Soluble Phenolic Compounds Research Articles

Optimization and comparison of nonconventional extraction techniques for soluble phenolic compounds from brocade orange (Citrus sinensis) peels.

Brocade orange (Citrus sinensis L. Osbeck) peels (BOPs) are rich in a variety of phenols with multiple and strong bioactivities. This study sought to utilize a response surface methodology to optimize the parameters of accelerated solvent extraction (ASE) to obtain phenolic extracts from BOPs. Total phenolic and flavonoid content (TPC and TFC), profiles, and antioxidant activities of extracts for free, esterified-, and glycosylated-bound phenols from ASE were compared with those derived from Soxhlet extraction (SE) (80°C, 6h) and heat-reflux extraction (HRE) (80°C, 3h). Maximum practical TPC and TFC under optimal ASE conditions (15min, 108°C, 82bar, and three cycles) were determined to be 32.82mg gallic acid equivalents/dry weight (DW) and 10.25mg rutin equivalents/DW, respectively. The profiles, contents, and corresponding bioactivities of the extracts significantly depended on extraction method, particularly with regard to phenolic fraction. Generally, ASE and HRE were associated with higher levels of extraction efficiency and higher quality targeted bioactive compounds with stronger antioxidant activity. More importantly, ASE represents a simple, efficient, and time-saving technique for the extraction of phenols. Furthermore, the finding that different phenolic fractions contain variable profiles and contents of phenols is useful for efforts to obtain targeted individual bioactive ingredients and make better use of biomass residues.

Andean Sprouted Pseudocereals to Produce Healthier Extrudates: Impact in Nutritional and Physicochemical Properties

The tailored formulation of raw materials and the combination of grain germination and extrusion processes could be a promising strategy to achieve the desired goal of developing healthier expanded extrudates without compromising sensory properties. In this study, modifications in the nutritional, bioactive profile and physicochemical properties of corn extrudates as influenced by the complete or partial replacement by sprouted quinoa (Chenopodium quinoa Willd) and cañihua (Chenopodium pallidicaule Aellen) were investigated. A simplex centroid mixture design was used to study the effects of formulation on nutritional and physicochemical properties of extrudates, and a desirability function was applied to identify the optimal ingredient ratio in flour blends to achieve desired nutritional, texture and color goals. Partial incorporation of sprouted quinoa flour (SQF) and cañihua flour (SCF) in corn grits (CG)-based extrudates increased phytic acid (PA), total soluble phenolic compounds (TSPC), γ-aminobutyric acid (GABA) and oxygen radical antioxidant activity (ORAC) of the extrudates. Sprouted grain flour usually results in an deleterious effect physicochemical properties of extrudates, but the partial mixture of CG with SQF and SCF circumvented the negative effect of germinated flours, improving technological properties, favoring the expansion index and bulk density and increasing water solubility. Two optimal formulations were identified: 0% CG, 14% SQF and 86% SCF (OPM1) and 24% CG, 17% SQF and 59% SCF (OPM2). The optimized extrudates showed a reduced amount of starch and remarkably higher content of total dietary fiber, protein, lipids, ash, PA, TSPC, GABA and ORAC as compared to those in 100% CG extrudates. During digestion, PA, TSPC, GABA and ORAC showed good stability in physiological conditions. Higher antioxidant activity and amounts of bioaccessible TSPC and GABA were found in OPM1 and OPM2 digestates as compared to those in 100% CG extrudates.

Physicochemical Properties and Sensory Attributes of Homemade Bakery Products from Two Local Varieties of Pineapple Compared with the Locally Available Market Products in Bangladesh

