Cold Plasma: A Sustainable Innovation for Enhancing Polyphenol Levels
Subject Areas : Nutraceutical Foods and Bioactive Extracts (Nutraceutic Foods Bioact. Ext.)
Saeedeh Karimlar
1
*
,
Zahra Teymouri
2
,
Neda Kabiri
3
1 - دانشکده کشاورزی دانشگاه تربیت مدرس
2 - PhD student in Food Science and Technology, Department of Food Science and Technology, College of Agriculture, Isfahan University of Technology, Isfahan, Iran
3 - Department of Food Science and Technology, Safadasht Branch, Islamic Azad University, Tehran, Ira
Keywords: Cold plasma, Bioactive compound, Green extraction, Polyphenols,
Abstract :
Cold plasma treatment, an eco-friendly, non-thermal technology that apply electricity and reactive gases like oxygen, nitrogen, and helium, is a promising innovation for diverse industries, particularly in the food sector. This approach deactivates enzymes, eliminates microorganisms, extends the shelf life of food, and preserves its quality. More importantly, it amplifies the presence of bioactive compounds in food products, such as flavonoids, polyphenols, and antioxidants. However, despite the rising interest in cold plasma applications, a comprehensive understanding of its impact on bioactive compounds remains a critical area for further research. This is where your role as researchers, food scientists, and professionals in the food processing industry becomes crucial. Recent studies have unveiled that pre-treating food products with cold plasma can significantly enhance the extraction of bioactive compounds, leading to heightened yields and improved nutritional value.
Abdi, S., Moslehishad, M. and Dejam, L., 2020. Effect of atmospheric pressure floating-electrode dielectric-barrier discharge (FE-DBD) plasma on microbiological and chemical properties of Nigella sativa L. Journal of Basic Research in Medical Sciences, 7(1), pp.61-69.
Albertos, I., Martín-Diana, A., Cullen, P.J., Tiwari, B.K., Ojha, S.K., Bourke, P., Álvarez, C. and Rico, D., 2017. Effects of dielectric barrier discharge (DBD) generated plasma on microbial reduction and quality parameters of fresh mackerel (Scomber scombrus) fillets. Innovative Food Science & Emerging Technologies, 44, pp.117-122.
Araújo Bezerra, J., Lamarão, C.V., Sanches, E.A., Rodrigues, S., Fernandes, F.A., Ramos, G.L.P., Esmerino, E.A., Cruz, A.G. and Campelo, P.H., 2023. Cold plasma as a pre-treatment for processing improvement in food: A review. Food Research International, 167, p.112663.
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Dantas, A.M., Batista, J.D.F., dos Santos Lima, M., Fernandes, F.A., Rodrigues, S., Magnani, M. and Borges, G.D.S.C., 2021. Effect of cold plasma on açai pulp: Enzymatic activity, color and bioaccessibility of phenolic compounds. Lwt, 149, p.111883
Elenilson, G., Alves Filho, Edy S., de Brito, Sueli Rodrigues., 2020. Chapter 8 - Effects of cold plasma processing in food components, Editor(s): Daniela Bermudez-Aguirre, Advances in Cold Plasma Applications for Food Safety and Preservation, Academic Press, Pages 253-268
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Gan, Z., Feng, X., Hou, Y., Sun, A. and Wang, R., 2021. Cold plasma jet with dielectric barrier configuration: Investigating its effect on the cell membrane of E. coli and S. cerevisiae and its impact on the quality of chokeberry juice. Lwt, 136, p.110223.
Grzegorzewski, F., Ehlbeck, J., Schlüter, O., Kroh, L.W. and Rohn, S., 2011. Treating lamb’s lettuce with a cold plasma–Influence of atmospheric pressure Ar plasma immanent species on the phenolic profile of Valerianella locusta. LWT-Food Science and Technology, 44(10), pp.2285-2289.
Hu, J., Chen, J., Zheng, Y., Huang, J., Xie, K., Li, Y., Peng, S., Chen, J. and Deng, S., 2023. Effect of atmospheric cold plasma treatment modes on the quality of red shrimp (Solenocera crassicornis) during cold chain storage. LWT, 190, p.115543.
Kim, J.E., Oh, Y.J., Won, M.Y., Lee, K.S. and Min, S.C., 2017. Microbial decontamination of onion powder using microwave-powered cold plasma treatments. Food Microbiology, 62, pp.112-123.
