Atmospheric cold plasma (ACP) treatment improved in-package shelf-life of strawberry fruit

Effects of different cold plasma treatments on chemical composition, phenolics bioaccessibility and microbiota of edible red mini-roses

This study evaluated the effect of dielectric barrier discharge (DBD) and glow discharge (glow) cold plasma treatments in color, sugars, organic acids, phenolics (concentration and bioaccessibility), antioxidant activity, volatiles, and microbiota of edible mini-roses. Plasma treatments did not affect the flowers' color, while they increased organic acids and phenolics. Flowers treated with DBD had a higher concentration of most phenolics, including hesperidin (84.04 μg/g) related to antioxidant activity, and a higher mass fraction of most volatiles, including octanal (16.46% after 5 days of storage). Flowers treated with glow had a higher concentration of pelargonidin 3,5-diglucoside (392.73 μg/g), greater bioaccessibility of some phenolics and higher antioxidant activity. Plasma treatments reduced the microbiota diversity in mini-roses. Regardless of the plasma treatment, phylum Proteobacteria, family Erwiniaceae, and genus Rosenbergiella were the dominant groups. Results indicate plasma treatments as promising technologies to improve the quality and increase phenolic and specific volatile compounds in mini-roses.

In-package cold plasma treatment to extend the shelf life of food

Conventional food preservation methods such as heat treatment, irradiation, chemical treatment, refrigeration, and coating have various disadvantages, like loss of food quality, nutrition, and cost-effectiveness. Accordingly, cold plasma is one of the new technologies for food processing and has played an important role in preventing food spoilage. Specifically, in-package cold plasma has become a modern trend to decontaminate, process, and package food simultaneously. This strategy has proven successful in processing various fresh food ingredients, including spinach, fruits, vegetables, and meat. In particular, cold plasma treatment within the package reduces the risk of post-processing contamination. Cryoplasm decontamination within packaging has been reported to reduce significantly the microbial load of many foods' spoilage-causing pathogens. However, studies are needed to focus more on the effects of in-package treatments on endogenous enzyme activity, pest control, and removal of toxic pesticide residues. In this review, we comprehensively evaluated the efficacy of in-package low-temperature plasma treatment to extend the shelf life of various foods. The mechanisms by which cold plasma interacts with food were investigated, emphasizing its effects on pathogen reduction, spoilage mitigation, and surface modification. The review also critically assessed the effects of the treatments on food quality, regulatory considerations, and their potential as viable technologies to improve food safety and packaging life. In-package cold plasma treatment could revolutionize food storage when combined with other sophisticated technologies such as nanotechnology.

Effects of Litsea cubeba Essential Oil-Chitosan/Corn Starch Composite Films on the Quality and Shelf-Life of Strawberry (Fragaria × ananassa)

In this work, we have developed a composite chitosan film incorporating the Litsea cubeba essential oil (LCEO) and starch with good physical properties, and investigated the effect of coating strawberries with this composite film. The best formula of the LCEO/chitosan/corn starch/glycerol (LCEO/CH/CS/gly) composite films is 0.25% LCEO, 2.75% CH, 0.40% corn starch, and 0.75% glycerol. Coating strawberries with CH/CS/gly film or LCEO/CH/CS/gly films resulted in significantly lower respiration intensity and a slower decay rate, much slower decreases in the firmness, and reductions in the sugar and ascorbic acid content of the fruit during storage (p < 0.05). The coatings also led to a much slower accumulation of malondialdehyde and anthocyanins (p < 0.05). The LCEO/CH/CS/gly film was generally more effective than the CH/CS/gly film; however, the effect was more obvious in the later stages of storage. Thus, coating strawberries with CH/CS/gly film or LCEO/CH/CS/gly film can be a viable method for extending the shelf-life of the fruit.

Synergistic Microbial Inhibition and Quality Preservation for Grapes through High-Voltage Electric Field Cold Plasma and Nano-ZnO Antimicrobial Film Treatment

To ensure their quality and safety, harvested grapes should be protected from microbial contamination before reaching consumers. For the first time, this study combined high-voltage electric field cold plasma (HVEF-CP) and nano-ZnO antimicrobial film to inhibit microbial growth on grapes. Using the response surface method, the optimal processing parameters of HVEF-CP (a voltage of 78 kV, a frequency of 110 Hz, and a time of 116 s) were identified to achieve 96.29% sterilization. The effects of co-processing with HVEF-CP and nano-ZnO antimicrobial film on the quality and safety of grapes during storage were explored. When stored at 4 °C and 20 °C, the co-processing extended the shelf life of grapes to 14 and 10 days, respectively. The co-processing increased the sterilization rate to 99.34%, demonstrating a synergistic effect between the two methods to ensure not only the safety of grapes but also their nutrient retention during storage. This novel approach is promising for the efficient, safe, and scalable preservation of grapes as well as other foods.

