Salmonella Enteritidis survival in different temperatures and nutrient solution pH levels in hydroponically grown lettuce.

Due to climate change, with contaminated and less fertile soils, and intense weather phenomena, a turn towards hydroponic vegetable production has been made. Hydroponic cultivation of vegetables is considered to be a clean, safe and environmentally friendly growing technique; however, incidence of microbial contamination i.e. foodborne pathogens, might occur, endangering human health. The aim of this study was to investigate the effects of different plant growth stages, pH (values 5, 6, 7, 8) and bacterial inoculum levels (3 and 6 log cfu/mL) on hydroponically cultivated lettuce spiked with Salmonella Enteritidis. The results revealed that the pH and inoculum levels affected the internalization and survival of the pathogen in the hydroponic environment and plant tissue. Younger plants were found to be more susceptible to pathogen internalization compared to older ones. Under the current growing conditions (hydroponics, pH and inoculum levels), no leaf internalization was observed at all lettuce growth stages, despite the bacterium presence in the hydroponic solution. Noticeably, bacteria load at the nutrient solution was lower in low pH levels. These results showed that bacterium presence initiates plant response as indicated by the increased phenols, antioxidants and damage index markers (H2O2, MDA) in order for the plant to resist contamination by the invader. Nutrient solution management can result in Taylor-made recipes for plant growth and possible controlling the survival and growth of S. Enteritidis by pH levels.

Preharvest Application of Commercial Products Based on Chitosan, Phosphoric Acid Plus Micronutrients, and Orange Essential Oil on Postharvest Quality and Gray Mold Infections of Strawberry.

Strawberry is a perishable fruit with a limited shelf life after harvest due to deterioration of quality and the development of gray mold, Rhizopus rot and other minor diseases. In this study, the effectiveness of commercial compounds based on chitosan, phosphoric acid plus micronutrients, and sweet orange essential oil (EO) in reducing decay and optimizing the quality of strawberries was analyzed. The plant canopy of a greenhouse crop was sprayed once and strawberry fruit were harvested three days later. Gray mold infections were evaluated after chilled storage for seven days at 4 ± 0.5 °C followed by five days shelf life. The qualitative parameters were recorded at harvest (initial day) and after three days of storage at room temperature (RT, 20 °C) or after cold storage and shelf life (CS, 4 °C). The application of sweet orange EO increased the antioxidant and flavonoid content at harvest, while a decrease was reported following three days of storage at RT. At the same time, increased ethylene production and weight loss were observed during CS three days after harvesting. Chitosan treatment maintained the harvest fruit quality and was effective in the control of postharvest decay. Our results suggest that the investigated natural compounds could improve strawberry quality after harvest. Since chitosan performed best in terms of maintaining quality and reducing postharvest decay, it could be considered as a good substitute for chemical-synthetic fungicides for the preservation of strawberry postharvest gray mold.

Bio-Guided Investigation of Sideritis cypria Methanol Extract Driven by in Vitro Antioxidant and Cytotoxic Assays.

Sideritis cypria Post is an endemic and endangered species of Northern Cyprus. The overall aim of the present study was to evaluate the total phenolic content, the antioxidant, the cytotoxic and the antimicrobial activity of the methanol extract obtained from the aerial parts of cultivated S. cypria. A bio-guided approach led to the isolation of 27 chemical compounds by using various analytical techniques. Their structures were elucidated on the basis of 1D and 2D NMR spectroscopy. The crude extract exerted strong antioxidant activity (DPPH and FRAP assays) which was attributed to its high total phenolic content. Furthermore, groups rich in phenolic content showed highest antioxidant property, whereas groups with phytosterols, diterpenoids and apigenin derivatives exerted cytotoxic effects in MDA-MB231 cancer cell line by the MTT method. Moreover, the cytotoxic activity of four isolated apigenin derivatives was evaluated in the same cancer cells. The antimicrobial activity of the extract and groups were measured, demonstrating lack of activity. To the best of our knowledge, this survey is the first report on the biological activities of the methanol extract of S. cypria.