Koddy, J.K., Miao, W., Hatab, S., Tang, L., Xu, H., Nyaisaba, B.M., Chen, M. and Deng, S., 2021. Understanding the role of atmospheric cold plasma (ACP) in maintaining the quality of hairtail (Trichiurus Lepturus). Food Chemistry, 343, p.128418.
Kumar, S., Pipliya, S. and Srivastav, P.P., 2023. Effect of cold plasma on different polyphenol compounds: A review. Journal of Food Process Engineering, 46(1), p.e14203.
Lacombe, A., Niemira, B.A., Gurtler, J.B., Fan, X., Sites, J., Boyd, G. and Chen, H., 2015. Atmospheric cold plasma inactivation of aerobic microorganisms on blueberries and effects on quality attributes. Food microbiology, 46, pp.479-484.
Li, M., Li, X., Han, C., Ji, N., Jin, P. and Zheng, Y., 2019. Physiological and metabolomic analysis of cold plasma treated fresh-cut strawberries. Journal of Agricultural and Food Chemistry, 67(14), pp.4043-4053.
Liu, X., Chen, X., Ou, Y., Li, F., Jiao, Y. and Shi, H., 2024. Pathogens inactivation and preservation of Pacific white shrimp by atmospheric cold plasma treatment. Innovative Food Science & Emerging Technologies, 93, p.103638.
Loureiro, A.D.C., Souza, F.D.C.D.A., Sanches, E.A., Bezerra, J.D.A., Lamarão, C.V., Rodrigues, S., Fernandes, F.A. and Campelo, P.H., 2021. Cold plasma technique as a pretreatment for drying fruits: Evaluation of the excitation frequency on drying process and bioactive compounds. Food Research International, 147, p.110462.
Muhammad, A.I., Xiang, Q., Liao, X., Liu, D. and Ding, T., 2018. Understanding the impact of nonthermal plasma on food constituents and microstructure—a review. Food and bioprocess technology, 11, pp.463-486.
Olatunde, O.O., Chantakun, K. and Benjakul, S., 2021. Microbial, chemical qualities and shelf-life of blue swimming crab (Portunus armatus) lump meat as influenced by in-package high voltage cold plasma treatment. Food Bioscience, 43, p.101274.
Paixão, L.M., Fonteles, T.V., Oliveira, V.S., Fernandes, F.A. and Rodrigues, S., 2019. Cold plasma effects on functional compounds of siriguela juice. Food and Bioprocess Technology, 12, pp.110-121.
Panpipat, W. and Chaijan, M., 2020. Effect of atmospheric pressure cold plasma on biophysical properties and aggregation of natural actomyosin from threadfin bream (Nemipterus bleekeri). Food and Bioprocess Technology, 13, pp.851-859.
Pankaj, S.K., Wan, Z., Colonna, W. and Keener, K.M., 2017. Effect of high voltage atmospheric cold plasma on white grape juice quality. Journal of the Science of Food and Agriculture, 97(12), pp.4016-4021.
Patúc, Jaroslav., 2020. Natural phenomena based on plasma. 10.13140/RG.2.2.25142.86080.
Pogorzelska-Nowicka, E., Hanula, M.M., Brodowska-Trębacz, M., Górska-Horczyczak, E., Jankiewicz, U., Mazur, T., Marcinkowska-Lesiak, M., Półtorak, A. and Wierzbicka, A., 2021. The effect of cold plasma pretreatment on water-suspended herbs measured in the content of bioactive compounds, antioxidant activity, volatile compounds and microbial count of final extracts. Antioxidants, 10(11), p.1740.
Pour, A.K., Khorram, S., Ehsani, A., Ostadrahimi, A. and Ghasempour, Z., 2022. Atmospheric cold plasma effect on quality attributes of banana slices: Its potential use in blanching process. Innovative Food Science & Emerging Technologies, 76, p.102945.
Ramazzina, I., Berardinelli, A., Rizzi, F., Tappi, S., Ragni, L., Sacchetti, G. and Rocculi, P., 2015. Effect of cold plasma treatment on physico-chemical parameters and antioxidant activity of minimally processed kiwifruit. Postharvest Biology and Technology, 107, pp.55-65.
Rodríguez Ó, Gomes WF, Rodrigues S, Fernandes FA. Effect of indirect cold plasma treatment on cashew apple juice (Anacardium occidentale L.). Lwt. 2017 Oct 1;84:457-63.
