1. Vpliv gnojenja z izrabljenim gobjim substratom na aktivnost talnih encimov v posameznih letnih časih : magistrsko deloAna Štuhec, 2024, master's thesis Abstract: Izrabljen substrat za gobe (IGS) je stranski proizvod gojenja gob, ki sestoji iz raznovrstnih organskih materialov. Po nekaj sezonah rabe se substrat izčrpa in praviloma velja za odpadek, vendar sodobne raziskave nakazujejo številne koristne možnosti uporabe izrabljenega gobjega substrata. V projektni raziskavi se je IGS uporabljal kot organsko gnojilo na treh različnih lokacijah v ekološki, integrirani in biodinamični pridelavi paradižnika v rastlinjakih. V vsaki od pridelav se je v triplikatih testiralo gnojenje z SMS, standardno gnojenje (S), SMS+S in kontrola brez gnojenja. V sklopu magistrskega dela smo na obravnavanih lokacijah jemali vzorce zemlje v vseh letnih časih, v vzorcih pa smo analizirali aktivnost encimov N-acetil-glukozaminidaza (NAG), fosfataza (PHOS), beta-glukozidaza (β0GLU), arilsulfataza (ARS), ureaza (URE), arilamidaza (ARN), alkalna fosfataza (PAK) in kisla fosfataza (PAC) po standardu ISO 20130:2018- Kakovost tal - Merjenje encimske aktivnosti v vzorcih tal s kolorimetričnimi substrati na mikrotitrski plošči. Primerjali smo razlike v encimski aktivnosti med posameznimi letnimi časi ter med različnimi načini gnojenja. Rezultati so pokazali, da različni letni časi vplivajo na aktivnost encimov v tleh, medtem ko dodatek gobjega substrata kot gnojila ne povzroči nujno povišanja encimske aktivnosti.
Keywords: talni encimi, izrabljen gobji substrat, aktivnost, gnojenje, kmetijstvo
Published in DKUM: 03.09.2024; Views: 35; Downloads: 11
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2. Vpliv cemprinovega lesa na rast plesni penicillum roqueforte in asperqillus niger : magistrsko deloBranka Kristl, 2024, master's thesis Abstract: V magistrskem delu smo testirali vpliv cemprinovega lesa na rast gliv in oblikovanje spor Aspergillus niger ter Penicillium roqueforte. Vpliv lesa smo testirali tako, da smo glive inkubirali v škatlah iz cemprinovega lesa. Kot primerjalno kontrolo za analizo rasti gliv smo uporabili še škatle iz bukovega in smrekovega lesa, plastike in čisto eterično olje
cemprina. Največji zaviralni učinek na rast testiranih gliv smo opazili v škatlah iz cemprinovega lesa, sledile so plastične škatle z dodatkom eteričnega olja cemprina. Rast gliv v drugih škatlah je bila primerljiva. Cemprinov les je imel največji zaviralni učinek na rast glive P. roqueforte, hkrati pa je zavrl tudi oblikovanje spor gliv. Cemprinov les ima zaradi svojih protiglivnih lastnosti potencial za uporabo v živilski industriji kot material
za izdelavo škatel za shranjevanje kruha in končnih pekovskih izdelkov, kjer sta pojav in kvar zaradi plesni pogosta.
Keywords: Pinus cembra, cemprin, Penicillium roqueforte, Aapergillus niger, protiglivno delovanje
Published in DKUM: 03.09.2024; Views: 24; Downloads: 6
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3. Probiotic mechanisms affecting glucose homeostasis : a scoping reviewMaša Pintarič, Tomaž Langerholc, 2022, review article Abstract: The maintenance of a healthy status depends on the coexistence between the host organism and the microbiota. Early studies have already focused on the nutritional properties of probiotics, which may also contribute to the structural changes in the gut microbiota, thereby affecting host metabolism and homeostasis. Maintaining homeostasis in the body is therefore crucial and is reflected at all levels, including that of glucose, a simple sugar molecule that is an essential fuel for normal cellular function. Despite numerous clinical studies that have shown the effect of various probiotics on glucose and its homeostasis, knowledge about the exact function of their mechanism is still scarce. The aim of our review was to select in vivo and in vitro studies in English published in the last eleven years dealing with the effects of probiotics on glucose metabolism and its homeostasis. In this context, diverse probiotic effects at different organ levels were highlighted, summarizing their potential mechanisms to influence glucose metabolism and its homeostasis. Variations in results due to different methodological approaches were discussed, as well as limitations, especially in in vivo studies. Further studies on the interactions between probiotics, host microorganisms and their immunity are needed.