Sonochemical treatment of packaging materials for prolonging fresh produce shelf life

Packaging bags made of polyethylene (PE) were sonochemically coated with edible antibacterial nanoparticles of chitosan (CS). In this work, the nanoparticles (NPs) were deposited on the surface of PE packaging bags by applying sonication waves on an acetic solution of chitosan. The characterization of CS NPs and PE bags was conducted by physicochemical techniques. The results showed that the coated bags had longer freshness than the uncoated ones. Furthermore, the characterization of cucumber, mushroom, and garlic placed into coated and uncoated PE bags was conducted by monitoring various parameters such as mass loss, total soluble solids, pH, and visual inspection. The study revealed that the PE bags coated with CS NPs showed a noticeable result in extending the shelf life of fresh produce. Finally, the antibacterial activity of PE bags was evaluated against various bacterial species. Hence, the PE bags coated with CS NPs could be a promising candidate for elongating the shelf life of packaged fresh produce.

Review of Plasma Processing for Polymers and Bio-Materials Using a Commercial Frequency (50/60 Hz)-Generated Discharge

This manuscript introduces the properties and diverse applications of plasma generated using commercial frequencies of 50/60 Hz. Commercial frequency (CF) derived plasma exhibits characteristics similar to DC discharge but with an electrical polarity and a non-continuous discharge. Due to the low-frequency nature, the reactor configurations usually are capacitively coupled plasma type. The advantages of this method include its simple power structure, low-reaction temperature, and low substrate damage. The electrical polarity can prevent charge buildup on the substrates and deposited films, thereby reducing substrate damage. The simple, low-cost, and easy-to-operate power structure makes it suitable for laboratory-scale usage. Additionally, the various applications, including plasma-enhanced vapor deposition, sputtering, dielectric barrier discharge, and surface modification, and their outcomes in the CF-derived plasma processes are summarized. The conclusion drawn is that the CF-derived plasma process is useful for laboratory-scale utilization due to its simplicity, and the results of the plasma process are also outstanding.

Edible coating enriched with cinnamon oil reduces the oxidative stress and improves the quality of strawberry fruit stored at room temperature

BACKGROUND

The present study aimed to assess the impact of a starch/gelatine coating containing cinnamon oil on selected quality attributes and redox status in strawberry fruit stored at room temperature (72 h).

RESULTS

Research showed that the application of cinnamon oil to an edible coating allows an improvement of the quality of strawberry fruit stored at room temperature. The cinnamon oil coating inhibits the development of yeast and mould, and reduces loss of soluble solids and ascorbic acid during 72 h storage at room temperature. Moreover, the coating with cinnamon oil clearly reduced the level of oxidative stress, which was manifested by a lower level of reactive oxygen species, as well as a lower activity of antioxidant enzymes. The elimination of oxidative stress in the cinnamon oil-coated fruit also contributed to lower PARP1 mRNA expression, inhibiting the metabolism of NAD⁺ and reducing ATP losses.

CONCLUSION

The coating of strawberry fruit with a starch/gelatine biofilm containing cinnamon oil is an effective method for delaying postharvest senescence of fruit and the storage degradation of tissue. © 2023 Society of Chemical Industry.

Emerging Postharvest Technologies to Enhance the Shelf-Life of Fruit and Vegetables: An Overview

Quality losses in fresh produce throughout the postharvest phase are often due to the inappropriate use of preservation technologies. In the last few decades, besides the traditional approaches, advanced postharvest physical and chemical treatments (active packaging, dipping, vacuum impregnation, conventional heating, pulsed electric field, high hydrostatic pressure, and cold plasma) and biocontrol techniques have been implemented to preserve the nutritional value and safety of fresh produce. The application of these methodologies after harvesting is useful when addressing quality loss due to the long duration when transporting products to distant markets. Among the emerging technologies and contactless and non-destructive techniques for quality monitoring (image analysis, electronic noses, and near-infrared spectroscopy) present numerous advantages over the traditional, destructive methods. The present review paper has grouped original studies within the topic of advanced postharvest technologies, to preserve quality and reduce losses and waste in fresh produce. Moreover, the effectiveness and advantages of some contactless and non-destructive methodologies for monitoring the quality of fruit and vegetables will also be discussed and compared to the traditional methods.