Sarangapani, C., O'Toole, G., Cullen, P.J. and Bourke, P., 2017. Atmospheric cold plasma dissipation efficiency of agrochemicals on blueberries. Innovative Food Science & Emerging Technologies, 44, pp.235-241.
Sharma, S., 2020. Cold plasma treatment of dairy proteins in relation to functionality enhancement. Trends in Food Science & Technology, 102, pp.30-36.
Silveira, M.R., Coutinho, N.M., Esmerino, E.A., Moraes, J., Fernandes, L.M., Pimentel, T.C., Freitas, M.Q., Silva, M.C., Raices, R.S., Ranadheera, C.S. and Borges, F.O., 2019. Guava-flavored whey beverage processed by cold plasma technology: Bioactive compounds, fatty acid profile and volatile compounds. Food Chemistry, 279, pp.120-127.
Song, A.Y., Oh, Y.J., Kim, J.E., Song, K.B., Oh, D.H. and Min, S.C., 2015. Cold plasma treatment for microbial safety and preservation of fresh lettuce. Food science and biotechnology, 24, pp.1717-1724.
Sruthi, N.U., Josna, K., Pandiselvam, R., Kothakota, A., Gavahian, M. and Khaneghah, A.M., 2022. Impacts of cold plasma treatment on physicochemical, functional, bioactive, textural, and sensory attributes of food: A comprehensive review. Food Chemistry, 368, p.130809.
Yodpitak, S., Mahatheeranont, S., Boonyawan, D., Sookwong, P., Roytrakul, S. and Norkaew, O., 2019. Cold plasma treatment to improve germination and enhance the bioactive phytochemical content of germinated brown rice. Food chemistry, 289, pp.328-339.
JFBE 1(2): 10-16,2025
Original research
Cold Plasma: A Sustainable Innovation for Enhancing Polyphenol Levels
Saeedeh Karimlar1*, Zahra Teymouri2 and Neda Kabiri3
1-PhD Candidate, Department of Food Science and Technology, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran. karimlarsaeedeh@gmail.com
2-PhD Candidate, Food industry, Agriculture College, Isfahan University of Technology, Iran
3-PhD Student, Department of Food Science and Technology Gorgan University of Agricultural Sciences and Natural Resources Gorgan, I. R. Iran
| A B S T R A C T |
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| Cold plasma treatment, an eco-friendly and non-thermal technology that utilizes electricity and reactive gases such as oxygen, nitrogen, and helium, has emerged as a promising innovation in food processing. Unlike conventional heat treatments, which often degrade heat-sensitive bioactive compounds and essential nutrients, cold plasma offers a non-destructive approach to preserving and enhancing the functional properties of food components. This technology effectively inactivates enzymes, eliminates microorganisms, extends shelf life, and maintains food quality while mitigating the nutrient loss commonly associated with thermal processing. More importantly, recent studies indicate that cold plasma treatment enhances the extraction and bioavailability of bioactive compounds, including flavonoids, polyphenols, and antioxidants, thereby improving the nutritional and functional properties of functional foods. However, despite its potential, a comprehensive understanding of the specific mechanisms underlying these improvements remains an area for further research. Addressing this knowledge gap is essential for optimizing cold plasma applications in food processing and maximizing its benefits for functional food development.
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| Keywords: Cold plasma, Bioactive Compound, Green Extraction, Polyphenols |
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| Received 8 November 2024; Accepted 14 March 2025 |
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| This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License, which permits Share, copy, and redistribution of the material in any medium or format or adapt, remix, transform, and build upon the material for any purpose, even commercially. |
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1. Introduction
As the global population is expected to reach 10 billion by 2050, there is an increasing demand for innovative food production and processing methods to meet the rising need for food. Ensuring a safe global food supply that meets nutritional needs and addresses environmental concerns is a significant challenge. It is crucial to implement environmentally friendly strategies to protect food from decay and pests, thereby extending its shelf life and enhancing global food security. Recent years have seen notable advancements in food processing, particularly in the development of minimally processed foods and non-thermal processing technologies. These innovations have resulted in products with fresh-like characteristics, minimized nutrient degradation, and an overall perception of high quality. By adopting these approaches, we can meet the growing food demands of the future and contribute to a more sustainable and secure food supply chain (Araújo Bezerra et al., 2023; Silveira et al., 2019).
