Utjecaj dodatka polifenolnih ekstrakata biljnoga podrijetla na funkcionalna svojstva čokolade

doctoral thesis

• Title (english): The effect of addition of plant derived polyphenolic extracts on functional properties of chocolate
• Author: Ana Belščak-Cvitanović
• Mentor: Draženka Komes (mentor)
• Committee member: Ksenija Durgo (predsjednik povjerenstva)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; Zagreb
• Defense date and country: 2013-12-13, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology
• Universal decimal classification (UDC): 54 - Chemistry. Crystallography. Mineralogy

Abstract

Uzevši u obzir rastuću popularnost funkcionalne hrane i učestalo konzumiranje konditorskih proizvoda, posebice čokolade, cilj ovog doktorskog rada je kreiranje inovativnih čokolada, obogaćenih polifenolnim ekstraktima tradicionalno korištenih ljekovitih biljnih vrsta. Primjenom spektrofotometrijskih i HPLC metoda provedena je karakterizacija bioaktivnog sastava i biološke aktivnosti biljnih sirovina i čokolada. Tri vrste čokolada različitog udjela kakaovih dijelova (30%, 38% i 72%), obogaćene su ekstraktima stolisnika, koprive i lista maline, implementiranima u čokolade u obliku vodenog koncentrata, mikročestica (dobivenih primjenom tehnike elektrostatičke ekstruzije) ili liofilizata. Novokreiranim čokoladama definirani su fizikalni parametri te stabilnost bioaktivnog sastava i senzorskih svojstava tijekom roka trajanja. Dodatak ekstrakata svih biljnih vrsta rezultirao je povećanjem udjela polifenolnih spojeva u odnosu na čiste čokoladne mase. Biljna vrsta nije imala značajan utjecaj na udjel polifenola, već na njihov sastav. Dodatak ekstrakta stolisnika obogatio je čokolade derivatima hidroksicimetnih kiselina, flavona i flavonola, ekstrakt koprive klorogenskom i kafeinskom kiselinom, dok je dodatak ekstrakta lista maline povećao udjel derivata elaginske kiseline. Dozirni oblik i udjel (1% i 3%) biljnih ekstrakata značajno je utjecao na ispitivane parametre kakvoće čokolada. Dodatak 3% koncentriranih, kao i liofiliziranih ekstrakata, rezultirao je najvećim povećanjem udjela polifenolnih spojeva, ali je 3% koncentriranog vodenog ekstrakta izazvalo nepoželjne promjene fizikalnih i senzorskih svojstava čokolada. Čokolade obogaćene liofiliziranim ekstraktima najbolje su senzorski prihvaćene.

Abstract (english)

Taking into account the increasing popularity of functional food, as well as regular consumption of confectionery products, especially chocolate, the aim of this dissertation is formulating innovative chocolates, enriched with polyphenolic extracts of traditionally used medicinal plants. The bioactive composition and biological activity of plant materials and chocolates were characterized using spectrophotometric and HPLC methods. Three types of chocolates with different cocoa content (30%, 38% and 72%), were enriched with yarrow, nettle and raspberry leaf extracts, implemented in chocolates in the forms of aqueous concentrated extracts, microcapsules (obtained using electrostatic extrusion) and lyophilizates. The physical properties and stability of bioactive composition and sensory characteristics during the shelf life of newly created chocolates were determined. The addition of all three types of plant extracts resulted with an increase of polyphenolic content in comparison to plain chocolates. Plant species did not influence the content of polyphenols but rather their composition. Yarrow extracts enriched the chocolates with hydroxycinnamic acid, as well as flavone and flavonol derivatives, nettle extracts with chlorogenic and caffeic acids and raspberry leaf extracts with ellagic acid derivatives. The dosage form and content (1% and 3%) of plant extracts exhibited a major impact on the evaluated quality aspects of chocolates. The addition of 3% of concentrated or lyophilized extracts resulted with the highest increase of polyphenolic compounds, but also caused adverse effects on physical and sensory properties of chocolates. Chocolates enriched with lyophilized extracts exhibited the best sensory acceptance.

• Keywords: antioksidansi; citotoksičnost; funkcionalna čokolada; mikroinkapsulacija; polifenoli
• Keywords (english): antioxidants; cytotoxicity; functional chocolate; microencapsulation; polyphenols
• Language: croatian
• URN:NBN: urn:nbn:hr:159:596346
• Promotion: 2014-07-06
• Study programme: Title: Food Technology; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti (doktor/doktorica znanosti)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2018-05-17 11:04:37