Analiza utjecaja temperature na fizikalna svojstva vodenih ekstrakata planinskog vrijeska (Satureja montana L.) pomoću UV-VIS i NIR spektroskopije

master's thesis

• Title (english): Analysis of temperature influence on physical properties of aqueous extracts of winter savoury (Satureja montana L.) with UV-VIS and NIR spectroscopy
• Author: Lucija Jović
• Mentor: Davor Valinger (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Process Engineering); (Laboratory for Measurement, Regulation and Automatisation); Zagreb
• Defense date and country: 2019-07-12, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Nutrition

Abstract

Planinski vrijesak (Satureja montana L.) je biljka karakteristična za podneblje Mediterana. Biljka je vrlo jednostavna za uzgoj i kroz povijest se često koristila kao ublaživač bolova u mišićima i prilikom liječenja grčeva i mučnina. U posljednje se vrijeme sve više koriste eterična ulja planinskog vrijeska koja su pokazala antibakterijska i antivirusna svojstva. U ovom radu provedena je analiza kinetike vodene ekstrakcije tri različita tipa vrijeska (svježeg, sušenog i kupovnog planinskog vrijeska (Satureja montana L.)) pri trima različitim temperaturama (T = 40, 60 i 80 °C) i ukupnom vremenu ekstrakcije od t = 90 min. Vodenim ekstraktima su određena fizikalna svojstva (električna vodljivost, ukupne otopljene tvari (TDS), pH), kemijska svojstva (ukupni polifenoli) te su snimani UV-VIS i NIR kontinuirani spektri. Uočeno je da porast temperature ekstrakcije ima za posljedicu porast električne vodljivosti, ukupnih otopljenih tvari i ukupnih polifenola u svim vodenim ekstraktima. Kako bi se pomoću umjetnih neuronskih mreža (ANN) uspjelo povezati UV-VIS i NIR spektre s fizikalnim svojstvima, napravljena je analiza glavnih komponenata (PCA), najprije UV-VIS spektara, a zatim NIR spektara. U slučaju predikcije ANN fizikalnih svojstava vodenih ekstrakata dobiveni su bolji rezultati, u smislu viših koeficijenata determinacije, za UV-VIS spektre gdje su za sva fizikalna svojstva bili u rasponu od R2 = 0,89 do R2 = 0,98.

Abstract (english)

Winter savory (Satureja montana L.) is traditional plant in the Mediterranean region. Through history the plant has often been used as a muscles pain reliever and in the treatment of cramps and nausea. Lately, essential oils of winter savory, which have shown antibacterial and antiviral properties, have been increasingly used. In this paper, the analysis of kinetics of aqueous extraction of three different types of savory (fresh, dried and purchasing winter savory (Satureja montana L.)) was performed at three different temperatures (T = 40, 60 and 80 ° C) during time of t = 90 min . For aqueous extracts physical properties (electrical conductivity, total dissolved solids (TDS), pH) and chemical properties (total polyphenols) were determined and for all the extracts UV-VIS and near infrared (NIR) spectra were recorded. It was observed that the increase in extraction temperature results in an increase in electrical conductivity, TDS and total polyphenols in all aqueous extracts. In order to predict the physical and chemical properties by UV-VIS and NIR spectroscopy with the use of artificial neural networks (ANN), principal component analysis was performed on UV-VIS spectra followed by NIR spectra. In the case of the prediction of the physical and chemical properties of the aqueous extracts, the results obtained with ANN models showed higher coefficients of determination for UV-VIS spectra, where for all physical properties they were in the range from R2 = 0,89 to R2 = 0,98.

• Keywords: planinski vrijesak (Satureja montana L.); ultraljubičasta-vidljiva (UV-VIS) spektroskopija; blisko infracrvena spektroskopija (NIR); umjetne neuronske mreže
• Keywords (english): winter savory (Satureja montana L.); ultraviolet–visible (UV-VIS) spectroscopy; near infrared spectroscopy (NIR); artificial neural networks
• Language: croatian
• URN:NBN: urn:nbn:hr:159:836374
• Study programme: Title: Nutrition; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra nutricionizma (magistar/magistra nutricionizma)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2019-12-09 13:19:40