Developing anthocyanin-based products

doctoral dissertation

Tünde Vatai (Author), Mojca Škerget (Mentor), Paolo Alessi (Co-mentor)

Abstract

Anthocyanins are group of polyphenols, responsible for the colours of yellow, orange, red, pink and blue of most of the flowers and fruits. The major drawback of their use and competitiveness compared to synthetic colorants is their colour instability, which may result in degradation of colour during processing and storage. The overall goal of the Ph. D. work was to develop a product, a natural colorant on anthocyanin base with adequate colour stability, which can be an alternative replacement for synthetic colorants in food and drug industry. Extraction of anthocyanins from grape marc, a by-product of the winery industry, was investigated considering their potential use as natural colorants. The optimal conventional extraction conditions were investigated with three different varieties of grape marc native to Slovenia. For comparison, experiments with a fresh (non-by-product) material -elder berry- were performed. The investigated operating parameters were: extraction solvent, solvent concentration and temperature. Influence of the pH value of the extraction media was investigated regarding the yield and degradation of anthocyanins. The stabilities of the obtained extracts during storage were compared. Supercritical fluid extraction (SFE) using carbon dioxide (CO2), was investigated for the pre-treatment of natural materials. Co-pigments influence the stability and colour of the anthocyanins. Therefore, the obtained extracts were analyzed on the content of some flavonoids. The second major part of the Ph.D. work focused on product formulation and stabilization of the anthocyanin extracts by using several high pressure techniques. Product formulation with SCF techniques, namely Concentrated Powder Form (CPFT), Particles from Gas Saturated Solution (PGSST) and Supercritical Antisolvent Precipitation (SAS) were carried out. Different anthocyanin-concentrates and carrier materials were tested. The products were analyzed for their colour properties (Lightness, Hue angle and Chroma values). The stability of the colour was monitored during prolonged storage.

Keywords

anthocyanins;natural colorants;extraction;SFE;carbon dioxide;product formulation;PGSS;CPF;SAS;stability;

Data

Language:	English
Year of publishing:	2009
Typology:	2.08 - Doctoral Dissertation
Organization:	UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher:	[T. Vatai]
UDC:	66.061-987:547.973(043.3)
COBISS:	13063702
Views:	4595
Downloads:	347
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	Slovenian
Secondary title:	DEVELOPING ANTHOCYANIN-BASED PRODUCTS
Secondary abstract:	Antocianini so skupina polifenolov, ki so odgovorni za barvno raznolikost cvetov in sadežev, od rumene, oranžne, rdeče, roza, do modre. V primerjavi s sintetičnimi barvili so nestabilni, kar predstavlja glavni problem pri njihovi uporabi in se lahko pokaže kot sprememba barve med procesiranjem in skladiščenjem. Glavni cilj doktorske disertacije je bil razviti produkt, naravno barvilo na osnovi antocianinov, ki bo ustrezno stabilen in bo predstavljal alternativo sintetičnim barvilom za uporabo v prehrambeni in farmacevtski industriji. Raziskovalno delo zajema študij ekstrakcije antocianinov iz grozdnih tropin, ki so stranski produkt v proizvodnji vina in predstavljajo potencialni vir naravnih barvil. V raziskavah smo uporabili tropine treh tradicionalnih sort rdečega grozdja, ki se pridelujejo v Sloveniji. Za primerjavo so bili eksperimenti narejeni tudi z uporabo svežega materiala - bezgovih jagod. Namen raziskav je bil določiti optimalne ekstrakcijske pogoje. Izvedla se je študija vpliva naslednjih parametrov: vrste in koncentracije topila za ekstrakcijo ter temperature. Študirali smo vpliv pH topila za ekstrakcijo na izkoristek in degradacijo antocianinov. Opazovali smo stabilnost dobljenih ekstraktov med skladiščenjem. Raziskali smo vpliv predobdelave naravnega materiala s superkritično ekstrakcijo s CO2. Poznano je, da ko-pigmenti vplivajo na stabilnost in barvo antocianinov, zato smo v dobljenih ekstraktih analizirali tudi vsebnost nekaterih flavonoidov. Drugi sklop raziskav v okviru doktorske disertacije zajema študij stabilizacije in formulacije antocianinov z uporabo visokotlačnih tehnologij ssuperkritičnimi fluidi (SCF). Raziskali smo naslednje SCF tehnike za formulacijo produkta: CPFT (Concentrated Powder Form; Koncentrirana praškasta oblika), PGSST (Particles from Gas Saturated Solution; Delci iz raztopin nasičenih s plinom), SAS (Supercritical Antisolvent Precipitation; Prekristalizacija z antitopilom). V raziskavah smo uporabili različne materiale na osnovi antocianinov (ekstrakte, sokove in koncentrate) ter različne nosilce, ki so uporabni v prehrambeni industriji. Izvedli smo analize barvnih lastnosti in stabilnosti barve med skladiščenjem dobljenih praškastih produktov.
Secondary keywords:	ekstrakcija;superkritični ogljikov dioksid;formulacija produktov;PGSS;CPF;SAS;naravna barvila;antocianini;stabilnost;
URN:	URN:SI:UM:
Type (COBISS):	Dissertation
Thesis comment:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages:	150 str.
ID:	8715618