Biološka aktivnost ekstraktov pitaje (hylocereus polyrhizus)

diplomsko delo visokošolskega strokovnega študijskega programa I. stopnje

Martina Švajger (Author), Maša Knez Hrnčič (Mentor), Maja Leitgeb (Co-mentor)

Abstract

Pitaja (Hylocereus polyrhizus) je plod kaktusa, ki raste v tropskih in subtropskih regijah. Nedavno se je uveljavila kot sadna rastlina z visoko gospodarsko vrednostjo. Plod rdeče pitaje ima tanko, rdeče obarvano lupino, prekrito s strukturami, podobnim luskam. Sočna sredica sadeža je obarvana rdeče do vijolično. Takšno obarvanost pripisujemo visoki vsebnosti betalainov, zlasti betacianinom, ki dajejo značilno vijolično obarvanje. Sredica vsebuje številna majhna semena z visoko vsebnostjo esencialnih maščobnih kislin. Namen diplomske naloge je bil pridobiti ekstrakte iz plodov rdeče pitaje (Hylocereus polyrhizus) po različnih ekstrakcijskih metodah in ob uporabi različnih konvencionalnih topil. Dobljenim ekstraktom smo nato določili biološko aktivnost. Pred izvedbo ekstrakcij smo plodove rdeče pitaje liofilizirali in zmleli na velikost delcev primernih za ekstrakcijo. Metode, po katerih smo pridobili ekstrakte, so bile Soxhletova ekstrakcija in ekstrakcija s hladnim topilom, ki ju uvrščamo med konvencionalne ekstrakcije, ter ultrazvočna ekstrakcija. Poleg vpliva različnih ekstrakcijskih metod na izkoristek in vsebnost bioloških učinkovin smo ugotavljali tudi vpliv različnih topil, kot so etanol, voda in zmes etanol-voda v razmerju 7:3. S pomočjo UV-Vis spektrofotometra smo dobljenim ekstraktom določili antioksidativno aktivnost, vsebnost fenolov in vitamina E, prisotnost proteinov in aktivnost posameznih encimov. Vsebnost vitamina C smo določili na podlagi porabljenega volumna pri titraciji z 0,005 mol/L jodovo raztopino. Največji izkoristek ekstrakcije smo dobili z ultrazvočno ekstrakcijo ob uporabi vode kot topila. Dobljeni rezultati so pokazali nižjo vsebnost fenolov od pričakovane. Posledično je bila nizka tudi antioksidativna aktivnost, kar smo določili z radikalsko metodo DPPH. Sklepamo, da je nizka vsebnost fenolov in antioskidativna aktivnost posledica degradacije betalainov med samim postopkom ekstrakcije. Vsem ekstraktom smo določili vsebnost vitamina C, vitamina E in proteine, med katerimi smo določili aktivnost lipoproteinske lipaze in α-amilaze. Vsebnost in aktivnost omenjenih bioloških učinkovin je bila manjša od pričakovanih.

Keywords

rdeča pitaja;Hylocereus polyrhizus;ekstrakcije;encimi;fenoli;antioksidanti;vitamini;diplomske naloge;

Data

Language:	Slovenian
Year of publishing:	2019
Typology:	2.11 - Undergraduate Thesis
Organization:	UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher:	[M. Švajger]
UDC:	66.061.3:577.151.6(043.2)
COBISS:	22604822
Views:	892
Downloads:	143
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Biological activity of pitaya (hylocereus polyrhizus) extracts
Secondary abstract:	Pitaya (Hylocereus polyrhizus) is the fruit of cactus which grows in tropical and subtropical regions. Recently has been recognized as a fruit plant with high economic value. Pitaya fruits have thin, red coloured peel, covered by structures which seem like scales. Juicy core of fruit is coloured from red to purple. That kind of colouring refers to high content of betalains, especially betacyanins which cause typical purple colouring. The core of fruit contains many different small seeds which have high content of essential fatty acids. The purpose of the thesis was to obtain extracts from red pitaya fruits (Hylocereus polyrhizus) by different extraction methods and by use of different conventional solvents. After that we determined biological activity of obtained extracts. Before starting extractions we lyophilized pitaya fruits and ground them into the size of particles suiltable for extraction. Soxhet extractions and extraction with cold solvent were the methods we used for obtaining extracts. These methods are conventional extractions, we also used ultrasound extraction. Beside the effect of different extraction methods on efficieny and the content of biological substances we were also establishing the effect of different solvents, such as ethanol, water and ethanol-water mixture in the ratio 7:3. We used UV-Vis spectrophotometer to determine antioxidant activity of obtained extracts, phenol and vitamin E content, the presence of proteins and the activity of individual enzymes. We determined the content of vitamin C based on the volume used in titration with iodine solution (0,005 mol/L). We got maximum extraction efficiency by ultrasound extraction by using water as a solvent. Obtained results showed lower content of phenols than we had expected. Consequently, there was low antioxidant activity which was determined by DPPH method. We conclude that low content of phenols and low antioxidant activity are the consequence of betalains degradation during the extraction. To all extracts we determined the content of C and E vitamins and proteins, among which we determined the activity of lipoprotein lipase and α-amylase. The content and activity of mentioned biological substances were lower than we had expected.
Secondary keywords:	red pitaya;Hylocereus polyrhizus;extractions;enzymes;phenols;antioxidants;vitamins;
URN:	URN:SI:UM:
Type (COBISS):	Bachelor thesis/paper
Thesis comment:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages:	XI, 61 str.
ID:	11185640