Federal University of Santa Catarina, Department of Chemical Engineering and Food Engineering, Center of Technology, Florianopolis, SC 88040-901, Brazil.
Federal University of Santa Catarina, Department of Chemical Engineering and Food Engineering, Center of Technology, Florianopolis, SC 88040-901, Brazil.
Int J Food Microbiol. 2019 May 2;296:43-47. doi: 10.1016/j.ijfoodmicro.2018.12.018. Epub 2019 Jan 15.
Ascospores of Neosartorya fischeri are heat-resistant and can survive thermal commercial treatments normally applied to the juices, as apple juice. Non-thermal processing of food such as exposure to ultraviolet light (UV-C) is reported to induce minimal quality changes while reduces microbial load. The main objective of this study was to determine the effect at different soluble solids concentration (12, 25, 30, 40, 50, 60 and 70 °Brix) on N. fischeri ascospores inactivation in apple juice, using UV-C light intensity (38 W/m). Weibull model was fitted to experimental data. Then, a secondary model was used to describe how the inactivation kinetic parameters varied with the changes in soluble solids concentration. Results showed that the UV-C light had influence on N. fischeri ascospores inactivation in apple juice even at the highest soluble solids concentrations used, reaching approximately 4 log reductions at all concentrations used. The inactivation parameters, obtained by Weibull model, were δ (dose for the first decimal reduction) and p (the shape factor). Exponential model was chosen to describe the influence of soluble solids concentration on δ and p parameters. It can be concluded that UV-C light is a promising treatment with a drastic impact on the loads of N. fischeri, especially when low soluble solids concentration is used and a model was obtained to describe Brix effect.
青霉属真菌的分生孢子耐热，能够在通常应用于果汁（如苹果汁）的商业热处理中存活。据报道，非热食品处理，如暴露在紫外光（UV-C）下，在降低微生物负荷的同时，只会引起最小的质量变化。本研究的主要目的是确定在不同可溶性固形物浓度（12、25、30、40、50、60 和 70°Brix）下，UV-C 光强度（38 W/m）对苹果汁中青霉属真菌分生孢子灭活的影响。使用 Weibull 模型拟合实验数据。然后，使用二次模型来描述灭活动力学参数如何随可溶性固形物浓度的变化而变化。结果表明，即使在使用的最高可溶性固形物浓度下，UV-C 光对苹果汁中青霉属真菌分生孢子的灭活也有影响，在所有使用的浓度下均可达到约 4 个对数减少。通过 Weibull 模型获得的灭活参数为 δ（第一个十进制减少的剂量）和 p（形状因子）。选择指数模型来描述可溶性固形物浓度对 δ 和 p 参数的影响。可以得出结论，UV-C 光处理具有很大的潜力，对青霉属真菌的负荷有很大的影响，特别是在使用低可溶性固形物浓度时，可以获得一个描述 Brix 效应的模型。