Pineapples (Ananas comosus L. Merr) contain beneficial properties and the object of the study is to compare the physical and chemical properties of two local varieties of pineapples and their prepared bakery products such as jelly and biscuit using flesh of pineapple as one of the raw materials and compare those with the locally available market products. Physico – chemical properties such as fruit weight, diameter, length, edible portion %, pH, Vitamin C, Titratable acidity, sugar content, total soluble solids, lipid content, crude protein, phenolic compound and sensory attributes (Firmness, sweetness, tartness, colour, and overall acceptability) of fresh pineapple fruit of Honey Queen (HQ) and Giant Kew (GK) were studied. Both the varieties contained high amount of moisture, GK 84.42% and HQ 83.95%. Further, HQ variety showed more than GK variety in almost all of the properties. The phenolic contents of the extracts as caffeic acid equivalents were found to be highest in methanol HQ (12.45%), GK (9.8%) while in water extract HQ (5.4%), and GK (5.3%). In terms of prepared bakery product from pineapple, Sample H (Home prepared) was more preferable than the locally market available brand in consideration of the physico-chemical properties that affected the sensory attributes acceptability having the overall acceptability score of 7 in a 9-point hedonic scale.

Size and harvest time of cladodes modulate the composition and physicochemical stability of prickly pear cactus mucilage

The objective was to carry out a physicochemical characterization of the mucilage obtained from different sizes of cladodes harvested at different times. Nopalea cochenillifera Salm Dyck cladodes were collected in two sizes (100 to 230 and 240 to 300 mm), at two different times (6 am and 8 pm), and processed for mucilage extraction. This was dried in an oven, and then hydrated and kept at 5 °C for 12 days. The mucilage yield after harvest was quantified, in addition to the characterization of the main bands in the infrared region. In the mucilage, the following physicochemical analyzes were performed: K+ and Na+ content, electrical conductivity, titratable acidity, pH, total phenolic compounds, vitamin C, total soluble solids, total soluble carbohydrates, total soluble proteins after harvest (day 0), and to the 12 days of storage at 5 ºC. Correlation between the variables was determined through principal component analysis (PCA). The highest mucilage yield was obtained in cladodes harvested at 6 am, regardless of size. The 6 am harvest showed higher acidity and protein content and lower concentrations of soluble solids, EC, Na+, K+, vitamin C, carbohydrates, and phenolic compounds. In conservation, the mucilage of the cladodes with sizes between 100 and 230 mm and the harvest at 6 am showed greater stability. Principal component analysis (PCA) showed a tendency of formed groups between different sizes, harvest times, and conservation days, indicating that different conditions for obtaining the cladodes result in differences in the composition and stability of the mucilage. Thus, the results show that, in addition to the climatic conditions, as proposed by other authors, the harvest time and the size of the cladode modulate the physicochemical and important ion composition and stability, which can change the technological and industrial applications of mucilage.

Impact of 24-epibrassinolide, spermine, and silicon on plant growth, antioxidant defense systems, and osmolyte accumulation of maize under water stress

The effect of triad application of the phytohormone 24-epibrassinolide (EBL), the polyamine spermine (Spm), and the element silicon (Si) has not yet been considered on plant growth and behavior in water-stressed conditions. We aimed to evaluate the impact of single/dual/triad application of 24-epibrassinolide (EBL), spermine (Spm), and silicon (Si) on the growth, photosynthetic metabolites, and antioxidant enzymes in the maize plant exposed to water stress. This study was conducted as a potential drought resistance system and plants' maintenance against oxidative damage. In this regard, one maize hybrid (Paya) was grown under well-watered and water-deficit conditions (interrupted irrigation at the flowering and the filling seed stages) with and without foliar spraying of EBL, Spm, and/or Si. Drought conditions remarkably reduced growth, productivity, water-related content (RWC), and chlorophyll content. However, the dual and triad applications of EBL (0.1 mg L−1), Spm (25 mg L−1), and Si (7 mg L−1) significantly improved the above parameters. Water stress considerably augmented the levels of H2O2 and MDA. Their content in stress-subjected plants was significantly reduced by triad application. In water-stressed circumstances and after foliar treatments, the activities of superoxide dismutase, catalase, and peroxidase as well as the amounts of total soluble proteins, phenolic compounds, proline, and glycine betaine all improved. Overall, triad application increased the plant's drought resistance and diminished ROS accumulation by raising the scavenging via the enhanced activity of the antioxidant enzymes.

Physicochemical Properties and Bioaccessibility of Phenolic Compounds of Dietary Fibre Concentrates from Vegetable By-Products.

