Mikroinkapsulacija polifenolnih spojeva zelenog čaja primjenom sušenja raspršivanjem

master's thesis

• Title (english): Microencapsulation of polyphenolic compounds of green tea by spray drying
• Author: Petra Ložnjak
• Mentor: Draženka Komes (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Chemistry and Technology of Carbohydrates and Confectionery Products); Zagreb
• Defense date and country: 2015-07-17, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Funkcionalni sastojci biljnog podrijetla i izražene biološke aktivnosti trenutačno su jedna od najaktualnijih tema znanstvenika i prehrambene industrije, posebice njihova inkapsulacija s ciljem očuvanja te čak i poboljšanja njihovih bioaktivnih svojstava. U ovom radu ispitana je mogućnost primjene različitih biopolimernih materijala kao nosača za mikroinkapsulaciju bioaktivnih spojeva zelenog čaja primjenom sušenja raspršivanjem pri niskoj temperaturi (130°C). Kao nosači korišteni su prirodni biopolimeri poput inulina, oligofruktoze, modificiranog kukuruznog škroba, alginata, karagenana, pektina, proteina sirutke, brašna graška, arapske gume, guar gume, gume sjemenki rogača i ksantana. Mikroinkapsuliranim uzorcima određene su fizikalne (veličina čestica, boja, gustoća) i reološke karakteristike, bioaktivni sastav primjenom UV-VIS spektrofotometrijskih metoda te tekućinske kromatografije visoke djelotvornosti (HPLC-PDA), dok su senzorska svojstva određena primjenom kvantitativne deskriptivne analize. Dobiveni rezultati pokazali su da upotreba inulina i proteina sirutke kao nosača daje najveći prinos (iskorištenje) proizvoda, dok se upotrebom inulina i pektina omogućuje najbolje očuvanje ukupnih polifenola i flavan-3-ola. Korištenje oligofruktoze i karagenana omogućilo je najbolje očuvanje boje, dok su uzorci u kojima su nosači bili modificirani kukuruzni škrob, inulin i karagenan pokazali najbolja senzorska svojstva, odnosno, niski intenzitet gorčine i trpkoće uz visoki intenzitet arome zelenog čaja. Upotreba hidrokoloidnih guma kao nosača omogućila je proizvodnju mikroinkapsuliranih prahova najmanje veličine čestica, dok je primjena inulina i oligofruktoze u tu svrhu rezultirala dobivanjem prahova velikih i nehomogenih čestica.

Abstract (english)

Plant derived functional ingredients with pronounced biological activity are currently one of the most popular research topics among both scientists and food industry, especially their encapsulation aiming to preserve or even improve their bioactive properties. In this study the potential of using different biopolymer materials as carriers for microencapsulation of green tea bioactive compounds by spray drying at low temperatures (130°C) was examined. The used carriers were natural biopolymers such as inulin, oligofructose, modified corn starch, alginate, carrageenan, pectin, whey protein, pea protein, acacia gum, guar gum, locust bean gum and xanthan. After microencapsulation, physical (particle size, color, density) and rheological properties of produced powders were determined, as well as the bioactive profile by UV-Vis spectrophotometry and high performance liquid chromatography (HPLC-PDA), while sensory properties of the samples were determined by using quantitative descriptive analysis. The obtained results showed that the use of inulin and whey proteins as the carriers enable the highest product yield, while the use of inulin and pectin allow the best loading capacity of total polyphenols and flavan-3-ols. The use of oligofructose and carrageenan enabled the best color preservation, while using starch, inulin and carrageenan provided the best sensory scored samples with lower bitterness and astringency intensity and a high green tea flavour intensity. Using hydrocolloid gums as the carriers, enabled the production of microencapsulated powders with the smallest particle size, while using inulin and oligofructose for that purpose resulted with larger and unhomogenous powders.

• Keywords: kafein; mikroinkapsulacija; polifenolni spojevi; sušenje raspršivanjem; zeleni čaj
• Keywords (english): caffeine; microencapsulation; polyphenolic compounds; spray drying; green tea
• Language: croatian
• URN:NBN: urn:nbn:hr:159:143389
• 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: 2017-04-28 08:59:00