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The present work aims to study the effects of cold gas plasma on some quality parameters of apple slices belonging to four different cultivars (Pink Lady®, Fuji, Red Delicious and Modì®), with particular attention to polyphenoloxidase (PPO) inhibition and related changes in colour and visual quality. Upon plasma exposure a noticeable reduction of superficial browning was observed in all cultivars but not always proportionally to treatment time; the effect on PPO activity was very variable and not correlated to the effect on enzymatic browning. Textural parameters were affected by plasma treatments only in Red Delicious apples. Generally, the response of the tissue to the treatments was variable according to the cultivar considered. The results obtained in this study indicate the necessity of further investigation about consequences of plasma treatment on specific tissue physiology in order to choose the better treatment parameters, optimizing its effect for the specific final product. The application on cold plasma to minimally processed fruit and vegetable has shown a good potential for enzymatic browning inhibition making it an interesting alternative to traditional dipping methods. Nevertheless, the effect on the tissue to the exposure to plasma active particles is not fully known yet. For the industrial application of the treatment, the response for example of different cultivars to the treatment is of high importance, in the first place for the selection of the more appropriate raw material but also to eventually adapt the process parameters to the specificity of the matrix. • Fresh-cut apple of different cultivar was subjected to cold gas plasma treatment. • Generally enzymatic browning was inhibited not proportionally to treatment time. • Effect on PPO was variable and not consistent with enzymatic browning inhibition. • The effect of cold gas plasma treatment is strictly cultivar dependent. [ABSTRACT FROM AUTHOR]

Featured Application: The application of cold plasma to agricultural products has recently drawn considerable attention as a technology for microbial decontamination and product stabilization. However, for an industrial application, it is fundamental to understand its effect on quality and nutritional value. This study is a contribution to the increased knowledge on this issue. Cold atmospheric plasma (CAP) has shown good potentiality for the decontamination and stabilization of fresh fruit and vegetable products; however, information about its effect on nutritional quality is still scarce. The aim of this research was to evaluate the impact of a form of indirect treatment known as Dielectric Barrier Discharge (DBD) on apple slices—more specifically, the polyphenolic profile and antioxidant activity of fresh-cut Pink Lady apples. Atmospheric plasma was generated using air as feed gas, and directed to apple slices for up to 30 min. The effect of plasma treatment on physico-chemical parameters was mainly observed as a slight acidification of the tissue and reduction of browning after an extended period of exposure. The samples' phenolic profile was significantly affected after 10 min of treatment, both in quantitative (an approximately 20% increase) and qualitative terms, while with increasing exposure time a progressive decrease of all polyphenol classes was observed. The antioxidant activity, evaluated by different in-vitro methods, followed a similar trend, increasing after 10 min of processing and then decreasing. Results highlighted how plasma exposure promotes a metabolic response of the fresh tissue, and the importance of carefully controlling the exposure time in order to minimize the loss of nutritional properties. [ABSTRACT FROM AUTHOR]

The increasing demand for high quality and safe food led to important technological innovations in food processing. Cold plasma appears as an emerging technology that has demonstrated efficiency in the removal of microbial contamination from fresh and minimally processed food. In this study, the proteomic profile of Salmonella Enteritidis SE86 subjected to cold plasma treatment was investigated. The number of viable S. Enteritidis SE86 cells was analyzed at different time intervals upon exposure to cold plasma and approximately 100 μg of S. Enteritidis SE86 protein extracts were analyzed by Multidimensional Protein Identification Technology (MudPIT). The results demonstrated that no significant changes in cell counts were detected for up to 20 min exposure to cold plasma, and 2 log reduction was achieved after 60 min. Overall, 1096 proteins were identified, with 249 detected only in plasma-treated samples, and 9 exclusive in non-treated control samples. The proteins uniquely detected in cold plasma-treated cells that showed higher abundance were glyoxalase I, ABC transporter substrate-binding protein and transcriptional activator OsmE, followed by some oxidoreductases. Proteins related with carbohydrate and nucleotide metabolism were mostly overexpressed in cold plasma treated cells, suggesting energy metabolism was increased. [ABSTRACT FROM AUTHOR]

Cold plasma is an emerging non-thermal processing technology that could be used for large scale leaf decontamination as an alternative to chlorine washing. In this study the effect of an atmospheric cold plasma apparatus (air DBD, 15 kV) on the safety, antioxidant activity and quality of radicchio (red chicory, Cichorium intybus L.) was investigated after 15 and 30 min of treatment (in afterglow at 70 mm from the discharge, at 22 °C and 60% of RH) and during storage. Escherichia coli O157:H7 inoculated on radicchio leaves was significantly reduced after 15 min cold plasma treatment (−1.35 log MPN/cm 2 ). However, a 30 min plasma treatment was necessary to achieve a significant reduction of Listeria monocytogenes counts (−2.2 log CFU/cm 2 ). Immediately after cold plasma treatment, no significant effects emerged in terms of antioxidant activity assessed by the ABTS and ORAC assay and external appearance of the radicchio leaves. Significant changes between treated and untreated radicchio leaves are quality defects based on the cold plasma treatment. Atmospheric cold plasma appears to be a promising processing technology for the decontamination of leafy vegetables although some criticalities, that emerged during storage, need to be considered in future studies. [ABSTRACT FROM AUTHOR]

The efficacy of atmospheric plasma treatment on microbial decontamination of different kinds of food products is already known. Recently, new applications of this innovative technology have been proposed, in order to test the improvement of quality maintenance of minimally processed fruit and vegetables. Nevertheless, the knowledge on the modifications of functional and nutritional properties of minimally processed fruit is still scarce. The objective of this study was to evaluate the effect of atmospheric double barrier discharge (DBD) plasma treatment on the quality maintenance of fresh-cut kiwifruit. Treatments of 10 and 20 min per side were performed and their consequences were evaluated during four days of storage in controlled conditions by monitoring parameters related to visual quality, texture, chlorophyll, carotenoids and polyphenols. The in vitro antioxidant activity was evaluated through a multimodal approach, combining different assays for the analysis of antiradical activity and reducing activity of antioxidants. According to the obtained results, plasma treatments positively influenced the quality maintenance of the product, by improving colour retention and reducing the darkened area formation during storage, not inducing any textural change compared with the control. Plasma treatments caused an immediate slight loss of pigments, but a better retention during storage. No significant changes in antioxidants content and antioxidant activity were observed among treated samples and control ones. [ABSTRACT FROM AUTHOR]