The aim of this study was to develop different encapsulation systems for catechins and pomegranate extracts. (±)-catechin and (‒)-epigallocatechin-3-gallate (EGCG) were encapsulated into liposomes that were further incorporated into alginate and chitosan microparticles. All the encapsulation systems enabled high encapsulation efficiency of the studied compounds (84-99%). Encapsulation enabled efficient protection of EGCG against degradation in adverse environmental conditions (pH 2.0, pH 6.0 and in fruit nectar), while encapsulation had no positive effect on stability of (±)-catechin. Interactions between EGCG and the encapsulation systems were evaluated by differential scanning calorimetry and Fourier transform infrared spectroscopy. In order to prepare particles in submicrometer size range that would be more appropriate for application in food products from sensorial aspect, emulsification method was used. The method enabled preparation of alginate particles in the size range from 120 to 660 nm. The pomegranate juice was lyophilized in the presence of polysaccharides alginate, pectin, chitosan or pullulan. In case of lyophilized samples with alginate and pectin the final products were in a form of a powder which facilitated the juice handling and enabled further characterization of the complexes. The alginate complexes protected the anthocyanins from pomegranate juice against thermal degradation while none of the complexes were able to sustain the antioxidant activity and the concentration of total polyphenolic compounds of pomegranate juice.
D.09 Tutoring for postgraduate students
COBISS.SI-ID: 4661368prof. dr. Natasa Poklar has received the gold medal of the University of Ljubljana for the year 2016. The gold medal of the University of Ljubljana is award for outstanding merit in developing a scientific, educational or artistic creation and to enhance the international reputation of the University of Ljubljana. In 2016 it was awarded 11 professors with gold medal at the University of Ljubljana
E.01 National awards
Slovenian Institute for Hop Research and Brewing made an update of technological guidelines for operation Hop production in collaboration with the subcontractor Agriculture and Forestry Chamber of Slovenia. The work was made in accordance to the amendments in the relevant regulations in the field of agriculture and water, and in accordance with professional guidelines in consensus with the contracting authority. The work included the update of the guidelines, extending the pictorial material, guidelines how to make records on work tasks, records of fertilizer use and plant protection products, the inclusion of chapters on the importance of record keeping and writing about the violations, rejection and cancellation of payments. Dr. Barbara Čeh carried out coordination of the work and writing guidelines.
F.12 Improvements to an existing service
COBISS.SI-ID: 285786880Within the popular science TV programme »Bite the science« we have presented some facts about invasive alien knotweed species present in Slovenia, namely Japanese knotweed (Fallopia japonica), Giant knotweed (F. sachalinensis) and their interspecific hybrid – Bohemian knotweed (F. x bohemica). We have briefly reviewed the results of our study of different tissues of all three taxon. The antioxidants content depends on extraction solvent, plant tissue, plant taxon and the harvest season. The composition of phenols in Bohemian knotweed is closer to Japanese knotweed. Flowers, leaves and stalks had similar, but quantitatively different phenolic profiles. We have demonstrated the biggest amount and variation of phenols in flowers and young leaves. The presence of trans-resveratrol, chlorogenic acid, catechin, quercetin and most likely caffeic acid was confirmed by using standard compounds. The rhizomes of Japanese knotweed were the main source of trans-resveratrol, but we were able to find them in the above-ground parts of knotweeds as well. The results indicate that above and below-ground parts of different knotweed taxons could be a new and inexpensive source of secondary plant metabolites – natural antioxidants, in the future.
D.11 Other
COBISS.SI-ID: 4696440Results of our own research work related to the methodology of test for the analysis of antioxidant potential (AOP) of food samples and model compounds were presented. It was shown that type of method and chemical environment where AOP is determined has a large influence on determined AOP. Problems of synergism between different antioxidants and standardization of the assay were also exposed, as also the application of methods for evaluation of AOP as a tool for rapid assessment of the content of particular compound that is predominant antioxidant in certain matrix.
B.05 Guest lecturer at an institute/university
COBISS.SI-ID: 4700792