magistrsko delo
Monika Nartnik (Author), Blaž Likozar (Mentor), Marjan Marinšek (Thesis defence commission member), Aleš Podgornik (Thesis defence commission member), Polona Žnidaršič Plazl (Co-mentor)

Abstract

V industriji predelovanja sadja velik problem predstavljajo olupki citrusov, ki sicer vsebujejo biološko aktivne snovi, eterična olja in podobne spojine, ki so sicer na trgu zaželene. A vendar olupki predstavljajo problem pri odlaganju zaradi visoke vsebnosti organskih snovi, prav tako je problematičen nizek pH ekstraktov iz olupkov. Odpadni olupki citrusov predstavljajo odličen vir za pridobivanje eteričnih olj iz flaveda – zunanjega, obarvanega dela olupka. Eterična olja so kompleksne mešanice hlapnih organskih spojin, ki imajo značilen vonj po rastlinah ali njihovih plodovih. V pomarančah večji del eteričnega olja predstavlja monociklični monoterpen limonen, ki ima vonj po limoni. Limonen se lahko iz olupkov pridobiva z ekstrakcijo trdno-tekoče, pri kateri poznamo več različnih tehnik, ki se delijo na tradicionalne in moderne. Tako med tradicionalne tehnike spadajo šaržna ekstrakcija trdno-tekoče, ekstrakcija po Soxhletu, hladno stiskanje in vodna ali parna destilacija. Moderne tehnike so se razvile z namenom, da se pri posameznih tradicionalnih tehnikah izboljša slabe lastnosti oziroma se poudari dobre. Pri vsem tem pa je tudi pomembno, da se zmanjšuje porabo organskih topil ali pa se jih popolnoma nadomesti z bolj zelenimi topili, med katere spadajo naravna globoka evtektična topila (angl. natural deep eutectic solvents, NADES). Slednja so mešanica dveh ali več čistih snovi v optimalnem razmerju, kot rezultat pa je temperatura tališča mešanice nižja od temperature tališča idealne mešanice. Komponente NADES so primarni metaboliti in/ali biološko obnovljive snovi in predstavljajo donorje ali akceptorje vodikovih vezi. Namen magistrskega dela je bila priprava NADES in primerjava z organskimi topili, koliko limonena ekstrahirajo. Skupen sinergijski učinek NADES z limonenom sem želela izkoristiti za aplikacijo v kremah, zato sem za donor vodikove vezi izbrala različne aminokisline, za akceptor vodikove vezi pa holin klorid ali glicerol. Ekstrakcijo z organskimi topili (metanol, etanol, etil acetat in aceton), sem izvajala po Soxhletu in šaržno, medtem ko je ekstrakcija z NADES potekala zgolj šaržno, saj ta niso hlapna. Analiza limonena v ekstraktih je potekala z GC-MS, analiza izluženih proteinov pa z UV-Vis spektrometrom. Ker so proteini kontaminant, sem teh želela ekstrahiranih čim manj. Ugotovila sem, da so izkoristki limonena pri Soxhletovi tehniki višji od izkoristkov pri šaržni tehniki. Ugotovila sem tudi, da noben pripravljen NADES ni ekstrahiral limonena.

Keywords

ekstrakcija trdno-tekoče;naravna globoka evtektična topila;organska topila;limonen;odpadni pomarančni olupki;magistrska dela;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UL FKKT - Faculty of Chemistry and Chemical Technology
Publisher: [M. Nartnik]
UDC: 66.061.34:665.5(043.2)
COBISS: 192989699 Link will open in a new window
Views: 32
Downloads: 0
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Other data

Secondary language: English
Secondary title: Comparison of extraction of essential oils from orange peels waste with selected organic solvents and natural deep eutectic solvents
Secondary abstract: Citrus peels, which otherwise contain biologically active substances, essential oils and similar compounds that are otherwise desirable on the market, pose a major problem in the fruit processing industry, because the peels themselves pose a disposal problem due to their high content of organic matter, the low pH of extracts the peels is also problematic. Waste citrus peels are an excellent source for obtaining essential oils from the flavedo - the outer, colored part of the peel. Essential oils are complex mixtures of volatile organic compounds that have the characteristic smell of plants or their fruits. In oranges, the major part of the essential oil is the monocyclic monoterpene limonene, which has a lemony fragrance. Limonene can be extracted from peels through solid-liquid extraction, with various techniques falling into traditional and modern ones. Traditional techniques include batch extraction, Soxhlet extraction, cold pressing, and water or steam distillation. Modern Techniques have been developed to improve the drawbacks of individual traditional techniques or to emphasize their strengths. Additionally, it is essential to reduce the use of organic solvents or replace them entirely with greener solvents, including natural deep eutectic solvents (NADES). The latter are mixtures of two or more pure compounds in an optimal ratio, resulting in a melting point lower than the melting point of an ideal mixture. The compounds in NADESs are primary metabolites and/or bio-renewable substances that act as hydrogen bond donors or hydrogen bond acceptors. The aim of master's thesis was preparation of NADESs and compare with organic solvents how much limonene they extract. I wanted to use the common synergistic effect of NADES with limonene for application in creams, that's why I used various amino acids as hydrogen bond donor and choline chloride or glycerol as hydrogen bond acceptor. Extraction with organic solvents (methanol, ethanol, ethyl acetate and acetone) was performed with batch extraction and using Soxhlet method, while extraction with NADESs was performed only with batch extraction since they are non-volatile. For analysis of limonene in extracts GC-MS was used, and for the analysis of extracted proteins UV-Vis spectrometry was used. Since proteins are contaminant I wanted to extract as few of them as possible. Results showed that yields of limonene obtained with the Soxhlet technique were higher than those obtained with the batch extraction. Results also showed that none of the prepared deep eutectic solvents extracted limonene.
Secondary keywords: solid-liquid extraction;natural deep eutectic solvents;limonene;orange peel waste;Eterična olja;Ekstrakcija (kemija);Univerzitetna in visokošolska dela;
Type (COBISS): Master's thesis/paper
Study programme: 1000376
Embargo end date (OpenAIRE): 2025-04-15
Thesis comment: Univ. v Ljubljani, Fak. za kemijo in kemijsko tehnologijo, smer Kemijsko inženirstvo
Pages: 1 spletni vir (1 datoteka PDF (51 str.))
ID: 23434976