Fresh produce, like fruits and vegetables, are important sources of nutrients and health‐promoting compounds. However, incidences of foodborne outbreaks associated with fresh produce often occur; it ...is thus important to develop and expand decay‐control technologies that can not only maintain the quality but can also control the biological hazards in postharvest, processing, and storage to extend their shelf life. It is under such a situation that plasma‐mediated treatments have been developed as a novel nonthermal processing tool, offering many advantages and attracting much interest from researchers and the food industry. This review summarizes recent developments of cold plasma technology and associated activated water for shelf life extension of fresh produce. An overview of plasma generation and its physical–chemical properties as well as methods for improving plasma efficiency are first presented. Details of using the technology as a nonthermal agent in inhibiting spoilage and pathogenic microorganisms, inactivating enzymes, and modifying the barrier properties or imparting specific functionalities of packaging materials to extend shelf life of food produce are then reviewed, and the effects of cold plasma‐mediated treatment on microstructure and quality attributes of fresh produce are discussed. Future prospects and research gaps of cold plasma are finally elucidated. The review shows that atmospheric plasma‐mediated treatments in various gas mixtures can significantly inhibit microorganisms, inactive enzyme, and modify packaging materials, leading to shelf life extension of fresh produce. The quality attributes of treated produce are not compromised but improved. Therefore, plasma‐mediated treatment has great potential and values for its application in the food industry.
The effect of cold plasma (CP) treatment on the degradation of anilazine fungicide in tomato juice was investigated. Anilazine solution of 5 mg/L was added to tomato juice samples and treated using a ...dielectric barrier discharge (DBD) cold plasma (CP) system with exposure times of 0, 1, 2, 3, 4 and 5 min. The gas chromatography‐mass spectrometry (GC‐MS) results showed that the reduction in anilazine in the tomato juice achieved 47% and 65% after treatments for 4 min and 5 min, respectively. The concentration of anilazine decreased significantly (P ≤ 0.05) with an increase in treatment time. Analysis of the quality attributes of tomato juice treated for 5 min showed that the quality of the treated juice remained acceptable with a slight decrease in pH from 4.28 to 4.18, an increase in total soluble solids (TSS) from 5.70 to 6.70 ◦Brix, an increase in the browning index from 2.35 to 4.54, a very low (but within the acceptable limit) total colour difference, and only minor changes in antioxidant capacity, total flavonoid and total phenolic content, as compared with the control samples. These results indicated that DBD cold plasma treatment could be an effective and rapid technique to degrade pesticide residues for the fruit juice industry.
The overall summary of this study was presented in the graphical , which shows that 5 min treatment time using DBD gave the best decontamination of anilazine fungicide residues in tomato juice. Also, the structural breakdown of anilazine fungicide after treatment with plasma reactive oxygen species was presented as a possible degradation pathway.
In recent years, applications of cold plasma treatments have shown high efficiency in sterilization of fresh fruit and vegetables. With encouraging results, development of this technique focuses on ...influences of cold plasma on the quality attributes of these fresh produce. More studies found that the quality attributes are maintained in an acceptable range or can even be improved under certain plasma treatment conditions. This review provides an overview of the multiple effects of cold plasma on the fresh produce, in terms of physical, chemical and physiological aspects. Besides, the possible mechanisms of how plasma influences these quality attributes is elaborated, which is useful for further modification and improvement of the plasma technology, so that quality enhancement and shelf life extension can be achieved. Future trends in the development of cold plasma technology are also presented. Cold plasma treatment is a potential technology for treating fresh fruit and vegetables to enhance their quality and extend their shelf life. However, knowledge of the effects of cold plasma on the quality changes of fresh fruit and vegetables is still limited. Therefore, there is a need for future studies to understand the mechanisms of plasma effects on controlling the interactions between plasma and food products in order to realize the early adoption of the technology to the food industry.
(
is a major causative agent of foodborne illness worldwide. Cold plasma (CP) was used to inactivate
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
was positively correlated with the treatment time and voltage.
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
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
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
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.
Microwave processing techniques have been extensively used in the food industry due to its significant reduction in cooking time and energy consumption. Microwave processing technologies such as ...microwave drying, heating and sterilizing play a significant role in food quality and safety control. However, few reviews have been published in recent years summarizing the latest developments in the application of microwave technology in the food industry.
