Stela Jokic

University of Osijek | UNIOS · Department of Process Engineering

Globalizacija, rast populacije i promjene u prehrambenim navikama, povećale su konzumaciju prerađene hrane u svijetu. Time se povećalo i generiranje otpada i nusproizvoda prehrambene industrije. Nedovoljno iskorištavanje nusproizvoda i otpada za posljedicu ima ne samo zagađenje okoliša već dovodi i do financijskih gubitaka imajući u vidu da je veći...

Health-oriented preferences, a demand for innovative food concepts, and technological advances have greatly influenced changes in the food industry and led to remarkable development of the functional food market. Incorporating herbal extracts as a rich source of bioactive compounds (BC) could be an effective solution to meet the high demand of cons...

The present study investigated the possibility of spent coffee ground (SCG) transformation to a cellulose-based enzyme immobilization carrier using a multistep extraction procedure. In the first step, SCGs were extracted with n-hexane by Soxhlet extraction in order to obtain SCG oil, while the remaining solid residue was subjected to continuous sol...

In this study, the integrated application of supercritical CO 2 and natural deep eutectic solvents (NADES) was investigated in order to establish a green procedure that enables obtaining and stabilizing the aroma volatile constituents of Rosmarinus officinalis L. Supercritical CO 2 was used to obtain rosemary extracts that possessed an abundance of...

This work investigated a green approach to obtain and stabilize Lavandula stoechas L. volatile organic compounds with sensory aroma characteristics by using alternative solvents, namely supercritical carbon dioxide (scCO2) and deep eutectic solvents (DES). The CO2 extracts were dispersed in different DES mixtures (betaine:ethylene glycol (1:3), bet...

Citrus fruits processing results in the generation of huge amounts of citrus by-products, mainly peels, pulp, membranes, and seeds. Although they represent a major concern from both economical and environmental aspects, it is very important to emphasize that these by-products contain a rich source of value-added bioactive compounds with a wide spec...

The aim of this work was to establish the potential of natural deep eutectic solvents (NADES) for the stabilization of aroma volatile organic compounds from a natural source. Satureja montana was used as a source of volatile components, as it is rich in terpenes of great commercial and biological importance, such as carvacrol, thymol, and thymoquin...

Ocimum basilicum L. is the most common Ocimum species, and it is used as an ornamental plant and in food condiments. This unique study examined the chemical composition and biological activities of six extracts from five basil cultivars, including their antimicrobial, antidiabetic, antilipidemic, neuroprotective, and anticollagenase activity. Moreo...

This study is focused on the investigation of the new ways of valorization and maximal utilisation of the fruit dust obtained from the orange peel during industrial processing in the filter tea production. Therefore, the possibility of the integration of two attractive “green” extraction methods, CO2-assisted extraction and ultrasound-assisted extr...

A green and sustainable procedure for obtaining Lavandula stoechas extracts with antioxidant and antimicrobial properties was investigated. Green solvents, supercritical CO2, and natural deep eutectic solvents (NADES) together with ultrasound-assisted extraction were used for the sequential extraction of terpene and polyphenols fractions. After the...

Sweet wormwood (Artemisia annua L.) valorization is gaining importance due to the presence of the health-promoting bioactive compound, artemisinin. Considering the wide possible application of artemisinin drug formulations, new, greener technologies in their production are welcome. In this study, artemisinin was extracted from A. annua leaves using...

The goal of this study was to establish a green methodology for obtaining safe, high-quality, and potent antibacterial extracts of Lavandula stoechas flowers. Supercritical carbon dioxide (scCO 2) at different conditions (pressure 100-300 bar, temperature 40 and 60°C, and CO 2 flow 10-30) was applied. Moreover, the impact of the parameters on the e...

This study aimed to investigate the effect of four green extraction techniques (ultrasoundassisted extraction, UAE; supercritical fluid extraction, SFE; subcritical water extraction, SWE; and extraction using deep eutectic solvents, DES) on the extraction of targeted flavonoids from edible feijoa flowers. The bioactive components in the obtained ex...

This work reports the preparation of amino acid-functionalized CQDs from citric acid by facile hydrothermal synthesis. The prepared N-doped CQDs exhibited excellent optical, physical, and chemical properties, and the differences were observed among the six different amino acids used as nitrogen dopants (Leu, Trp, Lys, Arg, Ala, His). Compared to th...

The content of bioactive compounds in four brown and one red algae from the Adriatic Sea (Dictyota dichotoma, Gongolaria barbata, Ericaria amentacea, Sargassum hornschuchii and Ellisolandia elongata) is explored. The efficiency of two different extraction methods viz. ultrasound-assisted extraction (UAE) and matrix solid-phase dispersion (MSPD) to...

