Effects of hydrogen-rich water on the nutrient composition and antioxidative characteristics of sprouted black barley

Effect of Sprouted Buckwheat on Glycemic Index and Quality of Reconstituted Rice

This study utilized sprouted buckwheat as the main component and aimed to optimize its combination with other grains to produce reconstituted rice with enhanced taste and a reduced glycemic index (GI). The optimal blend comprised wheat flour, sprouted buckwheat flour, black rice flour, and purple potato flour in a ratio of 34.5:28.8:26.7:10.0. Based on this blend, the reconstituted rice processed through extrusion puffing exhibited a purple-black hue; meanwhile, the instant reconstituted rice, produced through further microwave puffing, displayed a reddish-brown color. both imparted a rich cereal flavor. The starch in both types of rice exhibited a V-shaped structure with lower relative crystallinity. Compared to commercial rice, the reconstituted rice and instant reconstituted rice contained higher levels of flavonoids, polyphenols, and other flavor compounds, along with 1.63-fold and 1.75-fold more proteins, respectively. The GI values of the reconstituted rice and the instant reconstituted rice were 68.86 and 69.47, respectively; thus, they are medium-GI foods that can alleviate the increase in blood glucose levels.

Hydrogen Fertilization with Hydrogen Nanobubble Water Improves Yield and Quality of Cherry Tomatoes Compared to the Conventional Fertilizers

Although hydrogen gas (H2)-treated soil improves crop biomass, this approach appears difficult for field application due to the flammability of H2 gas. In this report, we investigated whether and how H2 applied in hydrogen nanobubble water (HNW) improves the yield and quality of cherry tomato (Lycopersicon esculentum var. cerasiforme) with and without fertilizers. Two-year-long field trials showed that compared to corresponding controls, HNW without and with fertilizers improved the cherry tomato yield per plant by 39.7% and 26.5% in 2021 (Shanghai), respectively, and by 39.4% and 28.2% in 2023 (Nanjing), respectively. Compared to surface water (SW), HNW increased the soil available nitrogen (N), phosphorus (P), and potassium (K) consumption regardless of fertilizer application, which may be attributed to the increased NPK transport-related genes in roots (LeAMT2, LePT2, LePT5, and SlHKT1,1). Furthermore, HNW-irrigated cherry tomatoes displayed a higher sugar-acid ratio (8.6%) and lycopene content (22.3%) than SW-irrigated plants without fertilizers. Importantly, the beneficial effects of HNW without fertilizers on the yield per plant (9.1%), sugar-acid ratio (31.1%), and volatiles (20.0%) and lycopene contents (54.3%) were stronger than those achieved using fertilizers alone. In short, this study clearly indicated that HNW-supplied H2 not only exhibited a fertilization effect on enhancing the tomato yield, but also improved the fruit's quality with a lower carbon footprint.

Exploration of the structural mechanism of hydrogen (H2)-promoted horseradish peroxidase (HRP) activity via multiple spectroscopic and molecular dynamics simulation techniques

Horseradish peroxidase (HRP) is an enzyme that is widely used in various fields. In this study, the effects of molecular hydrogen (H2) on the activity and structural characteristics of HRP were investigated by employing multiple spectroscopic techniques, atomic force microscopy (AFM) and molecular dynamics (MD) simulations. The results demonstrated that H2 could enhance HRP activity, especially in 1.5 mg/L hydrogen-rich water (HRW). The structural analysis results showed that H2 might alter HRP activity by affecting the active sites, secondary structure, hydrogen bonding network, CS groups, and morphological characteristics. The MD results also confirmed that H2 could increase the FeN bond distance in the active site, affect the secondary structure, and increase the number of hydrogen bonds. The MD results further suggested that H2 could increase the number of salt bridges, and lengthen the SS bonds in HRP. This study primarily revealed the mechanism by which H2 enhances the HRP activity, providing insight into the interactions between gas and macromolecular proteins. However, some of the results obtained via MD simulations still need to be verified experimentally. In addition, our study also provided a new convenient strategy to enhance enzyme activity.

