도가 증가할수록 감소하는 경향을 보였다. 쌀밥에 E. coli를 접종하여 항균제 농도에 따른 생육억제효과를 측정한 결과 항균제 농도가 높을수록 강하게 생육을 억제하였다. 항균제가 쌀밥의 관능에 미치는 영향은 맛, 냄새, 입안에서의 조직감에서는 유의적인 차이를 보이지 않았으나, 전체적인 기호도에서 1% 첨가군이 유의적인 차이를 보여 0.5%의 첨가가 적합한 것으로 나타났다.