Cold plasma treatment to improve germination and enhance the bioactive phytochemical content of germinated brown rice

Air and argon cold plasma effects on lipolytic enzymes inactivation, physicochemical properties and volatile profiles of lightly-milled rice

This study investigated the effectiveness of cold-plasma treatment using air and argon as input gas on deactivation of lipolytic enzymes in lightly-milled-rice (LMR). The results showed no significant inactivation in lipase and lipoxygenase using air-plasma. However, using argon as input gas, the residual activities of lipase and lipoxygenase were reduced to 64.51 % and 29.15 % of initial levels, respectively. Argon plasma treatment resulted in more substantial augmentation in peak and breakdown viscosities of LMR starch, suggesting an enhancement in palatability of cooked LMR with increased stickiness and decreased hardness. In contrast to the decrease in volatile compounds in LMR following argon plasma treatment, the concentrations of several prevalent aroma compounds, including 1-hexanol, 1-hexanal, and 2-pentylfuran, exhibited significant increments, reaching 1489.70 ng/g, 3312.10 ng/g, and 58.80 ng/g, respectively. These findings suggest the potential for enhancing various facets of the commercial qualities of LMR by utilizing different input gases during plasma treatment.

Investigating the impact of ultrasound-assisted cellulase pretreatment on the nutrients, phytic acid, and phenolics bioaccessibility in sprouted brown rice

This study aimed to elucidate the impact of ultrasound-assisted cellulase (UC) pretreatment on nutrients, phytic acid, and the bioavailability of phenolics during brown rice sprouting. It sought to unveil the underlying mechanisms by quantifying the activity of key enzymes implicated in these processes. The sprouted brown rice (SBR) surface structure was harmed by the UC pretreatment, which also increased the amount of γ-oryzanol and antioxidant activity in the SBR. Concurrently, the UC pretreatment boosted the activity of phytase, glutamate decarboxylase, succinate semialdehyde dehydrogenase, Gamma-aminobutyric acid (GABA) transaminase, chalcone isomerase, and phenylalanine ammonia lyase, thereby decreasing the phytic acid content and increasing the GABA, flavonoid, and phenolic content in SBR. In addition, UC-pretreated SBR showed increased phenolic release and bioaccessibility during in vitro digestion when compared to the treated group. These findings might offer theoretical direction for using SBR to maximize value.

Exploring Cold plasma technology: Enhancements in Carob seed germination, phytochemical Composition, and antioxidant activity

The cultivation of carob tree does not need many climatic and ecological requirements. The main limit to its large-scale cultivation is the defects for propagation with seeds. Addressing this, our study evaluated the effect of cold plasma pretreatment on carob seed germination. Impressively, cold plasma showcased beneficial effects by significantly increasing water uptake in seeds (CS: 1.71 ± 0.59; PS/3.99 ± 1.56) and decreasing the contact angle from 80.7° to 57.9°, enhancing the seed surface's hydrophilicity. While the germination rate enhancement was subtle, the treatment presented an innovative route to modifying the seed's physiochemical properties. Specifically, storage proteins like albumin, globulin, and prolamin were notably reduced (Albumin (from 7.67 to 4.95 mg/g DW), Globulin (from 8.52 to 5.80 mg/g DW) and Prolamin (from 3.53 to 1.66 mg/g DW)). Additionally, there was a decline in the overall content of polyphenols (from 846.88 to 760.94 mg GAE/100g DW) and flavonoids (from 790.93 to 502.95 mg GAE/100g DW) and a decrease in the ferric reducing power (from 34.48 to 26.39 mg AAE/g DW). However, radical scavenging activity remained consistent. Intriguingly, FTIR-ATR spectral analysis post plasma treatment indicated oxidative alterations in the seed coat, marked by a distinctive intensity at 1732 cm⁻1. This investigation suggests that the application of eco-friendly technology could provide improvements in seed surface's hydrophilicity, but appropriate conditions could be chosen to increase germination efficiency.

Effect of Germination on Mineral Content Changes in Brown Rice (Oryza sativa L.)

Minerals are the essential micronutrients for human health. Brown rice is a whole-grain food rich in minerals, with its bran portion limiting the application of minerals. In the present study, the changes in the contents of 23 different minerals (Na, Mg, K, Ca, B, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Sb, Ba, Li, Al, As, Cd, Sn, Hg, and Pb) in brown rice were evaluated during 17, 24, 30, 35, and 48 h of germination. The results showed that germination was associated with the decreased contents of Pb, Cd, As, Al, Li, Ba, Fe, Cr, Co, V, and Hg, and the increased content of Na in brown rice (p < 0.05). In contrast, this process was not significantly influential on the contents of Mg, K, Ca, B, Ni, Cu, Zn, Se, Sn, Sb, and Mn (p > 0.05). In addition, significant correlations were found among most of the mineral contents. Furthermore, according to the principal component analysis, three principal components of the different mineral contents were extracted to explain 96.60% of the cumulative variances. In summary, these findings demonstrated that germination represented a feasible approach to regulating and controlling the distribution of the mineral elements in brown rice, optimizing the levels of the mineral contents, and thus reducing the potential health risks.

