Federal University of Santa Catarina, Department of Chemical Engineering and Food Engineering, Center of Technology, Florianopolis, SC 88040-901, Brazil.
Federal University of Paraná, Food Engineering, Jandaia do Sul Campus, Jandaia do Sul, PR 86900-000, Brazil.
Int J Food Microbiol. 2020 Nov 16;333:108773. doi: 10.1016/j.ijfoodmicro.2020.108773. Epub 2020 Jun 25.
The present work aimed to evaluate and to model the influence of UV-C light treatments with different irradiances (6.5, 13, 21, and 36 W/m) on Aspergillus fischeri and Paecilomyces niveus ascospores inactivation in clarified apple juice. Approximately 5.0 and 6.0 log CFU/mL spores of P. niveus and A. fischeri, respectively, were suspended in 30 mL of clarified apple juice (pH 3.8, 12 ± 0.1°Brix) and exposed to UV-C light at different irradiances (as above) and exposure times (0 to 30 min). The first-order biphasic model was able to describe the experimental data with good statistical indices (RMSE = 0.296 and 0.308, R = 0.96 and 0.98, for P. niveus and A. fischeri respectively). At the highest irradiance level tested (36 W/m), the UV-C light allowed the reduction of 5.7 and 4.2 log-cycles of A. fischeri and P. niveus ascospores, respectively, in approximately 10 min. P. niveus was the most UV-C resistant mould. The results showed that, to a defined UV-C fluence, a change in the level of either time or UV-C irradiance did not affect the effectiveness of UV-C light for A. fischeri and P. niveus inactivation. Thus, the modeling of the inactivation as a function of the UV-C fluence allowed the estimation of the primary model parameters with all experimental data and, consequently, no secondary models were needed. The model parameters were validated with experiments of variable UV-C fluences. Accordingly, experimental results allowed to conclude that UV-C treatment at the irradiances tested is a promising application for preventing A. fischeri and P. niveus spoilage of juices.
本工作旨在评估并建立模型，以研究不同辐照度（6.5、13、21 和 36 W/m）的 UV-C 光处理对澄清苹果汁中aspergillus fischeri 和 Paecilomyces niveus 分生孢子失活动力学的影响。将约 5.0 和 6.0 log CFU/mL 的 P. niveus 和 A. fischeri 分生孢子分别悬浮在 30 mL 的澄清苹果汁（pH 3.8，12 ± 0.1°Brix）中，并在不同辐照度（如上所述）和暴露时间（0 至 30 分钟）下接受 UV-C 光照射。一阶双相模型能够用良好的统计指标来描述实验数据（对于 P. niveus 和 A. fischeri，RMSE 分别为 0.296 和 0.308，R 分别为 0.96 和 0.98）。在所测试的最高辐照度水平（36 W/m）下，UV-C 光可使 A. fischeri 和 P. niveus 分生孢子分别减少 5.7 和 4.2 log 循环，大约需要 10 分钟。P. niveus 是对 UV-C 最具抵抗力的霉菌。结果表明，对于一定的 UV-C 剂量，时间或 UV-C 辐照度水平的变化不会影响 UV-C 光对 A. fischeri 和 P. niveus 失活动力学的有效性。因此，将失活动力学建模为 UV-C 剂量的函数，可以用所有实验数据来估计主要模型参数，因此不需要二次模型。用不同 UV-C 剂量的实验对模型参数进行了验证。根据实验结果可以得出结论，在所测试的辐照度下进行 UV-C 处理是一种有前途的应用，可以防止 A. fischeri 和 P. niveus 对果汁的污染。
