Separacija vrednih spojin iz orehovih lupin s pod-kritično vodo

diplomsko delo visokošolskega strokovnega študijskega programa I. stopnje

Klemen Gradišnik (Author), Mojca Škerget (Mentor), Maja Čolnik (Co-mentor)

Abstract

Dandanes so prizadevanja po ohranjanju okolja, recikliranju, večji učinkovitosti procesov, uporabi čistih in obnovljivih virov vse bolj popularna in zaželjena. Primer procesa, ki je okolju prijazen, je ekstrakcija s pod-kritično vodo, saj je voda netoksično topilo. S tem procesom lahko odpadno in neuporabljeno biomaso različnih virov (oreščki, sadje, zelenjava, zelišča, ipd.) uporabimo za pridobivanje raznih vrednih spojin. Veliko oreščkov, kot je navadni oreh (Juglans regia L.), se prideluje po vsem svetu za pridobivanje užitnega jedra. Pri procesu pridobivanja orehovih jeder se mnogo lupin, ki niso užitne, zavrže, saj splošno veljajo za neuporaben stranski produkt. Vendar pa je znano, da orehova lupina vsebuje veliko (potencialno) koristnih spojin, ki se jih žal zavrže z lupinami vred. V okviru diplomske naloge smo izvedli ekstrakcijo orehovih lupin s pomočjo pod-kritične vode pri temperaturah od 200 do 300 °C in reakcijskih časih od 15 do 75 min. Zanimalo nas je kako različni reakcijski pogoji (čas, temperatura) vplivajo na izkoristek ekstrakcije ter katere spojine in v kakšnih količinah se z ekstrakcijo lahko separirajo iz orehovih lupin. S spektrofotometrično metodo smo preučili vsebnost totalnih fenolov in celokupnih flavonoidov v ekstraktih. Z radikalsko metodo DPPH smo v nastalih ekstraktih določili antioksidativno aktivnost, med tem ko smo s pomočjo HPLC metode v vzorcih določili količino nastalih furfuralov. Pri 200 °C in 60 min smo določili maksimalni izkoristek ekstrakcije in je znašal 31,61 %. Najvišjo vsebnost totalnih fenolov smo ugotovili pri 15 min in 300 °C in je bila 342,39 mg GA/g ekstrakta, med tem ko pa smo pri 15 min ter 200 °C dosegli maksimalno vsebnost celokupnih flavonoidov (8,88 mg QU/g ekstrakta). Antioksidativna aktivnost v ekstraktih iz orehovih lupin je bila v območju med 9,73 % in 72,15 %. S HPLC analizo smo ugotovili, da je v ekstraktih furfural najbolj zastopana komponenta. Tekom eksperimentalnega dela smo ugotovili, da je uporaba pod-kritične vode primerna metoda za separacijo vrednih komponent iz orehovih lupin.

Keywords

orehove lupine;pod-kritična voda;biomasa;separacija;ekstrakcija;vredne spojine;diplomske naloge;

Data

Language:	Slovenian
Year of publishing:	2021
Typology:	2.11 - Undergraduate Thesis
Organization:	UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher:	[K. Gradišnik]
UDC:	634.51:604.4(043.2)
COBISS:	80063491
Views:	287
Downloads:	72
Average score:	0 (0 votes)
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Other data

Secondary language:	English
Secondary title:	Separation of valuable compounds from walnut shells by sub-critical water
Secondary abstract:	The aspirations for preserving the environment, recycling, increasing processing efficiency, use of clean and renewable sources, etc. are nowadays very popular and desired. An example of an eco-friendly process is extraction with sub-critical water, as water is a non-toxic solvent. With this process, waste, and unused biomass of various sources (nuts, fruits, vegetables, herbs, etc.) can be used to obtain a range of valuable compounds. Many nuts, such as walnut (Juglans regia L.), are made all over the world to obtain edible kernels. In the process of obtaining walnut kernels, many shells that are not edible are discarded, as they are generally considered to be an unusable by-product. However, it is known that the walnut shell contains many (potentially) beneficial compounds, which are unfortunately discarded with shells. In this thesis, an extraction of walnut shells was performed by using sub-critical water at temperatures ranging from 200 to 300 °C and at reaction times ranging from 15 to 75 minutes. We wanted to know how different reaction conditions (time, temperature) affect the yield of the extraction, which compounds, and in what quantities they can be separated from walnut shells. The content of total phenols and total flavonoids in the extracts was determined by using the spectrophotometric method. By using the DDPH method, the antioxidant activity in the extracts was determined, while, by using the HPLC, the amount of furfurals produced in the samples was measured. At 200 °C and 60 minutes we determined the maximal extraction yield, which was 31.61%. We reached the maximum value of total phenols at 15 minutes and 300 °C, which was 342.3mg GA/g extract, while reaching a maximum value of total flavonoids (8.88mg QU/g extract) at 15 minutes and 200 °C. Antioxidant activity in walnut shell extracts ranged between 9.73% and 72.15%. Using HPLC analysis, furfural was determined as the most represented component in the extracts. During the experimental work, we found that the use of sub-critical water is an appropriate method for the separation of valuable components from walnut shells.
Secondary keywords:	walnut shells;sub-critical water;biomass;separation;extraction;valuable compounds;
Type (COBISS):	Bachelor thesis/paper
Thesis comment:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages:	X, 36 str.
ID:	13256305