Decontamination potential of date palm fruit via non-thermal plasma technique

The potential of the surface dielectric barrier discharge technique (SDBD) was evaluated to decontaminate the date palm fruit. Preliminary investigations emphasized that Aspergillus niger fungus was predominant in most date samples as a post-harvest infestation. The influence of SDBD techniques on the viability of A. niger isolated from date varieties was investigated and documented. Physical and chemical characterizations of treated dates were assessed, and statistical correlation coefficients were calculated and elucidated. A 4 log₁₀ reduction of A. niger radial growth was observed at 3 min exposure/15 days of incubation. Simultaneous reductions in pH, water activity, and moisture content of treated dates were observed when compared to untreated dates. Statistical analysis showed a positive correlation between physical and chemical variables with the viability of A. niger in treated samples. Therefore, we believe that SDBD treatment will be a promising technique for decontaminating date fruits from attacked fungi, which will positively impact sustainable food security and consumer health.

Effects of resveratrol treatment on quality and antioxidant properties of postharvest strawberry fruit

Strawberry fruit is one of people's favorite fruits. It has high nutritional value and health care effects. Strawberries lose their edible value quickly after being picked because of their thin skin, which is easily damaged. In order to find a method to maintain the quality of strawberries, the effects of resveratrol treatment on the nutritional quality and antioxidant metabolism of strawberry fruit were studied. The result indicated that 100 μM resveratrol was the optimal concentration to delay the occurrence of decay. Strawberry fruit treated with resveratrol delayed the decrease in firmness, total soluble solids (TSS), total phenolics content (TPC), total flavonoid content (TFC), vitamin C (Vc) content,1,1-diphenyl-2-picrylhydrazyl (DPPH), and 2,2'-azino-bis (3-ethylbezothi- azot-hiazoline-6-sulfonic acid) (ABTS) radical scavenging capacities. The malondialdehyde (MDA) content, hydrogen peroxide (H₂ O₂ ) content, and superoxide anion (O₂ ^•- ) production of control fruit were significantly higher than those of treated fruit. Strawberry fruit treated with resveratrol also increased the activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) during storage. Therefore, resveratrol has been proved to effectively improve the nutritional quality and antioxidant properties of strawberry fruit. PRACTICAL APPLICATIONS: Strawberry fruit is rich in nutrients, which is beneficial to human health. But strawberry fruit has high water content and soft tissue, which is easy to be damaged and decayed. Therefore, it is particularly important to find a way to maintain strawberry fruit quality. In this study, resveratrol has good antioxidant, health care, and antibacterial properties. Resveratrol treatment can maintain the nutritional quality of strawberry fruit and can be used as an effective method for strawberry fruit preservation.

Recent trends and technological development in plasma as an emerging and promising technology for food biosystems

The rising need for wholesome, fresh, safe and “minimally-processed” foods has led to pioneering research activities in the emerging non-thermal technology of food processing. Cold plasma is such an innovative and promising technology that offers several potential applications in the food industry. It uses the highly reactive, energetic and charged gas molecules and species to decontaminate the food and package surfaces and preserve the foods without causing thermal damage to the nutritional and quality attributes of food. Cold plasma technology showed promising results about the inactivation of pathogens in the food industry without affecting the food quality. It is highly effective for surface decontamination of fruits and vegetables, but extensive research is required before its commercial utilization. Recent patents are focused on the applications of cold plasma in food processing and preservation. However, further studies are strongly needed to scale up this technology for future commercialization and understand plasma physics for getting better results and expand the applications and benefits. This review summarizes the emerging trends of cold plasma along with its recent applications in the food industry to extend shelf life and improve the quality of food. It also gives an overview of plasma generation and principles including mechanism of action. Further, the patents based on cold plasma technology have also been highlighted comprehensively for the first time.