Keywords: probiotic, mechanism, glucose, metabolism, homeostasis
Published in DKUM: 28.06.2024; Views: 404; Downloads: 9
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4. Antimicrobial properties of different hop (Humulus lupulus) genotypesZala Kolenc, Tomaž Langerholc, Gregor Hostnik, Miha Ocvirk, Sara Štumpf, Maša Pintarič, Iztok Jože Košir, Andreja Čerenak, Alenka Garmut, Urban Bren, 2023, original scientific article Abstract: The antimicrobial activity of hop extracts obtained from different hop genotypes were investigated against Staphylococcus aureus and Lactobacillus acidophilus. In this study the pure xanthohumol, purified β-acids rich fraction, as well as α-acids with β-acids rich fraction were used to test antimicrobial activity against Staphylococcus aureus and Lactobacillus acidophilus; whereby, the antimicrobial activity of different hop extracts against Lactobacillus acidophilus was studied for the first time. Microbial susceptibility to purified hydroacetonic extracts from different hop varieties was investigated by the broth microdilution assay to determine the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). The hop hydroacetonic extracts were more effective against Staphylococcus aureus than against Lactobacillus acidophilus. Strong inverse correlations of MIC and MBC values were obtained with xanthohumol, cohumulone, n+adhumulone, colupulone and n+adlupulone contents, suggesting that the identified chemical hop compounds are directly responsible for antimicrobial effects. Moreover, the effect of the growth medium strength on the MIC values of hop extracts against Staphylococcus aureus was systematically investigated for the first time. The current study also reveals the effect of different hop extracts on Staphylococcus aureus, which responds to their presence by lag phase extension and generation time prolongation.
Keywords: hop extract, xanthohumol, Staphylococcus aureus, Lactobacillus acidophilus, minimum inhibitory concentration, minimum bactericidal concentration
Published in DKUM: 09.05.2024; Views: 197; Downloads: 11
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5. Antioxidant activity of different hop (Humulus lupulus L.) genotypesZala Kolenc, Tamara Hribernik, Tomaž Langerholc, Maša Pintarič, Maja Prevolnik Povše, Urban Bren, 2023, original scientific article Abstract: The antioxidant activity (AA) of hop extracts obtained from different hop genotypes (n = 14) was studied. For comparison, the purified β-acids-rich fraction and α-acids-with-β-acids-rich fraction were also used to test the antioxidative potential. The AA of purified hydroacetonic hop extracts was investigated using the Ferric Reducing Ability of Plasma (FRAP), Oxygen Radical Absorption Capacity (ORAC) and Intracellular Antioxidant (IA) methods. The FRAP values in different hop genotypes ranged between 63.5 and 101.6 μmol Trolox equivalent (TE)/g dry weight (DW), the ORAC values ranged between 1069 and 1910 μmol TE/g DW and IA potential values ranged between 52.7 and 118.0 mmol TE/g DW. Significant differences in AA between hop genotypes were observed with all three methods. AAs were determined using three different methods, which did not highly correlate with each other. We also did not find significant correlations between AA and different chemical components, which applies both to AA determined using individual methods as well as the total AA. Based on this fact, we assume that the synergistic or antagonistic effects between hop compounds have a more pronounced effect on AA than the presence and quantity of individual hop compounds.
