1. Mesocellular silica foam as immobilization carrier for production of statin precursorsDino Skendrović, Mateja Primožič, Tonči Rezić, Ana Vrsalović Presečki, 2024, izvirni znanstveni članek Ključne besede: immobilization, aldolase, DERA, statins, mesoporous silica, pore size
Objavljeno v DKUM: 04.09.2024; Ogledov: 59; Prenosov: 4
 Celotno besedilo (6,28 MB) |
2. Antibacterial Komagataeibacter hansenii nanocellulose membranes with avocado seed bioactive compoundsKaja Kupnik, Mateja Primožič, Vanja Kokol, Željko Knez, Maja Leitgeb, 2024, izvirni znanstveni članek Ključne besede: bacterial nanocellulose membrane, avocado seed extracts, extraction, swelling, release, antibacterial activity
Objavljeno v DKUM: 23.08.2024; Ogledov: 65; Prenosov: 1
Celotno besedilo (1,80 MB) |
3. Mango peels as an industrial by-product: a sustainable source of compounds with antioxidant, enzymatic, and antimicrobial activityNika Kučuk, Mateja Primožič, Petra Kotnik, Željko Knez, Maja Leitgeb, 2024, izvirni znanstveni članek Opis: Plant waste materials are important sources of bioactive compounds with remarkable health-promoting benefits. In particular, industrial by-products such as mango peels are sustainable sources of bioactive substances, with antioxidant, enzymatic, and antimicrobial activity. Appropriate processing is essential to obtain highly bioactive compounds for further use in generating value-added products for the food industry. The objective of the study was to investigate and compare the biological activity of compounds from fresh and dried mango peels obtained by different conventional methods and unconventional extraction methods using supercritical fluids (SFE). The highest total phenolic content (25.0 mg GAE/g DW) and the total content of eight phenolic compounds (829.92 µg/g DW) determined by LC-MS/MS were detected in dried mango peel extract obtained by the Soxhlet process (SE). SFE gave the highest content of proanthocyanidins (0.4 mg PAC/g DW). The ethanolic ultrasonic process (UAE) provided the highest antioxidant activity of the product (82.4%) using DPPH radical scavenging activity and total protein content (2.95 mg protein/g DW). Overall, the dried mango peels were richer in bioactive compounds (caffeic acid, chlorogenic acid, gallic acid, catechin, and hesperidin/neohesperidin), indicating successful preservation during air drying. Furthermore, outstanding polyphenol oxidase, superoxide dismutase (SOD), and lipase activities were detected in mango peel extracts. This is the first study in which remarkable antibacterial activities against the growth of Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus) were evaluated by determining the microbial growth inhibition rate after 12 and 24 h incubation periods for mango peel extracts obtained by different methods. Ethanolic SE and UAE extracts from dried mango peels resulted in the lowest minimum inhibitory concentrations (MIC90) for all bacterial species tested. Mango peels are remarkable waste products that could contribute to the sustainable development of exceptional products with high-added value for various applications, especially as dietary supplements.
Ključne besede: mangifera indica, peels, bioactive substances, LC-MS/MS, proteins, enzymes, antibacterial activity
Objavljeno v DKUM: 12.08.2024; Ogledov: 96; Prenosov: 4
Celotno besedilo (6,49 MB) |
4. Alginate beads with encapsulated bioactive substances from mangifera indica peels as promising peroral delivery systemsNika Kučuk, Mateja Primožič, Željko Knez, Maja Leitgeb, 2024, izvirni znanstveni članek Opis: Since various bioactive substances are unstable and can degrade in the gastrointestinal tract, their stabilization is crucial. This study aimed to encapsulate mango peel extract (MPE) into edible alginate beads using the ionotropic gelation method for the potential oral delivery of bioactive substances. Mango peels, generally discarded and environmentally harmful, are rich in health-promoting bioactive substances. The alginate beads were examined for entrapment efficiency, particle size, morphology, thermal stability, physiochemical interactions, release profile under gastrointestinal conditions, and antibacterial efficacy. The study demonstrated the successful encapsulation of MPE with an efficiency of 63.1%. The in vitro release study showed the stability of the alginate beads in simulated gastric fluid with a maximum release of 45.0%, and sustained, almost complete release (99.4%) in simulated intestinal fluid, indicating successful absorption into the human body. In both fluids, the MPE release followed first-order kinetics. Encapsulation successfully maintained the antibacterial properties of MPE, with significant inhibitory activity against pathogenic intestinal bacteria. This is the first study on MPE encapsulation in alginate beads, presenting a promising oral delivery system for high-added-value applications in the food industry for dietary supplements, functional foods, or food additives. Their production is sustainable and economical, utilizing waste material and reducing environmental pollution.