This review focuses on recent applications of microwave processing technologies including microwave drying, heating, and sterilizing in fruit (banana, apple, olive, sour cherries, pomegranate arils, blueberries, kiwifruit, aronia, strawberry, and grape tomato), vegetables (potato, bamboo shoot, purslane leaves, onion, green bean, pumpkin, eggplant, edamame, sea tangle, garlic, kale, red cabbage, tomato, cassava, lentils, chickpea, broccoli, Brussels sprouts, cauliflower, jalapeño peppers, and coriander foliage), and meat products (sardine fish, restructured silver carp slices, sea cucumber, beef semitendinosus muscle, bovine supraspinatus muscle, camel longissimus dorsi muscle, foal meat, bovine gluteus medium muscle, chicken steak, mature cows semimembranosus and semitendinosus muscles, kavurma (a ready-to-eat meat product), salmon, cod, drumettes, and beef slices), changes in product quality as affected with microwave processing are discussed in details, and future directions of research are presented.
Microwave drying has the advantages of low energy consumption and high efficiency as compared to conventional drying, while producing more porous structure of foods. Microwave drying usually combines with other conventional drying to enhance the quality of a food product. Compared with the traditional method, microwave heating or cooking can generally retain higher levels of bioactive components, antioxidant activity and attractive color of vegetables, while microwave cooking with water can cause a serious drop in nutrients due to leaching and thermal liability. Microwave sterilization has the capacity to completely inactivate microorganisms and effectively destroy enzyme activity, and less effect on antioxidant activity, texture and color of food products compared with conventional pasteurization.
•Applications of microwave treatments in fruit, vegetables and meat are presented.•The effects of microwave processing on food product quality are discussed.•Moisture migration and distribution during microwave drying is reported.•Microwave heating of food materials and its characteristics are reviewed.•The effects of microwave sterilization on microorganisms are discussed.
Cold plasma (CP) is an emerging technology, which has attracted the attention of scientists globally. It was originally developed for ameliorating the printing and adhesion properties of polymers ...plus a variety of usage domains in electronics. In the last decade, its applications were extended into the food industry as a powerful tool for non-thermal processing, with diverse forms for utilization.
This review presents an overview of recent studies on the application of cold plasma in the food industry. Specific areas discussed include microbial decontamination of food products, packaging material processing, functionality modification of food materials and dissipation of agrochemical residues. The application of CP has also been expanded into areas, such as hydrogenation of edible oils, mitigation of food allergy, inactivation of anti-nutritional factors, tailoring of seed germination performance and effluent management. In addition, the paper provides a summary of plasma chemistry and sources, factors influencing plasma efficiency and strategies for augmentation. Furthermore, key areas for future research are highlighted and salient drawbacks are discussed.
The recent studies conducted on the interaction of reactive species with food contact surfaces establish plasma processing as an eco-friendly technique with minimal changes to food products, making it a befitting alternative to traditional techniques. Active researches focused on up-scaling for commercial applications are urgently required.
•Cold plasma technology has continued to gain positive ratings in the food industry.•Interaction of reactive species with food materials minimally affects quality parameters.•New pathways for their utilization during food processing were highlighted.•Future research pathways to facilitate their recognition were proposed.
Natural edible films have recently gained a lot of interests in future food packaging. Polysaccharides and proteins in edible materials are not toxic and widely available, which have been confirmed ...as sustainable and green materials used for packaging films due to their good film-forming abilities. However, polysaccharides and proteins are hydrophilic in nature, they exhibit some undesirable material properties. Cold plasma (CP), as an innovative and highly efficient technology, has been introduced to improve the performance of polysaccharides and proteins-based films. This review mainly presents the basic information of polysaccharides and proteins-based films, principles of CP modified biopolymer films, and the effects of CP on the structural changes including surface morphology, surface composition, and bulk modification, and properties including wettability, mechanical properties, barrier properties, and thermal properties of polysaccharides, proteins, and polysaccharide/protein composite-based films. It is concluded that the CP modified performances are mainly depending on the polysaccharides and proteins raw materials, CP generation types and treatment conditions. The existing difficulties and future trends are also discussed. Despite natural materials currently not fully substitute for traditional plastic materials, CP has exhibited an effective solution to shape the future of natural materials for food packaging.
