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The drying of medicinal and aromatic plants (MAPs) is one of the main preservation methods for these products that can prolong their shelf life, if performed properly. The current study aimed to examine the effects of different drying conditions (sun, shade, and oven drying at 42 °C) on the quality characteristics of Thymus capitatus, Mentha piperita, and Sideritis cypria; their essential oil (EO) yield; and their biological properties (antioxidant and antibacterial activities). According to the results of the current study, oven drying resulted in faster moisture loss for all investigated species and slightly darker products. For T. capitatus, sun drying resulted in higher EO carvacrol content, whereas EOs obtained from shade and oven drying (at 42 °C) presented high total phenolic content and great antimicrobial activity. For M. piperita, shade drying resulted in a higher EO yield and higher iso-menthone content, whilst the EO obtained from oven-dried mint plants presented great antibacterial activity against the investigated foodborne pathogens. S. cypria plants dried in an air-ventilated oven produced an EO rich in β-caryophyllene and α-pinene, which also presented great antioxidant and antibacterial activity. The findings of the current study indicate that traditional drying methods, such as sun and shade, can result in good-quality dried MAPs that can yield EOs with significant biological activities, along with minimum energy consumption and lower carbon dioxide production (lower environmental carbon footprint), as opposed to oven drying. However, the drying-process duration could be a limitation at the industrial scale. [ABSTRACT FROM AUTHOR]

Biochar has been promoted mostly as a soil supplement that improves plant growth/yield and to a lesser extent as a growing medium component. The alarmed situation for peat substitution in growing medium renders biochar as a promising substitute for current research. In this study, biochar derived by wood-based materials was evaluated at different ratios (0, 5, 10, 15, and 20% v/v) for peat partial substitution for Antirrhinum majus pot production. Biochar had increased potassium content and pH, which affected the growing media properties (total pores space and water filled capacity) and decreased nitrogen and phosphorus content in the media. Adding ≥15% biochar increased plant height and decreased flowering, but no effect was observed on plant biomass produced. The presence of biochar increased the total phenols and flavanols content and antioxidant capacity, with greater effects at the higher biochar rates used. This resulted in lipid peroxidation and an increase in hydrogen peroxide content, causing oxidative stress. Potassium and magnesium accumulated more but nitrogen and phosphorus were accumulated less in snapdragon leaves. Biochar at 10% can be considered as a successful candidate to partially substitute peat, and efforts to improve growing media characteristics are required for A. majus pot production. [ABSTRACT FROM AUTHOR]

To sustain the increasing needs of a rapidly growing population, agriculture has relied on the use of synthetic fertilizers to intensify its production. However, the economical, environmental and health impacts associated with their use have raised significant concerns, especially given the scarcity of phosphorus. Utilizing nutrient-recovered materials like struvite can enhance circularity in agriculture and reduce its reliance on synthetic fertilizers. The objective of this study was to assess the implementation of struvite as a complete substitute to triple superphosphate, for radish and spinach seedling production and early growth, with or without supplementary fertigation. In addition, two rates of struvite were examined (0.68 and 1.37 g L−1 substrate) to evaluate its solubility. In the germination of radish, struvite had similar performance with conventional fertilization, while in spinach, the use of struvite decreased mean germination times. Both plants maintained comparable growth, chlorophyll content and antioxidant capacity when struvite was used, in comparison to conventional fertilizers. However, higher struvite rates under un-fertigated conditions significantly increased the chlorophyll b and total chlorophylls in the spinach, while phenolics and flavonoids decreased, contingent on the fertigation applications. In the radish, struvite maintained similar MDA and H2O2 levels to conventional fertilization, while decreases occurred in the spinach, with the application of ST1 under un-fertigated conditions, compared with conventional fertilization. The P and N contents of the plants were also affected, though these effects varied depending on the plant species, fertigation applications and struvite rates. This variance can be attributed to the characteristics of struvite, the plant species and the cultivation practices. The results of this study suggest that struvite can be successfully implemented in seedling production, establishing significant prospects for its commercialization and use in nurseries. [ABSTRACT FROM AUTHOR]

Purslane (Portulaca oleracea L.) is a common weed that attracts research and agricultural attention because of its significant nutritional value, and it is used commercially. The present work rated the effect of different nitrogen (N) concentrations, i.e., N50: 50 mg L−1; N100: 100 mg L−1; N200: 200 mg L−1; and N300: 300 mg L−1, on the growth, physiology, antioxidant capacity, and nutrient accumulation in the different plant parts of hydroponically grown purslane. Seedlings were transplanted to a Nutrient Film Technique (NFT) system and exposed to different N levels. The plants grown in high N levels of 300 mg L−1 had decreased biomass production, leaf number, leaf stomatal conductance, and total flavonoid content because of the increased oxidative stress, as shown by the elevated lipid peroxidation levels. Several enzymatic (superoxide dismutase) and non-enzymatic (ascorbic acid, total phenolics) plant antioxidant activities were activated to counteract the oxidative factors. Plants grown in intermediate N levels in the NS (i.e., 100 mg L−1) had decreased oxidative stress as several enzymatic antioxidant activities, i.e., peroxidases and catalases, were increased. Additionally, the water use efficiency and nitrogen uptake, as well as leaf stomatal conductance and leaf chlorophyll fluorescence, were increased in plants grown at a N level of 200 mg L−1. The mineral accumulation in the leaves, stems, and roots fluctuated, with increased calcium, magnesium, and sodium content being observed in the plants grown at high N levels in the nutrient solution. The stems accumulated less N compared with the leaves, but the N content and accumulation rates in purslane leaves were not affected by the N levels in the nutrient solution. Therefore, to increase the yield, nutritional value, and water use efficiency of purslane that is grown hydroponically, a concentration of 200 mg L−1 N in the nutrient solution is recommended. [ABSTRACT FROM AUTHOR]