Chemical Composition and Plant Growth of Centaurea raphanina subsp. mixta Plants Cultivated under Saline Conditions.

The aim of this report was to study the effect of salinity (control: 2dS/m, S1: 4 dS/m and S2: 6 dS/m) and harvest time (first harvest on 9 May 2018 and second harvest on 19 April 2018) on the growth and the chemical composition of Centaurea raphanina subsp. mixta plants. The plants of the first harvest were used for the plant growth measurements (fresh weight and moisture content of leaves, rosette diameter, number and thickness of leaves), whereas those of the second harvest were not used for these measurements due to the flowering initiation, which made the leaves unmarketable due to their hard texture. The results of our study showed that C. raphanina subsp. mixta plants can be cultivated under mild salinity (S1 treatment) conditions without severe effects on plant growth and yield, since a more severe loss (27.5%) was observed for the S2 treatment. In addition, harvest time proved to be a cost-effective cultivation practice that allows to regulate the quality of the final product, either in edible form (first harvest) or for nutraceutical and pharmaceutical purposes as well as antimicrobial agents in food products. Therefore, the combination of these two agronomic factors showed interesting results in terms of the quality of the final product. In particular, high salinity (S2 treatment) improved the nutritional value by increasing the fat, proteins and carbohydrates contents in the first harvest, as well as the tocopherols and sugars contents (S1 and S2 treatments, respectively) in the second harvest. In addition, salinity and harvest time affected the oxalic acid content which was the lowest for the S2 treatment at the second harvest. Similarly, the richest fatty acid (α-linolenic acid) increased with increasing salinity at the first harvest. Salinity and harvest time also affected the antimicrobial properties, especially against Staphylococcus aureus, Bacillus cereus and Trichoderma viride, where the extracts from the S1 and S2 treatments showed high effectiveness. In contrast, the highest amounts of flavanones (pinocembrin derivatives) were detected in the control treatment (second harvest), which was also reflected to the highest antioxidant activity (TBARS) for the same treatment. In conclusion, C. raphanina subsp. mixta plants seem to be tolerant to medium salinity stress (S1 treatment) since plant growth was not severely impaired, while salinity and harvesting time affected the nutritional value (fat, proteins, and carbohydrates) and the chemical composition (tocopherols, sugars, oxalic acid, fatty acids), as well as the bioactive properties (cytotoxicity and antimicrobial properties) of the final product.

Interactive effects of salinity and silicon application on Solanum lycopersicum growth, physiology and shelf-life of fruit produced hydroponically.

BACKGROUND: Using water with high salinity for plant fertigation may have detrimental effects on plant development and total yield and on the quality of the crop produced. As a possible means to alleviate the negative effects of salinity, silicon (Si) can be incorporated in the nutrient solution supplied to plants. In the present study, hydroponically grown tomato (Solanum lycopersicum Mill.) plants were subjected to two different salinity levels (0 and 50 mmol L-1 NaCl) with and without the application of Si (0 and 2 mmol L-1 K2 SiO3 ) in order to evaluate its possible positive impact on mitigation of salinity stress-induced symptoms. An additional experiment was implemented with postharvest Si application (sodium silicate) to investigate effects on the shelf-life of tomato fruit. RESULTS: Salinity (50 mmol L-1 NaCl) decreased plant size, total yield and fresh fruit weight while a high percentage of blossom end rot symptoms of tomato fruit was also observed. The application of Si in the nutrient solution counteracted these detrimental effects, generating a higher yield and healthier fruit (lower blossom end rot incidence) compared to the untreated plants (no application of Si). Salinity improved several quality-related traits in tomato fruit, resulting in higher marketability, whereas the addition of Si (pre- and postharvest) maintained fruit firmness following storage thereby increasing the shelf-life of tomato fruit. CONCLUSIONS: These findings indicate that Si application (pre- and postharvest) could provide an effective means of alleviating the unfavorable effects of using low-quality water in plant fertigation on tomato plant development, fruit yield and post-harvest quality, through increased fruit firmness. © 2019 Society of Chemical Industry.