Impacts of cold plasma treatment on physicochemical, functional, bioactive, textural, and sensory attributes of food: A comprehensive review

Cold plasma processing is a technique that uses electricity and reactive carrier gases, such as oxygen, nitrogen, or helium, to inactivate enzymes, destroy microorganisms, preserve food, and maintain quality without employing chemical antimicrobial agents.The review collates the latest information on the interaction mechanism and impact of non-thermal plasma, as an emerging processing technology, on selected physical properties, low-molecular-weight functional components, and bioactive properties of food. Significant changes observed in the physicochemical and functional properties. For example, changes in pH, total soluble solids, water and oil absorption capacities, sensory properties such as color, aroma, and texture, bioactive components (e.g., polyphenols, flavonoids, and antioxidants), and food enzymes, antinutrients, and allergens were elaborated in the present manuscript. It was highlighted that the plasma reactive species result in both constructive and antagonistic outcomes on specific food components, and the associated mechanism was different in each case. However, the design's versatility, characteristic non-thermal nature, better economic standards, and safer environmental factors offer matchless benefits for cold plasma over conventional processing methods. Even so, a thorough insight on the impact of cold plasma on functional and bioactive food constituents is still a subject of imminent research and is imperative for its broad recognition as a modern non-conventional processing technique.

Evaluation of the Effects of Cold Plasma on Cell Membrane Lipids and Oxidative Injury of Salmonella typhimurium

Salmonella typhimurium (S. typhimurium) is a major causative agent of foodborne illness worldwide. Cold plasma (CP) was used to inactivate S. typhimurium and to investigate the effect of CP on cell membrane lipids and oxidative injury of cells. Results indicated that the inactivation effect of CP on S. typhimurium was positively correlated with the treatment time and voltage. S. typhimurium was undetectable (total number of surviving colonies <2 log CFU/mL) after 5 min treatment with the voltage of 50 V. CP treatment caused damage to the cell membrane of S. typhimurium and the leakage of cell contents, and the relative content of unsaturated fatty acids in cell membrane decreased. Cell membrane lipids were oxidized; the malondialdehyde content increased from 0.219 nmol/mL to 0.658 nmol/mL; the catalase activity of S. typhimurium solution increased from 751 U/mL to 2542 U/mL; and the total superoxide dismutase activity increased from 3.076 U/mL to 4.54 U/mL, which confirmed the oxidative damage in S. typhimurium cell membrane caused by CP treatment. It was demonstrated that the potential application of plasma-mediated reactive oxygen species is suitable for destroying the structures of the cell membrane and ensuring the microbial safety of fresh food samples.

Cold Plasma Processing on Fruits and Fruit Juices: A Review on the Effects of Plasma on Nutritional Quality

This review aims to present the effects of cold plasma technology on the nutritional quality of fruits and fruit juices. This review focuses on the chemical changes induced by plasma on several bioactive compounds, such as sugars, starch, lipids, vitamins, phenolic compounds, carotenoids, and anthocyanins. The main plasma-reacting species that reacts with fruit compounds are presented and discussed. The review presents the mechanisms that lead to the improvement and degradation of the main compounds, showing both the advantages and disadvantages of cold plasma technology.

Making salty cucumbers and honeyed apples by applying the sonochemical method

Sonochemistry was applied in the last few years for coating surfaces of various substrates for imparting desired properties to the surface. In the current paper the coating of cucumbers with NaCl nanoparticles and apples with honey nanoparticles was accomplished by applying the sonochemical method. In both coating the nanoparticles were deposited from aqueous solutions. The products were characterized by Inductively coupled plasma, Dynamic light scattering, Scanning electron microscopy, and Nuclear magnetic resonance.

Applications of Cold Atmospheric Pressure Plasma Technology in Medicine, Agriculture and Food Industry

In recent years, cold atmospheric pressure plasma (CAPP) technology has received substantial attention due to its valuable properties including operational simplicity, low running cost, and environmental friendliness. Several different gases (air, nitrogen, helium, argon) and techniques (corona discharge, dielectric barrier discharge, plasma jet) can be used to generate plasma at atmospheric pressure and low temperature. Plasma treatment is routinely used in materials science to modify the surface properties (e.g., wettability, chemical composition, adhesion) of a wide range of materials (e.g., polymers, textiles, metals, glasses). Moreover, CAPP seems to be a powerful tool for the inactivation of various pathogens (e.g., bacteria, fungi, viruses) in the food industry (e.g., food and packing material decontamination, shelf life extension), agriculture (e.g., disinfection of seeds, fertilizer, water, soil) and medicine (e.g., sterilization of medical equipment, implants). Plasma medicine also holds great promise for direct therapeutic treatments in dentistry (tooth bleaching), dermatology (atopic eczema, wound healing) and oncology (melanoma, glioblastoma). Overall, CAPP technology is an innovative, powerful and effective tool offering a broad application potential. However, its limitations and negative impacts need to be determined in order to receive regulatory approval and consumer acceptance.