The agro-food industry generates a large volume of by-products, whose revaluation is essential for the circular economy. From these by-products, dietary fibre concentrates (DFCs) can be obtained. Therefore, the objective of this study was to characterise (a) the proximal composition by analysing soluble, insoluble and total Dietary Fibre (DF), (b) the physicochemical properties, and (c) the phenolic profile of artichoke, red pepper, carrot, and cucumber DFCs. In addition, the bioaccessibility of phenolic compounds was also evaluated after in vitro gastrointestinal and colonic digestions. The results showed that the DFCs had more than 30 g/100 g dw. The water holding and retention capacity of the DFCs ranges from 9.4 to 18.7 g of water/g. Artichoke DFC presented high concentration of phenolic compounds (8340.7 mg/kg) compared to the red pepper (304.4 mg/kg), carrot (217.4 mg/kg) and cucumber DFCs (195.7 mg/kg). During in vitro gastrointestinal digestion, soluble phenolic compounds were released from the food matrix, chlorogenic acid, the principal compound in artichoke and carrot DFCs, and hesperetin-7-rutinoside in red pepper cucumber DFCs. Total phenolic content decreased after in vitro colonic digestion hence the chemical transformation of the phenolic compounds by gut microbiota. Based on the results, DFCs could be good functional ingredients to develop DF-enriched food, reducing food waste.

Combining Transcriptomics and Polyphenol Profiling to Provide Insights into Phenolics Transformation of the Fermented Chinese Jujube.

As an important medicine homologous food, Chinese jujube is rich in nutrition and medicinal value. To enhance the bioactive compounds level of Chinese jujube products, three kinds of fungi strains (Rhizopus oryzae, Aspergillus niger and Monascus purpureus) were firstly selected to evaluate their effects on total soluble phenolic compounds (TSPC) and total soluble flavonoids compounds (TSFC) contents during liquid state fermentation of Chinese jujube. As the best strain, the highest contents of TSPC and TSFC could increase by 102.1% (26.02 mg GAE/g DW) and 722.8% (18.76 mg RE/g DW) under M. purpureus fermentation when compared to the unfermented sample, respectively. Qualitative and quantitative analysis of individual polyphenol compounds indicated that proto-catechuic acid, p-hydroxybenzoic acid and chlorogenic acid showed the highest level in the fer-mented Chinese jujube at the 7th day, which was enhanced by 16.72-, 14.05- and 6.03-fold when compared to the control, respectively. Combining with RNA sequencing, function annotation of CAZymes database and polyphenol profiling, three potential transformation pathways of poly-phenol compounds were proposed in the fermented Chinese jujube by M. purpureus, such as the conversion of insoluble bound phenolic acids, rutin and anthocyanin degradation. These findings would be beneficial for better understanding of the biotransformation mechanism of polyphenol compounds in fungi fermentation.

Bioactive compounds and physical-chemical characteristics of two genotypes of peach trees submitted to nitrogen fertilization

Nitrogen, which is the primary nutrient peach trees need, may affect their fruit quality. Thus, this study aimed at evaluating the effect of nitrogen fertilization on two genotypes of peach trees, regarding their fruit quality, in three consecutive crops. The experiment was carried out in the experimental area that belongs to the Embrapa Clima Temperado, located in Pelotas, Rio Grande do Sul (RS), Brazil, from 2016, 2016, 2017 and 2018. Four doses of nitrogen (0, 60, 120 and 180 Kg ha-1) and two peach tree genotypes (‘Cascata 1513’ and ‘Cascata 1067’) were used. For the fruit, we evaluated epidermis color, pulp firmness, epidermis firmness, soluble solids concentration, titratable acidity, concentration of total phenolic compounds, anthocyanins and antioxidant activity. Fruit underwent physical, chemical and bioactive compound analyses. Results showed that the highest dose of nitrogen (180 Kg ha-1) applied to the soil retards fruit ripening, while no application of nitrogen fertilization brings fruit maturation forward. Nitrogen fertilization via soil does not favor anthocyanins in fruit. Doses of 60 and 120 Kg ha-1 of nitrogen are recommended because they lead to improvement in peach color, epidermis firmness and acidity. Peach tree genotypes influence soluble solids, juice pH, phenolic compounds and antioxidant activity of their fruit.