Variation of microbial load and biochemical activity of ready-to-eat salads in Cyprus as affected by vegetable type, season, and producer.

Fresh vegetables are important components of an everyday balanced diet making ready to-eat-salads (RTE) a commodity widely consumed. However, in the past few years these products have been linked with outbreaks of salmonellosis and listeriosis; thus the continuous investigation of their safety is an essential requirement. A total of 216 samples of ready-to-eat salads from the Cypriot market were analysed to determine the microbiological quality and safety, along with physicochemical attributes of the salads and identify possible correlations between them. The samples were randomly collected from four retail outlets and correspond to five different salad producing companies. Furthermore, the effects of season, salad producer and type of salad and/or their interactions with the tested parameters were investigated. The results revealed that the higher microbial load among seasons was observed in samples collected during spring. Escherichia coli was found in 11.57% of samples and 2.62% of isolates were found to be able to produce extended spectrum ß-lactamase (ESBL). All samples were found negative for Salmonella enterica, whereas Listeria monocytogenes was present in 3.70% of samples. Higher levels of spoilage bacteria (lactic acid bacteria and Pseudomonas spp.) were detected during winter and spring. Additionally, the %CO2 production was affected by the type of salad, while the interaction between producer and type of salad, affected total phenolic content and antioxidant activity of samples. A positive correlation of phenols and antioxidants with the presence of Staphylococcus spp., Pseudomonas spp., E. coli and Bacillus cereus was observed, suggesting that excessive handling increases microbial load and plant stress.

The Effects of Biostimulants, Biofertilizers and Water-Stress on Nutritional Value and Chemical Composition of Two Spinach Genotypes (Spinacia oleracea L.).

In the present study, the effect of biostimulants application on the nutritional quality and bioactive properties of spinach cultivated in protected environment under water stress conditions was evaluated. For this purpose, four commercially available biostimulant products (Megafol (MEG), Aminovert (AM), Veramin Ca (V), Twin Antistress (TA), and two spinach genotypes (Fuji F1 and Viroflay) were tested under two irrigation regimes (normal irrigation (W+), and water-holding (W-). Fat and carbohydrates content was favored by water stress when Megafol (MEGW+) and Veramin (VW+) were applied on Fuji plants, while calorific value was also increased by MEGW+ treatment. In contrast, protein and ash content increased when AMW- and TAW+ were applied on Viroflay plants. Raffinose and glucose were the most abundant sugars, followed by sucrose and fructose, with the highest contents recorded for Fuji plants when AMW+ (fructose, glucose and total carbohydrates), CW- (sucrose), and TAW- (raffinose) treatments were applied. Regarding organic acids, oxalic and malic acid which had the highest contents for the TAW- (Viroflay plants) and AMW- (Fuji plants) treatments, respectively. α- and γ-tocopherol were the only isoforms detected with MEGW- and VW- inducing the biosynthesis of α-tocopherol, while AMW+ increased γ-tocopherol content in Fuji plants. The main fatty acids were α-linolenic and linoleic acids which were detected in the highest amounts in AMW-, AMW+, and TAW+ the former and in AMW-, VW-, and CW+ the latter. Regarding phenolic compounds content, peak 12 (5,3',4'-Trihydroxy-3-methoxy-6:7-methylenedioxyflavone-4'-glucuronide) was the most abundant compound, especially in Viroflay plants under normal irrigation and no biostimulants added (CW-). The antioxidant and cytotoxic activity of the tested samples did not show promising results when compared with the positive controls, while a variable antibacterial activity was recorded depending on the tested biostimulant, irrigation regime and genotype. In conclusion, a variable effect of the tested biostimulants and irrigation regimes was observed on bioactive properties and chemical composition of both spinach genotypes which highlights the need for further research in order to make profound conclusions regarding the positive effects of biostimulants under water stress conditions.

Physiochemical properties of petunia edible flowers grown under saline conditions and their postharvest performance under modified atmosphere packaging and ethanol application.