Keywords: hop, antioxidant activity, FRAP, ORAC, intracellular antioxidative potential, genotypes
Published in DKUM: 20.03.2024; Views: 262; Downloads: 12
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6. Food risk analysis : Towards a better understanding of “hazard” and “risk” in EU food legislationAna-Andreea Cioca, Livija Tušar, Tomaž Langerholc, 2023, original scientific article Abstract: For risk communication, it is important to understand the difference between “hazard” and “risk”. Definitions can be found in Codex Alimentarius and the European Union (EU) General Food Regulation (EC) No. 178/2002. The use of these terms as synonyms or their interchange is a recurrent issue in the area of food safety, despite awareness-raising messages sent by EFSA (European Food Safety Authority) and other interested entities. A quick screening of the EU’s food regulations revealed several inconsistencies. Hence, it was considered necessary to further investigate if regulations could act as a source for this problem. A software tool was developed to support the detection and listing of inconsistent translations of “hazard” and “risk” in certain EU food regulations. Subsequently, native-speaking experts working in food safety from each EU country were asked to provide their individual scientific opinion on the prepared list. All data were statistically analysed after applying numerical scores (1–5) describing different levels of consistency. Results showed that the most common problem was the interchange of “hazard” with “risk” and vice versa. This lack of consistency can create confusion that can further translate into misjudgments at food risk assessment and communication levels.
Keywords: risk analysis, risk communication, hazard, risk, food regulation, food safety
Published in DKUM: 12.03.2024; Views: 437; Downloads: 341
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7. The Influence of Chestnut Extract and Its Components on Antibacterial Activity against Staphylococcus aureusSara Štumpf, Gregor Hostnik, Tomaž Langerholc, Maša Pintarič, Zala Kolenc, Urban Bren, 2023, original scientific article Abstract: Increasing antimicrobial resistance has caused a great interest in natural products as alternatives or potentiators of antibiotics. The objective of this study was to isolate individual tannins from crude chestnut extract as well as to determine the influence of both crude extracts (tannic acid extract, chestnut extract) and individual pure tannins (gallic acid, vescalin, vescalagin, castalin, castalagin) on the growth of Gram-positive Staphylococcus aureus bacteria. Their antibacterial activity was monitored by measuring the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) as well as the duration of the lag phase, growth rate and generation time. The effect of growth medium strength on the MIC of different tannins was also investigated. Bacterial growth was followed spectrophotometrically, and MIC values were determined by the microdilution method. The MIC values of various isolated compounds allowed us to determine the bioactive compounds and their contribution to antimicrobial activity. It was found that MIC values increase with increasing growth medium strength and that the lag phase lengthens with increasing tannin concentrations, while the growth rates decrease. Comparing the results of the two studies, the antimicrobial activity of tannins against S. aureus was not as pronounced as in the case of E. coli, which may indicate that a different mechanism of action is responsible for the antimicrobial effects of tannins on Gram-positive than on Gram-negative bacteria, or that a different mechanism is more pronounced.
Keywords: tannins, antibacterial activity, MIC, MBC, Staphylococcus aureus, lag phase, generation time
Published in DKUM: 20.02.2024; Views: 346; Downloads: 58
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8. Application of Lactobacillus reuteri B1/1 (Limosilactobacillus reuteri) improves immunological profile of the non-carcinogenic porcine-derived enterocytesViera Karaffová, Jana Teleky, Maša Pintarič, Tomaž Langerholc, Dagmar Mudroňová, Erik Hudec, Zuzana Ševčíková, 2023, original scientific article Abstract: In our previous studies, Lactobacillus reuteri B1/1, which was renamed Limosilactobacillus reuteri (L. reuteri), was able to modulate the production of pro-inflammatory cytokines and other components of the innate immune response in vitro and in vivo. In this study, we evaluated the effect of Lactobacillus reuteri B1/1 in two concentrations (1 x 10(7) and 1 x 10(9) CFU) on the metabolic activity, adherence ability and relative gene expression of pro-inflammatory interleukins (IL-1 beta, IL-6, IL-8, IL-18), lumican and olfactomedin 4 produced by non-carcinogenic porcine-derived enterocytes (CLAB). CLAB cells were cultured in a 12-well cell culture plate at a concentration of 4 x 10(5) cells/well in DMEM medium in a controlled humidified atmosphere for 48 h. A 1 mL volume of each probiotic bacterial suspension was added to the CLAB cells. Plates were incubated for 2 h and 4 h. Our results revealed that L. reuteri B1/1 was able to adhere to CLAB cells in sufficient numbers in both concentrations. In particular, the concentration of 109 L. reuteri B1/1 allowed to modulate the gene expression of pro-inflammatory cytokines, as well as to increase the metabolic activity of the cells. In addition, administration of L. reuteri B1/1 in both concentrations significantly stimulated gene expression for both proteins in the CLAB cell line after 4 h of incubation.
