The combination of UV-C radiation and mild heat (UV-H) treatment is a promising strategy for synergistically increasing microbial inactivation in low UV-transmitting juices. In this research, we explored the suitability of UV-H treatment in carrot juice pasteurization and its impact on juice quality during shelf-life compared to that of thermal pasteurization. UV-H treatment at 60 °C (3.92 J/mL, 3.6 min) enabled reductions of over 5 log₁₀ cycles in the reference pathogens and a significant reduction in spoilage yeasts, bacteria, and bacterial spores. The activity of pectin methylesterase and polyphenol oxidase was reduced by UV-H treatment to levels close to those of low-temperature pasteurization (60 °C/18.1 min). The native population of total aerobic bacteria, lactic acid bacteria, and yeasts and molds of UV-H-treated juice remained undetectable during 29 days of cold storage. Furthermore, viscosity, cloud stability, and the color of fresh juice were better preserved by UV-H treatment than by thermal pasteurization throughout storage.

Industrial relevance

This study demonstrates that UV-H treatment is a beneficial alternative to conventional thermal processing in carrot juice pasteurization, since appropriate inactivation levels of pathogenic and spoilage microorganisms can be reached while better preserving the quality attributes of fresh juice throughout its shelf-life.

UV-C辐射和温和加热（UV-H）处理的结合是协同增加低紫外线透过汁液中微生物灭活的一种有前途的策略。在这项研究中，我们探讨了UV-H处理在胡萝卜汁巴氏消毒中的适用性以及与热巴氏消毒相比在货架期内对果汁质量的影响。在60°C（3.92 J / mL，3.6分钟）下进行UV-H处理可减少超过5 log ₁₀循环中参考病原体的循环，显着减少了腐败酵母，细菌和细菌孢子。果胶甲基酯酶和多酚氧化酶的活性通过UV-H处理降低至接近低温巴氏杀菌（60°C / 18.1分钟）的水平。在冷藏29天期间，总的好氧细菌，乳酸菌，酵母菌和经过UV-H处理的果汁的霉菌的本地种群仍然无法检测到。此外，在整个存储过程中，通过UV-H处理比通过热巴氏灭菌能更好地保持粘度，浊度稳定性和新鲜果汁的颜色。

行业相关性

这项研究表明，UV-H处理是胡萝卜汁巴氏杀菌中常规热处理的有益替代方法，因为可以达到适当的灭活水平，使病原性和腐败性微生物达到最佳状态，同时在整个保质期内更好地保存鲜榨果汁的品质。