Regulating the physicochemical, structural characteristics and digestibility of potato starch by complexing with different phenolic acids

The effects of ferulic acid (FA), protocatechuic acid (PA), and gallic acid (GA) on the physicochemical characteristics, structural properties, and in vitro digestion of gelatinized potato starch (PS) were investigated. Rapid viscosity analysis revealed that the gelatinized viscosity parameters of PS decreased after complexing with different phenolic acids. Dynamic rheology results showed that phenolic acids could reduce the values of G' and G″ of PS-phenolic acid complexes, demonstrating that the addition of phenolic acids weakened the viscoelasticity of starch gel. Fourier-transform infrared spectra and X-ray diffraction results elucidated that phenolic acids primarily reduced the degree of short-range ordered structure of starch through non-covalent interactions. The decrease in thermal stability and the more porous microstructure of the complexes confirmed that phenolic acids could interfere with the gel structure of the starch. The addition of different phenolic acids decreased the rapidly digestible starch (RDS) content and increased the resistant starch (RS) content, with GA exhibiting the best inhibitory capacity on starch in vitro digestibility, which might be associated with the number of hydroxy groups in phenolic acids. These results revealed that phenolic acids could affect the physicochemical characteristics of PS and regulate its digestion and might be a potential choice for producing slow digestibility starch foods.

Targeted metabolic reveals different part of maize in polyphenolic metabolites during germination and hypoglycemic activity analysis

In this study, qualitative and quantitative analyses of phenolic compounds in the maize germinating seed embryo, radicle, and germ were performed at 0, 48, and 96 h post-germination, followed by the evaluation of their hypoglycemic activity. The results revealed the accumulation of 80 phenolics in different parts of germinated maize, of which 47, 48, and 53 were present in the seed embryo, radicle, and germ. After germination 22, 26, and 34 polyphenols were found to differential accumulate in the seed embryo, radicle, and germ. At 96 h post-germination, the content of monomeric phenols in the germ was higher than that in the radicle and seed embryo. Moreover, the inhibitory activity of polyphenols in the germ towards α-glucosidase and α-amylase was higher than that in the radicle and seed embryo. These results indicate that germination can effectively improve the type and content of phenolic compounds in different parts of maize.

The role of guar gum in improving the gel and structural characteristics of germinated highland barley starch

Germinated highland barley has been shown to have many health benefits, but the weakening of the starch gel properties during the germination limits its further application. In this study, germinated highland barley starch (GBS) was obtained after germination treatment. Guar gum (GG) was added to explore the effects of gelatinization on the rheology, gel and structural characteristics of GBS, and the potential of preparing gel-based products was also evaluated. The results showed that the addition of GG significantly increased the viscosity, gel strength and viscoelasticity of GBS, which was beneficial to the formation of gel, and promoted its formation of an ordered and compact gel network structure. The study provides a theoretical reference for the preparation of gel-based food with highland barley starch, and increases the application range of highland barley.

Hydrogen-Rich Water Treatment of Fresh-Cut Kiwifruit with Slightly Acidic Electrolytic Water: Influence on Antioxidant Metabolism and Cell Wall Stability

The synergistic impact of hydrogen-rich water (HRW, 394 ppb) and slightly acidic electrolyzed water (SAEW, pH of 6.25 ± 0.19) on the antioxidant metabolism of fresh-cut kiwifruit during storage was investigated (temperature: (3 ± 1) °C, humidity: 80%-85%). Compared with control group, H+S treatment increased the contents of active oxygen-scavenging enzymes (SOD, CAT, POD, and APX) and inhibited the increase of O₂^•- and H₂O₂ contents during the storage of fresh-cut kiwifruit. Meanwhile, H+S treatment could reduce the activities of the cell wall-degrading enzymes PG, PME, PL, Cx, and β-Gal, inhibit the formation of soluble pectin, delay the degradation rate of propectin, cellulose, and pseudocellulose, and maintain higher fruit hardness and chewability. The results showed that H+S treatment could enhance free radical scavenging ability and reduce the cell wall metabolism of fresh-cut kiwifruit, maintaining the good texture found in fresh-cut fruit.

Preharvest application of hydrogen nanobubble water enhances strawberry flavor and consumer preferences

The improvement of fruit flavor is a challenge for producers and breeders. This study investigated the effects and mechanisms of preharvest hydrogen nanobubble water (HNW) application on the flavor of cultivated strawberry (Fragaria × ananassa 'Benihoppe'). Compared with surface water, HNW enhanced the volatile profiles, sugar-acid ratio, and sensory attributes (e.g., aroma, flavor, and overall liking) with/without fertilizer application. Meanwhile, flavor components such as esters (e.g., ethyl hexanoate), acids (e.g., hexanoic acid), and soluble sugars (including glucose, fructose, and sucrose) significantly contributed to increased strawberry flavor achieved with HNW. Importantly, HNW may alleviate the negative effects of fertilizers on strawberry fruit aroma. Further study elucidated that the aroma-related genes (including FaLOX, FaADH, FaAAT, FaQR, FaOMT, and FaNES1) were involved in the accumulation of specific volatiles after HNW treatment. This study provided evidence that the practical application of H₂ can improve horticultural product quality at a lower carbon cost.