BACKGROUND: Edible flowers have both great nutritional value and sensory appeal; however, their shelf-life is limited to a few days because they are highly perishable. RESULTS: The impact of postharvest ethanol (ET) treatment and modified atmosphere packaging (MAP) on the quality and storage of edible flowers collected from short-term salt-stressed plants was tested. Hydroponically grown petunia (Petunia x hybrita L.) plants were subjected to salinity (0-50-100 mmol L-1 NaCl) and harvested flowers were stored for up to 14 days in MAP and/ET vapours. The salinity of 100 mmol L-1 NaCl decreased plant biomass and negatively affected physiological processes as a result of stomata closure. Flower polyphenols, antioxidants, carotenoids and anthocyanins increased with 50 mmol L-1 of NaCl, indicating a higher nutritional value. Short-term exposure of petunia to salinity decreased the flower N, K and Ca concentrations. During storage for 7 days, salinity lead to deteriorated flowers that showed browning as a result of tissue breakdown, whereas CO2 production and weight loss were unaffected by salinity. After 14 days of storage, salinity decreased flower respiration and increased weight loss, whereas ET application completely destroyed the flowers. Carotenoids and anthocyanins were decreased by a combination of salinity and ET. Petunia flowers revealed the induction of both non-enzymatic (i.e. proline content) and enzymatic (catalase) mechanisms to overcome the stress caused by salinity at harvest stage and/or ethanol at storage. CONCLUSION: The results of the present study demonstrate that a short-stress salinity of 50 mmol L-1 NaCl can be used for petunia growth and also that flowers of nutritional value can be stored for up to 7 days, whereas ET application failed to preserve petunia flowers. © 2019 Society of Chemical Industry.

Effects of Ascophyllum nodosum seaweed extracts on lettuce growth, physiology and fresh-cut salad storage under potassium deficiency.

BACKGROUND: Potassium (K) deficiency in leafy vegetables such as lettuce is a major concern regarding quality. Seaweed (SW) extracts, as biostimulants, are biodegradable materials and have become increasingly popular as they are reported to enhance crop growth and yield. RESULTS: In order to overcome K deficiencies (i.e. 375 vs 125 mg L-1 ), alternative foliar applications with extracts of Ascophyllum nodosum SW or K were examined using lettuce plants which were grown hydroponically. Potassium deficiency (at 125 mg L-1 ) reduced plant biomass, photosynthetic rate, leaf stomatal conductance, lettuce potassium content and tissue antioxidant capacity as compared with the higher K level (375 mg L-1 ). Application of SW increased the relative growth of lettuce in the low-K treatment. The K level and/or SW application altered the plant's enzyme protective activity (superoxide dismutase, SOD; catalase, CAT; peroxidase, POD) against oxidative stress and hydrogen peroxide (H2 O2 ) production. Spray applications of SW mitigated the effects of K deficiency on indicators of enzyme activity and plant damage, back to levels of high K content (375 mg L-1 ). The high K level, but also SW application, increased the antioxidant activity of the processed lettuce before storage. Foliar application of the SW extract increased the quality of cut lettuce grown in 125 mg L-1 K conditions by reducing the rate of respiration and increasing consumer preference. CONCLUSION: The SW application could alter the detrimental effects of K deficiency during lettuce growth and storage of processed products. © 2018 Society of Chemical Industry.

Magnesium and manganese induced changes on chemical, nutritional, antioxidant and antimicrobial properties of the pansy and Viola edible flowers.

Pansy and viola edible flowers were grown hydroponically with different levels of Mg and Mn. The nutritional composition was determined using standard methods. Free sugars, fatty acids, organic acids, tocopherols, and phenolic compounds were analyzed using various HPLC and GC devises. The extract's antimicrobial, antioxidant, cytotoxicity, and anti-inflammatory activity were assessed. The results indicated that Mg enrichment negatively affected plant growth and mineral accumulation but improved photosynthetic performance. The edible flowers contained significant amounts of protein, low levels of fat, and varying sugar contents, such as glucose and fructose. Various fatty acids and phenolic compounds were identified, with different concentrations depending on the treatment. The flowers exhibited antioxidant potential, antimicrobial activity, cytotoxic effects, and anti-inflammatory properties. The correlations between the investigated parameters not only expand knowledge on Mg and Mn interaction but also catalyze significant advancements in sustainable agriculture and food health, fostering a healthier and more conscious future.

