11. A novel derivatization procedure and chiral gas chromatographic method for enantiomeric purity screening of L-carnitineIrena Vovk, Alen Albreht, Borut Zupančič, 2014, original scientific article Keywords: L-carnitine, D-carnitine, GC-FID, derivatization, enantiomeric separation, food supplements
Published in DiRROS: 12.04.2016; Views: 4470; Downloads: 772
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12. Structural and degradation studies of a biocompatible Zn-L-tartrate metal-organic frameworkAna Palčić, Andreas Puškarić, Matjaž Mazaj, Emanuela Žunkovič, Nataša Zabukovec Logar, Josip Bronić, 2015, original scientific article Abstract: New anhydrous Zn-l-tratrate was synthesized under hydrothermal conditions. Crystal structure which was solved by powder X-ray diffraction data from monoclinic unit cell (I2, a=11.7557(1), b=9.0319(1), c=5.0750(1), β=91.920(1)) consists of the three-dimensional framework where each Zn atom coordinates four tartrate ligands in distorted octahedral geometry. Due to its biocompatible components, the degradation of material was studied in aqueous media under different pH values (pH=1–7) and in the simulated body fluid (pH=7.4) performed by the measurement of the released Zn2+ concentrations at thermostatic conditions (37 °C). The results showed that under acidic conditions approximately 60% of Zn2+ is released from the investigated material after 6 h of degradation process. With the increase of the solution’s pH, the rate of degradation gradually decreases. XRD and SEM analyses indicate that in aqueous media the compound slowly disintegrates and does not undergo hydrolysis process regardless of pH. Biocompatibility of the compound and its controllable rate of degradation even in acid conditions open its potential use in the fields of bio-applications.
Graphical abstract
The degradation kinetics of Zn-l-tar MOF material in aqueous media at different pH conditions.
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Keywords: Zn-tartrate, coordination polymers, hydrothermal synthesis, biomedical application, food supplement
Published in DiRROS: 26.01.2015; Views: 4995; Downloads: 472
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13. Amino- and ionic liquid-functionalised nanocrystalline ZnO via silane anchoring - an antimicrobial synergyMarjeta Čepin, Vasko Jovanovski, Matejka Podlogar, Zorica Crnjak Orel, 2015, original scientific article Abstract: Temperature has critical impact on food quality and
safety within food supply chain, therefore, food should
be kept at the defined storage temperature range.
Final consumer should be assured when buying food
about actual temperature and thermal history of the
selected food product and this is why it should be indicated
on the packed or prepacked item.
The chromogenic temperature indicator for cold food
chain was prepared from suitable active material
packed in the properly structured holder. When temperature
rises above the defined storage temperature,
the active material changes colour and physical state
(solid/liquid). Simultaneously, special packaging structure
enables irreversible recording of the time exposed
to the elevated temperature. The active material was
made of thermochromic composite, consisting of dye,
developer and solvent. It changes colour at its melting
point, being coloured below and discoloured above
it. The temperature is called activation temperature of
the composite. Its value was adjusted by appropriate
solvent and additives used for preparation of the composite,
to reach the desired value. The temperature
dependent colour change of the composite was determined
by colorimetric measurements. The conditions
for best observation of the change by naked eye were
also examined. The structure of the active material’s
holder was analyzed for best displaying of the time
spend at high temperature (above the activation temperature).
Functioning of the indicator was examined with
growth of pathogens as a function of migration of
the active material at temperature above the required
storage temperature of the food. It was found out that
the described chromogenic temperature indicator for
cold food chain shows the thermal history of food storage
by colour-, phase- and migration changes of the
active composite material and consequently would be
reliable as indicator in cold food chain to indicate temperature
abuse and would disclose potential growth of
psychrophilic microorganisms.
Keywords: Chromogenic temperature indicator, Food
cold chain, Food quality and safety, Temperature control, Thermal history
Published in DiRROS: 16.12.2014; Views: 6168; Downloads: 944
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