Hydrogen-rich water promotes the formation of bulblets in Lilium davidii var. unicolor through regulating sucrose and starch metabolism

HRW increased the content of starch and sucrose via regulating a series of sucrose and starch synthesis genes, which induced the formation of bulblets and adventitious roots of Lilium davidii var. unicolor. Hydrogen gas (H₂), as a signaling molecule, has been reported to be involved in plant growth and development. Here, the effect of hydrogen-rich water (HRW) on the formation of bulblets and adventitious roots in the scale cuttings of Lilium davidii var. unicolor and its mechanisms at the molecular levels were investigated. The results revealed that compared with distilled water treatment (Con), the number of bulblets and adventitious roots were significantly promoted by different concentrations of HRW treatment. Treatment with 100% HRW obtained the most positive effects. RNA sequencing (RNA-seq) analysis found that compared with Con, a total of 1702 differentially expressed genes (DEGs, upregulated 552 DEGs, downregulated 1150 DEGs) were obtained under HRW treatment. The sucrose and starch metabolism, cysteine and methionine metabolism and phenylalanine metabolism were significantly enriched in the analysis of the Kyoto encyclopedia of genes and genomes (KEGG). In addition, the genes involved in carbohydrate metabolism were significantly upregulated or downregulated (upregulated 22 DEGs, downregulated 15 DEGs), indicating that starch and sucrose metabolism held a central position. The expressions of 12 DEGs were identified as coding for key enzymes in metabolism of carbohydrates was validated by qPCR during bulblet formation progress. RNA-seq analysis and expression profiles indicated that the unigene levels such as glgc, Susy, otsA and glgP, BMY and TPS were well correlated with sucrose and starch metabolism during HRW-induced bulblet formation. The change of key enzyme content in starch and sucrose metabolism pathway was explored during bulblet formation in Lilium under HRW treatment. Meanwhile, compared with Con, 100% HRW treatment increased the levels of sucrose and starch, and decreased the trehalose content, which were agreed with the expression pattern of DEGs related to the biosynthesis pathway of sucrose, starch and trehalose. Therefore, this study suggested that HRW could promote the accumulation of sucrose and starch contents in mother scales, and decreased the trehalose content, this might provide more energy for bulblet formation.

Hydrogen agronomy: research progress and prospects

Agriculture is the foundation of social development. Under the pressure of population growth, natural disasters, environmental pollution, climate change, and food safety, the interdisciplinary "new agriculture" is becoming an important trend of modern agriculture. In fact, new agriculture is not only the foundation of great health and new energy sources, but is also the cornerstone of national food security, energy security, and biosafety. Hydrogen agronomy focuses mainly on the mechanism of hydrogen gas (H₂) biology effects in agriculture, and provides a theoretical foundation for the practice of hydrogen agriculture, a component of the new agriculture. Previous research on the biological effects of H₂ focused chiefly on medicine. The mechanism of selective antioxidant is the main theoretical basis of hydrogen medicine. Subsequent experiments have demonstrated that H₂ can regulate the growth and development of plant crops, edible fungus, and livestock, and enhance the tolerance of these agriculturally important organisms against abiotic and biotic stresses. Even more importantly, H₂ can regulate the growth and development of crops by changing the soil microbial community composition and structure. Use of H₂ can also improve the nutritional value and postharvest quality of agricultural products. Researchers have also shown that the biological functions of molecular hydrogen are mediated by modulating reactive oxygen species (ROS), nitric oxide (NO), and carbon monoxide (CO) signaling cascades in plants and microbes. This review summarizes and clarifies the history of hydrogen agronomy and describes recent progress in the field. We also argue that emerging hydrogen agriculture will be an important direction in the new agriculture. Further, we discuss several scientific problems in hydrogen agronomy, and suggest that the future of hydrogen agronomy depends on contributions by multiple disciplines. Important future research directions of hydrogen agronomy include hydrogen agriculture in special environments, such as islands, reefs, aircraft, and outer space.

Hydrogen Commonly Applicable from Medicine to Agriculture: From Molecular Mechanisms to the Field

The emerging field of hydrogen biology has to date mainly been applied in medicine. However, hydrogen biology can also enable positive outcomes in agriculture. Agriculture faces significant challenges resulting from a growing population, climate change, natural disasters, environmental pollution, and food safety issues. In fact, hydrogen agriculture is a practical application of hydrogen biology, which may assist in addressing many of these challenges. It has been demonstrated that hydrogen gas (H₂) may enhance plant tolerance towards abiotic and biotic stresses, regulate plant growth and development, increase nutritional values, prolong the shelf life, and decrease the nitrite accumulation during the storage of vegetables, as well as increase the resilience of livestock to pathogens. Our field trials show that H₂ may have a promising potential to increase yield and improve the quality of agricultural products. This review aims to elucidate mechanisms for a novel agricultural application of H₂ in China. Future development of hydrogen agriculture is proposed as well. Obviously, hydrogen agriculture belongs to a low carbon economy, and has great potential to provide "safe, tasty, healthy, and high-yield" agricultural products so that it may improve the sustainability of agriculture.