Pulsed light treatment enhances starch hydrolysis and improves starch physicochemical properties of germinated brown rice

BACKGROUND

Recently, germinated brown rice (GBR) has gained substantial attention as a functional food because of its nutritional attributes. Notably, pulsed light technology (PLT) has emerged as a promising tool for enhancing rice germination and, consequently, has improved the nutritional and functional qualities of GBR-derived products. However, further research is required to comprehensively understand the impact of PLT on GBR physicochemical properties. The present study aimed to investigate the stimulating effects of PLT on starch hydrolysis, starch structure and functional properties of GBR.

RESULTS

The PLT substantially boosted α-amylase activity during brown rice germination, leading to a 10.9% reduction in total starch content and a 17.3% increase in reducing sugar content, accompanied by elevated free water levels. Structural analysis indicated no changes in starch crystalline types, whereas gelatinization temperature slightly increased. Pasting properties exhibited a significant drop in peak viscosity. Scanning electron microscopy showed surface erosion of starch granules with microstructural changes. Furthermore, correlation analysis established positive links between α-amylase activity, reducing sugar accumulation, starch structure and functional properties in GBR.

CONCLUSION

The present study demonstrates that PLT enhanced the physicochemical properties of GBR starch, significantly improving the stability of GBR products, thereby contributing to expanded applicability of rice starch in the food industry. © 2023 Society of Chemical Industry.

Germination-induced changes in anthocyanins and proanthocyanidins: A pathway to boost bioactive compounds in red rice

This study aimed to investigate the specific changes in the anthocyanins and proanthocyanidins content of red rice during germination. Different methods including chemical detection, UPLC-QToF/MS, and metabolite analysis were used to examine these changes. The findings showed a significant increase in the overall levels of polyphenols and pigments in red rice as the germination period advanced. Specifically, the proanthocyanidins being the predominant pigments showed a significant increase during later stages of germination. Whereas, the anthocyanin levels reached their peak after 12 h of germination and subsequently declined. Furthermore, six anthocyanins and three proanthocyanidins were identified among the pigment constituents. Additionally, several significant precursor substances associated with pigments were identified, and their contents showed a significant increase, indicating that the proanthocyanidin synthesis pathway is activated by germination. These dynamic changes suggest that germination effectively stimulated the synthesis and accumulation of both anthocyanins and proanthocyanidins, thereby improving the nutritional value of red rice.

Application of cold argon plasma on germination, root length, and decontamination of soybean cultivars

Applying cold discharge plasma can potentially alter plants' germination characteristics by triggering their physiological activities. As a main crop in many countries, soybean was examined in the present study using cultivars such as Arian, Katoul, Saba, Sari, and Williams in a cold argon plasma. This study has been motivated by the importance of plant production worldwide, considering climate change and the increasing needs of human populations for food. This study was performed to inspect the effect of cold plasma treatment on seed germination and the impact of argon plasma on microbial decontamination was investigated on soybeans. Also, the employed cultivars have not been studied until now the radicals generated from argon were detected by optical emission spectrometry (OES), and a collisional radiative model was used to describe electron density. The germination properties, including final germination percentage (FGP), mean germination time (MGT), root length, and electrical conductivity of biomolecules released from the seeds, were investigated after the plasma treatments for 30, 60, 180, 300, and 420 s. The decontamination effect of the plasma on Aspergillus flavus (A.flavus) and Fusarium solani (F.solani) was also examined. The plasma for 60 s induced a maximum FGP change of 23.12 ± 0.34% and a lowest MGT value of 1.40 ± 0.007 days. Moreover, the ultimate root length was 56.12 ± 2.89%, in the seeds treated for 60 s. The plasma exposure, however, failed to yield a significant enhancement in electrical conductivity, even when the discharge duration was extended to 180 s or longer. Therefore, the plasma duration of 180 s was selected for the blotter technique. Both fungi showed successful sterilization; their infectivity inhibition was 67 ± 4 and 65 ± 3.1%, respectively. In general, the cold plasma used for soybeans in the present study preserved their healthy qualities and reduced the degree of fungal contamination.

Impact of germination on the techno-functional properties, nutritional composition, and health-promoting compounds of brown rice and its products: A review

Rice is a popular grain and forms part of the daily diet of people throughout the world. However, the consumption of rice and its products is sometimes limited by its high glycemic index due to its high starch content, low protein content and quality, and low bioavailability of minerals due to the presence of anti-nutritional factors. This has partly stimulated research interest in recent times toward the use of bioprocessing techniques such as germination as cheap and natural means to improve the nutritional quality, digestibility, and health properties of cereals, including rice, to partially achieve nutrition and food security in the developing regions of the world. This review highlights the impact of germination on the nutritional quality, health-promoting properties, and techno-functional characteristics of germinated brown rice grains and their products. The review demonstrated that germinated rice grains and their products have improved nutritional quality and digestibility, modified functional properties, and showed antioxidant, anti-inflammatory, anti-diabetic, anti-obesity, anti-cancer, and anti-cardiovascular activities. Germination appears to be a suitable bioprocessing method to improve the nutritional quality and bioactive constituents and modify the techno-functional properties of rice grains for diverse food applications and improved global nutrition and food safety.