Phytochemical Profiles and Biological Activities of Plant Extracts from Aromatic Plants Cultivated in Cyprus.

Medicinal and aromatic plants' properties, still an interesting research area, are attributed to the presence of various specialized products that possess important pharmacological activities. In the present study, six medicinal/aromatic plants (Sideritis cypria, Origanum dubium, Melissa officinalis, Mentha piperita, Thymus capitatus, and Salvia fruticosa) were evaluated for their phytochemical and nutritive composition, as well as their biological activities, including antioxidant, antimicrobial, and cytotoxic properties. The results obtained indicate that M. piperita was rich in proteins and minerals such as N and Mg, while S. cypria accumulated more K, Na, P, and Ca. The highest content of phenols and flavonoids was observed in M. piperita, followed by O. dubium and T. capitatus, which eventually influenced their high antioxidant capacity. NMR screening revealed the presence of (i) triterpenoids and hydroxycinnamic acid derivatives in M. officinalis; (ii) terpenoids, flavonoids, and phenolic acid derivatives in S. fruticosa; (iii) flavonoids and phenolic acid derivatives in M. piperita; (iv) phenolic monoterpenes in O. dubium and T. capitatus; and (v) terpenoids, flavones, and phenylethanoid glycosides in S. cypria. The results of the antimicrobial activity showed that the tested samples overall had quite good antimicrobial potential. High antibacterial activity was found in O. dubium and T. capitatus, while O. dubium and S. cypria exhibited great antifungal activities. The studied species also had an important effect on the viability of female-derived and colon cancer cells. In particular, in colon cancer cells, the extracts from T. capitatus, M. officinalis, M. piperita, and S. fruticosa exhibited a stronger effect on cell viability in the more metastatic cell line at significantly lower concentrations, indicating an important therapeutic potential in targeting highly metastatic tumors. This finding is worth further investigation. The present study unveiled interesting phytochemical profiles and biological properties of the six medicinal/aromatic plants, which should be further explored, contributing to green chemistry and the possible creation of natural health products for humans' health/nutrition and additives in cosmetics.

Ammonium to total nitrogen ratio affects the purslane (Portulaca oleracea L.) growth, nutritional, and antioxidant status.

Purslane (Portulaca oleracea L.) is a widespread weed, which is greatly appreciated for its high nutritional value. The present work evaluated the effect of different ammonium/total nitrogen ratios (NH4/Total N: Nr 0.01-0.15) on growth, physiological and biochemical parameters, and nutrient accumulation in different plant parts of hydroponically grown purslane, under two growing seasons, spring and autumn. Young seedlings of purslane were transferred to a Nutrient Film Technique (NFT) system and they were exposed to different Nr levels. The pH and the electrical conductivity of the nutrient solution were kept constant at 5.8 and 2.3 mS cm-1, respectively. After the end of the cultivation periods (19 days for spring and 22 days for autumn), a series of assessments (growth parameters, mineral content in different plant organs, antioxidant status of the plant, etc.) were done. Plant height, leaf number, root fresh weight and plant biomass revealed decreased trends at the higher NH4/total N ratios, especially during the autumn growing season. Total phenols, flavonoids and antioxidant capacity appeared increased at Nr ≤ 0.10 during both seasons (autumn and spring), revealing higher nitrogen accumulation rates and increased water and nutrient use efficiency. Purslane plants grown in Nr 0.05-0.10 revealed a less intense oxidative stress, with decreased lipid peroxidation levels that was the result of the activation of both enzymatic (superoxide dismutase, catalase and peroxidase) and non-enzymatic (ascorbic acid) antioxidant capacity of the plant. Increased Nr resulted in the accumulation of potassium, while calcium and magnesium levels in leaves were decreased. Additionally, the greater water use efficiency was measured for plants grown under Nr 0.01-0.05. Therefore, the recommended ammonium/total nitrogen ratio for purslane production of increased yield, improved nutritional value and efficient use of water and nitrogen sources is to employ Nr of 0.05, while additional care should be addressed during autumn periods as plants are subjected to greater impacts of the Nr ratio.

