Suchergebnisse

Herein, we studied the effect of UV-C (shortwave ultraviolet) irradiation on the quality and inhibition of the browning of fresh-cut Chinese yam (Dioscorea opposita). The irradiation of 0, 4, 8, 12, and 24 kJ m-2 were applied to fresh-cut Chinese yam, and quality characteristics were evaluated during 16 days of storage at 4°C. The results indicated that UV-C treatment (8 KJ m-2) effectively decreased the browning degree, polyphenol oxidase (PPO) and peroxidase (POD) activities, and total bacteria count (TBC). However, the phenylalanine ammonia lyase (PAL) activity, PAL gene expression, respiration rate, and total phenol content increased. The UV-C treatment of 8 kJ m-2 resulted in a lower degree of membrane damage, as evidenced by the lower soluble quinone accumulation and browning index (BI), and retained the soluble solid content and hardness during storage. Increasing irradiation intensity would enhance cell damage while did not reduce browning. The results also showed that UV-C treatment alone had great potential to inhibit the browning of fresh-cut vegetables.

Coronavirus disease-2019 (COVID-19) pandemic has affected millions of people since December 2019. Summarizing the development of COVID-19 and assessing the effects of control measures are very critical to China and other countries. A logistic growth curve model was employed to compare the development of COVID-19 before and after the emergency response took effect. We found that the number of confirmed cases peaked 9–14 days after the first detection of an imported case, but there was a peak lag in the province where the outbreak was concentrated. Results of the growth curves indicated that the fitted cumulative confirmed cases were close to the actual observed cases, and the R(2) of all models was above 0.95. The average growth rate decreased by 44.42% nationally and by 32.5% outside Hubei Province. The average growth rate in the 12 high-risk areas decreased by 29.9%. The average growth rate of cumulative confirmed cases decreased by approximately 50% after the emergency response. Areas with frequent population migration have a high risk of outbreak. The emergency response taken by the Chinese government was able to effectively control the COVID-19 outbreak. Our study provides references for other countries and regions to control the COVID-19 outbreak.