Role of short germination and milling on physical properties, amino acid and metabolomic profiles of high amylose rice fractions

Short germination is a process that can improve bioactive compounds in rice. This work aimed investigate the physical properties, phenolic compounds (PC), antioxidant activity and amino acids composition of husk + bran, brown and milled rice with high amylose content after short germination (16 h). α-amylase activity (Falling Number, FN) and enthalpy (ΔH) were unchanged (p < 0.05). RVA curve profiles were similar, even though after short germination and milling. Globally, metabolomics analysis identified 117 PC, in which 111 (bound), 104 (free) and 21 revealed in both extracts. p-Coumaric, trans-ferulic and ferulic acids were the most abundant PC revealed in all fractions. The portion husk + bran showed the highest level of total antioxidant activity (709.90 µmol TE) in both free and bound fractions. In terms of total amino acids, there was no statistical difference (p < 0.05) among non-germinated and germinated samples, contrary to free amino acids content. Glutamic acid (Glu) presented the highest values combining short germination and milling (1725-1900 mg/100 g) consequently, leads to higher value of GABA (12.21 mg/100 g). The combination of short germination and milling demonstrated a good strategy to improve the nutritional quality of rice, unless the thermal and pasting properties have been altered, contribute to potential health benefits on human nutrition.

Health-promoting germinated rice and value-added foods: a comprehensive and systematic review of germination effects on brown rice

Over the last 30 years, thousands of articles have appeared examining the effects of soaking and germinating brown rice (BR). Variable germination conditions and methods have been employed to measure different health-beneficial parameters in a diverse germplasm of BR. Research results may therefore appear inconsistent with occasional anomalies, and it may be difficult to reach consensus concerning expected trends. Herein, we amassed a comprehensive review on germinated brown rice (GBR), attempting to codify 133 peer-reviewed articles regarding the effects on 164 chemical parameters related to health and nutrition in BR and in value-added food products. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA-2020) approach was used to direct the flow of the literature search. A pair-wise comparison t-test was performed to deliver an overall approach indicating when a given compound has been found to significantly increase or decrease through germination, which was grouped into GABA and polyamines, γ-Oryzanol and phytosterols, phenolic compounds, vitamins, proteins and amino acids, starchy carbohydrates, free sugars, lipids, minerals and phytic acid. This resource will stimulate interest in germinating rice and optimistically help increase both production and consumption of highly nutritious, health-beneficial rice with pigmented bran.

Effect of processing methods and storage on the bioactive compounds of black rice (Oryza sativa L.): a review

Compared to brown and white rice, black rice contains more nutrients and numerous unique bioactive substances, such as essential amino acids, dietary fiber, γ-oryzanols, γ-aminobutyric acid, phenolic compounds, and anthocyanins, which makes it highly valuable for development and use. Whole-grain black rice typically requires a certain amount of processing prior to consumption, with the primary goal of enhancing the taste and texture of whole grains and their products. However, various new processing technologies have been effectively applied to the processing of black rice and the enhancement of its qualitative characteristics, but they also have both positive and negative effects on its nutritional quality. Therefore, evaluation of changes in concentrations of the bioactive substances as natural antioxidants due to processing and storage conditions is critical for establishing dietary guidelines for rice. This review highlights the primary bioactive components of black rice and provides a discussion of the impact of processing methods and storage on the bioactive components of black rice. Furthermore, we summarized the issues that currently exist in the processing and storage of black rice.

Recent developments in applications of physical fields for microbial decontamination and enhancing nutritional properties of germinated edible seeds and sprouts: a review

Germinated edible seeds and sprouts have attracted consumers because of their nutritional values and health benefits. To ensure the microbial safety of the seed and sprout, emerging processing methods involving physical fields (PFs), having the characteristics of high efficiency and environmental safety, are increasingly proposed as effective decontamination processing technologies. This review summarizes recent progress on the application of PFs to germinating edible seeds, including their impact on microbial decontamination and nutritional quality and the associated influencing mechanisms in germination. The effectiveness, application scope, and limitation of the various physical techniques, including ultrasound, microwave, radio frequency, infrared heating, irradiation, pulsed light, plasma, and high-pressure processing, are symmetrically reviewed. Good application potential for improving seed germination and sprout growth is also described for promoting the accumulation of bioactive compounds in sprouts, and subsequently enhancing the antioxidant capacity under favorable PFs processing conditions. Moreover, the challenges and future directions of PFs in the application to germinated edible seeds are finally proposed. This review also attempts to provide an in-depth understanding of the effects of PFs on microbial safety and changes in nutritional properties of germinating edible seeds and a theoretical reference for the future development of PFs in processing safe sprouted seeds.

