Karakterizacija funkcijonalnih spojeva izoliranih iz espresso kave „Karoma“ i srebrne pokožice kao njenog nusproizvoda

master's thesis

• Title (english): Characterization of functional compounds isolated from espresso coffee and silver skin as its byproduct
• Author: Marina Šango
• Mentor: Antonela Ninčević Grassino (mentor)
• Committee member: Suzana Rimac Brnčić (predsjednik povjerenstva)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Chemistry and Biochemistry); (Laboratory for Analytical Chemistry); Zagreb
• Defense date and country: 2020-07-16, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Proizvodnjom espresso kave, prženjem zrna sirove kave nastaju znatne količine nusproizvoda - srebrne pokožice. U ovom radu je ispitana mogućnost iskorištenja srebrne pokožice kao izvora različitih funkcionalnih spojeva, poput fenola, flavonoida, masnih kiselina i pektina. Izuzev pektina, ostali navedeni spojevi su određeni i u samoj espresso kavi. Nakon mikrovalovima potpomognute ekstrakcije uzoraka (T = 50 i 70 °C, t = 5 i 15 minuta i 50 i 70 %-tne vodene otopine etanola), UV/Vis spektrofotometrijom je potvrđeno da srebrna pokožica sadrži manje fenola (7,23 - 9,32 mg g-1) u odnosu na kavu (57,79 - 70,98 mg gˉ¹). Metodom plinske kromatografije, nakon Soxhlet ekstrakcije uzoraka je pokazano da u srebrnoj pokožici dominiraju zasićene, a u kavi nezasićene masne kiseline. Nakon refluksiranja uzoraka srebrne pokožice i izolacijom pektina iz različitih kiselih ekstrakata utvrđeno je da najveći udio galakturonske kiseline (57,86 %) kao pokazatelja čistoće i primjene pektina kao prehrambenog aditiva daje klorovodična kiselina.

Abstract (english)

With production of espresso coffee by roasting raw coffee beans significant amounts of by-product is generated. In this work, the possibility of using silverskin as a source of various functional compounds, such as phenols, flavonoids, fatty acids and pectin was studied. Apart from pectin, the other listed compounds are also determined in espresso coffee itself. After microwave - assisted extraction of the samples (T = 50 and 70 ⁰C, t = 5 and 15 minutes and 50 % and 70 % acqueous ethanol solution), UV/Vis spectrophotometry it is confirmed that the silver epidermis contained less phenol (7.23 - 9.32 mg g-1) compared to coffee (57.79 - 70.98 mg gˉ¹). The method of gas chromatography, after Soxhlet extraction of samples, showed that saturated fatty acids dominate in silverskin and unsaturated fatty acids in coffee. After refluxing silverskin samples and isolating pectin from various acidic extracts, it is found that the highest proportion of galacturonic acid (57.86 %), as an indicator of purity and application of pectin as a food additive, is given by hydrochloric acid.

• Keywords: ekstrakcija; espresso kava; masne kiseline; pektin; polifenoli; srebrna pokožica
• Keywords (english): extraction; espresso coffee; fatty acids; pectin; polyphenols; silverskin
• Language: croatian
• URN:NBN: urn:nbn:hr:159:229267
• Study programme: Title: Food Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka prehrambenog inženjerstva (magistar/magistra inženjer/inženjerka prehrambenog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-07-20 12:26:01