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Stinging nettle (Urtica dioica L.) is a perennial plant species that is often perceived as a weed, but in recent years it has attracted interest for its medicinal and nutritional properties. Wild nettle is primarily a variable plant material of unexplored composition, so recent research aims to the importance of its cultivation. Optimal yield and nutritional quality of the final product are influenced by a number of abiotic, biotic and anthropogenic factors, which are difficult to control due to fluctuating environmental conditions during field cultivation. Modern greenhouse hydroponic cultivation techniques, such as floating hydroponics, can eliminate the problems of field cultivation and allow earlier harvesting, higher yields and better quality of plant material. Optimal conditions for plant growth are achieved by proper management of the abiotic factors of air and nutrient solution during cultivation. Since different plant species differ considerably in their uptake of certain nutrients, it is necessary to determine the optimum composition of nutrient solution for each species depending on the cropping season and the purpose of the final product. The aim of this study was to determine the specialized metabolites and antioxidant properties of fresh nettle leaves depending on the content of two different nutrient solutions (EC 1.8 mS cm -1 and EC 3.0 mS cm -1) in floating hydroponics. The nutrient solution with the lower amount of nutrients resulted in higher levels of total phenolics (238.4 mg GAE 100 g-1) and lower levels of vitamin C (80.3 mg 100 g -1) and antioxidant capacity (2413.8 μmol TE L -1).

The aim of this study was to assess the nutritional composition of fruits of some citrus species (sweet orange, grapefruit, clementine and kumquat) and to determine their basic physicochemical parameters, bioactive compounds content, and antioxidant capacity. According to the analyzed data, kumquat fruits had the highest dry matter content (18.71%) and total acid content (3.08%), while the highest values of total soluble solids (13.41%), pH value (3.92), vitamin C (53.69 mg/100 g FW), total phenols (162 mg GAE/100 g FW), β-carotene (1053.17 µg/100 g FW), and antioxidant capacity (1.70 mmol TE/kg) were determined in clementine fruits. Considering the nutritional composition of citrus fruits, it can be concluded that they are a rich source of various bioactive compounds, especially vitamin C, carotenoids, and polyphenols, and are characterized by their high antioxidant capacity, which is important for health. Moreover, the cultivation of citrus fruits is an important factor in the Croatian economy, which should be promoted in the future, and the potential of the southern part of Croatia for the cultivation of these citrus fruits should be exploited to the maximum., Cilj ovog istraživanja bio je valorizirati nutritivni sastav plodova određenih vrsta citrusa: slatke naranče, grejpa, klementine i kumkvata, analizirajući njihova osnovna fizikalno-kemijska svojstva, sadržaj bioaktivnih spojeva i antioksidacijski kapacitet. Prema analiziranim podacima, plodovi kumkvata imali su najviše vrijednosti ukupne suhe tvari (18,71%), ukupnih kiselina (3,08%), dok su istodobno u plodovima klementine utvrđene najviše vrijednosti topljive suhe tvari (13,41%), pH vrijednosti (3,92), vitamina C (53,69 mg/100 g FW), ukupnih fenola (162 mg GAE/100 g FW), β-karotena (1053,17 µg/100 g FW) i antioksidacijskog kapaciteta (1,70 mmol TE/L.) Temeljem analiziranih parametara nutritivnog sastava plodova različitih vrsta citrusa može se zaključiti kako su agrumi bogat izvor različitih bioaktivnih spojeva, posebice vitamina C, karotenoida i polifenola, pa ih stoga karakterizira i visok antioksidacijski kapacitet, a što je od iznimne važnosti i za zdravlje ljudi. Štoviše, uzgoj agruma važan je čimbenik u hrvatskom gospodarstvu, koji bi trebalo dodatno promovirati, dok potencijal južnog dijela Hrvatske za uzgojem ovih agruma treba maksimalno iskoristiti.

Rosa canina L., also called dog rose or rosehip, is a perennial shrub of the Rosaceae family. It is native to Europe, Central Asia, and parts of the North Africa (Jürgens et al., 2007). In its natural range, which includes Croatia, dog rose is a well-known plant species with a rich and documented historical background and a long tradition of use as an important food source and medicine. Consumption of wild R. canina fruits is common in many European countries and is considered a natural remedy in the treatment of colds, coughs, and flu, as well as gastrointestinal disorders (Sen et al., 1996). A variety of pharmacological and nutritional effects have been scientifically proven for rosehip and its products (Chrubasik et al., 2008 ; Fan et al., 2014), and associated with the specific chemical composition and characteristic phytochemicals such as phenolics, carotenoids, unsaturated fatty acids, and high concentrations of vitamins (especially vitamin C) (Winther et al., 2016). Previous studies have shown that bioactive compounds are prone to qualitative and quantitative variation depending on numerous factors, such as plant genotype, maturity stage, and the environmental conditions (Koczka et al., 2018 ; Yang et al., 2018). In Croatia, rosehip is a widespread plant species that occurs in all three geographical regions (continental, alpine and Mediterranean). Our aim was to investigate the diversity of R. canina populations sampled in different geographical regions, in terms of content of main phytochemicals (vitamin C, total polyphenols, flavonoids, carotenoids) and antioxidant capacity.