Chemical alterations of grain surface by cold plasma technology: Comparison of buckwheat and wheat grain responses to oxygen low-pressure plasma

Cold plasma (CP) has a great potential for decontamination or improvement of grain germination. However, disputing results have been reported, as plasma treatment can affect species and varieties of grains in different ways. The differences may be due to the chemical composition of grain pericarps, the structure of the grains and metabolic response mechanisms. CP treatment decreased grain germination rate, speed and activity of α-amylase of buckwheat grains. Such effects on both varieties of wheat grains were present after longer exposure to plasma. Lipid peroxidation was highest in buckwheat grains, whereas wheat grains were less affected. Plasma-treated Gorolka variety exhibited a low level of lipid peroxidation, no different to untreated grains, compared to Primorka grains, where longer treatment triggered higher levels of lipid peroxidation. The response of grains to CP treatment depends on the chemical and structural properties of grains pericarp, as well as plant tolerance to certain abiotic conditions.

Proposing Signaling Molecules as Key Optimization Targets for Intensifying the Phytochemical Biosynthesis Induced by Emerging Nonthermal Stress Pretreatments of Plant-Based Foods: A Focus on γ-Aminobutyric Acid

Emerging evidence has confirmed the role of emerging nonthermal stressors (e.g., electromagnetic fields, ultrasonication, plasma) in accumulating bioactive metabolites in plant-based food. However, the signal decoding mechanisms behind NonTt-driven phytochemical production remain unclear, hindering postharvest bioactive component intensification. This study aims to summarize the association between signaling molecules and bioactive secondary metabolite production under nonthermal conditions, demonstrating the feasibility of enhancing phytochemical accumulation through signaling molecule crosstalk manipulation. Nonthermal elicitors were found to be capable of inducing stress metabolisms and activating various signaling molecules, similar to conventional abiotic stress. A simplified pathway model for nonthermally induced γ-aminobutyric acid accumulation was proposed with reactive oxygen species and calcium signaling being versatile pathways responsive to nonthermal elicitors. Manipulating signal molecules/pathways under nonthermal conditions can intensify phytochemical biosynthesis. Further research is needed to integrate signaling molecule responses and metabolic network shifts in nonthermally stressed plant-based matrices, balancing quality modifications and intensification of food functionality potential.

Cold Plasma-Assisted Extraction of Phytochemicals: A Review

In recent years, there has been growing interest in bioactive plant compounds for their beneficial effects on health and for their potential in reducing the risk of developing certain diseases such as cancer, cardiovascular diseases, and neurodegenerative disorders. The extraction techniques conventionally used to obtain these phytocompounds, however, due to the use of toxic solvents and high temperatures, tend to be supplanted by innovative and unconventional techniques, in line with the demand for environmental and economic sustainability of new chemical processes. Among non-thermal technologies, cold plasma (CP), which has been successfully used for some years in the food industry as a treatment to improve food shelf life, seems to be one of the most promising solutions in green extraction processes. CP is characterized by its low environmental impact, low cost, and better extraction yield of phytochemicals, saving time, energy, and solvents compared with other classical extraction processes. In light of these considerations, this review aims to provide an overview of the potential and critical issues related to the use of CP in the extraction of phytochemicals, particularly polyphenols and essential oils. To review the current knowledge status and future insights of CP in this sector, a bibliometric study, providing quantitative information on the research activity based on the available published scientific literature, was carried out by the VOSviewer software (v. 1.6.18). Scientometric analysis has seen an increase in scientific studies over the past two years, underlining the growing interest of the scientific community in this natural substance extraction technique. The literature studies analyzed have shown that, in general, the use of CP was able to increase the yield of essential oil and polyphenols. Furthermore, the composition of the phytoextract obtained with CP would appear to be influenced by process parameters such as intensity (power and voltage), treatment time, and the working gas used. In general, the studies analyzed showed that the best yields in terms of total polyphenols and the antioxidant and antimicrobial properties of the phytoextracts were obtained using mild process conditions and nitrogen as the working gas. The use of CP as a non-conventional extraction technique is very recent, and further studies are needed to better understand the optimal process conditions to be adopted, and above all, in-depth studies are needed to better understand the mechanisms of plasma-plant matrix interaction to verify the possibility of any side reactions that could generate, in a highly oxidative environment, potentially hazardous substances, which would limit the exploitation of this technique at the industrial level.

Evaluation of Precision and Sensitivity of Back Extrusion Test for Measuring Textural Qualities of Cooked Germinated Brown Rice in Production Process

The textural qualities of cooked rice may be understood as a dominant property and indicator of eating quality. In this study, we evaluated the precision and sensitivity of a back extrusion (BE) test for the texture of cooked germinated brown rice (GBR) in a production process. BE testing of the textural properties of cooked GBR rice showed a high precision of measurement in hardness, toughness and stickiness tests which indicated by the repeatability and reproductivity test but the sensitivity indicated by coefficient of variation of the texture properties. The findings of our study of the effects on cooked GBR texture of different soaking and incubation durations in the production of Khao Dawk Mali 105 (KDML 105) GBR, as measured by BE testing, confirmed that our original protocol for evaluation of the precision and sensitivity of this texture measurement method. The coefficients of determination (R2) of hardness, toughness and stickiness tests and the incubation time at after 48 hours of soaking were 0.82, 0.81 and 0.64, respectively. The repeatability and reproducibility of reliable measurements, which have a low standard deviation of the greatest difference between replicates, are considered to indicate high precision. A high coefficient of variation where relatively wide variations in the absolute value of the property can be detected indicates high sensitivity when small resolutions can be detected, and vice versa. The sensitivity of the BE tests for stickiness, toughness and hardness all ranked higher, in that order, than the sensitivity of the method for adhesiveness, which ranked lowest. The coefficients of variation of these texture parameters were 31.26, 20.59, 19.41 and 18.72, respectively. However, the correlation coefficients among the texture properties obtained by BE testing were not related to the precision or sensitivity of the test. By obtaining these results, we verified that our original protocol for the determination of the precision and sensitivity of food texture measurements which was successfully used for GBR texture measurement.