Keywords: Lactobacillus reuteri B1/1, CLAB cells, pro-inflammatory cytokine, metabolic activity
Published in DKUM: 20.02.2024; Views: 266; Downloads: 11
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9. Ocena kulture varnosti živil na osnovi znanja vedenja in odnosa zaposlenih v gostinstvu : magistrsko deloBiserka Keramitchievska, 2024, master's thesis Abstract: Slaba kultura varnosti hrane je vedno večji dejavnik tveganja za izbruhe bolezni, ki se prenašajo s hrano. Ocena kulture varnosti hrane je pomembno orodje za analizo znanja o varnosti hrane in vedenja zaposlenih pri delu z živili. Vzpostavitev pozitivne kulture varnosti hrane med zaposlenimi v gostinstvu zahteva zavzetost vodstva, odnos zaposlenih glede varnosti hrane, organizacijske in administrativne značilnosti prehranskega obrata, zavedanje o tveganju in upoštevanje izgorelosti zaposlenih. Namen magistrskega dela je bil s pregledom literature in z uporabo polstrukturiranega intervjuja oceniti kulturo varnosti hrane na osnovi znanja in odnosa zaposlenih v gostinstvu na vzorcu zaposlenih pri delu z živili v gostinski dejavnosti. V raziskavi je sodelovalo 11 zaposlenih v gostinstvu (dve ženski in devet moških). Vsi so imeli več kot osem let delovnih izkušenj. S pomočjo kvalitativne vsebinske analize smo pridobili tri teme: zagotavljanje varnosti hrane, dejavniki, ki vplivajo na kulturo varnosti hrane, in izzivi pri zagotavljanju pozitivne kulture varnosti hrane. Na podlagi pregleda strokovnih in znanstvenih objav ter polstrukturiranih intervjujev smo ugotovili, da je treba dvigniti raven kulture varnosti hrane v izbranih restavracijah in da se intervjuvanci načeloma zavedajo pomembnosti elementov zagotavljanja varnosti hrane, vendar se držijo pravil predvsem zaradi stalnega nadzora in groženj zniževanja plač. Glavni kuharji imajo visoko znanje o pravilih varnosti hrane, vendar imajo težave pri vodenju novozaposlenih in neizkušenih zaposlenih.
Keywords: varnost hrane, kultura varnosti hrane, tveganja, ocena kulture varnosti hrane
Published in DKUM: 30.01.2024; Views: 522; Downloads: 57
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10. Načrt trženja in možnosti vstopa nizko-alergenega a2-mleka na trg : magistrsko deloMarina Lakatuš, 2023, master's thesis Abstract: Nizko-alergeno A2-mleko predstavlja inovativno in zdravju prijazno alternativo za potrošnike z intoleranco na laktozo ali prebavnimi težavami. V magistrski nalogi smo se osredotočili najprej na načrt trženja in analizo možnosti vstopa nizko-alergenega A2-mleka kmetije Sinkovič na trg. Temeljito smo proučili analizo trga, identifikacijo ciljnih segmentov potrošnikov in prepoznavanje njihovih potreb, želja ter preferenc. Raziskovali smo tržne priložnosti in izzive, da identificiramo potencialne ciljne segmente, ki bi lahko imeli največjo naklonjenost in povpraševanje po nizko-alergenem A2-mleku. Na podlagi pridobljenih podatkov smo ugotovili, da bodo stroški marketinga znašali 2.174 € letno. Z analizo SWOT smo analizirali prednosti, slabosti, priložnosti in nevarnosti vstopa A2-mleka na trg. Poslovni model canvas je bil uporabljen kot orodje za lažje razumevanje različnih segmentov podjetja. Nadalje se je z oceno ekonomike ocenila ekonomičnost pridelave A2-mleka. Rezultati kažejo, da je pridelava A2-mleka ekonomsko upravičena, saj koeficient ekonomičnosti (KE) glede na izračune znaša 2,60.
Keywords: načrt trženja, A2-mleko, SWOT analiza, canvas.
Published in DKUM: 10.10.2023; Views: 494; Downloads: 49
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