The Critical Role of Phenolics on Gasification of Biomass Hydrolysate

The study was designed to solubilize sorghum by water extraction and investigate the effect of phenolics depending on the time in sorghum hydrolysate for hydrogen gas production by aqueous-phase reforming. The Folin-Ciocalteau method was used to determine the total water soluble phenolics of the sorghum hydrolysate. There were no significant changes in the total amount of phenolic compounds during the first weeks. It was observed that the total amount of water soluble phenolic compounds of sorghum hydrolysates showed changes monthly (300-400 ppm). The gas volume produced reached up to 40-50 mL was obtained when the hydrolysates were gasified. APR of biomass hydrolysates in the presence of a reforming catalyst (Pt 5% on activated carbon) produced various amount of gas mixture which consisted of H2, CH4 and CO2 gases. The results showed that the decrease in total water soluble phenolics of sorghum hydrolysate had no significant effect on gasification, depending on the time.

Screening and Estimation of Bioactive Compounds of Azanza garckeana (Jakjak) Fruit Using GC-MS, UV–Visible Spectroscopy, and HPLC Analysis

Azanza garckeana (F. Hoffm). Exell and Hillc. is an important food and medicinal plant that has been used in tropical Africa. Therefore, this study aimed to investigate the nutritional value of jakjak fruit using different analytical techniques. The obtained results have demonstrated that jakjak fruit is very rich in total soluble sugar, constituting about 48% of the dry weight. Moreover, the chromatographic analysis revealed that jakjak fruit contained a high amount of glucose, fructose, maltose, and ascorbic acid. Further, GC-MS analysis detected four compounds related to secondary metabolites. Some of these detected constituents have medicinal value. For example, phenol, 2,4-bis (1,1-dimethylethyl) has been reported to have many functions such as antioxidant activity, anticancer, antifungal, and antibacterial properties. Furthermore, the antioxidant potential of different concentrations of deionized water and methanolic extracts was estimated using 2,2-diphenyl-1-picrylhydrazyl (DPPH). The results showed that the scavenging activity of the DPPH radical was found to be raised with increasing concentrations of fruit extracts. The concentration (50%) of both methanol and deionized water gave the best inhibition percentage (91.7 and 84.4%), respectively. In contrast, the methanolic extract has shown significant results compared to deionized water. This study concluded that jakjak fruit is very rich in total soluble sugar and phenolic compounds, which can be used as a source of polysaccharides and antioxidants for the human diet as well as raw materials for downstream industries.

Profiling carotenoid and phenolic compounds in fresh and canned fruit of peach cultivars: Impact of genotype and canning on their concentration

Peach (Prunus persica (L.) Batsch) is widely consumed both fresh and processed. Scarce information exists regarding the fate of phytochemicals after the peach canning process. The aim of the current study was to evaluate the compositional variability and impact of processing on the bioactive compounds profile of eight non-melting peach cultivars, both in fresh and canned forms, thermally processed with either light syrup (LS) or grape juice (GJ) as the packing medium. LC–MS analysis demonstrated that the phytochemical profile is primarily genotype dependent. Prediction profile statistics revealed that cv. ‘Andross’, a predominant clingstone peach cultivar, possessed the highest desirability score among all the examined cultivars. Free zeaxanthin and lutein remained relatively unaffected by the canning process compared to free β-carotene, whereas soluble phenolic compounds, such as neochlorogenic acid, chlorogenic acid, procyanidin B1 and catechin, showed a large decrease following canning. Using GJ, an additional source of polyphenols, as packing medium led to a reduction of losses for the bioactive compounds. Overall, the experimental findings demonstrated that, besides the thermal degradation of some sensitive to heating compounds, there is a bidirectional flow of the bioactive compounds between the fruit tissue and the liquid matrix, as balanced out by diffusion processes.

