Abstract:
Effects of steam sterilization, gamma-irradiation, UV-irradiation and ozonation on microbial inactivation, pyrrolizidine alkaloid degradation and volatile compound profile in oregano were investigated. Steam sterilization and gamma-irradiation were the most effective treatments in inactivating microorganisms. These treatments resulted in 0.87-2.15 log reductions in total aerobic mesophilic bacteria counts and reduced yeast-mold and Enterobacteriaceae counts below the detectable level. Steam sterilization caused increased levels of pyrrolizidine alkaloids (PAs) and decreased levels of their N-oxide forms (PANOs) demonstrating a simultaneous conversion of PANOs into the corresponding PAs. Ozone treatment caused significant decreases in the levels of individual and total PAs/PANOs. After ozone treatment, decreases of 54.4, 53.9, 61.6 and 61.4% were observed in the levels of europine-N-oxide, europine, lasiocarpine-N-oxide and lasiocarpine, respectively. Steam sterilization, UV-irradiation and ozone treatments significantly altered the composition of the volatile compounds of oregano as evidenced by decreased levels of major components and the formation of some new compounds.
摘要:
蒸汽灭菌的效果,γ-辐照,紫外线照射和臭氧化对微生物灭活的影响,研究了牛至中吡咯啶生物碱的降解和挥发性化合物的分布。蒸汽灭菌和γ辐照是灭活微生物的最有效方法。这些处理导致需氧嗜温细菌总数减少0.87-2.15log,酵母霉菌和肠杆菌科细菌总数减少到可检测水平以下。蒸汽灭菌导致吡咯啶生物碱(PA)的水平升高,其N-氧化物形式(PANO)的水平降低,表明PANO同时转化为相应的PA。臭氧处理导致个体和总PAs/PANO的水平显著降低。臭氧处理后,减少54.4,53.9,61.6和61.4%的水平观察到的欧洲-N-氧化物,欧洲松,拉西卡品-N-氧化物和拉西卡品,分别。蒸汽灭菌,紫外线照射和臭氧处理显着改变了牛至挥发性化合物的组成,主要成分的含量降低和一些新化合物的形成证明了这一点。