1. Sustainable extraction of hemp seed and formulation extracts into organogels with analytical profiling of fatty acidssubcritical fluids in food processingSara Karlovšek, Taja Žitek Makoter, Teo Makoter, Željko Knez, Maša Knez Marevci, 2025, izvirni znanstveni članek Opis: Sustainable extraction methods for natural extracts are crucial for mitigating environmental impact. Strategies that focus on waste reduction and resource efficiency contribute to long-term conservation. Hemp seeds, which were previously treated as waste product, are now valued for their nutrition and functional properties. This study investigated sustainable extraction methods for obtaining natural extracts from hemp seeds, with a focus on reducing environmental impact through efficient resource utilization and waste reduction. The extraction methods compared included supercritical fluid extraction (SFE), Soxhlet extraction (SOX), ultrasound-assisted extraction (UAE), cold maceration (CM), and cold pressing (CP). The contents of antioxidants, total phenols, and fatty acids in the extracts were analyzed via gas chromatography–mass spectrometry (GC–MS). The extracts were subsequently formulated into organogels to evaluate the stability of the fatty acids. The results showed that SFE and CP were the most efficient and environmentally friendly methods, with SFE allowing complete separation of the solvent from the extract. CP was also found to be effective and environmentally friendly. The study confirmed that formulating extracts in organogels effectively inhibited fatty acid oxidation, although a reduction in fatty acid content was observed during gel production. Overall, the formulation of extracts in organogels increased their stability, especially in preventing fatty acid degradation.
Ključne besede: supercritical fluid extraction, ultrasound extraction, cold pressing method, fatty acids, stability of formulations
Objavljeno v DKUM: 15.10.2025; Ogledov: 0; Prenosov: 10
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2. Synergistic effect of supercritical and ultrasound-assisted ginger (Zingiber officinale Roscoe) extractsTaja Žitek Makoter, Nika Kučuk, Vesna Postružnik, Maja Leitgeb, Željko Knez, Mateja Primožič, Maša Knez Marevci, 2022, izvirni znanstveni članek Opis: Proper processing of natural material is crucial to obtain an extract with high content of
biologically active components. Dried, grinded ginger roots were extracted by ultrasonic method
and supercritical extraction with CO2
. The aim of the study was to determine if a mixture of the two
types of extracts attained by different methods and solvents exhibits better bioavailability than each
extract itself. Therefore, both extracts were analytically evaluated and then mixed in a ratio of 1:1.
The supercritical extract (SCG extract) and the mixed extract (mixG extract) had high antioxidant
activity (78% and 73%) and total phenols (827 mg/g ext. and 1455 mg/g ext.), which is also consistent
with the levels of gingerol (303 mg/g ext. and 271 g/g ext.) and shogaol (111 mg/g ext. and 100 g/g
ext.) in the extracts. In comparison to both pure extracts higher levels of total phenols were found
in the extract mixG. This could be the reason for the significant inhibition of melanoma cells and
antimicrobial potential (against Staphylococcus aureus, Escherichia coli, and Candida albicans). The
combination of the extracts resulted in a significant increase in the inhibition of selected microbial
and melanoma cells WM-266-4 compared to the control. Cell viability decreased below 60% when
mixG extract was applied. Antimicrobial activity has been confirmed.
Ključne besede: ginger, supercritical fluid extraction, ultrasound-assisted extraction, antimicrobial activity
Objavljeno v DKUM: 09.05.2025; Ogledov: 0; Prenosov: 15
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3. Ellagitannin content in extracts of the chestnut wood aesculusTaja Žitek Makoter, Maša Knez Marevci, Željko Knez, 2024, izvirni znanstveni članek Ključne besede: antioxidant activity, chestnut wood, conventional extraction, extraction, fractionation, polyphenols, tannins, ultrasound extraction
Objavljeno v DKUM: 05.09.2024; Ogledov: 70; Prenosov: 27
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4. Extraction of active compounds from mixtures of hemp (Cannabis sativa) with Pants of the Zingiberaceae familyVesna Postružnik, Taja Žitek Makoter, Darko Goričanec, Petra Kotnik, Željko Knez, Maša Knez Marevci, 2023, izvirni znanstveni članek Ključne besede: supercritical fluid extraction, ultrasound-assisted extraction, hemp, ginger, turmeric, cardamom
Objavljeno v DKUM: 08.05.2024; Ogledov: 234; Prenosov: 29
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