Pressurized Liquid Extraction: A Powerful Tool to Implement Extraction and Purification of Food Contaminants

Pressurized liquid extraction (PLE) is considered an advanced extraction technique developed in the mid-1990s with the aim of saving time and reducing solvent with respect to traditional extraction processes. It is commonly used with solid and semi-solid samples and employs solvent extraction at elevated temperatures and pressures, always below the respective critical points, to maintain the solvent in a liquid state throughout the extraction procedure. The use of these particular pressure and temperature conditions changes the physicochemical properties of the extraction solvent, allowing easier and deeper penetration into the matrix to be extracted. Furthermore, the possibility to combine the extraction and clean-up steps by including a layer of an adsorbent retaining interfering compounds directly in the PLE extraction cells makes this technique extremely versatile and selective. After providing a background on the PLE technique and parameters to be optimized, the present review focuses on recent applications (published in the past 10 years) in the field of food contaminants. In particular, applications related to the extraction of environmental and processing contaminants, pesticides, residues of veterinary drugs, mycotoxins, parabens, ethyl carbamate, and fatty acid esters of 3-monochloro-1,2-propanediol and 2-monochloro-1,3-propanediol from different food matrices were considered

Genetička, biokemijska, hranjiva i antimikrobna svojstva šipka (Punica granatum L.) uzgojenog u Istri

This study characterises the genetic variability of local pomegranate (Punica granatum L.) germplasm from the Slovenian and Croatian areas of Istria. The bioactive components and antioxidant and antimicrobial properties of ethanol and water extracts of different parts of pomegranate fruit were also determined, along with their preliminary nutritional characterisation. Twenty-six different genotypes identified with microsatellite analysis indicate the great diversity of pomegranate in Istria. The pomegranate fruit ethanol extracts represent rich sources of phenolic compounds (mean value of the mass fraction in exocarp and mesocarp expressed as gallic acid is 23 and 16 mg/g, respectively). The ethanol extracts of pomegranate exocarp and mesocarp showed the greatest antimicrobial activity against Candida albicans, Candida parapsilosis, Rhodotorula mucilaginosa, Exophiala dermatitidis and Staphylococcus aureus, and the same water extracts against S. aureus and Escherichia coli. To the best of our knowledge, this study represents the first report of the characterisation of pomegranate genetic resources from Istria at different levels, including the molecular, chemical, antimicrobial and nutritional properties.U ovom je radu opisana genetička raznolikost germplazme šipka (Punica granatum L.) s područja slovenskog i hrvatskog dijela Istre. U etanolnim i vodenim ekstraktima različitih dijelova ploda šipka pronađeni su bioaktivni spojevi, te su ispitana njihova antioksidacijska i antimikrobna svojstva i preliminarno određena hranjiva svojstva ekstrakata. Dvadeset i šest različitih genotipova utvrđenih analizom mikrosatelita upućuju na veliku raznolikost šipka u Istri. Etanolni ekstrakti ploda šipka predstavljaju bogat izvor fenolnih spojeva (srednja vrijednost masenog udjela, izraženog kao galna kiselina, bila je 23 mg/g u egzokarpu i 16 mg/L u mezokarpu). Etanolni ekstrakti egzokarpa i mezokarpa šipka imali su snažan antimikrobni učinak na sljedeće vrste: Candida albicans, Candida parapsilosis, Rhodotorula mucilaginosa, Exophiala dermatitidis i Staphylococcus aureus, dok su vodeni ekstrakti egzokarpa i mezokarpa uspješno suzbijali rast bakterija S. aureus i Escherichia coli. Prema našim spoznajama, ovo je prva karakterizacija genetičkih izvora šipka iz Istre, koja obuhvaća molekularna, kemijska, antimikrobna i hranjiva svojstva plodova

An Integrated Characterization of Jujube (Ziziphus jujuba Mill.) Grown in the North Adriatic Region

