diplomsko delo visokošolskega strokovnega študijskega programa I. stopnje
Karin Jakopič (Author), Maša Knez Hrnčič (Mentor), Vesna Postružnik (Co-mentor)

Abstract

Namen diplomskega dela je optimizirati postopek predobdelave cvetnega prahu z namenom izolacije ekstraktov z visoko vsebnostjo antioksidantov ter vitaminov. Uporabili smo različne ekstrakcijske metode; ultrazvočno ekstrakcijo, hladno in vročo maceracijo ter ekstrakcijo po Soxhletu. Pri vseh ekstrakcijah smo kot topilo uporabili mešanico etanola in vode (70 % etanol). Z različnimi postopki predobdelave materiala (mletje v električnem mlinčku, trenje s terilnico in z dušikom pod tlakom) in omenjenimi postopki ekstrakcije smo dobili 16 različnih ekstraktov. Ekstraktom smo določevali izkoristek in spektorfotometrično določevali mikronutriente in sekundarne metabolite kot so vitamin C, fenolne spojine in proantocianidini ter antioksidativni učinek. Kromatografsko smo poskušali določiti še vitamine (A, D in E ). S predobdelavo cvetnega prahu smo pridobili različne strukture in velikosti materiala, kateremu smo s sejalno analizo določili najpogosteje zastopano zrno in izračunali koeficient enakomerne zrnatosti. Ekstrakte smo ovrednotili s kvalitativno in kvantitativno analizo vsebnosti želenih komponent. Rezultati kažejo da na kakovost ekstrakta vplivajo različni dejavniki, kot so izbira topila, postopki obdelave pred ekstrakcijo, čas in temperatura ekstrakcije ter ustrezna ekstrakcijska metoda. Postopek predobdelave bistveno vpliva na izkoristek ekstraktov, saj izzove spremembo v mikrostrukturi cvetnega prahu. Med določevanjem vsebnosti komponent v cvetnem prahu smo opazili vpliv temperature in časa. Za čimboljše vsebnosti antioksidativne aktivnosti, totalnih fenolov, proantocianidinov in izkoristka se je med ekstrakcijami potrebno izogibati visokim temperaturam. Veliko nižje vsebnosti kot z ostalimi ekstrakcijskimi metodami dobimo ravno s Soxhletovo ekstrakcijo v primeru določevanja vsebnosti totalnih fenolov, proantocianidinov in izkoristka. Opazimo da je predobdelava z dušikom pod tlakom in kombinacija tlaka in mletja v večini primerov dala najboljše rezultate.

Keywords

cvetni prah;predobdelava;ekstrakcija;antioksidanti;fenolne spojine;proantocianidini;vitamini;diplomske naloge;

Data

Language: Slovenian
Year of publishing:
Typology: 2.11 - Undergraduate Thesis
Organization: UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher: [K. Jakopič]
UDC: 66.061.3:638.178.2(043.2)
COBISS: 170917891 Link will open in a new window
Views: 67
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Other data

Secondary language: English
Secondary title: Effect of material pre-treatment on the vitamin content of pollen extracts
Secondary abstract: The purpose of the thesis is to attain extracts with a high proportion of active components from bee pollen. The recovery of compounds of interest is afftected by the pre-treatment of the material, solvent and the application of different extraction methods. Ultrasonic extraction, cold and hot maceration and Soxhlet extraction have been carried out. For all extractions, a mixture of ethanol and water (70 % ethanol) was used as a solvent. Sixteen different extracts were obtained by different pre-treatment procedures of the material grinding in an electric grinder, milling with a blender and exposure to nitrogen under pressure. The extracts were subjected to further spectrophotometric analyses; determination of micronutrients such as vitamin C, antioxidants, phenolic compounds and proanthocyanidins. Also cromatographic identification of vitamins (A, D and E) has been initialized. By pollen pretreatment different sizes of particles and size distribution profiles of samples of material were obtained. Sieving analysis was used to determine the most represented grain in pollen and to calculate the coefficient of uniformity. The extracts were evaluated by qualitative and quantitative analysis. The results show that extractions are affected by different factors such as the choice of solvent, pre-extraction treatment procedures, extraction time and temperature, and the selection of appropriate extraction method. The type of pre-treatment has a different effect on the yield of extracts, as each pre-treatment gave a different change in the microstructure of the pollen. During the determination, method the influence of temperature and time on the content of components in the pollen. High temperatures should be avoided during extraction to maximise the recovery. Soxhlet extraction method gave lower yields of total phenolics, proanthocyanidins and also the total mass yield. It has been noticed that the nitrogen pressure pre-treatment and the combination of pressure and grinding gave the best results in most cases.
Secondary keywords: pollen;pre-treatment;extraction;antioxidants;phenolic compounds;proanthocyanidins;vitamins;
Type (COBISS): Bachelor thesis/paper
Embargo end date (OpenAIRE): 2025-09-18
Thesis comment: Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages: 1 spletni vir (1 datoteka PDF (XI, 38 f.))
ID: 19871458