Thermal processes can compromise the quality of foods. To address this, non-thermal technologies have been developed to minimize the negative effects of heat on food, as well as to enhance processing speed and efficiency. One such innovative technology is cold plasma, which holds promise in various food processing applications. Cold plasma can preserve and clean food items, serving as a precursor to activities such as drying, extracting, cooking, curing, and hydrogenation. Additionally, the reactive plasma species generated during cold plasma treatment can improve the sensory and nutritional properties of foods (Elenilson et al., 2020, Jiajie et al., 2023).
2.What Is Cold Plasma?
Plasma, often referred to as the "fourth state of matter," is an ionized gas containing free electrons, positive ions, excited neutral atoms, free radicals, and photons. It is the most abundant state of matter in the universe, comprising over 99.9% of observable matter, excluding dark matter. Unlike solids, liquids, and gases, plasma exhibits unique properties such as electrical conductivity, sensitivity to electromagnetic fields, and the ability to generate reactive chemical species. These characteristics make it highly valuable in various applications, including industrial processing, medical treatments, and food preservation (Burducea et al., 2023; Muhammad et al., 2018). Plasma can be broadly categorized into thermal (hot) plasma and non-thermal (cold) plasma. Thermal plasma exists in a state of thermodynamic equilibrium, where both electrons and heavy particles (ions and neutral molecules) have nearly the same high temperature, often reaching thousands of degrees Kelvin. This type of plasma is commonly used in welding, plasma torches, and nuclear fusion. Cold plasma, on the other hand, operates under non-equilibrium conditions, meaning that while electrons attain high energy levels, the overall gas temperature remains low, often near room temperature. This characteristic makes cold plasma particularly suitable for applications where excessive heat could damage materials, such as in food processing, medical sterilization, and biological treatments. In the food industry, cold plasma technology involves two key components: inputs and outputs. The inputs consist of energy sources such as electricity or microwaves, as well as carrier gases like air, helium, argon, oxygen, or nitrogen. The outputs include highly reactive species such as ultraviolet (UV) light, ozone, and other reactive compounds that contribute to microbial inactivation and surface modifications. Unlike conventional chemical treatments, cold plasma typically leaves no harmful residues, making it an environmentally friendly alternative. The presence of reactive oxygen species (ROS), reactive nitrogen species (RNS), charged particles, and excited molecules enhances its effectiveness in microbial decontamination, enzyme inactivation, and food quality preservation (Albertos et al., 2017; Koddy et al., 2021). Understanding the fundamental differences between thermal and cold plasma, along with their unique properties, allows for their targeted application in various fields, particularly in food safety and quality enhancement.
2.1. Types of Plasma
Plasmas can be distinguished into two main types: equilibrium (thermal) plasma and nonequilibrium (low temperature) plasma, also known as non-thermal or cold atmospheric plasma. In thermal plasma, all the various chemical components, electrons, and ions are in a state of thermodynamic temperature equilibrium. Conversely, cold plasma can be generated at either atmospheric or reduced pressures with minimal power input. This type of plasma is often produced by electric discharge in a gas at lower pressure or by using microwaves, resulting in temperatures ranging from 30-60 °C. In contrast, thermal plasmas are typically formed at higher pressures (around 100 kPa) and require a substantial amount of power input (up to 50 MV), usually achieved through the use of radio frequency or microwaves (Olatunde et al., 2021; Liu et al., 2024).
2.2. Natural phenomena based on plasma
We categorize many natural phenomena as potentially paranormal, but they actually demonstrate how limited our understanding is of the uneven distribution of electric charges, ions, electric fields, and their effects on our planet. The natural rotating plasmid, such as ball lightning and similar forms, and the non-rotating plasma, like atmospheric lightnings, Aurora Borealis, the solar corona, firestorms, burning fuels, and plasma in atomic and hydrogen bomb explosions, as well as experimental plasma discharges known as "cords," reveal the complexity of these phenomena. Notably, the Sun and all stars are examples of natural rotating plasmids. (Patúc 2020)
The term "plasma" was coined by American chemist and physicist Irving Langmuir in 1928 during his experiments on electrical discharges in gas at the General Electric Research and Development Center in upstate New York. There does not seem to be any documentation explaining the rationale behind this suggestion, making it challenging to provide a definitive answer. Langmuir's concept proposed that the electrons, ions, and neutrals in an ionized gas could be viewed as corpuscular material moving within a fluid-like medium. This innovative idea led to the introduction of the term "plasma" to describe ionized gas, a term that had already been in use in medicine and biology for some time (Franklin and Braithwaite, 2009)
3. The effect of Cold Plasma on polyphenol compound Extraction
This review offers an overview of the fundamentals of cold plasma technology and the detailed mechanism of interaction between reactive plasma species and polyphenol compounds found in food, such as simple phenolic acid, individual phenolic compounds, flavonoids, and anthocyanins.