The modern lifestyle today creates a certain pressure on people who are forced to adapt to such a way of living. Energy drinks (EDs), beverages containing certain stimulating ingredients, are increasingly being offered on the market. Given the unclear impact of EDs consumption on the health of the individual, the focus of this study was to determin...

Due to the lack of less-volatile compounds composition data of macroalgal supercritical CO2 (SC-CO2) extracts, the main goal of this study was to investigate their chemical profiles. SC-CO2 extraction (40 °C and 300 bar) was performed on seven macroalgal species including five brown (Halopteris filicina, Fucus virsoides, Dictyopteris polypodioides,...

The particles from the gas-saturated solutions (PGSS) process was employed to micronize brown algae pigments separated by different extraction techniques. The particle formation of pigments with a coating material, polyethylene glycol (PEG), was carried out by the PGSS process using supercritical CO2. Environmental scanning electron microscopy (ESE...

Während der Herstellung, Lagerung und Wärmebehandlung unterliegt Gänseschmalz einem oxidativen Verfall. In dieser Arbeit wurde der Einfluss von natürlichen und synthetischen Antioxidantien und Synergisten (Rosmarinextrakt, Grüntee-Extrakt, Salbeiextrakt, Alpha-Tocopherol, Tocopherol-Mischung, Propylgallat, Zitronensäure, Ascorbinsäure, Kaffeesäure,...

To study the efficiency of two green-based extraction techniques for the isolation of bioactive constituents from black elderberry press cake, changes in phenolic compounds and main anthocyanin contents were analyzed. Polyphenolic content was correlated with antioxidant and antidiabetic potential by radical-scavenging activity and monitoring of α-a...

Purpose Fruit crops by-products and waste have been a particular object of new fortified products creation, especially of the food and pharmaceutical industry. In this research, new approaches for valorization of Rosa canina herbal dust (industrial waste from filter tea production) and its functional ingredients were proposed. Methods In the first...

Natural products are increasingly in demand in dermatology and cosmetology. In the present study, highly valuable supercritical CO2 (sCO2) extracts rich in bioactive compounds with antiradical and antibacterial activity were obtained from the inflorescences of industrial hemp. Volatile compounds were analyzed by gas chromatography in tandem with ma...

U ovom radu istraživan je utjecaj procesnih parametara prešanja sjemenki crnog kima na prinos hladno prešanog ulja te njegovu kvalitetu. Prešanje sjemenki crnog kima provedeno je na laboratorijskoj pužnoj preši za proizvodnju hladno prešanih biljnih ulja. Prešanjem su dobivena tri proizvoda: sirovo ulje, uljni talog i pogača. Prilikom prešanja mije...

Phytochemicals, or phytonutrients, are a group of biologically active substances from plants [...]

The present research is a comprehensive investigation of Dasycladus vermicularis (Scopoli) Krasser 1898 from the Adriatic Sea (Croatia) regarding volatilome–volatile organic compounds (VOCs, mostly nonpolar compounds) and less polar nonvolatile compounds for the first time. Headspace solid-phase microextraction (HS-SPME) and hydrodistillation (HD)...

Cosmetic products are complex mixtures of ingredients with different physical, chemical and functional properties formulated in order to obtain the product with desired activity and quality. This paper provides a comprehensive review on the effectiveness of the environmentally friendly extraction technique based on the application of GRAS solvent C...

Macroalgal pigments can serve as indicators of an environmental stresses due to their higher accumulation during these conditions. Even though they exhibit protective role, a stress can cause their degradation. Many factors influence the pigment content in macroalgae including the temperature of seawater, salinity and acidification, but they are al...

The aim of present research was to contribute to G. barbata and E. crinita chemodiversity and to the knowledge of specially protected Cystoseira areas. Headspace solid-phase microextraction (HS-SPME) and hydrodistillation (HD) were applied to the fresh (FrGb) and air-dried G. barbata (DrGb) and to the fresh (FrEc) and air-dried E. crinita (DrEc). S...

In the past few decades, the spray drying technique has gained wide acceptance as an alternative drying technique for transferring liquid forms into stable dry powder forms with application in the food, pharmaceuticals and cosmetic industry. Spray drying technique enables short operation time, drying of heat sensitive materials, desirable mois...

Peppers are grown all around the world, usually for fresh consumption, as well as for the industrial production of different products. Pepper (Capsicum annuum L.) seeds are mostly considered a by-product. Recent investigations have shown that pepper seeds have the potential to be a valuable source of edible oil and fiber-rich flour and protein afte...

