The main objectives of this study were to investigate the effects of the applied essential oil (EO) isolation method, conventional hydro-distillation (HD), and microwave-assisted hydro-distillation (MHD) on the chemical profile of sea fennel (Crithmum maritimum L.) essential oil and to investigate the main constituents present in the liquid by-products of EOs isolation (hydrolate and residual wastewater). Headspace-solid phase microextraction (HS-SPME) was used to isolate hydrolate components, while gas chromatography coupled with mass spectrometry (GC-MS) was used to detect and analyse the chemical constituents of the essential oils and hydrolates. The phenolic composition of the wastewater extracts was analysed by high performance liquid chromatography (HPLC). The EO obtained by MHD had a higher yield of limonene and sabinene. The chemical composition of the hydrolates differed from the EO compositions. The content of terpinen-4-ol in the MHD hydrolate was higher, while several compounds were detected in relatively high proportions only in the HD hydrolate. MHD also resulted in a higher phenolic content of the wastewater, where an increase in the concentration of chlorogenic acid was also observed. It can be concluded that the isolation method had a great influence on the profile of sea fennel EOs, especially on their corresponding hydrolates and residual wastewater extracts. Due to their valuable chemical composition, these by-products can be a cost-effective source of bioactive compounds that have great potential for use in various industries.

The aim of this study was to produce non-fermented preserved sea fennel leaves in different pickle juices prepared with apple cider vinegar, wine vinegar and alcoholic vinegar, and to compare their chemical parameters (pH, titratable acidity and salt content), organoleptic properties (color and texture parameters; volatile aromatic compound profiles) and sensory attributes. The pH of the samples ranged from 3.49 to 3.64, the lowest being in the alcoholic vinegar sample and the highest being in the wine vinegar sample, while the titratable acidity and salinity were higher in the alcoholic vinegar pickle juice than those in the other two samples. The volatile aromatic compounds of the samples were also detected. The reddish color of the wine vinegar negatively affected the sea fennel color parameters (L* and b*), and was also negatively evaluated by the panelists, while the alcoholic vinegar maximally preserved the green tones of the leaf (a*). Firmness influences the quality perceived by consumers and was therefore also tested as one of the most important parameters for evaluating the textural and mechanical properties of the different products. All sensory parameters of the sea fennel preserved in alcoholic vinegar, namely color, texture, taste, aroma and overall impression, were given the highest scores, while the sample preserved in wine vinegar received the lowest scores. The intense aroma of the wine vinegar was described as a negative characteristic (off-flavor) of the sample.

Extreme environmental conditions affect the synthesis and accumulation of bioactive metabolites in halophytic plants. The aim of this study was to investigate the presence and quantity of key health-promoting phytochemicals in Croatian sea fennel, one of the most popular Mediterranean halophytes with a wide range of uses. The EOs were characterised by a high content of limonene (up to 93%), while the fatty acid profile shows a low content of oleic acid and the presence of valuable linoleic acid (ω-6) and linolenic acid (ω-3) in high percentages. The dominances of lutein and α-tocopherol were also confirmed in all samples. The results confirm the great variability in the chemistry of sea fennel populations in the Mediterranean region, with significant differences in the composition of the Croatian samples compared to the others, as well as the presence and high concentrations of the analysed bioactive compounds that contribute to the plant's health-promoting attributes.

Olive leaves are a highly available by-product from table olive and olive oil production. They are nowadays strongly valuable for their major bioactive compounds and their beneficial effects. To determine the differences between two Croatian domestic (Lastovka, Oblica) and two introduced (Leccino, Frantoio) cultivars, physical and chemical analysis of olive leaves were performed: surface area, color variability, total phenolic amounts, and essential oil volatile profiles were analyzed at three harvest periods. All cultivars greatly differed in surface area, with cv. Lastovka being the smallest. Color variability resulted in an overall decrease in darkness and amounts of green and yellow that could be attributed to a decrease in photosynthetic demand and chlorophyll content. The highest amount of total phenolic content occurred in the summer months, followed by a reduction until October. Essential oils volatiles were determined by GC-MS and showed great diversity not only amongst cultivars but also between harvest periods, with overall 45 compounds identified. Principal component analysis distinguished domestic cultivar Oblica from the other observed cultivars, mainly due to its essential oil volatile fingerprint. Compounds that differentiated cv. Oblica were aldehydes ((E,Z)-2,4-heptadienal, (E,E)-2,4-heptadienal, decanal), ketones ((E)-β-damascone, dihydrodehydro-β-ionone), sesquiterpenes (cyclosativene, α-copaene, α-muurolene) and saturated hydrocarbons (tetradecane, hexadecane). Essential oil volatile fingerprint attributed the highest to the biodiversity of domestic cv. Oblica through all three harvest periods.

Leaves play a central role in plant fitness, allowing efficient light capture, gas exchange and thermoregulation, ensuring optimal growing conditions for the plant. Phenotypic variability in leaf shape and size has been linked to environmental heterogeneity and habitat characteristics. Therefore, the study of foliar morphology in plant populations can help us to identify the environmental factors that may have influenced the process of species diversification. In this study, we used European wild pear (Pyrus pyraster (L.) Burgsd., Rosaceae) as a model species to investigate the phenotypic variability of leaves under different environmental conditions. Using leaf morphometric data from 19 natural populations from the north-western part of the Balkan Peninsula, a high level of variability among and within populations were found. Leaf traits related to leaf size were more variable compared to leaf shape traits, with both influenced by geographic and environmental factors. Consequently, patterns of isolation by environment (IBE) and distance (IBD) were identified, with IBE showing a stronger influence on leaf variability. Multivariate statistical analysis revealed that European wild pear populations from the north-western part of the Balkan Peninsula can be divided into two morphological clusters, consistent with their geographical distance and environmental conditions. Our results confirm a high level of phenotypic variability in European wild pear populations, providing additional data on this poorly studied species, emphasizing phenotypic plasticity as a major driver in the adaptation of this noble hardwood species to rapid climate change.