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Kvaliteta rada u vrtiću i školi kao odgojno – obrazovnim ustanovama danas je neizostavan imperativ. Ono što jamči tu kvalitetu rada su odgojitelji i učitelji koji svakodnevnim praćenjem interesa djece i njihova zanimanja nude kvalitetne poticajne materijale kojima će zadovoljiti tu prirodnu potrebu. Projektnim pristupom u radu s djecom, odgojno – obrazovni djelatnici na najbolji mogući način potiču razvoj i napredak djeteta, nadograđujući njihove interese, potrebe i sposobnosti. Ovaj diplomski rad usmjeren je na učenje i rad s djecom vrtićke i školske dobi upravo kroz projekte. Cilj rada je, pregledom literature na temu projektnoga učenja u vrtićima i školama, njihovim značajkama i posebnostima te prednostima tog načina rada, pružiti bolji uvid u u specifičnosti projektnog pristupa u dječjim vrtićima i školama. The quality of working in kindergarten and school as an educational institutions, nowdays is an indispensable imperative. What guarantees that exact quality are educators and teachers who, by monitoring interest of children offer high – quality materials that will support that natural need on a daily basis. Educational employees by implementing project – based approach with children, encourage development and progress of a child, by upgrading their interests, needs and capabilities. This thesis is focused on a learning and working with children from an early age to the age of nine through projects. The aim of this thesis is to provide insight to the features, specifics and benefits of project – based learning by using relevant literature on this particular subject matter. It presents ways and methods of project work and tend to encourage all the educators and teachers to implement the project – based learning in their work to enrich their own skills and to offer a child priceless experience of learning.

Cilj ovog rada bila je optimizacija vremena ekstrakcije i amplitude ultrazvuka na učinkovitost izolacije fenolnih spojeva, klorofila a i b te karotenoida iz listova koprive primjenom ekstrakcije potpomognute ultrazvukom. Ekstrakcija je provedena pri konstantnoj frekvenciji od 26 kHz i promjeru sonde (2 mm), a izvori varijacije bili su: amplituda ultrazvuka (25, 50, 75 i 100 %) i vrijeme ekstrakcije (5, 10, 15, 20, 30 i 40 minuta). Optimalnim uvjetima za ekstrakciju ukupnih fenola pokazalo se vrijeme ekstrakcije od 40 minuta pri amplitudi od 75 % . Isto vrijeme je optimalno i za ekstrakciju klorofila a, ali pri amplitudi 100 %. Za ekstrakciju klorofila b i karotenoida, optimalno vrijeme je 30 minuta te amplituda 75 %. Navedeni optimalni uvjeti pokazuju da je za ekstrakciju ukupnih fenola i klorofila a bolja duţa ekstrakcija pri višim amplitudama, dok je za ekstrakciju klorofila b i karotenoida bolje provesti kraću ekstrakciju pri nešto niţim amplitudama ultrazvuka. The aim of this study was to determine the optimal conditions for efficiency of phenolic compounds, chlorophyll a and b and carotenoids isolation using ultrasound – assisted extraction from nettle leaves. The extraction was performed at constant frequency (24 kHz) and the 2 mm probe. Sources of variation were: the amplitude (25, 50, 75 and 100 %) and the extraction time (5, 10, 15, 20, 30 and 40 minutes). Results showed that optimal conditions for phenolic compounds extraction were the extraction time 40 min and 75 % amplitude. The same time was optimal for chlorophyll a extraction, but the amplitude was 100 %. For chrolophyll b and carotenoids the optimal extraction time was 30 min and 75 % amplitude. These optimal conditions indicate that is better to use longer time and higher amplitude for phenolic compounds and chlorophyll a extraction, but for the extraction of chlorophyll b and carotenoids shorter time and lower amplitude show better results.

Urtica dioica L., commonly known as nettle, is a perennial plant from the Urticaceae family. Nettle leaves are rich in bioactive compounds, such as the phenolic compounds, which are exceptionally important for the growth and reproduction of the plant and are considered to have a significant effect on human health and are strong antioxidants. For the isolation of the phenolic compounds, various extraction techniques are used, such as conventional methods requiring extended extractability times and a higher amount of solvent. One of the most commonly used non thermal eco-friendly techniques for isolation of bioactive compounds from plants is ultrasound assisted extraction (UAE), whose advantages are shortening the time of extraction, reduced solvent consumption, reduced extraction temperature, and lower energy consumption. Hence, the aim of this study was to determine the optimal conditions for the extraction of phenolic compounds in dried nettle leaves (Urtica dioica L.) using ultrasound assisted extraction (UAE) with GRAS solvent 96% ethanol. Parameters varied during the experiment were: the amplitude of ultrasound (25-100 %) and the extraction time (5-40 min), conducted at ambient temperature. The total polyphenolic content (TPC) of nettle extracts was determined spectrophotometrically using the Folin-Ciocalteu method. The highest yield of the total phenolics extraction was 563, 12 mg GAE/100g, achieved with the following extraction conditions: 20 minutes at an amplitude of 75 %.

Svrha ovog istraživanja bila je odrediti stabilnost vitamina C u sokovima šipka tretiranim netoplinskim tehnikama skladištenim 7 dana na 4°C. Sokovi su tretirani zasebno ultrazvukom i hladnom plazmom te kombinacijom tih dviju tehnika. Izvori varijacija bili su amplituda i vrijeme (za ultrazvuk), frekvencija i vrijeme (za hladnu plazmu) te svi ovi parametri za kombinirane tretmane. Rezultati svih tretmana uspoređeni su sa svježim i pasteriziranim sokovima (90 °C/1 min). Dobiveni rezultati su statistički obrađeni te rezultati svih primijenjenih tretmana u odnosu na netretirani uzorak (svježi sok) obzirom na sadržaj askorbinske kiseline pokazuju da među tretmanima, bilo toplinskim (pasterizacija) ili netoplinskim (ultrazvuk i hladna plazma, zasebno te kombinirano), nije bilo signifikantne razlike u sadržaju askorbinske kiseline u sokovima šipka. Ipak, pogledaju li se svi utjecaji netoplinskih tehnika ponaosob ili u kombinaciji, dobiveni rezultati pokazuju da svi izvori varijacija značajno doprinose stabilnosti vitamina C. The aim of the study was to evaluate effects of non-thermal technologies on vitamin C stability in pomegranate juice during 7 days of storage at 4°C. The juices were treated separately with sonication and cold gas plasma and with a combination of those two technologies. Outcomes of separate and combined treatments were observed at different operating conditions: treatment time and amplitude for ultrasonic treatment and treatment time. All results were compared with fresh (untreated) and pasteurised pomegranate juices (90 °C/1 min). Statistical analysis showed that there were no significant differences in the content of ascorbic acid in pomegranate juices between thermal treatments (pasteurisation) and non- thermal treatments (sonication and cold gas plasma, applied separately or combined). However, taking all influences of non thermal technologies (applied separately or combined) into account, the obtained results show that all sources of variations significantly contribute to the stability of vitamin C in pomegranate juices.