Nitrate is a major source of the inorganic nitrogen taken up by the roots of plants. Nitrate sources are generally derived from inorganic minerals by an energy-consuming chemical process; as a result, the price of chemical fertilizers is gradually increasing year by year. NO₃-N, generated from N₂ using the plasma technique, is an alternative method of producing nitrate from the air. Therefore, in this research, we aimed to determine the efficiency of generating NO₃-N using plasma-activated water (PAW) to replace nitrates from chemical fertilizer in a nutrient solution. Green oak lettuce (Lactuca sativa L.) was grown in a hydroponics system using the double-pot technique. The plants were supplied with three different nutrient solutions (based on Hoagland’s solution), i.e., T1, no nitrate in the nutrient solution (NO₃⁻ = 0); T2, using nitrate sourced from a commercial chemical fertilizer (normal nitrate); and T3, using a nitrate source generated using the pinhole plasma jet technique (plasma nitrate). The other macronutrients and micronutrients in each treatment were equally supplied. The results show that, at the harvested stage (21 days after the plants received treatment), the no-nitrate (T1) treatment provided lower growth and yields. Moreover, compared with the normal nitrate (T2) and plasma nitrate (T3), the results indicate that most growth and yields showed no statistical differences. In terms of nitrate accumulation within plants, it was found that the normal nitrate treatment (T2) had the highest levels of nitrate accumulation, in both the underground and aboveground parts of green oak lettuce. These results confirmed that plasma nitrate could be an alternative source of nitrate N which provided a safer way for the environment and human health in terms of nitrate accumulation. In addition, data related to the chemical analysis of free amino acid concentrations in each treatment are discussed in this research.

The effect of argon (Ar) and oxygen (O₂) gases as well as the treatment times on the properties of modified bamboo fibers using dielectric barrier discharge (DBD) plasma at generated power of 180 W were investigated. The plasma treatment of bamboo fibers with inert gases leads to the generation of ions and radicals on the fiber surface. Fourier transform-infrared spectroscopy (FTIR) confirmed that the functional groups of lignin and hemicellulose were reduced owing to the removal of the amorphous portion of the fibers by plasma etching. X-ray diffraction analysis (XRD) results in an increased crystallinity percentage. X-ray photoelectron spectroscopy (XPS) results showed the oxygen/carbon (O/C) atomic concentration ratio increased with increasing treatment time. The fiber weight loss percentage increased with increased treatment time. Scanning electron microscopy (SEM) images showed that partial etching of the fiber surface led to a higher surface roughness and area and that the Ar + O₂ gas plasma treatment provided more surface etching than the Ar gas treatment because of the oxidation reaction of the O₂ plasma. The mechanical properties of fiber-reinforced epoxy (FRE) matrix composites revealed that the F_(tr)RE-Ar (30) samples showed a high tensile strength, whereas the mechanical properties of the F_(tr)RE-Ar + O₂ sample decreased with increased treatment time.

Water, soil, and food products contain pesticide residues. These residues result from excessive pesticides use, motivated by the fact that agricultural productivity can be increased by the use of these pesticides. The accumulation of these residues in the body can cause health problems, leading to food safety concerns. Cold plasma technology has been successfully employed in various applications, such as seed germination, bacterial inactivation, wound disinfection, surface sterilization, and pesticide degradation. In recent years, researchers have increasingly explored the effectiveness of cold plasma technology in the degradation of pesticide residues. Most studies have shown promising outcomes, encouraging further research and scaling-up for commercialization. This review summarizes the use of cold plasma as an emerging technology for pesticide degradation in terms of the plasma system and configuration. It also outlines the key findings in this area. The most frequently adopted plasma systems for each application are identified, and the mechanisms underlying pesticide degradation using cold plasma technology are discussed. The possible factors influencing pesticide degradation efficiency, challenges in research, and future trends are also discussed. This review demonstrates that despite the nascent nature of the technology, the use of cold plasma shows considerable potential in regards to pesticide residue degradation, particularly in food applications.

Bamboo cellulose fiber (BF)-reinforced epoxy (EP) composites were fabricated with BF subjected to plasma treatment using argon (Ar), oxygen (O₂), and nitrogen (N₂) gases. Optimal mechanical properties of the EP/BF composites were achieved with BFs subjected to 30 min of plasma treatment using Ar. This is because Ar gas improved the plasma electron density, surface polarity, and BF roughness. Flexural strength and flexural modulus increased with O₂ plasma treatment. Scanning electron microscopy images showed that the etching of the fiber surface with Ar gas improved interfacial adhesion. The water contact angle and surface tension of the EP/BF composite improved after 10 min of Ar treatment, owing to the compatibility between the BFs and the EP matrix. The Fourier transform infrared spectroscopy results confirmed a reduction in lignin after treatment and the formation of new peaks at 1736 cm⁻¹, which indicated a reaction between epoxy groups of the EP and carbon in the BF backbone. This reaction improved the compatibility, mechanical properties, and water resistance of the composites.

Cold plasma technology is gaining attention as a promising approach to enhancing the bioactivity of plant extracts. However, its impact on green coffee bean extracts (GCBEs) still needs to be explored. In this study, an innovative underwater plasma jet system was employed to investigate the effects of cold plasma on Coffea arabica GCBEs, focusing on the conjugation reflected by the change in composition and bioactivity. The DPPH radical scavenging antioxidant activity exhibited a gradual increase with plasma treatment up to 35 min, followed by a decline. Remarkably, at 35 min, the plasma treatment resulted in a significant 66% increase in the DPPH radical scavenging activity of the GCBE. The total phenolic compound content also displayed a similar increasing trend to the DPPH radical scavenging activity. However, the phenolic profile analysis indicated a significant decrease in chlorogenic acids and caffeine. Furthermore, the chemical composition analysis revealed a decrease in free amino acids, while sucrose remained unchanged. Additionally, the SDS-PAGE results suggested a slight increase in protein size. The observed enhancement in antioxidant activity, despite the reduction in the two major antioxidants in the GCBE, along with the increase in protein size, might suggest the occurrence of conjugation processes induced by plasma, particularly involving proteins and phenolic compounds. Notably, the plasma treatment exhibited no adverse effects on the extract’s safety, as confirmed by the MTT assay. These findings indicate that cold plasma treatment holds significant promise in improving the functional properties of GCBE while ensuring its safety. Incorporating cold plasma technology into the processing of natural extracts may offer exciting opportunities for developing novel and potent antioxidant-rich products.