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Plasma activated water (PAW) recently received much attention as an alternative food preservation method. However, its effects on food quality are still scarce. This study evaluates the effect of PAW processing time on bioactive compounds of rocket-salad leaves including: 18 phenolic compounds, vitamin C, riboflavin, nicotinic acid, and nicotinamide. Moreover, the impact of PAW on both antioxidant (DPPH) and peroxidase (POD) activities was also investigated. This was performed using HPLC-DAD, HPLC-MS/MS, and spectrophotometric analysis. All treatments induced non-significant increases in total phenolic contents. However, depending on processing time, significant increases or decreases of individual phenolic compounds were observed. PAW-10 and -20 increased the ascorbic acid content to 382.76 and 363.14 mg/100 g, respectively, compared to control (337.73 mg/100 g). Riboflavin and nicotinic acid contents were increased significantly in PAW-20 (0.53 and 1.26 mg/100), compared to control (0.32 and 0.61 mg/100 g, respectively). However, nicotinamide showed non-significant increase in all treatments. Antioxidant activity improved significantly only in PAW-20, while peroxidase activity was reduced up to 36% in the longest treatment. In conclusion, PAW treatment could be an effective technique for rocket decontamination since it positively influenced the quality of rocket, improving the retention of polyphenols and vitamins. [ABSTRACT FROM AUTHOR]

The present study investigates the application of annealing and plasma-activated water (PAW) for starch modification, as alternative methods compared to the chemical one. Native potato starch was subjected to PAW, annealing with distilled water (DW-ANN), and the combination of the two (PAW-ANN) at different incubation times (1, 4, 8, and 12 h). The changes in rheological, pasting, and thermal properties were evaluated. The results showed that all treatments promoted significant modifications of the investigated parameters. In particular, while the pasting properties of the potato starch remained unchanged after the PAW treatment, G' (elastic) and G" (viscous) of the PAW-treated starch were significantly (p < 0.05) higher than those of the native. DW-ANN significantly increased all rheological parameters and reduced peak viscosity, breakdown, and setback and significantly (p < 0.05) incremented pasting temperature, holding strength, and final viscosities of the potato starch may be due to cross-linking reaction. The combination of treatment (PAW-ANN) showed a synergistic effect leading to strong gel formation up to 4 h, while further treatment reduced the possibility of depolymerization. In conclusion, the combined treatment is a promising new green method to modify the properties of starch and improve its stability within a short treatment time. • Plasma-activated water and annealing were combined for potato starch modification. • Effect of incubation time was investigated for the first time. • All treatments increased the starch viscosity. • The thermal stability and the stability against retrogradation were increased. • The treatments showed a synergistic effect, allowing to reduce total processing time. [ABSTRACT FROM AUTHOR]

Featured Application: The actual emergency linked to the pandemic from SARS-CoV-2 brought about the need of a new critical control point (CCP) linked to the external packaging contamination of packaged foods. Therefore, cold plasma technology is of great interest in handling this new criticality as it can be applied in both the production and distribution steps of the food supply chain. The accidental contamination of food and food packaging surfaces with SARS-CoV-2 is of increasing concern among scientists and consumers, particularly in relation to fresh foods that are consumed without further cooking. The use of chemical sanitizers is often not suitable for these kinds of commodities; therefore, a non-thermal sanitation technology could help to increase safety in relation to the food supply chain. Cold plasma has proven to be a promising strategy for virus inactivation. This research is aimed at evaluating the ability of a cold plasma sanitation system to inactivate SARS-CoV-2 RNA on packaged foods. Two different plastic materials were investigated and subjected to 5- and 10-min exposure to plasma after experimental inoculum of the RNA. In addition to viral degradation, possible changes in the performance of the materials were evaluated. Shelf-life of the foods, after exposure of the packages to plasma, was also investigated. Results showed that 10 min of exposure was sufficient to almost completely eliminate the viral RNA from package surfaces. The treatment did not produce any significant variation in packaging material performance or the shelf-life of the tested packaged products, indicating the potentiality of this treatment for the decontamination of packaged products. [ABSTRACT FROM AUTHOR]

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]

This study investigated the effect of different CAP exposures on the activity of horseradish peroxidase (HRP) in phosphate buffer and in model systems with different concentrations of monosaccharides (glucose, fructose) and disaccharides (sucrose, trehalose) to evaluate the potential role of sugars in enzyme inactivation. Spectroscopic analyses (fluorescence, circular dichroism, UV–Vis absorption) were conducted to highlight structural modifications possibly responsible for HRP inactivation. In phosphate buffer, the inactivation of HRP by CAP resulted dependent on both the treatment time (up to 70% after 30 min) and ozone concentration in the chamber. HRP residual activity was fitted with a very good approximation by the Weibull model. Sugars reduced the CAP efficacy, and this effect was concentration-dependent and much higher for disaccharides than monosaccharides. UV and fluorescence spectra showed that sugars differently preserved HRP tertiary structure, hindering heme degradation and quenching of aromatic amino acids. Likewise, sugars differently affected the loss of secondary structures. These findings only partially explained the diverse protective effects of sugars on HRP. Other factors, such as the different sugars' abilities to quench plasma reactive species, reduce the system mobility, and stabilize proteins by preserving their hydration shell, were retained to play a role in the reduction of HRP inactivation. This study deepened the knowledge of the effect of CAP on peroxidase activity and demonstrated that the presence of mono and disaccharides, naturally found in fruits and vegetables and widely employed in food and beverage industries, can mitigate the inactivation and structural alterations induced by CAP on peroxidase enzymes. • Cold atmospheric plasma (CAP) can reduce the activity of horseradish peroxidase (HRP). • The inactivation efficiency depends on plasma exposure time and ozone concentration. • Cold atmospheric plasma affected the HRP tertiary and secondary structures. • Sugars reduced the CAP efficacy with a concentration-dependent effect. • Disaccharides protect more than monosaccharides the HRP activity and conformation. [ABSTRACT FROM AUTHOR]

Plasma-activated water (PAW), characterized by acidic pH and content of highly reactive species (nitrite, nitrate, hydrogen peroxide, ozone), was applied as a strategy to modify the structure and functionality of potato, normal maize, and waxy maize starches. PAW was generated with a corona discharge at 15 kV, 5 kHz for 1 min. Starches were mixed with PAW just after generation for 20 min and then dried. Native and PAW-treated starches were evaluated for rheological, pasting, gelatinization, and hydration properties, and subjected to Fourier-transform infrared (FTIR) spectroscopy. Results showed significant (p < 0.05) changes in almost all the considered parameters, dependent on the starch characteristics. While an increase in most pasting and rheological parameters and gel hardness was observed for normal maize and potato starches, the opposite result was found for waxy maize. FTIR results indicated significant changes in functional groups related to the ability to bind water for all starches. The results obtained in this study highlighted PAW as a promising novel and green alternative method to modify the properties of starch; however further research needs to be tailored to the specific properties of the raw material. [Display omitted] • Rheological, pasting properties and hydration parameters were changed by PAW. • The viscosity of waxy maize decreased, while potato and normal maize increased. • The solubility of starches increased with PAW treatment. • Different degrees of modification of starches were observed. • The current study will be helpful to use PAW as an alternative noble green technology for starch modification. [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 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]