3.1. Polyphenols
Polyphenolic compounds are plant-based chemical compounds that contain at least one aromatic ring with a reactive hydroxyl group. These compounds are classified into various groups based on the number of phenolic rings and related structural elements, such as flavonoids and phenolic acids. Natural polyphenols are a diverse group of plant compounds, with over 8,000 known compounds. Found in fruits and vegetables, polyphenolic compounds are essential components contributing to the antioxidant properties of these foods. They encompass flavonols, flavones, isoflavones, flavan‐3‐ols, lignans, and anthocyanidins. These compounds safeguard food from free radical activity and help preserve its quality. Upon ingestion, they deliver cumulative effects of antioxidant, anti-inflammatory, and antimicrobial properties within the body (Sruthi et al, 2022).
The impact of cold plasma on polyphenol compounds largely depends on the food matrix and plasma process parameters, including voltage, feed gas, and treatment time (Kumar et al., 2023; Panpipat et al., 2020). Flavonoids degrade faster than other polyphenols due to their high ability to scavenge plasma-generated free radicals. The reactive species cause oxidative degradation, double bond cleavage of polyphenol compounds, and assist in the extraction of phenolic compounds. It is noteworthy that cold plasma technology has both positive and negative impacts on polyphenol concentration (Sharma et al., 2020).
Cold plasma is a promising technology that has the potential to be integrated into extraction processes adhering to green chemistry principles, as well as to reduce the resources required in traditional solvent-based extraction methods. Several studies in the food industry have investigated the effects of cold plasma on bioactive compounds like vitamin C, carotenoids, and phenolic compounds (Paixão et al., 2019). A recent study found that using cold plasma technology during the processing of guava-flavored whey beverages resulted in enhanced properties, including increased concentrations of bioactive and volatile compounds. Additionally, the study noted that the fatty acid profile of the beverage was influenced by various process parameters, such as processing time and flow rate ( Silveira, et al.,2019).
This study investigated the influence of glow discharge plasma on the quality of siriguela (purple mombin) juice by adjusting the processing time (5–15 minutes) and nitrogen gas flow rate (10–30 mL/min). Pre-processing and post-processing evaluations were conducted to analyze physicochemical properties and bioactive compounds. Noteworthy findings include the preservation of vitamin C levels and product color following processing. Conversely, the plasma treatment resulted in increased levels of pigments, total phenolics, antioxidant activity, and B vitamins within the juice. Notably, the antioxidant activity exhibited an increase, while polyphenol oxidase activity decreased by approximately 20% (at a nitrogen gas flow rate of 20 mL/min for 15 minutes). Moreover, under specific processing conditions, peroxidase exhibited a slight activation of 6%. The study emphasizes the necessity of optimizing cold plasma food processing to achieve the desired impact on bioactive compounds in siriguela juice. The variability in treatment effectiveness is linked to processing times and intensities, impacting the extraction and degradation of bioactive compounds (Paixão et al., 2019).
The study investigated the effects of cold plasma on the enzymatic activity, color, bioactive compounds, and antioxidant activity of avocado pulp with lime extract (PL) and without extract (PW). Various experimental conditions were tested, including different durations (10, 20, and 30 minutes) and gas flow rates (10, 20, and 30 ml). The results showed that a gas flow rate of 20 ml/20 min in PL effectively reduced POD and PPO activities, minimized browning, and preserved the color. Cold plasma treatment increased the levels of phenolic and carotenoid compounds in PW under specific conditions, as well as in PL, leading to enhanced antioxidant activity. Strong correlations were found between phenolic content and ORAC-H in both PL (0.85) and PW (0.75). Furthermore, levels of myristic and palmitic acids decreased after cold plasma treatment, while oleic, linoleic, and linolenic acid levels increased. The study concluded that the combination of lime extract in avocado pulp with cold plasma technology is effective in maintaining quality characteristics and improving bioactive content (Batista et al., 2021).