Adaptive Redox Reactions Promote Naturalization of Rare Orchid Epipactis atrorubens on Serpentine Dumps Post Asbestos Mining

Epipactis atrorubens (Hoffm.) Besser. is a regionally rare orchid species with highly ornamental properties due to its very beautiful bright flowers, therefore it is of considerable interest as a horticultural plant for use in botanical gardens and greenhouses. The objective of the research was to assess metal accumulation and some pro- and antioxidant reactions in E. atrorubens, colonizing serpentine dumps post asbestos mining. Additionally, some physicochemical properties of substrates, microbiotic characteristics and water status were investigated in orchids growing on two serpentine dumps and in a natural forest habitat of the Middle Urals, Russia. The dump substrates were characterized by the strong stoniness and the high content of Mg, Ni, Cr and Co (by 1.8 times on average) compared to the natural habitat. In these sites, E. atrorubens was characterized by increased mycorrhization. In the rhizome and roots of E. atrorubens the concentrations of most metals studied were considerably higher (more than 4 times on average) than in the leaves. It was found that orchids colonizing serpentine dumps produced more lipid peroxidation products (by 1.4 times on average) in the leaves which was accompanied by the more active synthesis of such non-enzymatic antioxidants as ascorbate, free proline, soluble phenolic compounds (including flavonoids) and non-protein thiols. The study suggests that non-enzymatic antioxidants increased the adaptive potential of E. atrorubens and contributed to its naturalization on serpentine dumps post asbestos mining.

Pasteurization Modifies the Sensorial Attributes and Nutritional Profile of Orange Pulp By-Product.

After orange processing, different by-products are generated, i.e., peels, seeds and pulps. The pulp is highly perishable, being an unstable food matrix that needs a preservation process to be stored and used again in the food production chain. Pasteurization is the technique of choice before aseptically packaging and storing under refrigerated conditions. In this study, the effect of pasteurization has been evaluated on the chemical, functional and sensorial profiles. Ash content decreased (p < 0.05) after the thermal treatment. Indeed, magnesium, calcium and zinc diminished, although copper was found to be higher (p < 0.05) in the pasteurized product. Total dietary fiber decreased (p < 0.05), but soluble dietary fiber raised (p < 0.05) due to hydrolysis caused by pasteurization. SDF:IDF ratio, hydration properties, and fat binding capacity were improved. Total soluble phenolic compounds remained similar but FRAP and DPPH scavenging activity decreased (p < 0.05) in the pasteurized by-product. Regarding the sensorial profile, pasteurization produced darkening, appearance of a cooked smell and an increase in bitterness. Therefore, pasteurization deteriorates the sensorial profile being able to change the attributes of an added-pasteurized-pulp juice; however, it is a good choice to preserve the orange pulp by-product to formulate food products different from juices or other beverages.

Optimization of reaction conditions for the design of cereal-based dietary fibers with high antioxidant capacity.

Bound antioxidants are distinguished by their strong potential to defend the body against oxidative stress. Cereal bran fractions contain antioxidant compounds bound to dietary fiber, but this only occurs to a limited extent. Increasing the quantity of bound antioxidant compounds using soluble phenolic compounds is thought to be a possible method for designing cereal-based dietary fibers with high antioxidant potential. Certain cereal bran samples (wheat, oat, rye, and rice) were reacted with different concentrations of beverages (green tea infusion, black tea infusion, espresso, and red wine), rich in various soluble phenolic compounds. The interactive effects of parameters (time, temperature, and pH) and the optimum conditions for the reaction were determined using response surface methodology. Green tea infusion (30 g·L-1 ) was found to be the most effective beverage. The pH rather than the time and temperature had significant (O p< 0.0001) effects on the reaction. Neutral or slightly alkaline conditions (pH7.0-7.9) and mild temperatures (at about 50 °C) were found to be optimum to increase the antioxidant capacity of cereal bran samples. The total antioxidant capacity of oat bran treated with green tea infusion under optimum conditions (53.3°C, pH7.4, 60.0min) reached 226.42 ± 0.88 mmol Trolox equivalent·kg-1 . The free amino groups in cereal bran were also found to decrease (32-95%) after treatment. It is possible to design functional cereal-based dietary fibers, rich in bound antioxidant compounds through treatment with green tea infusion under optimum conditions. © 2022 Society of Chemical Industry.