The article discusses the importance of the Lamiaceae family of plants, which includes species like thyme, mint, oregano, basil, and sage. These plants are known for their aromatic properties and are widely used in various industries such as food, cosmetics, and pharmaceuticals. The article also highlights recent research on topics such as plant cultivation methods, extraction techniques for essential oils, and the preservation of fresh produce using natural compounds. The collection of scientific papers aims to explore the potential of these plants and their extracts in various applications while optimizing growth conditions and extraction methods. [Extracted from the article]

Very little is known about the preservation and storage of fresh medicinal and aromatic plants (MAPs) and/or herbs. As with many leafy vegetables, i.e., lettuce, fresh spearmint is a very perishable product throughout the production line and requires special handling/processing. The current study aimed to examine the antibacterial activity of selected MAPs (Origanum dubium, Salvia fruticosa and Sideritis cypria) grown in Cyprus towards foodborne pathogens. Then, the most effective MAPs' essential oil (EO) and hydrosol (at different doses; combination of concentration and time of dipping submerge) were tested to preserve fresh spearmint quality and safety. The results showed that O. dubium EO and hydrosol presented great in vitro antibacterial activity against four foodborne pathogens and those products were further selected for application on fresh spearmint. During sensory evaluation, it was observed that higher O. dubium EO concentrations and longer time of application resulted into a less marketable product (less acceptable with less spearmint-like aroma), while hydrosol resulted in a more marketable product even at high doses. In general, EO and hydrosol applications increased spearmint's antioxidants (including polyphenols, flavonoids, and ascorbic acid), resulting in a product of increased nutritional value. The bacterial populations of Salmonella enterica and Listeria monocytogenes inoculated on fresh spearmint were decreased with the EO and hydrosol application doses applied, and their effects were evident even after six days of storage at 4 °C. From the findings of this study, it can be concluded that O. dubium EO and hydrosol could be a potential sanitation method for fresh spearmint preservation. [ABSTRACT FROM AUTHOR]

The use of natural products (including essential oil—EO from medicinal and aromatic plants) on fresh commodities such as leafy greens has gained a lot of attention due to the beneficial effects of those products. However, fresh herbs are highly perishable commodities, and very little is known for their postharvest preservation. The present study aimed to (i) investigate the effects of Cypriot oregano (Origanum dubium) EO and hydrosol (at different concentrations and times of application) on fresh basil's quality attributes and preservation and (ii) examine the efficacy of selected doses of O. dubium EO and hydrosol against two major foodborne pathogens inoculated on fresh basil stored at 4 °C for six days. The results of the current study indicated that the application of O. dubium EO at high concentrations in combination with a longer dipping time presented a less aromatic (less basil-like aroma) and preferable commodity, whereas hydrosol application resulted in a more acceptable and marketable commodity. In addition, an increase in antioxidant capacity and ascorbic acid content were observed with the EO, whilst hydrosol application was found to decrease basil's antioxidant capacity. Both investigated products (EO and hydrosol) where found to present great antibacterial activity against Salmonella enterica and Listeria monocytogenes inoculated on fresh basil even six days after the application. Overall, the investigated natural products (i.e., O. dubium EO and hydrosol) could be considered alternative sanitizing agents during the postharvest processing of fresh basil, whilst preserving and/or improving its nutritional value (i.e., an increase in antioxidants or flavonoids). However, caution should be taken when using it at high concentrations; thus, further research is needed for future commercial-scale use and on other fresh produce. [ABSTRACT FROM AUTHOR]

Plant residues derived from the agro-industrial sector and their disposal are still unsolved issues despite the various research and applications. The current study assessed the possible peat substitution in growing media with solid residues derived from the distillation of Origanum dubium Boiss (OD) and Sideritis cypria Post (SC) after essential oils production. Residues of OD and SC (0–5–10–20% v/v) and their mixture (OD + SC) were examined to partially substitute peat for the production of pansy (Viola × wittrockiana) plants. The presence of OD, SC, and OD + SC residues increased the pH, the electrical conductivity, the organic matter content, and the levels of minerals in the growing media mixtures compared to sole peat while decreasing the total porosity (up to 36.8%) and the available free air (up to 58.3%). The OD residues' presence in the peat-based media revealed more detrimental effects than the SC, while the OD + SC mixture received intermediate effects. Low residue ratios (≤5% OD, ≤10% SC, ≤10% OD + SC) sustain plant growth and photosynthetic activity of plants, while higher ratios decrease plant growth, chlorophyll content and mineral accumulation due to inappropriate growing media properties, causing plant oxidative stress. This was verified using the increase in malondialdehyde (up to 4.5 times) and hydrogen peroxide (up to 2.1 times) content in plants and the activation of several non-enzymatic antioxidant processes, including total phenols, flavonoids, and antioxidant capacity of the plants. Therefore, OD, SC, and OD + SC at 5%, 10%, and 10%, respectively, can partially substitute peat, as they result in appropriate plant growth and development. However, the growing media's properties must be improved to ensure adequate yields as well. [ABSTRACT FROM AUTHOR]