Cilj rada bio je analizirati i usporediti nutritivnu kvalitetu mutnih, svježe cijeđenih sokova iz plodova četiriju različitih sorti jabuka: 'Idared', 'Jonagold', 'Golden Delicious' i 'Cripps Pink'. S obzirom na analizirani mehanički sastav utvrđeno je da najbolje iskorištenje ploda za dobivanje soka ima sorta 'Idared' (45,51%), zatim slijedi sorta 'Golden Delicious (44,22%), 'Jonaglod' (36,56%) te sorta 'Cripps Pink' (25,75%). Prema rezultatima dobivenim u ovom istraživanju sok sorte 'Golden Delicious' pokazuje najveći omjer TST/UK, zatim sok sorte 'Jonagold', 'Idared', dok je najmanji omjer utvrđen kod soka sorte 'Cripps Pink'. Najveći sadržaj vitamina C (6,75 mg/100g svježeg ploda) kao i najveći sadržaj ukupnih fenola (55,84 mgGAE/100 g svježe tvari) utvrđeni su u soku sorte 'Jonagold' Temeljem dobivenih rezultata može se zaključiti da su plodovi svih istraživanih sorti pogodni za proizvodnju mutnog soka, ali i da mogu biti dobra podloga za proizvodnju ostalih sokova od raznih vrsta voća, The aim of the study was to analyse and compare the nutritional quality of cloudy, freshly squeezed fruit juices from four different apple cultivars: ‘Idared’, ‘Jonagold’, ‘Golden Delicious’ and ‘Cripps Pink’. Considering the analysed mechanical composition, it was determined that the best yield of fruit for juice production has the cultivar 'Idared' (45.51%), followed by the cultivar ‘Golden Delicious’ (44.22%), 'Jonaglod' (36.56%) and the 'Cripps Pink' cultivar (25.75%). According to the results obtained in this study, the juice of the 'Golden Delicious' cultivar shows the highest TST/UK r atio, followed b y t he j uice o f t he 'Jonagold' a nd 'Idared' cultivars, while the lowest ratio was found for the juice of the 'Cripps Pink' cultivar. The highest content of vitamin C was determined in the juice of the cultivar 'Jonagold' (6.75 mg/100 g of fresh fruit) as well as the highest content of total phenols (55.84 mg GAE/100 g of fresh matter). Based on the obtained results, it can be concluded that the fruits of all investigated cultivars are suitable for the production of cloudy juice, but also that they can be a good base for the production of juices from various types of fruit.

Nettle is a highly valued medicinal plant that is still largely neglected, both in terms of nutrition and use for pharmacological purposes. Tinctures, i.e., alcoholic extracts, are becoming increasingly popular nettle products, mainly because they allow better availability of phytochemicals and their stability over a longer period of time. The production of alcoholic extracts is a chemically demanding process that is still usually carried out using conventional techniques, which have numerous drawbacks. The use of green technologies such as ultrasound-assisted extraction (UAE), which is characterized by high efficiency of phytochemical extraction, shorter treatment time, and a much lower environmental footprint, is a suitable and sustainable solution. Therefore, the aim of this study is to determine the influence of the extraction method, conventional and ultrasound (by varying two ultrasound equipment systems), time and ethanol concentration on the extraction of specialized metabolites from nettle powder. Ultrasonic extraction using a probe system significantly contributed to increase the ascorbic acid yield, polyphenolic compounds, and antioxidant capacity of nettle extracts compared to conventional extraction. In addition, when a probe system was used during UAE, significantly less time was required for isolation of individual specialized metabolites compared to ultrasonic extraction in the bath. Ethanol concentration (50 and 80% v/v) also proved to be an important factor in the efficiency of extraction of specialized metabolites, with 80% ethanol being more effective for the isolation of ascorbic acid and pigment compounds (chlorophyll and carotenoids), while 50% v/v for the extraction of polyphenolic compounds. It can be concluded that extraction with the ultrasonic probe system is much more efficient in obtaining higher yields of specialized metabolites from nettle powder in a shorter time (average process duration 5–10 min) both compared to UAE in the bath and classical extraction. However, optimization of the key factors of time, solvent type, and ultrasonic power is necessary to maintain the nutritional quality of the nettle extract in order to obtain a final product with a high specialized metabolites content, antioxidant capacity, and functional value. The future application of alcoholic nettle extracts is based on the fact that these products have significant potential as functional foods and pharmacological preparations for the treatment of a number of but also to strengthen the immune system, mainly due to the rich nutritional composition and high content of various specialized metabolites. The prepared extracts can be safely taken orally by diluting the tinctures with water immediately before ingestion.

International audience; The South American plant Stevia rebaudiana Bertoni is a great source of noncaloric sweeteners (steviol glycosides), mainly concentrated in its leaves, but also has important antioxidant compounds (vitamin C, polyphenols, chlorophylls, and carotenoids) and other important macro- and micronutrients such as folic acid and all of the essential amino acids except tryptophan. Traditionally, conventional methods have been used to recover nutritionally valuable compounds from plant food matrices. However, nowadays, the need for obtaining greener, sustainable, and viable processes has led both food industries and food scientists to develop new processes in full correspondence with the green extraction concept. This review focuses on some of the most promising nonconventional and emerging technologies, which may constitute a potential alternative to conventional methods or even could be combined to obtain a synergistic effect, thus reducing extraction time as well as solvent consumption and avoiding the use of toxic solvents.