Monosaccharide profile of “Mendim Me Zon”: Beverage from Solanum aethiopicum Shum berries

Solanum aethiopicum Shum is a plant belonging Solanaceae family. These berries are used for their food and pharmacological virtues. For instance, they are commonly consumed in the form of hot-drink, so called “Mendim Me Zon” used by the forest people. Revitalizing and detoxifying properties are attributed to this beverage. The bioactivity of this drink is often attributed to its secondary metabolites. While monosaccharides also have a biological activity that may contribute to the virtues of this tea. The present work was carried out to analyse the carbohydrate fraction of “Mendim Me Zon”. The extract prepared following the preparation conditions of “Mendim Me Zon” was analysed to determine its proximate composition, including soluble carbohydrates, proteins and total phenolic compounds. The monosaccharide profile was established using gas chromatography. Results show that carbohydrates were its most abundant constituent in the extract, although the taste was bitter. This taste is certainly determined by phenolic compounds present in the extract. Gas chromatography analysis of the extract showed that extract was composed of pentose (fucose), hexoses (mannose, galactose and glucose), hexosamines (glucosamine and galactosamine), uronic acid (glucuronic acid) and sialic acid (N-acetyl-neuraminic acid). Fructose was absent from the extract, while the mannose was relatively more abundant. These results might suggest that “Mendim Me Zon” contains monosaccharides and their derivatives with many beneficial biological functions. The monosaccharide profile justifies the traditional use of this drink as a nutraceutical. However, further studies including toxicological one are still needed to determine the safety and efficacy of “Mendim me Zon”.

Season and Ecotype Effects on Soluble Phenolic Compounds Content and Antioxidant Potential of Tamarindus indica and Mitragyna inermis

Season and Ecotype Effects on Soluble Phenolic Compounds Content and Antioxidant Potential of Tamarindus indica and Mitragyna inermis

Improving Nutritional and Health Benefits of Biscuits by Optimizing Formulations Based on Sprouted Pseudocereal Grains.

A mixture design (MD) was used to evaluate the effect of replacing wheat flour (WF) with sprouted cañihua (Chenopodium pallidicaule Aellen), kiwicha (Amarathus caudatus L.), and quinoa (Chenopodium quinoa Willd.) flours (SCF, SKF, and SQF, respectively) on the content of phytic acid (PA), γ-aminobutyric acid (GABA), total soluble phenolic compounds (TSPC), and antioxidant activity (AA) in biscuits. Generally, sprouted pseudocereal flours contained lower amounts of starch and protein, comparable fat, ash, PA content, and increased levels of bioactive compounds (GABA and TSPC) and AA compared with wholegrain flours. Moreover, it was confirmed that sprouted pseudocereal flours were nutritionally superior to refined WF. MD allowed the modeling of target parameters showing that PA, GABA, TSPC, and AA were positively influenced by the proportion of flours in the biscuit. The models that better described the variation in nutritional parameters as a function of the formulation displayed typically linear and binary interactions terms. SKF exerted the highest influence on the increased content of PA. Therefore, to increase mineral bioavailability, the use of SCF and SQF in the formulation of biscuits was suggested. SCF and SQF positively influenced in GABA, TSPC, and AA in biscuits. The optimal ternary blends of flours that maximize the content of bioactive compounds and AA of biscuits and simultaneously minimize PA content were identified. To study the fate of biscuits in digestion, the optimal formulation for biscuits containing SQF/SCF was selected. For this type of baked product, reduced starch digestibility and glycemic index was observed compared with the control (100% WF). Moreover, the amounts of bioaccessible GABA, TSPC, and AA were higher in gastric and intestinal digests compared with control biscuit. Overall, these results highlighted the nutritional and health benefits of incorporation of flours from sprouted Andean grains in the production of biscuits.

Reformulating Bread Using Sprouted Pseudo-cereal Grains to Enhance Its Nutritional Value and Sensorial Attributes.

