Abstract Infestations with fungi in chestnuts are one of the major safety issues during process and storage, resulting in short shelf-life and high economic losses. The purpose of this research was to study possible applications of radio frequency (RF) treatments for pasteurization of chestnuts to replace chemical methods. Thermal lethal kinetic models of fungi isolated from spoilage chestnuts and parameters of the developed model were determined. A 6 kW, 27 MHz free-running oscillator RF system combined with hot air heating was used to validate the treatment parameters based on thermal lethal kinetic models of fungi. The results showed that four mycotoxigenic fungi dominated and were isolated at frequency of 58.31 ± 2.39% for Penicillium crustosum, 17.78 ± 5.00% for Penicilluim discolor, 15.66 ± 7.67% for Penicillium expansum, and 14.24 ± 6.71% for Penicillium glabrum from a total sample size of one hundred spoilage nuts. Modified Weibull distribution model (R2 = 0.939 to 0.999) had a better description of the inactivation behavior of Penicillium sp. than the first-order kinetic model (R2 = 0.829 to 0.993) and P. crustosum was the most heat resistant fungi in chestnuts. Heating chestnuts to 60 °C or higher using hot air assisted RF energy resulted in 4-log reductions of P. crustosum isolated from moldy chestnuts. Quality of chestnuts was not influenced by the hot air assisted RF treatments because no significant differences in moisture, firmness, and color were observed between thermal treatments and untreated controls. Meanwhile, RF treatments also help to inhibit the growth of fungi during accelerated shelf life storage. The RF treatments may provide a rapid and environmentally friendly method to replace chemical fungicide for pasteurizing chestnuts.

中文翻译：

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通过热空气辅助射频处理热灭活板栗中的真菌

摘要 板栗真菌感染是加工和储存过程中的主要安全问题之一，导致板栗货架期短，经济损失高。本研究的目的是研究射频 (RF) 处理在栗子巴氏杀菌中的可能应用，以取代化学方法。确定了从腐败栗子中分离出的真菌的热致死动力学模型和所开发模型的参数。6 kW、27 MHz 自激振荡器射频系统与热空气加热相结合，用于验证基于真菌热致死动力学模型的处理参数。结果表明，四种产霉菌毒素真菌占主导地位，分离率分别为：壳青霉 58.31±2.39%、变色青霉 17.78±5.00%、膨胀青霉 15.66±7.67% 和 14.24±6。从一百个腐败坚果的总样本量中获得 71% 的青霉。修正的 Weibull 分布模型（R2 = 0.939 到 0.999）更好地描述了青霉菌的灭活行为。与一级动力学模型（R2 = 0.829 至 0.993）相比，壳皮壳菌是栗子中最耐热的真菌。使用热空气辅助 RF 能量将栗子加热到 60 °C 或更高，导致从发霉的栗子中分离出的壳皮壳菌减少了 4 对数。栗子的质量不受热空气辅助射频处理的影响，因为在热处理和未处理的对照之间没有观察到水分、硬度和颜色的显着差异。同时，RF 处理还有助于在加速保质期储存期间抑制真菌的生长。