Research Progress and Future Trends of Low Temperature Plasma Application in Food Industry: A Review

Food nutrition, function, sensory quality and safety became major concerns to the food industry. As a novel technology application in food industry, low temperature plasma was commonly used in the sterilization of heat sensitive materials and is now widely used. This review provides a detailed study of the latest advancements and applications of plasma technology in the food industry, especially the sterilization field; influencing factors and the latest research progress in recent years are outlined and upgraded. It explores the parameters that influence its efficiency and effectiveness in the sterilization process. Further research trends include optimizing plasma parameters for different food types, investigating the effects on nutritional quality and sensory attributes, understanding microbial inactivation mechanisms, and developing efficient and scalable plasma-based sterilization systems. Additionally, there is growing interest in assessing the overall quality and safety of processed foods and evaluating the environmental sustainability of plasma technology. The present paper highlights recent developments and provides new perspectives for the application of low temperature plasma in various areas, especially sterilization field of the food industry. Low temperature plasma holds great promise for the food industry's sterilization needs. Further research and technological advancements are required to fully harness its potential and ensure safe implementation across various food sectors.

Cold Plasma Treatment Increases Bioactive Metabolites in Oat (Avena sativa L.) Sprouts and Enhances In Vitro Osteogenic Activity of their Extracts

Cold plasma treatment has been studied to enhance the germination, growth, and bioactive phytochemical production in crops. Here, we aimed to investigate the effects of cold plasma treatment on the growth, bioactive metabolite production, and protein expression related to the physiological and osteogenic activities of oat sprouts. Oat seeds were soaked for 12 h, and then exposed to plasma for 6 min/day for 3 days after sowing. Plasma exposure did not significantly change the growth of oat sprouts; however, increased the content of bioactive metabolites. A single exposure for 6 min on the first day (T-1) increased the content of free amino acids (39.4%), γ-aminobutyric acid (53%), and avenacoside B (23%) compared to the control. Hexacosanol content was the highest in T-3 (6 min exposure on each day for 3 days), 28% higher than that in the control. Oat sprout extracts induced the phosphorylation of adenosine 5'-monophosphate-activated protein kinase and osteoblast differentiation was enhanced by increasing the alkaline phosphatase (ALP) activity; all these effects were induced by plasma treatment. Avenacoside B content was positively correlated with ALP activity (r = 0.911, p < 0.1). These results suggest that plasma treatment has the potential to improve the value of oat sprouts and that it may be used in food fortification to enhance nutritional value for promoting human health.

Cycloartenyl Ferulate Is the Predominant Compound in Brown Rice Conferring Cytoprotective Potential against Oxidative Stress-Induced Cytotoxicity

Since brown rice extract is a rich source of biologically active compounds, the present study is aimed to quantify the major compounds in brown rice and to compare their cytoprotective potential against oxidative stress. The content of the main hydrophobic compounds in brown rice followed the order of cycloartenyl ferulate (CAF) (89.00 ± 8.07 nmol/g) >> α-tocopherol (αT) (19.73 ± 2.28 nmol/g) > γ-tocotrienol (γT3) (18.24 ± 1.41 nmol/g) > α-tocotrienol (αT3) (16.02 ± 1.29 nmol/g) > γ-tocopherol (γT) (3.81 ± 0.40 nmol/g). However, the percent contribution of CAF to the radical scavenging activity of one gram of whole brown rice was similar to those of αT, αT3, and γT3 because of its weaker antioxidant activity. The CAF pretreatment displayed a significant cytoprotective effect on the hydrogen peroxide-induced cytotoxicity from 10 µM, which is lower than the minimal concentrations of αT and γT required for a significant protection. CAF also enhanced the nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation coincided with the enhancement of the heme oxygenase-1 (HO-1) mRNA level. An HO-1 inhibitor, tin protoporphyrin IX (SnPP), significantly impaired the cytoprotection of CAF. The cytoprotective potential of CAF is attributable to its cycloartenyl moiety besides the ferulyl moiety. These results suggested that CAF is the predominant cytoprotector in brown rice against hydrogen peroxide-induced cytotoxicity.