Sideritis L. essential oils: A systematic review.

Essential oils are extensively used in the food, cosmetic, perfume, pharmaceutical, and agrochemical industries due to their aroma and pharmacological properties. The Lamiaceae family is mainly represented by widely well-known medicinal and aromatic plants that produce essential oil. Over the years, Sideritis L. essential oils have attracted great interest due to their chemical variability among the different taxa and their pharmacological activities. In-depth research of previously published literature was performed on electronic databases with several key search words for the collection of the available data and a total of 128 scientific studies were used since 1983. To date, 155 accepted Sideritis samples have been studied originating from 15 countries and more than 250 compounds have been reported in 87 Sideritis taxa overall. Furthermore, antimicrobial and antioxidant effects have been the most studied pharmacological activities. This review summarizes and critically discusses the research work on the chemical composition and pharmacological activities of essential oil of the genus Sideritis based on the currently valid taxonomy. Additionally, statistical analysis is encompassed to provide a deeper comprehensive understanding of the high chemical polymorphism of Sideritis essential oils. We expect that this review will encourage researchers to investigate unexplored Sideritis taxa and will contribute to revealing uncharted scientific territory and future perspectives on these plants.

Effects of the extraction techniques on the chemical composition and bioactive properties of lemon balm (Melissa officinalis L.) plants grown under different cropping and irrigation regimes.

The present study aims to determine the combined effect of cropping system and irrigation regime on the chemical composition and bioactive properties of lemon balm aerial parts. For this purpose, lemon balm plants were grown under two farming systems (conventional farming vs organic farming) and two irrigation levels (full irrigation vs deficit irrigation) and harvested twice throughout the growing period. The collected aerial parts were subjected to three different methods of extractions, namely infusion, maceration and ultrasound-assisted extraction and the obtained extracts were evaluated in terms of chemical profile and bioactivities. Five organic acids with varied composition among the tested treatments were identified in all the tested samples for both harvests, namely, citric, malic, oxalic, shikimic and quinic acid. Regarding phenolic compounds composition, the most abundant ones were rosmarinic acid, lithospermic acid A isomer I and hydroxylsalvianolic E, especially for the maceration and infusion extraction methods. Full irrigation resulted in lower EC50 values than deficit irrigation only in the treatments of the second harvest, while variable cytotoxic and anti-inflammatory effects were recorded in both harvests. Finally, in most cases the lemon balm extracts has similar or better activity than the positive controls, while the antifungal activity of lemon balm extracts was stronger than the antibacterial effects. In conclusion, the results of the present study showed that the implemented agronomic practices, as well as the extraction protocol may significantly affect the chemical profile and bioactivities of lemon balm extracts, suggesting that both the farming system and the irrigation schedule may improve the quality of the extracts depending on the implemented extraction protocol.

Origanum dubium (Cypriot Oregano) as a Promising Sanitizing Agent against Salmonella enterica and Listeria monocytogenes on Tomato and Cucumber Fruits.