In the present study, ground ivy was harvested from different natural habitats in Croatia and subjected to screening analysis for nutritional and bioactive composition. To achieve maximum recovery of phenolic compounds, different extraction techniques were investigated—heat-assisted (HAE), microwave-assisted (MAE) and subcritical water (SWE) extrac...

Alchemilla vulgaris L. is a good source of antioxidant components with an emphasis on phenolic acids and tannins. In this study, gallic acid, ellagic acid, and hydrolyzable tannins (HT) were extracted from this plant with different deep eutectic solvents (DESs), varying the amount of added H2O, temperature and extraction time. Seventeen DESs (n = 3...

Ericaria crinita and Ericaria amentacea from the Adriatic Sea (Croatia) were investigated with respect to the presence of less-polar compounds for the first time after fractionation by solid-phase extraction (SPE). The composition of less-polar fractions of freeze-dried E. crinita (FdEc) and E. amentacea (FdEa) were analyzed by high-performance liq...

The growing popularity of integration of functional compounds into food and pharmaceutical products has greatly influenced the intense investigation of aromatic plants as its notable sources. One of the insufficiently explored plant species—Mountain Germander (Teucrium montanum)—may represent a prominent source of biologically active components—pol...

Spontaneous precipitation of calcium oxalate monohydrate (COM) in additive-free systems with nearly the same initial supersaturation has been investigated. The influence of thermodynamic parameters such as: temperature (t = 25, 36.5 and 48 °C), calcium concentration range of 5 mmol dm −3 ≤ ci(Ca 2+) ≤ 10 mmol dm −3 and pH (5.6, 6.5 and 7.5), on the...

The triboelectric nanogenerator (TENG) is a widely used energy-harvesting unit for self-power applications. The electrical output performance of the TENG could be significantly improved by ion implantation and explore new triboelectric materials beyond the conventional series. In this present work, the phase pure hydrothermally synthesized ZnO part...

Oct-1-en-3-ol has been studied among oxylipins as a global metabolome that induce the defense of marine algae. The present short review summarized the research of oct-1-en-3-ol as the stress response molecule in marine algae including different aspects: (i) its biosynthesis from fatty acids; (ii) its distribution in marine algae; (iii) a direct eff...

Codium adhaerens from the Adriatic Sea (Croatia) was comprehensively investigated regarding less polar compounds for the first time. Although there are several phytochemical studies on C. adhaerens from other regions, this is the first report on volatile organic compounds (VOCs) from fresh (FrCa) and air-dried (DrCa) samples. The novelty is also re...

The present study was designed to demonstrate the potential of supercritical extracts from Achillea millefolium and Rosa canina herbal dust, and their mixtures, as a source of valuable aromatic and lipophilic compounds. The supercritical carbon dioxide extraction (SFE-CO2) was performed at the pressures from 10-30 MPa, providing the total extractio...

This study aimed to optimize heat- (HAE), microwave-assisted (MAE) and subcritical water extraction (SWE) of phenolic compounds from underutilized traditional herb ground ivy (Glechoma hederacea L.) using response surface methodology. Independent variables were extraction time, temperature and sample/solvent ratio, while dependent variables were to...

Carbon quantum dots (CQDs) have recently emerged as innovative theranostic nanomaterials, enabling fast and effective diagnosis and treatment. In this study, a facile hydrothermal approach for N-doped biomass-derived CQDs preparation from Citrus clementina peel and amino acids glycine (Gly) and arginine (Arg) has been presented. The gradual increas...

The search for an efficient drug or inhibitor in the formation process of kidney stones has been a promising research topic towards reducing the risks of the formation of disease. However, several challenges have been faced in investigating the most common constituents of kidney stones, calcium oxalate and its hydrate forms (COM, COD and COT). This...

This study intends to valorize by-products of the industrial processing of tobacco to obtain nicotine and phenolics as value-added compounds. Three influential parameters of the microwave-assisted extraction-MAE (temperature, treatment time, and solvent/solid ratio) were studied for the optimization of the extraction protocol for tobacco leaves and...

Ugljikove kvantne točke posljednjih nekoliko godina posebno privlače pažnju znanstvenika zbog svojih iznimnih kemijskih i optičkih svojstava, relativno jednostavnog načina priprave, izvrsne biokompatibilnosti te mogućnosti funkcionalizacije površine, omogućavajući širok spektar primjene. Kvantne točke definirane su kao nuldimenzionalni (0D) nanomat...

With globalization, growing popularization and changes in dietary habits where more processed food is consumed, a generation of food wastes and by-products has increased. Under-exploitation of by-products and waste leads to finance losses and environmental pollution although most of the waste are a rich source of bioactive compounds. Using spray dr...

