Modeliranje i optimiranje fizikalno-kemijskih karakteristika i UV spektara vodenih ekstrakata lavande i melise

master's thesis

• Title (english): Modelling and optimizing physical-chemical characteristics and UV spectra of water extracts of lavander and melissa
• Author: Ana-Marija Cvetković
• Mentor: Jasenka Gajdoš Kljusurić (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: 2017-07-19, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Nutrition

Abstract

Hrana koju konzumiramo sastoji se od velikog broja poznatih i nepoznatih biološki aktivnih sastojaka koji su prisutni u malim količinama, ali imaju povoljan utjecaj na ljudsko zdravlje. Danas se sve više pozornosti pridaje samoniklom bilju, bilo u formi čajeva, ulja ili začina, koje je od davnina prisutno u ljudskoj upotrebi. U ovom radu istraživani su vodeni ekstrakti lavande i melise. Za svaku biljku provedene su ekstrakcije pri temperaturama 40 °C, 60 °C, 80 °C sa izuzimanjem uzoraka u pravilnim vremenskim intervalima. Cilj ovoga istraživanja bio je ispitati odnos fizikalnih parametara u vodenim biljnim ekstraktima s obzirom na temperature i vrijeme trajanja ekstrakcije i odrediti koncentraciju ukupnih polifenola u ekstraktima te im izmjeriti antioksidacijsku aktivnost primjenom ABTS metode. Primjenom jednostavnih linearnih regresijskih modela utvrđena je postojanost veze između fizikalnih i kemijskih parametara vodenih ekstrakata istraživanih biljaka. Provela se i UV-VIS spektroskopska analiza uzoraka čiji spektri su korišteni u modelima parcijalne linearne regresije metodom najmanjih kvadrata, tzv. PLS regresija. Primjenom PLS regresije može se zaključiti kako se UV spektroskopija pokazala kao potencijalno uspješna metoda u predikciji fizikalnih i kemijskih karakteristika istraživanih biljnih ekstrakata. Značajna odstupanja između eksperimentalnih rezultata i rezultata dobivenih primjenom PLS modela primjećena su za antioksidacijsku aktivnost određenu ABTS metodom.

Abstract (english)

The food we consume consists of a large number of known and unknown bioactive compounds present in small quantities, which have positive effects on human health. Today, increased attention has been given to medicinal plants in the form of teas, oils or spices, which people have been using since ancient times. In this research, aqueous extracts of lavender and melissa were investigated. For each medicinal plant, extractions were performed at 40 °C, 60 °C, and 80 °C with sampling at regular time intervals. The aim of this study was to investigate the relations between physical parameters in aqueous plant extracts with regard to the temperature and duration of extraction, determine the total polyphenolic content in aqueous extracts and measure their antioxidative activity by ABTS method. Using simple linear regression models, strong correlations between physical and chemical parameters of aqueous plant extracts were determined. UV-VIS spectroscopic analysis of samples was also conducted and spectra were used in the partial linear regression modelling (Partial Least Squares, PLS). Applying the modelling using partial linear regression, it can be concluded that UV spectroscopy turned out to be a potentially successful method for predicting physical and chemical characteristics of the investigated aqueous plant extracts. Significant differences between the experimental results and the results obtained applying the PLS model were detected for the antioxidative activity determined by ABTS method.

• Keywords: samoniklo ljekovito bilje; polifenoli; antioksidacijska aktivnost; UV spektroskopija; multivarijatna analiza
• Keywords (english): wild medicinal plants; polyphenols; antioxidative activity; UV spectroscopy; multivariate analysis
• Language: croatian
• URN:NBN: urn:nbn:hr:159:374007
• 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: Open access
• Created on: 2017-11-15 14:05:01