Žižula (Ziziphus jujuba Mill.) ima dobra hortikulturna svojstva, koja uključuju prilagodbu uvjetima suše, abiotskim i biotskim stresovima, te pozitivan utjecaj na zdravlje ljudi. U ovom je istraživanju opisana genska raznolikost germplazme žižule s istarskog poluotoka, te su određeni važni kemijski spojevi, antioksidacijski, antibakterijski i protugljivični učinak ekstrakata plodova žižule te njihova hranjiva svojstva. Rezultati analize gena pokazuju da većina uzoraka s istarskog poluotoka pripada dvjema nedavno introduciranim sortama, \u27Li\u27 i \u27Lang\u27, te najrasprostranjenijoj lokalnoj sorti Domaća žižula\u27. Lokalna sorta ima sitnije plodove od sorata \u27Li\u27 i \u27Lang\u27, s tanjim i mesnatijim mezokarpom. Kemijska je analiza pokazala da su plodovi lokalne sorte vrijedan izvor vlakana ((9,7±0,6) g/100 g), te da su bogati mineralima poput kalija ((829±51) g/ 100 g suhe tvari), kalcija ((1 77±1 1 ) g/ 1 00 g suhe tvari) i fosfora ((129±19) g/ 100 g suhe tvari). Vodeni su ekstrakti imali blagu antibakterijsku aktivnost, dok su etanolni ekstrakti imali veće masene udjele fenolnih spojeva (5,8-8,7 mg/g), izražene kao ekvivalent galne kiseline (GAE), od vodenih ekstrakata, no nisu imali antimikrobnu aktivnost. Osim fenolnih spojeva, i ostali spojevi u plodu žižule mogu imati veću biološku aktivnost. Na osnovi rezultata ovih analiza smatramo da lokalna istarska sorta žižule ima potencijal za uzgoj.Jujube (Ziziphus jujuba Mill.) has favourable horticultural properties including adaptation to arid conditions, abiotic and biotic stresses, as well as positive impact on human health. The present study describes the characterization of genetic diversity of the germplasm of jujube from the Istrian peninsula, the determination of important chemical compounds, antioxidative properties in relation to antibacterial and antifungal activities of jujube fruit extracts, and the determination of nutritional properties of jujube fruit. The results of the genetic analysis showed that most of the samples from the Istrian peninsula belong to two recently introduced varieties, \u27Li\u27 and \u27Lang\u27, and the most widespread local variety \u27Navadna žižola\u27. The local variety has smaller fruit than the ‘Li’ and ‘Lang’ varieties, with thick and fleshy mesocarp. Chemical analysis indicated that fruits of the local variety contained a valuable source of dietary fibre ((9.7±0.6) g/100 g) and were rich in minerals such as (in g/100 g dry mass): potassium (829±51), calcium (177±11) and phosphorus (129±19). Aqueous extracts showed slight antibacterial activity, while ethanol extracts had higher mass fractions of phenolic compounds (expressed as gallic acid equivalents (GAE), 5.8-8.7 mg/g) than the aqueous extracts, but did not show antimicrobial activity. Compounds other than phenolic compounds in jujube fruit may be more biologically active. Based on the results of these analyses, the local Istrian jujube variety is a promising candidate for cultivation potential

Developing an Olive Biorefinery in Slovenia: Analysis of Phenolic Compounds Found in Olive Mill Pomace and Wastewater

The valorization of olive pomace through the extraction of phenolic compounds at an industrial scale is influenced by several factors that can have a significant impact on the feasibility of this approach. These include the types and levels of phenolic compounds that are present, the impact that seasonal variation and cultivar type have on the phenolic compound content in both olive pomace and mill effluents and the technological approach used to process the olive crop. Chemical analysis of phenolic compounds was performed using an HPLC-diode-array detector (DAD)-qTOF system, resulting in the identification of 45 compounds in olive mill wastewater and pomace, where secoiridoids comprised 50–60% of the total phenolic content. This study examined three different factors that could impact the phenolic compound content of these processing streams, including cultivar types typically grown on local farms in Slovenia, the type of downstream processing used and seasonality effects. Olive crop varieties sourced from local farms showed high variability, and the highest phenolic content was associated with the local variety “Istrska Belica”. During processing, the phenolic content was on average approximately 50% higher during two-phase decanting compared to three-phase decanting and the type of compound present significantly different. An investigation into the seasonal effects revealed that the phenolic content was 20% higher during the 2019 growing season compared to 2018. A larger sample size over additional growing seasons is required to fully understand the annual variation in phenolic compound content. The methods and results used in this study provide a basis for further analysis of phenolic compounds present in the European Union’s olive crop processing residues and will inform techno-economic modelling for the development of olive biorefineries in Slovenia