Exploration of high voltage atmospheric cold plasma as a practical tool for reducing food spoilage

该研究项目旨在建立在先前工作的基础上，建立介质阻挡放电高压大气冷等离子体（HVACP）的潜力，以显着改善食品安全性和延长食品保质期，比现有的处理和洗涤方法需要更少的能源和水，从而实现更可持续和环保的制造过程。在未来5年的资助期内，我们计划开展三个平行的研究方向，以扩大对高压大气冷等离子体（HVACP）的科学认识，并展示其作为改善食品安全和质量的实际干预技术的潜在应用。1将深入研究HVACP的机理，利用空气作为50kv以上电压的填充气体，对气体等离子体的产生特性和产生的反应性气体（RGS）的产生以及这些RGS在储存过程中的稳定性进行研究，以潜在地提高新鲜食品的安全性和延长保质期。专场2将研究在不同HVACP电压和处理时间下改性气体混合物（即CO2， N2, O2, H2, Ne）的RGS生成化学。以前的工作已经证明，改变气体成分和电压会改变RGS，这可以在不改变绿叶蔬菜等敏感食品质量的情况下延长保质期。第三方向将是优化HVACP处理，以延长新鲜农产品（如西红柿）的保质期，并对处理过的食品的质量、安全性和毒理学进行评估。HVACP可以仅使用空气和少量电力（100w或更少）来产生。使用空气作为填充气体将在80千伏电压下产生约5000 ppm的活性氮和活性氧。对于许多新鲜农产品应用，空气HVACP处理是一种低成本的选择，有利于延长保质期和提高安全性。然而，一些产品，如绿叶蔬菜，可能会受到空气中产生的RGS的影响，因此，使用气体混合物利用HVACP处理是可取的，以产生更有益的RGS剖面。通过改变HVACP气体成分，RGS的数量和类型可以增加到30,000 ppm以上，并产生独特的气体化学（“特征”）。假设是，这些定制的HVACP气体化学物质可以提供非热RGS处理，可以选择性地靶向和破坏细菌、酵母、霉菌、真菌毒素、化学污染物、酶或病毒，而不会破坏新鲜农产品或产生有毒化合物。这三个研究轨道的成功完成将实现扩大HVACP科学认识的总体目标，并展示其作为提高食品安全和质量的实际干预技术的潜在应用，将有可能导致更广泛的行业采用和新鲜水果和蔬菜保存方法的革命性变化。

This research program aims to build on previous work establishing the potential for a dielectric barrier discharge high voltage atmospheric cold plasma (HVACP) to deliver significant improvement in food safety and extension of food shelf-life with much less energy and water requirements than existing treatments and washes leading to a more sustainable and environmentally friendly manufacturing process. In the next five-year funding period, we propose to engage in the three parallel research tracks with the goal of expanding the scientific understanding of high voltage atmospheric cold plasma (HVACP) and demonstrate its potential application as a practical intervention technology for improving food safety and quality. Track 1 will be an in-depth mechanistic study of the HVACP utilizing air as the fill gas at voltages above 50 kV on the gas plasma generation characteristics and the resulting reactive gas species (RGS) generation and the stability of these RGS during storage to potentially improve safety and extend shelf-life fresh foods. Track 2 will be an examination of RGS generation chemistry for modified gas blends (i.e., CO2, N2, O2, H2, Ne) under different HVACP voltages and treatment times. Previous work has demonstrated that changing gas composition along with voltage changes RGS which can achieve shelf-life extension with no quality change on sensitive foods such as leafy greens. Track 3 will be optimization of HVACP treatment to extend the shelf-life of fresh produce, such as tomatoes, and provide an evaluation of quality, safety, and toxicology of treated food. HVACP can be generated using only air and a small amount of electricity (100 W or less). Using air as the fill gas will generate approximately 5,000 ppm of reactive nitrogen and reactive oxygen species at 80 kV. For many fresh produce applications HVACP treatment with air is a low cost option and is beneficial for extending shelf-life and improving safety. However some products, such as leafy greens, can be impacted by the RGS generated in air and therefore utilization of HVACP treatment using gas blends is desirable to create more beneficial RGS profiles. By changing HVACP gas composition the number and type of RGS can be increased to over 30,000 ppm and create unique gas chemistries (`signatures'). The hypothesis is that these tailored HVACP gas chemistries can deliver non-thermal RGS treatments that can selectively target and destroy bacteria, yeast, molds, mycotoxins, chemical contaminants, enzymes, or viruses without damaging the fresh produce or producing toxic compounds. The successful completion of these three research tracks will achieve the overall goal of expanding scientific understanding of HVACP, and demonstration of its potential application as a practical intervention technology for improving food safety and quality will potentially lead to broader industry adoption and a revolutionary change to preservation methods of fresh fruit and vegetables.