PDF(Pubmed)
Abstract：
Enzymatic browning in fruits and vegetables, driven by polyphenol oxidase (PPO) activity, results in color changes and loss of bioactive compounds. Emerging technologies are being explored to prevent this browning and ensure microbial safety in foods. This study assessed the effectiveness of pulsed light (PL) and ultraviolet light-emitting diodes (UV-LED) in inhibiting PPO and inactivating Escherichia coli ATTC 25922 in fresh apple juice (Malus domestica var. Red Delicious). Both treatments\' effects on juice quality, including bioactive compounds, color changes, and microbial inactivation, were examined. At similar doses, PL-treated samples (126 J/cm2) showed higher 2,2- diphenyl-1-picrylhydrazyl inhibition (9.5%) compared to UV-LED-treated samples (132 J/cm2), which showed 1.06%. For microbial inactivation, UV-LED achieved greater E. coli reduction (>3 log cycles) and less ascorbic acid degradation (9.4% ± 0.05) than PL. However, increasing PL doses to 176 J/cm2 resulted in more than 5 log cycles reduction of E. coli, showing a synergistic effect with the final temperature reached (55 °C). The Weibull model analyzed survival curves to evaluate inactivation kinetics. UV-LED was superior in preserving thermosensitive compounds, while PL excelled in deactivating more PPO and achieving maximal microbial inactivation more quickly.
摘要：
水果和蔬菜中的酶褐变，由多酚氧化酶（PPO）活性驱动，导致颜色变化和生物活性化合物的损失。正在探索新兴技术来防止这种褐变并确保食品中的微生物安全。这项研究评估了脉冲光（PL）和紫外线发光二极管（UV-LED）在抑制新鲜苹果汁（Malusdomesticavar中的PPO和灭活大肠杆菌ATTC25922中的有效性。红色美味）。两种处理对果汁质量的影响，包括生物活性化合物,颜色变化,和微生物灭活，进行了检查。在相似的剂量下，与UV-LED处理的样品（132J/cm2）相比，PL处理的样品（126J/cm2）显示出更高的2,2-二苯基-1-吡啶酰肼抑制（9.5％），显示1.06%。对于微生物灭活，UV-LED比PL实现更大的大肠杆菌减少(>3个对数循环)和更少的抗坏血酸降解(9.4%±0.05)。然而,将PL剂量增加到176J/cm2导致大肠杆菌减少超过5个对数周期，显示与达到的最终温度(55°C)的协同效应。Weibull模型分析了存活曲线以评估失活动力学。UV-LED在保存热敏化合物方面表现优异，而PL擅长灭活更多的PPO，更快地实现最大的微生物灭活。