In recent years, the use of natural products such as essential oils (EOs) and other plant extracts for the preservation of fresh produce has attracted much interest from the food industry. Many endemic medicinal and aromatic plants, such as Cypriot oregano (Origanum dubium), present a plethora of properties that can be utilized by the fruit and vegetable sectors of the food industry. The purpose of the present study was to assess the effects of O. dubium EO and hydrosol (at different concentrations and durations of dipping application) for the preservation of tomato and cucumber fruit quality, and their effectiveness as sanitizing agents against two foodborne pathogens (Listeria monocytogenes and Salmonella enterica). The results of this study indicated that increased concentrations of EO, combined with a longer duration of application, resulted in less marketable fruit compared to hydrosol application. Interestingly, EO application at lower concentrations and shorter durations of application (i.e., 0.01% for 5 min) increased fruit antioxidant, ascorbic acid and carotenoid levels (for tomato fruit), suggesting an increase in the nutritional value of the treated fruit, compared to the control. EO and hydrosol were able to decrease the bacterial populations (both bacteria) on fruits. Both products were especially effective against L. monocytogenes, even seven days after their application and storage at 11 °C (up to an approx. 3 log reduction with the EO application). Overall, the results of this study suggest that the use of O. dubium EO and hydrosol could be considered as alternative sanitation means for tomatoes and cucumbers.

Physiological and biochemical responses of Tanacetum balsamita L. to the foliar application of Dobogen biostimulant, glucose and KNO3 under salinity stress.

Salinity is one of the predominant abiotic stress factors that influence the growth and productivity of plants. Salinity adversely impacts the growth responses via ionic toxicity, osmotic stress, impaired nutrients uptake, hormonal disparity, and the over-production of reactive oxygen species. To study the effects of salinity stress (0, 50, 100, and 150 mM) and foliar treatments (dH2O, 2 g L-1 Dobogen biostimulant, 2 g L-1 KNO3, and 2 g L-1 D-glucose) on the growth and physiological responses of Tanacetum balsamita, a factorial experiment was conducted based on the completely randomized design at the research greenhouse of Azarbaijan Shahid Madani University, Iran. The results showed the significant interaction effects of salinity and foliar sprays on chlorophyll a, K+, Na+, Mg2+, Fe2+, Zn2+, Mn2+, and Si content, K/Na ratio, and total phenolics and flavonoids content. The highest phenolic content was acquired with 100 mM salinity and foliar spray of Dobogen and glucose, 50 mM NaCl × KNO3 application, and 50 mM salinity × no-foliar application. The highest K/Na ratio was observed in control plants and controls × KNO3 and/or Dobogen application. The greatest Si content was recorded with no-salinity × Dobogen and KNO3 applications and no-saline × no-foliar (control) plants. The independent effects of treatments influenced malondialdehyde, flavonoids, proline contents, and catalase activity. Chlorophyll b and superoxide dismutase were affected by the salinity. Total soluble solids and Ca2+ content were responsive to the foliar applications. Malondialdehyde and proline content was the highest at 150 mM salinity. Salinity adversely affected the physiological responses of costmary. However, foliar treatments partially ameliorated the salinity effect, and the results with more detailed studies would be advisable to the extension section and pioneer farmers.

Polar constituents, biological effects and nutritional value of Sideritis sipylea Boiss.

The present study focuses on the polar constituents and biological effects of the methanol extract and the infusion of wild Sideritis sipylea Boiss. from Samos island (Greece), as well as on the nutritional and mineral contents of this plant. The total phenolic content and antioxidant activity were examined. In addition, the anti-acetylcholinesterase property was evaluated, revealing strictly lower results than the control, galanthamine. Furthermore, the nutritional value of the plant is reported herein for the first time, revealing a promising source of protein. To the best of our knowledge, this study is the first work on the infusion of this species and the nutritional value of the plant.

The Combined and Single Effect of Marjoram Essential Oil, Ascorbic Acid, and Chitosan on Fresh-Cut Lettuce Preservation.