Ključne besede: alginate beads, encapsulation, Mangifera indica, mango peels, characterization, in vitro release, antbacterial activity
Objavljeno v DKUM: 02.08.2024; Ogledov: 99; Prenosov: 8
Celotno besedilo (6,98 MB) |
5. Imobilizacija terapevtskega encima na magnetne nanodelcePatricija Potisk, 2024, magistrsko delo Opis: Namen magistrskega dela je uspešna imobilizacija encima lizocima na magnetne nanodelce. Praktična uporaba prostih encimov je pogosto omejena zaradi njihove relativno nizke stabilnosti in aktivnosti. Z namenom, da se le-ta ohrani ali poveča, se poslužujemo različnih metod imobilizacije encimov. V okviru magistrskega dela smo najprej sintetizirali magnetne nanodelce, ki so služili kot nosilci za imobilizacijo biokatalizatorja. Nanodelce smo prevlekli z različnimi polimeri: z aminosilanom, arabinogalaktanom in dekstranom. Preden smo nanje imobilizirali lizocim, smo jih funkcionalizirali z mrežnim povezovalcem glutaraldehidom oziroma epiklorohidrinom. Uporabljena koncentracija mrežnega povezovalca je pomembno vplivala na aktivnost imobiliziranega lizocima in na učinkovitost imobilizacije. Najvišje aktivnosti imobiliziranega lizocima smo pri aminosilanskih nanodelcih dosegli, ko smo uporabili mrežni povezovalec gluteraldehid s koncentracijo 1 % (v/v), pri arabinogalaktanskih nanodelcih pa s koncentracijo 15 % (v/v). V primeru dekstranskih nanodelcev je optimalno koncentracijo mrežnega povezovalca predstavljal 1 % (v/v) epiklorohidrina. Za prosti in imobilizirani lizocim smo nato določili dva kinetična parametra, maksimalno hitrost in Michaelis-Mentenovo konstanto. Raziskali smo tudi termično stabilnost lizocima. Rezultati so pokazali, da je imobilizirani lizocim ohranil aktivnost tudi po 24-urni izpostavitvi pri temperaturi 50 °C, medtem ko je prosti encim pri enakih pogojih denaturiral. Proučili smo tudi stabilnost imobiliziranega encima, ki smo ga tri tedne hranili na 4 °C. Encim, ki je bil imobiliziran na aminosilanskih in arabinogalaktanskih nanodelcih, je po dveh tednih skladiščenja ohranil 86 % oziroma 78 % začetne aktivnosti, po treh tednih skladiščenja pri 4 °C pa je njegova aktivnost upadla. Lizocim, imobiliziran na dekstranske nanodelce, se je tako pri študiji termične stabilnosti kot tudi pri študiji stabilnosti pri 4 °C izkazal za najmanj stabilnega.
Ključne besede: lizocim, imobilizacija, magnetni nanodelci, mrežni povezovalec, aktivnost
Objavljeno v DKUM: 25.07.2024; Ogledov: 134; Prenosov: 38
Celotno besedilo (2,03 MB) |
6. Protimikrobna aktivnost funkcionaliziranih micelarnih struktur za terapevtske nameneAnja Mešl, 2024, magistrsko delo Opis: Glive predstavljajo dragocen vir prehranskih dopolnil, aminokislin, beljakovin, vitaminov, mineralov, ogljikovih hidratov in maščob. Proizvajajo številne bioaktivne spojine, ki jih lahko uporabljamo v industriji, biotehnologiji, farmaciji in medicini. Terapevtski gobi Ganoderma lucidum in Pleurotus ostreatus se že vrsto let uporabljata v zdravilne namene.
Cilj magistrske naloge je bil optimizirati pogoje rasti micelarnih struktur (MS), kot so pH, čas gojenja in vrsta hranilnega tekočega medija, saj ti pogoji bistveno vplivajo na rast micelija in izoblikovanje MS. Najvišjo prirast MS G. lucidum smo dosegli v hranilnem mediju z dodatkom sladnega ekstrakta, medtem ko za P. ostreatus v mediju z dodatkom glukoze. Ugotovili smo, da je bila pri obeh glivah zagotovljena najboljša rast pri pH 8,5. Nadalje smo z optimiranjem časa ugotovili, da sta za nastanek MS G. lucidum potrebna 2 tedna, medtem ko za P. ostreatus 3 tedni.
MS predstavljajo naravne, trajnostne in biorazgradljive materiale, ki se lahko uporabljajo tudi za terapevtske namene, kot je izdelava obližev za celjenje ran, saj se v njihovo strukturo učinkovito ujamejo različne učinkovine s protimikrobnimi lastnostmi. Proučevali smo morfologijo, kemijsko sestavo in hidrodinamične lastnosti pridobljenih MS. MS smo tudi funkcionalizirali z ultrazvočnim ekstraktom iz olupkov manga oz. antibiotikom ciprofloksacinom kot referenčno učinkovino. Primerjali smo njihove karakteristike z referenčnimi strukturami (MS brez funkcionalizacije z učinkovinami) ter določili učinkovitost ujetja, in vitro sproščanje ter protimikrobne lastnosti funkcionaliziranih MS. Rezultati kažejo na učinkovito ujetje učinkovin v MS obeh terapevtskih gob in postopno sproščanje učinkovin iz MS. Prav tako so MS z ekstraktom oz. antibiotikom uspešno zavirale rast Gram-negativnih (Escherichia coli, Pseudomonas aeruginosa) in Gram-pozitivnih bakterij (Bacillus cereus, Staphylococcus aureus).
Ključne besede: micelarne strukture, Ganoderma lucidum, Pleurotus ostreatus, karakterizacija, funkcionalizacija, protimikrobnost
Objavljeno v DKUM: 16.07.2024; Ogledov: 149; Prenosov: 28
Celotno besedilo (4,85 MB) |
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9. Enzymatic, Antioxidant, and Antimicrobial Activities of Bioactive Compounds from Avocado (Persea americana L.) SeedsKaja Kupnik, Mateja Primožič, Vanja Kokol, Željko Knez, Maja Leitgeb, 2023, izvirni znanstveni članek Ključne besede: avocado seed, Persea Americana, HPLC, phenolic compounds, enzymatic activity, phytochemistry, antioxidant, antimicrobial activity
Objavljeno v DKUM: 10.04.2024; Ogledov: 346; Prenosov: 329
Celotno besedilo (2,58 MB)
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