Novel nonthermal food processing practices: Their influences on nutritional and technological characteristics of cereal proteins

Cereals, as the main crops cultivated and consumed in the world, are a rich source of carbohydrates, proteins, dietary fiber, and minerals. Despite the nutritional importance, their technological applicability in food matrices is also considerably important to be determined. Cereal processing is done to achieve goals as increasing the shelf-life, obtaining the desired technological function, and enhancing the nutritional value. Nonthermal processing is preferred regarding its potential to provide beneficial impacts with minimum adverse effect. Technological functionality and nutritional performance are considered as the most basic challenges through cereal processing, with proteins as the main factor to take part in such roles. Technological and nutritional functionalities of proteins have been found to be changed through nonthermal processing, which is generally attributed to conformational and structural changes. Therefore, this study is aimed to investigate the impact of nonthermal processing on nutritional and technological characteristics of cereal proteins.

Biochemical and Physiological Plant Processes Affected by Seed Treatment with Non-Thermal Plasma

Among the innovative technologies being elaborated for sustainable agriculture, one of the most rapidly developing fields relies on the positive effects of non-thermal plasma (NTP) treatment on the agronomic performance of plants. A large number of recent publications have indicated that NTP effects are far more persistent and complex than it was supposed before. Knowledge of the molecular basis and the resulting outcomes of seed treatment with NTP is rapidly accumulating and requires to be analyzed and presented in a systematic way. This review focuses on the biochemical and physiological processes in seeds and plants affected by seed treatment with NTP and the resulting impact on plant metabolism, growth, adaptability and productivity. Wide-scale changes evolving at the epigenomic, transcriptomic, proteomic and metabolic levels are triggered by seed irradiation with NTP and contribute to changes in germination, early seedling growth, phytohormone amounts, metabolic and defense enzyme activity, secondary metabolism, photosynthesis, adaptability to biotic and abiotic stress, microbiome composition, and increased plant fitness, productivity and growth on a longer time scale. This review highlights the importance of these novel findings, as well as unresolved issues that remain to be investigated.

Effect of Plasma Activated Water on Selected Chemical Compounds of Rocket-Salad (Eruca sativa Mill.) Leaves

Plasma activated water (PAW) has proven to be a promising alternative for the decontamination of rocket leaves. The impact of PAW on the volatile profile, phytosterols, and pigment content of rocket leaves was studied. Leaves were treated by PAW at different times (2, 5, 10, and 20 min). Compounds of the headspace were detected and quantified using GC–MS analysis. A total of 52 volatile organic compounds of different chemical classes were identified. Glucosinolate hydrolysis products are the major chemical class. PAW application induced some chemical modifications in the volatile compounds. Changes in the content of the major compounds varied with the increase or decrease in the treatment time. However, PAW-10 and -2 were grouped closely to the control. A significant decrease in the content of β-sitosterol and campesterol was observed after PAW treatment, except for PAW-10, which showed a non-significant reduction in both compounds. A significant increase in β carotene, luteolin, and chlorophyll b was observed after the shortest treatment time of PAW-2. A reduction in chlorophyll content was also observed, which is significant only at longer treatment, or PAW-20. Overall, PAW has proven to be a safe alternative for rocket decontamination.

Impact of Germination Time on Resveratrol, Phenolic Acids, and Antioxidant Capacities of Different Varieties of Peanut (Arachis hypogaea Linn.) from China

In China, peanut sprouts are popular among consumers as functional vegetables. This study reports the change in total phenolic content (TPC), total flavonoid content (TFC), monomeric anthocyanin content (MAC), vitamin C, trans-resveratrol content, antioxidant capacities, and phenolic profile of three different varieties of peanut during 8 days of germination. The TPC, TFC, and antioxidant capacity of peanut samples were reduced and then increased with an increase in germination time. TFC values were highly correlated with 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) values. MAC values of peanuts were first increased and then decreased during 8 days of germination. The TFC, DPPH, and FRAP values of germinated peanuts were lower compared to the non-germinated peanut. Germination of peanut samples enhanced the total phenolic acids and trans-resveratrol content, but the vitamin C content of peanut sprouts was lower than ungerminated peanuts.

Effects of Dielectric Barrier Ambient Air Plasma on Two Brassicaceae Seeds: Arabidopsis thaliana and Camelina sativa

We investigated low-temperature plasma effects on two Brassicaceae seeds (A. thaliana and C. sativa) using dielectric barrier discharge in air. Comparisons of plasma treatments on seeds showed distinct responses on germination rate and speed. Optimal treatment time giving optimal germination is 15 min for A. thaliana with 85% increase compared to control after 48 h of germination and 1 min for C. sativa with 75% increase compared to control after 32 h of germination. Such germination increases are associated with morphological changes shown by SEM of seed surface. For better understanding at the biochemical level, seed surfaces were analyzed using gas chromatography-mass spectrometry which underlined changes of lipidic composition. For both treated seeds, there is a decrease of saturated (palmitic and stearic) fatty acids while treated C. sativa showed a decrease of unsaturated (oleic and linoleic) acids and treated A. thaliana an increase of unsaturated ones. Such lipid changes, specifically a decrease of hydrophobic saturated fatty acids, are coherent with the other analyses (SEM, water uptake and contact angle). Moreover, an increase in A. thaliana of unsaturated acids (very reactive) probably neutralizes plasma RONS effects thus needing longer plasma exposure time (15 min) to reach optimal germination. For C. sativa, 1 min is enough because unsaturated linoleic acid becomes lower in treated C. sativa (1.2 × 107) compared to treated A. thaliana (3.7 × 107).