Food endogenous enzymes have impacts on color, texture and flavor of foods during food processing or preservation. Cold plasma is a novel non-thermal food processing technology, which has been ...extensively studied for contamination elimination and shelf life extension of foods. Particularly, much work has been reported about the effects of cold plasma on enzyme activities and alterations about enzymes conformational structures. It is thus necessary to understand the mechanisms of actions and applications of cold plasma technology in the conformation of food endogenous enzymes. This review focuses on the applications of cold plasma for the inactivation of various endogenous enzymes, including peroxidase, polyphenol oxidase, lysozyme, α-chymotrypsin, alkaline phosphatase, and pectin methylesterase. The activations of several enzymes, such as superoxide dismutase, catalase, and lipase, by cold plasma are also discussed. In addition, this review highlights the transformation of conformational structures including primary and spatial structures induced by chemical reactive species during cold plasma treatments, such as reactive oxygen species and reactive nitrogen species, especially, active sites consisting of prosthetic group and specific amino acids are demonstrated. Both extrinsic and intrinsic factors affecting cold plasma treatments are also described. In general, cold plasma exhibits the ability to activate or inactivate enzymes activities with affecting the conformational structures of enzyme. Further studies should be focused on exploration at molecular level for providing more insight on the interaction mechanism. In addition, equipment and process parameters of cold plasma operation for different fresh food products should be optimized for achieving appropriate control on enzyme variation and obtaining maximum efficiency.
Tropomyosin (TM) is a major allergen in crustaceans, which often causes allergy and is fatal to some consumers. Currently, the most effective treatment is to avoid ingesting TM, although most adverse ...events occur in accidental ingestion. In this review, the molecular characterization, epitopes, cross‐reactivity, and pathogenesis of TM are introduced and elucidated. Modification of TM by traditional processing methods such as heat treatment and enzymatic hydrolysis, and innovative processing technologies including high‐pressure treatment, cold plasma (CP), ultrasound, pulsed electric field (PEF), pulsed ultraviolet, microwave and irradiation are discussed in detail. Particularly, enzymolysis, PEF, and CP technologies show great potential for modifying TM and more studies are needed to verify their effectiveness for the seafood industry. Possible mechanisms and the advantages/disadvantages of these technologies for the mitigation of TM allergenicity are also highlighted. Further work should be conducted to investigate the allergenicity caused by protein segments such as epitopes, examine the interaction sites between the allergen and the processing techniques and reveal the reduction mechanism of allergenicity.
Aims
The aim of the current study was to investigate the effect of plasma‐mediated oxidative stress on the post‐treatment viability of Listeria monocytogenes at the physiological and molecular ...levels.
Methods and Results
107 CFU/ml L. monocytogenes in 10 ml phosphate‐buffered saline (PBS) was treated with atmospheric non‐thermal plasma for 0, 30, 60, 90 and 120 s respectively. Optical diagnostics using optical emission spectroscopy (OES) confirmed that dielectric barrier discharge (DBD) plasma was a significant source of ample exogenous reactive oxygen and nitrogen species (RONS). The development of extracellular main long‐lived species was associated with plasma exposure time, accompanied by a massive accumulation of intracellular ROS in L. monocytogenes (p < 0.01). With the exception of virulence genes (hly), most oxidation resistance genes (e.g. sigB, perR, lmo2344, lmo2770 and trxA) and DNA repair gene (recA) were upregulated significantly (p < 0.05). A visible fragmentation in genomic DNA and a decline in the secretion of extracellular proteins and haemolytic activity (p < 0.01) were noticed. The quantitate oxygen consumption rates (OCRs) and extracellular acidification rates (ECARs) confirmed the viability attenuation from the aspect of energy metabolism. Survival assay in a real food system (raw milk) further suggested not only the viability attenuation, but also the resuscitation potential and safety risk of mild plasma‐treated cells during post‐treatment storage.
Conclusion
DBD plasma had the potential to inactivate and attenuate the virulence of L. monocytogenes, and it was recommended that plasma exposure time longer than 120 s was more suitable for attenuating viability and avoiding the recovery possibility of L. monocytogenes in raw milk within 7 days.
Significance and Impact of the Study
The current results presented a strategy to inactivate and attenuate the viability of L. monocytogenes, which could serve as a theoretical basis for better application of non‐thermal plasma in food in an effort to effectively combat foodborne pathogens.
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