The fluorescent carbon quantum dots (CQDs) represent an emerging subset of carbonaceous nanomaterials, recently becoming a powerful tool for biosensing, bioimaging, and drug and gene delivery. In general, carbon dots are defined as zero-dimensional (0D), spherical-like nanoparticles with <10 nm in size. Their unique chemical, optical, and electroni...

Laurencia genus has been the most promising source of sesquiterpenes (among all macroalgae) including those with high degree of halogenation, especially bromination. Related published reviews do not report novel researches included in this study and are not focused exclusively on this genus or sesquiterpenes. The present review reports novel struct...

In this study, an efficient utilization and valorization of mandarin peel (Citrus unshiu Marc. var. Kuno) was investigated using innovative and green extraction techniques. The first step of this study included the extraction and analysis of the volatile compounds by performing a supercritical CO2 (SC-CO2) extraction under different operating press...

The endemic brown macroalga Fucus virsoides J. Agardh from the Adriatic Sea was in the focus of the present research. The volatiles of fresh (FrFv) and air-dried (DrFv) samples of F. virsoides obtained by headspace solid-phase microextraction (HS-SPME) and hydrodistillation (HD) were analyzed by gas chromatography equipped with flame ionization det...

Three fractions of tobacco waste (scrap, dust and midrib) were subjected to a high voltage electric discharge (HVED) assisted extraction procedure under different experimental conditions: solvent:solid ratio (300, 500, 700 mL/g), frequency (40, 70, 100 Hz) and treatment time (15, 30, 45 min), in order to study the influence of these conditions on t...

This study is focused on simple voltammetric determination of hesperidin by using electroactivated PGE in model systems and in real samples in order to evaluate the adequacy of the developed method in pharmaceutical analysis. Electroactivation of the electrode was performed in various potentials ranging from -1.4 V to 2.0 V in the phosphate buffer...

A tobacco solid waste was extracted by a sequence of supercritical CO2 (SC-CO2) extraction and subcritical water extraction (SWE). The tobacco waste lipophilic compounds (targeted fatty acids, free base nicotine and VOCs) were extracted using the series of the main operation parameters for the SC-CO2 extraction (pressure: 100-300 bar, temperature:...

Supercritical carbon dioxide and Soxhlet extraction were employed for delivering Marrubium vulgare extracts. By varying process temperature and pressure, the impact of different densities of carbon dioxide on the extraction yield and chemical profile of the extracts was investigated. The highest extraction yields of M. vulgare were obtained by supe...

The aim of this study was to extract Allium ursinum L. for the first time by supercritical carbon dioxide (SC‐CO 2 ) as green sustainable method. The impact of temperature in the range from 40 to 60 °C and pressure between 150 and 400 bar on the quality of the obtained extracts and efficiency of the extraction was investigated. The highest extracti...

Due to the lack of phytochemical composition data, the major goals of the present study on Amphiroa rigida J.V. Lamouroux were to: (a) investigate and compare volatilome profiles of fresh and air-dried samples obtained by headspace solid-phase microextraction (HS-SPME) and hydrodistillation (HD) followed by gas chromatography and mass spectrometry...

Salvia officinalis L. is a good source of antioxidant compounds such as phenolic diterpenes carnosic acid and carnosol. From 17 deep eutectic solvents (DESs) used, choline chloride: lactic acid (1:2 molar ratio) was found to be the most suitable for the extraction of targeted compounds. The influence of H2O content, extraction time, and temperature...

Pileća mast podliježe oksidacijskom kvarenju tijekom proizvodnje, skladištenja i toplinske obrade. U ovom radu istraživan je utjecaj dodatka prirodnih i sintetskih antioksidanasa (ekstrakt zelenog čaja, ekstrakt ružmarina, ekstrakt kadulje, ekstrakt rtanjskog čaja, alfa tokoferol, mješavina tokoferola, TBHQ (terc-butilhidrokinon), kofeinska kiselin...

Tobacco waste is a solid waste highly diverse in granulation and point of separation in the manufacturing process. The objective of this study was to investigate the efficacy of eutectic solvents in the extraction of bioactive compounds from tobacco waste. Influence of extraction parameters on the properties of the obtained extracts (total phenol,...

Electroactivated disposable pencil graphite electrode (ePGE) was used for hesperidin detection with cv and dpv Electroactivation efficiency of the pencil graphite electrode (PGE) was examined with EIS and SECM. Enhancement of electron transfer kinetics after electroactivation was found. Hesperidin is irreversibly oxidized on ePGE (oxidation was the...

The stability of chocolate is mainly influenced by cocoa butter re-crystallization during storage, shown through fat bloom (appearance of white layers of cocoa butter on chocolate surface). The aim of this study was to examine the influence of cocoa shell addition on stability of dark and milk chocolate over a one-year storage period. Dark and milk...