A recent study investigated the impact of an 8-minute cold plasma pre-treatment (20 kHz) on the content of antioxidants, antioxidant activity, volatile compounds profile, microbial count, pH, and color in herb extracts. The study encompassed 12 herbs: Echinacea purpurea, Salvia officinalis, Urtica dioica, Polygonum aviculare, Vaccinium myrtillus, Taraxacum officinale, Hypericum perforatum, Achillea millefolium, Sanguisorba officinalis, Leonurus cardiaca, Ballota nigra, and Andrographis paniculata. Before the cold plasma treatment, the herbs were ground and suspended in water, representing a novel approach that had not been previously studied. The findings revealed that most plasma-treated extracts exhibited a higher content of polyphenols (11 out of 12). Moreover, the content of flavonoids and anthocyanins increased in four extracts, with the anthocyanin content showing a marked increase compared to the control (up to 77%). The antioxidant activity, assessed through different methods (ABTS, DPPH, FRAP), was also higher in nine plasma-treated solutions. Additionally, the cold plasma treatment reduced the total aerobic bacteria count, influenced the color, and raised the pH of the extracts. The surface structure of the plant material post-extraction was significantly damaged, likely leading to a higher extraction yield of bioactive compounds and consequently resulting in greater antioxidant activity in the cold plasma-treated extracts) Pogorzelska-Nowicka et al., 2021).
In a study conducted by Loureiro et al., the impact of various excitation frequencies (200, 500, and 800 Hz) of cold plasma technique as a pretreatment for drying tucumã was investigated. The SEM images depicted alterations on the pretreated tucumã’s surface, resulting in improved drying rate and water diffusivity, thereby reducing the drying time. Samples treated with 200 and 800 Hz exhibited minimal color variation and reduced drying time. Furthermore, the pretreatment led to an increase in the concentration of phenolic compounds (45.3 mg GAE g−1) and antioxidant compounds (799.8 µM ET) (p < 0.05). Notably, carotenoids were observed to be more susceptible to degradation at 500 Hz. The findings suggest that the proposed pretreatment involving the application of the cold plasma technique for drying foods has the potential to preserve and enhance their nutritional quality.( Loureiro et al., 2021).
In a recent study, researchers investigated the use of atmospheric pressure non-thermal plasma for decontaminating medicinal plants. Nigella sativa seeds were treated with atmospheric pressure floating-electrode dielectric-barrier discharge (FE-DBD) plasma for 15, 30, and 40 minutes, and the total microbial count of the seeds was analyzed. The results demonstrated a significant reduction in microorganism density at all three exposure times compared to the control, with complete elimination of microorganisms observed after 40 minutes of exposure. No significant changes were observed in the levels of total phenolic compounds and antioxidant activity before and after plasma exposure. However, the levels of linoleic acid and oleic acid decreased after 40 minutes of FE-DBD plasma exposure, indicating the potential oxidation of unsaturated fatty acids. Additionally, the ratio of unsaturated fatty acids to saturated fatty acids significantly decreased under these conditions (Abdi et al., 2020).
In a recent study, researchers explored the use of high-voltage atmospheric cold plasma (HVACP) as a pretreatment for grape pomace to facilitate the extraction of phenolic compounds. The study involved applying HVACP at 60 kV for varying periods (5, 10, and 15 minutes). The results revealed that HVACP treatment disrupted the epidermal cell structures of the grape pomace, reduced the water contact angle of grape peels, and accelerated grape drying. These effects became more pronounced with longer treatment periods. Furthermore, HVACP treatment led to a 10.9–22.8% increase in the yield of phenolic extracts, which exhibited a higher concentration of anthocyanins and demonstrated improved antioxidant capacity (16.7–34.7%) (Bao et al., 2020).
The study monitored the changes in bioactive phytochemicals of six varieties of Thai germinated brown rice (GBR) alongside cold plasma-treated GBR (PGBR). Following treatment with optimal plasma conditions, the
germination percentage, root length, and seedling height of the most responsive rice cultivar increased by 84%, 57%, and 69% respectively. Notably, there were no significant differences in the antioxidant activities of the GBRs and PGBRs for all rice cultivars. However, the PGBR group exhibited higher levels of γ-oryzanols during the 2-day germination period compared to the GBR group. Certain PGBR cultivars reached their peak values for total phenolic compounds, total vitamin E, simple phenolics, phytosterols, triterpenoids, and anthocyanins one day earlier than the corresponding values for GBR. Conversely, the concentrations of 2-acetyl-1-pyrroline reduced significantly with prolonged germination time in both GBR and PGBR samples (Yodpitak et al., 2019).