Response of Two Different Wheat Varieties to Glow and Afterglow Oxygen Plasma

Cold plasma technology has received significant attention in agriculture due to its effect on the seeds and plants of important cultivars, such as wheat. Due to climate change, wherein increasing temperatures and droughts are frequent, it is important to consider novel approaches to agricultural production. As increased dormancy levels in wheat are correlated with high temperatures and drought, improving the germination and root growth of wheat seeds could offer new possibilities for seed sowing. The main objective of this study was to evaluate the influence of direct (glow) and indirect (afterglow) radio-frequency (RF) oxygen plasma treatments on the germination of two winter wheat varieties: Apache and Bezostaya 1. The influence of plasma treatment on seed surface morphology was studied using scanning electron microscopy, and it was observed that direct plasma treatment resulted in a high etching and nanostructuring of the seed surface. The effect of plasma treatment on germination was evaluated by measuring the germination rate, counting the number of roots and the length of the root system, and the fresh weight of seedlings. The results of this study indicate that the response of seeds to direct and indirect plasma treatment may be variety-dependent, as differences between the two wheat varieties were observed.

Chemical changes of food constituents during cold plasma processing: A review

There is a growing demand for the consumption of nutritious and safe food products. Cold plasma is a novel non-thermal technology that in recent years, has found numerous applications in the food industry. Study on the applications of this technology and its effects on food quality is increasing. Like any other technology, using cold plasma for the processing of foods can be associated with food quality challenges. This paper reviews the effect of cold plasma on the chemical structure of different food constituents as well as its influence on food characteristics. The emphasis is on the recent studies about the plasma mechanisms of action and chemical alterations of different food components. The studies show that the interaction of plasma-reactive species with food components depends on process conditions. Developing the functional characteristics and reducing the anti-nutritional compounds are of promising potentials of cold plasma. Finally, the research gaps, the salient drawbacks, and future prospects of this technology are highlighted.

Antioxidant Effects of Anthocyanin-Rich Riceberry™ Rice Flour Prepared Using Dielectric Barrier Discharge Plasma Technology on Iron-Induced Oxidative Stress in Mice

Redox-active iron generates reactive oxygen species that can cause oxidative organ dysfunction. Thus, the anti-oxidative systems in the body and certain dietary antioxidants, such as anthocyanins, are needed to control oxidative stress. We aimed to investigate the effects of dielectric barrier discharge (DBD) plasma technology in the preparation of Riceberry™ rice flour (PRBF) on iron-induced oxidative stress in mice. PRBF using plasma technology was rich in anthocyanins, mainly cyanidine-3-glucoside and peonidine-3-glucoside. PRBF (5 mg AE/mg) lowered WBC numbers in iron dextran (FeDex)-loaded mice and served as evidence of the reversal of erythrocyte superoxide dismutase activity, plasma total antioxidant capacity, and plasma and liver thiobarbituric acid-reactive substances in the loading mice. Consequently, the PRBF treatment was observed to be more effective than NAC treatment. PRBF would be a powerful supplementary and therapeutic antioxidant product that is understood to be more potent than NAC in ameliorating the effects of iron-induced oxidative stress.

Emerging cold plasma treatment on rice grains: A mini review

Future demand of rice is projected to increase with the increase of global population. However, the presence of bacteria, insects, and fungi has resulted in various changes in the physical and chemical characteristics of rice grain. To make it worse, the overuse of post-harvest chemicals (fungicide and pesticide) has caused possible risks to human health through either occupational or non-occupational exposure. For the last few years, cold plasma has been developed as an alternative non-thermal emerging technology for rice grains treatment due to its ability to inactivate or decontaminate pathogens without causing thermal damage and free of any harmful residues. Therefore, this review describes the operational mechanism of cold plasma treatment technology on rice grains, existing reactor system designs, and parameters influenced by the treatment technology (reactor design parameters and treatment process parameters). Possible advanced investigation on future reactor design modification as well as standard operating range of influenced parameters were suggested for improved efficiency and effectiveness of cold plasma treatment.

Enhancement of seed germination and microbial disinfection on ginseng by cold plasma treatment

BACKGROUND

This study aimed to investigate the effect of cold plasma treatment on the improvement of seed germination and surface sterilization of ginseng seeds.

METHODS

Dehisced ginseng (Panax ginseng) seeds were exposed to dielectric barrier discharge (DBD) plasma operated in argon (Ar) or an argon/oxygen mixture (Ar/O2), and the resulting germination and surface sterilization were compared with those of an untreated control group. Bacterial and fungal detection assays were performed for plasma-treated ginseng seeds after serial dilution of surface-washed suspensions. The microbial colonies (fungi and bacteria) were classified according to their phenotypical morphologies and identified by molecular analysis. Furthermore, the effect of cold plasma treatment on the in vitro antifungal activity and suppression of Cylindrocarpon destructans in 4-year-old ginseng root discs was investigated.