Differential response of fragrant rice cultivars to salinity and hydrogen rich water in relation to growth and antioxidative defense mechanisms

Salinity negatively effects the growth and productivity of crop plants; however, the effects of hydrogen rich water (HRW) on the early growth of fragrant rice under salinity stress are rarely investigated. In present study, two HRW treatments: foliar application (F-HRW) and irrigation (I-HRW) were applied on the two fragrant rice cultivars, Yuxiangyouzhan and Xiangyaxiangzhan, grown under normal and salt stress conditions, i.e., 0 and 150 mmol NaCl L^-1, respectively. Plants without HRW application were grown as control (CK). Results showed that the dry weight per unit plant height (mg cm^-1) was increased by 12.6% and 23.0% in F-HRW and I-HRW, respectively under salt stress as compared with CK. Application of HRW, regardless of the application method, modulated the antioxidant activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) while reduced malondialdehyde (MDA) contents under salt stress. Moreover, significant and positive relations were observed among total dry weight and shoot dry weight, dry weight per unit plant height, SOD and CAT activity in root. Overall, F-HRW application modulated the early growth and related physiological attributes in fragrant rice under salt stress whereas I-HRW was found to mitigate salt stress. Novelty statement: Involvement of endogenous H₂ in plants for regulating various physiological functions is of great importance to stimulate and/or activate the antioxidant defense responses against oxidative stress; however, there is a lack of research in this aspect. The present study investigated the effects of hydrogen rich water (HRW) on the growth and physiological attributes of two fragrant rice cultivars grown under salt-stress. It was noteworthy to find that application of HRW either foliar application or irrigation improved the morphological characters, i.e., dry weight per unit plant height and enhanced the activities of antioxidants, i.e., peroxidase, superoxide dismutase and catalase whilst decreased the malonaldehyde content. Overall, the application of HRW modulates plant growth and physiological attributes in fragrant rice cultivars under salt-stress conditions. This study will be helpful in improving the early growth and/or stand establishment of fragrant rice nursery under saline conditions.

Downstream Signalling from Molecular Hydrogen

Molecular hydrogen (H2) is now considered part of the suite of small molecules that can control cellular activity. As such, H2 has been suggested to be used in the therapy of diseases in humans and in plant science to enhance the growth and productivity of plants. Treatments of plants may involve the creation of hydrogen-rich water (HRW), which can then be applied to the foliage or roots systems of the plants. However, the molecular action of H2 remains elusive. It has been suggested that the presence of H2 may act as an antioxidant or on the antioxidant capacity of cells, perhaps through the scavenging of hydroxyl radicals. H2 may act through influencing heme oxygenase activity or through the interaction with reactive nitrogen species. However, controversy exists around all the mechanisms suggested. Here, the downstream mechanisms in which H2 may be involved are critically reviewed, with a particular emphasis on the H2 mitigation of stress responses. Hopefully, this review will provide insight that may inform future research in this area.

Comparative Study of the Effects of Light Controlled Germination Conditions on Saponarin Content in Barley Sprouts and Lipid Accumulation Suppression in HepG2 Hepatocyte and 3T3-L1 Adipocyte Cells Using Barley Sprout Extracts

Barley sprouts (BS) contain physiologically active substances and promote various positive physiological functions in the human body. The levels of the physiologically active substances in plants depend on their growth conditions. In this study, BS were germinated using differently colored LED lights and different nutrient supplements. Overall, there were 238 varied BS samples analyzed for their total polyphenol and flavonoid contents. Principal component analysis (PCA) was performed to determine the relationship between the germinated samples and their total polyphenol and flavonoid contents, and those with high levels were further analyzed for their saponarin content. Based on the PCA plot, the optimal conditions for metabolite production were blue light with 0.1% boric acid supplementation. In vitro experiments using the ethanol extract from the BS cultured in blue light showed that the extract significantly inhibited the total lipid accumulation in 3T3-L1 adipocytes and the lipid droplets in HepG2 hepatocytes. These findings suggest that specific and controlled light source and nutrient conditions for BS growth could increase the production of secondary metabolites associated with inhibited fat accumulation in adipocytes and hepatocytes.