The study investigated the effects of using indirect cold plasma treatment on the levels of vitamin C, polyphenols, and flavonoids, as well as the antioxidant activity (FRAP, DPPH, ABTS), and sucrose, fructose, and glucose contents in cashew apple juice (Anacardium occidentale L). The treatments were conducted using a benchtop plasma system, considering two operational variables: N2 plasma flow rate (10, 30, and 50 mL/min) and treatment time (5, 10, and 15 min). The plasma treatment resulted in increased levels of vitamin C, flavonoids, and polyphenols, as well as enhanced antioxidant activity. However, prolonged exposure to plasma led to a decrease in most bioactive compounds, underscoring the importance of optimizing the process conditions (Rodríguez et al., 2017)
Another study showed the impact of cold plasma on microorganisms in Echium and Mint, in comparison to a heat treatment method. One gram of powdered Echium and Mint leaves was evenly spread on a glass slide and subjected to plasma exposure for 30 minutes. The study measured the phenolic compounds and color changes in Mint and Echium as a result of both plasma and heat treatments. The findings indicated that plasma did not significantly affect the phenolic compounds or color changes, whereas the heat method had a notable impact. Consequently, cold plasma could serve as an effective alternative to heat treatment for decontaminating spices without compromising their quality
(Jazayeri and Abdi 2024).
5. Advantages and Disadvantages
Cold plasma technology has emerged as a promising non-thermal processing method with a wide range of applications in the food and biological industries. One of its primary advantages lies in its cost-effectiveness and operational efficiency, as it functions under ambient temperature and atmospheric pressure conditions. Unlike conventional thermal and chemical treatments, cold plasma enables rapid processing while preserving the structural and nutritional integrity of heat-sensitive materials. Moreover, it exhibits antimicrobial efficacy by generating reactive species such as ozone, hydroxyl radicals, and nitric oxides, which effectively inactivate pathogenic and spoilage microorganisms (Misra et al., 2016). This property makes cold plasma particularly valuable for enhancing food safety without the need for excessive chemical additives or high-temperature processing. Additionally, the reduced energy consumption compared to traditional sterilization and decontamination techniques further underscores its sustainability and economic feasibility. Despite these advantages, several limitations must be considered. One notable challenge is the uneven treatment of large or irregularly shaped food matrices, which may result in inconsistent microbial inactivation and variable physicochemical modifications (Pankaj et al., 2017). Additionally, the exposure of food products to reactive plasma species can accelerate lipid oxidation, potentially leading to undesirable changes in sensory attributes such as flavor and aroma. The impact of cold plasma on the color and texture of fruits and vegetables has also been documented, with some studies indicating alterations in pigment stability and surface microstructure due to oxidative stress and dehydration effects (Jiang et al., 2020). Furthermore, the use of noble gases, particularly helium, in plasma generation can substantially elevate operational costs, posing an economic barrier to large-scale industrial implementation. These challenges highlight the need for further research to optimize process parameters, mitigate adverse effects, and enhance the overall efficiency of cold plasma applications in food processing.
Table 1. Influence of plasma treatments on phenolic compounds
Food | Treatment Conditions | Point(s) of Assay | Effect of Plasma Treatment on Phenolic Compounds | Reference |
Strawberries (fresh cut) | Air (dielectric barrier discharge, electric source) Voltage (45 kV) and time (1 min) | 7 days at 4 ◦C | Increase TPC, flavonoid, and anthocyanin contents up to day 5 | Li et al., 2019 |
Blueberries (uncut) | Air (capillary tube, electric source) frequency (47 kHz), gas flow (4 ft3 /m), and time (15–120 s) | After treatment | Reduction of anthocyanin content as treatment time increased | Lacombe et al., 2015 |
Apples (fresh cut) | Air (dielectric barrier discharge, electric source) Power (150 W), frequency (12.7 kHz), gas flow (1.5 L/min), and time (30 and 120 min) | After treatment | Reduced TPC; reduction of some procyanidin dimers and trimers (120 min) | Ramazzina et al., 2015 |