RESULTS

Seeds treated with plasma in Ar or Ar/O2 exhibited a higher germination rate (%) compared with the untreated controls. Furthermore, the plasma treatment exhibited bactericidal and fungicidal effects on the seed surface, and the latter effect was stronger than the former. In addition, plasma treatment exhibited in vitro antifungal activity against C. destructans and reduced the disease severity (%) of root rot in 4-year-old ginseng root discs. The results demonstrate the stimulatory effect of plasma treatment on seed germination, surface sterilization, and root rot disease suppression in ginseng.

CONCLUSION

The results of this study indicate that the cold plasma treatment can suppress the microbial community on the seed surface root rot in ginseng.

Reduction of T-2 and HT-2 mycotoxins by atmospheric cold plasma and its impact on quality changes and germination of wheat grains

Wheat (Triticum aestivum) is susceptible to mycotoxin contamination, which can result in significant health risks and economic losses. This research examined the ability of air atmospheric cold plasma (air-ACP) treatment to reduce pure and spiked T-2 and HT-2 mycotoxins' concentration on wheat grains. This study also evaluated the effect of ACP treatment using different gases on wheat grain germination parameters. The T-2 and HT-2 mycotoxin solutions applied on round cover-glass were placed on microscopy slides and wheat grains (0.5 g) were individually spiked with T-2 and HT-2 on their surfaces. Samples were then dried at room temperature (∼24 °C) and treated by air-ACP for 1 to 10 min. Ten minutes of air-ACP treatment significantly reduced pure T-2 and HT-2 concentrations by 63.63% and 51.5%, respectively. For mycotoxin spiked on wheat grains, 10 min air-ACP treatment significantly decreased T-2 and HT-2 concentrations up to 79.8% and 70.4%, respectively. No significant change in the measured quality and color parameters was observed in the ACP-treated samples. Wheat grain germination parameters were not significantly different, when treated with ACP using different gases. Air-ACP treatment and ACP treatment using 80% nitrogen + 20% oxygen improved the germination of wheat grains by 10% and 6%, respectively. This study demonstrated that ACP is an innovative technology with the potential to improve the safety of wheat grains by reducing T-2/HT-2 mycotoxins with an additional advantage of improving their germination. PRACTICAL APPLICATION: Atmospheric cold plasma (ACP) technology has a huge potential to degrade mycotoxins in food grains. This study evaluated the efficacy of ACP to reduce two major mycotoxins (T-2 and HT-2 toxins) in wheat grains. The results of this study will help to develop and scale-up the ACP technology for mycotoxin degradation in grains.

An untargeted metabolomic insight into the high-pressure stress effect on the germination of wholegrain Oryza sativa L

High hydrostatic pressure (HHP) technique is used as a novel abiotic stress factor for efficiently enhancing the biosynthesis of selected bioactive phytochemicals in germinated wholegrain, but the information about HHP stress-induced metabolic changes remains rather limited. Thus, the current work employed an untargeted gas chromatography-mass spectrometry-based metabolomic approach combining with multivariate models to analyze the effect of mild HHP stress (30 MPa/5 min) on the overall metabolome shifts of wholegrain brown rice (WBR) during germination. Simultaneously, major phenolics in germinated WBR (GBR) were detected by ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry, to explore the potential relationship between HHP stress-induced rice metabolome alternations and the biotransformation of bioactive components. The results demonstrated that the influence of HHP stress on GBR metabolite profiles was defined by germination durations, as revealed by the differentiation of the stressed grains from the naturally germinated grains at different germination points according to principal component analysis. This was further confirmed by the results of orthogonal projections to latent structures discriminant analysis, in which the discriminating metabolites between naturally germinated and HHP-stressed grains varied across the germination process. The metabolite signatures differentiating natural and HHP-stressed germination included glycerol-3-phosphate, monosaccharides, gamma-aminobutyric acid, 2,3-butanediol, glyceryl-glycoside, amino acids and myo-inositol. Besides, HHP stress led to the increase in ribose, arabinitol, salicylic acid, azelaic acid and gamma-aminobutyric acid, as well as the reduced phenolic acids. These results demonstrated that HHP stress before germination matched with appropriate process parameters could be used as a promising technology to tailor metabolic features of germinated products, thus exerting targeted nutrition and health implications.

Effect of dielectric barrier discharge cold plasma treatments on flavor fingerprints of brown rice

A non-thermal processing method was developed to promote preservation of brown rice using dielectric barrier discharge cold plasma (DBD-CP). Physicochemical properties including free fatty acid (FFA) content, surface color change, volatile organic components (VOCs) and flavor fingerprints were evaluated in brown rice submitted to DBD-CP. FFA levels were 25.2% lower in treated samples compared to the control, and a more stable surface color was obtained at the end of the storage period. A total of 35 major VOCs could be detected in treated samples, and reduced levels of hexanal can be used as an indicator of DBD-CP treatment in brown rice during storage. Moreover, the flavor fingerprints in DBD-CP treated groups can be successfully distinguished through headspace gas chromatography ion mobility spectrometry. Collectively, application of DBD-CP treatment could be utilized as a feasible approach to promote stabilization of brown rice and preserve flavor during storage.