Sprouting is an effective treatment for improving nutritional and bioactive properties as well as lowering the anti-nutritional compounds in pseudo-cereals. Enhancing nutritional properties when using sprouted pseudo-cereals flours as a baking ingredient requires tailored formulation. Simplex centroid designs and response surface methodology has been applied in the present study to define the ideal proportions of ternary blends of sprouted kiwicha (SKF), cañihua (SCF) and wheat flours (WF) to simultaneously enhance the content in bioactive compounds (γ-aminobutyric acid, GABA, total soluble phenolic compounds and TSPC), as well as sensory (odor, color, taste and texture) and functional attributes (antioxidant activity, AA) while reducing phytic acid (PA) content of bread. The effect of gastric and intestinal digestion on bioactive compounds, AA, PA and starch hydrolysis was also evaluated. Mixture design allowed for the identification of optimal formulation (5% SKF, 23.1% SCF, 71.9% WF) that can be used to obtain breads with higher content of GABA, TSPC, AA, overall sensorial acceptability (scores > 7) and reduced PA content and glycemic index. Moreover, this study demonstrated that these nutritional and health benefits provided by the replacement of WF by sprouted pseudo-cereal flours remained upon digestion. The results of this study indicated that WF replacement with SKF and SCF is sensory acceptable and improved the nutritional quality of bread.

Exogenous arginine treatment additively enhances growth and tolerance of Salicornia europaea seedlings under salinity

The effects of foliar application of 5 mM arginine (Arg) on the growth and control of salinity-induced osmotic and oxidative stresses (0, 200, 400 and 600 mM NaCl) in Salicornia europaea seedlings were investigated. Despite higher levels of lipid peroxidation, lower membrane stability index (MSI), decreased pigment content and phenolic compounds, and reduced activity of antioxidant enzymes observed under salinity, seedling growth indices, including plant height and biomass, increased significantly, and some protective and antioxidant molecules such as proline and flavonoids accumulated. Soluble protein level increased at the low salt concentration (200 mM) but decreased at other doses. Exogenous Arg treatment alone had less or no effect on plant biomass and other metabolites, but in combination with salt, further enhanced growth parameters, MSI and accumulation of soluble protein, phenolic compounds and proline. Arg-induced changes under salinity were associated with decreased lipid peroxidation, flavonoids content and antioxidant enzymes activity. These results show that S. europaea seedlings are well tolerant to applied salt doses. The treatment with exogenous Arg alone affects plant growth slightly, but in combination with salt, synergistically increases growth and salt tolerance of these plants by enhancing the accumulation of proline and antioxidant molecules instead of enzymatic antioxidant.

Impact of Adult Popillia japonica (Coleoptera: Scarabaeidae) Foliar Feeding Injury on Fruit Yield and Quality of a Temperate, Cold-Hardy Wine Grape, 'Frontenac'.

Popillia japonica (Newman), is a highly polyphagous, invasive species, first recorded in the U.S. in 1916, and detected in Minnesota in the late 1960s. Historically, research on this pest in the Midwest U.S. has focused primarily on ornamental and turf crops, with little attention placed on adult feeding damage to fruit crops. Recently, wine grape producers in the region noted substantial increases in defoliation from P. japonica feeding, confirming concerns for this perennial high value crop. To address these concerns, studies were conducted during the summers of 2020-2021 to understand the impact of P. japonica foliar feeding on the quality and yield of wine grapes. Trials utilized vines of the wine grape variety, 'Frontenac.' In addition to open plots, whole vines were caged within fine mesh netting and infested with P. japonica at 0, 25, 50, and 100 beetles per meter-row of vine. Beetles used for infestations were collected from natural field populations of P. japonica and left to feed until grapes were ready for harvest. During harvest, data collection included leaf samples for obtaining average percent defoliation, cluster weights, and berry subsamples for soluble solid content, pH, titratable acidity, and phenolic compound measurements. Results from these studies demonstrated that as beetle population density and defoliation per m-row increases, at-harvest measurements of quality parameters are significantly and negatively affected (P < 0.05) when compared with uninfested vines. The negative impacts to fruit quality exhibited in these studies will be important in the development of future management strategies for P. japonica in 'Frontenac.'