Onion powder | He (chamber, MW source) MW intensity (400 W), frequency (2.45 GHz), gas flow (1 L/min), pressure (0.7 kPa), and time (40 min) | 28 days at 4 and 25 ◦C | No effect on quercetin content | Kim et al., 2017 |
White grape juice | Air (dielectric barrier discharge, electric source) Voltage (80 kV) and time (1–4 min) |
| Reduced TPC and flavonoid contents; increased flavonol | Pankaj et al., 2017 |
Chokeberry juice
| Plasma jet power: 4 W Feed gas: Argon gas Frequency: 25 kHz Time: 3 and 5 min | After treatment | Increase by 20% in Amazonian juice at 10 min and 10 ml/min | Gan et al., 2021 |
Blueberries | DBD plasma Voltage: 60 and 80 kVTime: 2 and 5 min | 5 days at 4 ◦C | Decrease by 40% at 80 kV and 5 min | Sarangapani et al., 2017 |
Fresh lettuce | RF glow discharge Power: 75 and 150 W Feed gas: Oxygen Time: 20–300 s | After treatment | Increase by 250% at 150 W and 2 min | Song et al., 2015 |
Banana slices | DBD plasma Voltage: 4.8–6.9 kV Frequency: 12–22 kHz Time: 35–155 s | 16 days at 4 and 25 ◦C | Increase by 30% at 6.9 kV and 155 s | Pour et al., 2022 |
Sour cherry marasca juice | Gas phase plasma Power: 4 W Voltage: 2.5 kV Frequency: 25 kHz Feed gas: Argon gas Time: 3, 4, and 5 min Flow rate: .75, 1, 1.25 L/min | 10 days at 4 ◦C | Increase by 37% at 1.0 L/min and 3 min | Artés-Hernández et al., 2021 |
Acai pulp | DBD plasmaVoltage: 20 kV Frequency: 50, 500, and 750 Hz Time: 5, 10, and 15 min | After treatment | Decrease by 37% at 20 kV, 50 Hz, and 10 min | Dantas et al., 2021 |
Lamb's lettuce | Plasma jet Power: 35 W Feed gas: Argon gas Frequency: 27.12 MHz Flow rate: 20 SCCM Time: 1–2 min | 7days at 25 and 4 ◦C | No significant change | Grzegorzewski et al., 2011 |
Amazonian juice | Glow plasma Frequency: 80 kHz Time: 10, 20, and 30 min Flow rate: 10, 20, and 30 ml/ min | After treatment | Increase by 57% at 2.0 L/min and 5 min | Castro et al., 2020 |
Kiwi fruit | DBD plasma Feed gas: Air relative humidity: 60% Time: 10 + 10 and 20 + 20 min | 3 days at 28 ◦C | increase by 5% at 15 kV and 40 min | Ramazzina et al., 2015 |
Fresh cut pitaya | Glow plasma Power: 80 W Feed gas: Nitrogen gas Frequency: 50 kHz Flow rate: 10, 20, and 30 ml/ min Time: 5, 10, and 15 min | After treatment | Decrease by 49% at 1 L/min and 5 min | Li et al., 2019 |
Sriguela juice | Gas phase plasma Power: 4 W Voltage: 2.5 kV Frequency: 25 kHz Feed gas: Argon gas Time: 3, 4, and 5 min Flow rate: .75, 1, 1.25 L/min | 7 days at 25 ◦C | Increase by 134% at 5.87kV and 180 s | Kumar et al., 2023 |
6. Conclusion and Future Prospects
Thermal processing may engender adverse effects such as a cooked flavor, texture modifications, and changes in sensory attributes, which have prompted the exploration of non-thermal food processing technologies within the food industry. Cold plasma, encompassing antimicrobial processes, poses untapped potential, particularly in its impact on allergens and anti-nutritional factors a field ripe for further investigation. Demonstrating promise as a non-thermal food processing method, cold plasma utilizes charged, highly reactive gaseous molecules and species to deactivate contaminating microorganisms in food, garnering considerable attention from the global scientific community. Plasma pretreatment offers the potential to optimize the extraction of bioactive compounds, elevating both yield and nutritional quality, thus emerging as a technology with potential utility in the valorization of grape processing byproducts for functional food and nutraceutical applications within the winemaking industry. Despite its proven efficacy across various food sectors, including cereals, fruits, vegetables, dairy, and meat processing, cold plasma technology faces substantial challenges, like scaling up productivity and treating large-format foods. This technology underscores potential for reduced drying time, enhanced extraction efficiency, and the production of meats devoid of trans isomers thus offering healthier food alternatives. However, notwithstanding the multitude of advantages derived from cold plasma applications, there remain several challenges, necessitating further inquiry to optimize and regulate the effects of plasma on the nutritional and sensory quality of food. Moreover, a deeper understanding of plasma's role across different chemical groups present in food, and the development of larger or more potent plasma systems, warrant extensive scientific inquiry. Promoting a richer comprehension of cold plasma technology and its future prospects necessitates meticulous scientific inquiry to comprehensively ascertain its potential.
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