Increasing demands by consumers for fresh, nutritional, and convenient food has led to the increase of fresh-cut produce market. Nowadays, there is a turn towards the investigation of natural products (i.e., essential oils, organic acids, and edible coatings) in an effort to lower the usage of chemical synthetic compounds (i.e., chlorine) as postharvest sanitizers. The aim of the present study was to assess the effectiveness of Origanum majorana essential oil (EO), ascorbic acid (AA), chitosan, and their combinations on quality attributes of fresh-cut lettuce stored for six days at 7 °C. When applied, Chitosan+AA resulted to a less acceptable product (visual quality and aroma), while the application of marjoram EO was able to preserve the visual quality of fresh-cut lettuce and at the same time resulted in a pleasant aroma. The application of EO+AA and Chitosan+AA increased total phenolics and antioxidant levels of fresh-cut lettuce on the fourth and sixth day of storage. The EO and EO+AA increased damage index (hydrogen peroxide and lipid peroxidation) of fresh-cut lettuce, while at the same time these treatments decreased the activity of enzymes related with plant tissue browning (i.e., peroxidase activity and polyphenol oxidase). Chitosan decreased total valuable counts and yeasts and molds counts on the sixth day of storage, while EO, AA, EO+Chitosan, and Chitosan+AA decreased yeasts and molds after four days of application. The findings of the present work indicating that the combination of marjoram EO, AA, and chitosan could be considered further as alternative means for fresh-cut produce preservation.

Vapour Application of Sage Essential Oil Maintain Tomato Fruit Quality in Breaker and Red Ripening Stages.

Consumers seek safe, high-nutritional-value products, and therefore maintaining fresh produce quality is a fundamental goal in the food industry. In an effort to eliminate chemical-based sanitizing agents, there has been a shift in recent decades toward the usage of eco-friendly, natural solutions (e.g., essential oils-EOs). In the present study, tomato fruits (Solanum lycopersicum L. cv. Dafni) at breaker and red ripening stage were exposed to sage essential oils (EO: 50 µL L-1 or 500 µL L-1) for 2, 7 and 14 days, at 11 °C and 90% relative humidity (RH). Quality-related attributes were examined during (sustain effect-SE) and following (vapour-induced memory effect-ME; seven days vapours + seven days storage) vapour treatment. In breaker tomatoes, EO-enrichment (sustained effect) retained fruit firmness, respiration rates, and ethylene emission in low EO levels (50 µL L-1). In contrast, breaker fruit metabolism sped up in high EO levels of 500 µL L-1, with decreased firmness, increased rates of respiration and ethylene, and effects on antioxidant metabolism. The effects were more pronounced during the storage period of 14 days, comparing to the fruit exposed to common storage-transit practice. In red fruits, the EOs impacts were evidenced earlier (at two and seven days of storage) with increased rates of respiration and ethylene, increased ß-carotene, and decreased lycopene content. In both breaker and red ripening fruit, EO application decreased weight losses. Considering the fruits pre-exposed to EOs, quality attributes were more affected in green fruits and affected to a lesser level in the red ones. Furthermore, based on appearance, color, and texture evaluations, organoleptic trials demonstrated an overwhelming preference for EO-treated red fruit during choice tests. EOs had lower effects on total phenolics, acidity, total soluble solids, and fruit chroma, with no specific trend for both breaker and red tomatoes. Natural volatiles may aid to retain fruit quality in parallel with their antimicrobial protection offered during storage and transportation of fresh produce. These effects may persist after the EO is removed from the storage conditions.

Copper Tolerance and Accumulation on Pelargonium graveolens L'Hér. Grown in Hydroponic Culture.

Heavy metal contamination is a major health issue concerning the commercial production of medicinal and aromatic plants (MAPs) that are used for the extraction of bioactive molecules. Copper (Cu) is an anthropogenic contaminant that, at toxic levels, can accumulate in plant tissues, affecting plant growth and development. On the other hand, plant response to metal-induced stress may involve the synthesis and accumulation of beneficial secondary metabolites. In this study, hydroponically grown Pelargonium graveolens plants were exposed to different Cu concentrations in a nutrient solution (4, 25, 50, 100 µM) to evaluate the effects Cu toxicity on plant growth, mineral uptake and distribution in plants, some stress indicators, and the accumulation of bioactive secondary metabolites in leaf tissues. P. graveolens resulted in moderately tolerant Cu toxicity. At Cu concentrations up to 100 µM, biomass production was preserved and was accompanied by an increase in phenolics and antioxidant capacity. The metal contaminant was accumulated mainly in the roots. The leaf tissues of Cu-treated P. graveolens may be safely used for the extraction of bioactive molecules.