Aromatski profil i senzorska svojstva ultrazvučno tretiranih sokova od brusnice i borovnice

master's thesis

• Title (english): Senzoric properties of juices treated by ultrasound
• Author: Helena Bedić
• Mentor: Anet Režek Jambrak (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Food Processes Engineering); Zagreb
• Defense date and country: 2013-09-25, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Svrha ovog rada je dizajnirati eksperiment ultrazvučnog tretiranja bistrih voćnih sokova i nektara od brusnice i borovnice kako bi uz uštedu vremena, energije i sirovine dobili optimalni rezultati. Dobiveni rezultati opisani su i obrađeni uz pomoć metode odzivne površine (RSM). Tretman sokova proveden je ultrazvukom visoke snage (10 – 600 W). Sokovi su tretirani prema dobivenom planu i to pri različitim amplitudama (60,90 i 120 μm), temperaturama (20, 40 i 60° C) i vremenu tretiranja (3, 6 i 9 min). Tretirani uzorci uspoređivani su sa termički obrađenim odnosno pasteriziranim uzorcima (80° C / 2 min). Određivan je aromatični profil sokova i nektara uz pomoć SPME/HS i GC/ MS metode. Također su određivana senzorska svojstva, parametri boje (L, a i b), topljiva suha tvar (°Bx) i pH vrijednost. Dobivenim rezultatima utvrdilo se da nakon ultrazvučnog tretmana dolazi do nastajanja novih spojeva (estera) u odnosu na netretirane uzorke ili pak dolazi do gubitka nekih spojeva koji su prisutni u netretiranom uzorku. Senzorska analiza sokova pokazala je da nakon tretiranja sokova dolazi do statistički značajne promjene tj smanjenja svih senzorskih svojstava (boja, miris, okus i opća kvaliteta), ali je to izvan granica odbacivanja proizvoda. Kod mjerenja parametara boje zabilježeno je da u odnosu na netretirane uzorke pasterizirani uzorci imaju veću promjenu u zasićenosti boje (ΔH), svjetlini boje (ΔL) i ukupnoj promjeni boje (ΔE) dok kod ultrazvučno tretiranih uzoraka nisu zabilježile značajne promjene.

Abstract (english)

The purpose of this study is to design an experiment ultrasound treatment clear fruit juices and nectars of cranberries and blueberries in order to save time, energy and raw materials to get optimal results. The Planning of experiments were done with the help of the central composite design, a combined 3 most important parameters of ultrasound treatment (range, curing time and temperature). The results are described and analyzed using response surface methods (RSM). Treatment juices conducted ultrasonic high power (10-600 W). Juices are treated the resulting plan and at different amplitudes (60, 90 and 120 microns), temperatures (20, 40 and 60° C) and time of treatment (3.6 and 9 min). The treated samples were compared with the heat-treated or pasteurized milk samples (80° C / 2 min). We determined the aromatic profile of juices and nectars with SPME / HS and GC / MS methods. It was also scheduled on sensory properties, color parameters (L, a and b), total soluble solids (° Bx) and pH value. The results found that after ultrasonic treatment leads to the formation of new compounds (esters), compared to untreated samples, or comes to the disappearance of some compounds that were present prior to the untreated sample. Sensory analysis juices showed that sensory characteristics when treating samples leads to a statistical decrease in all tested parameters (color, smell, taste and overall quality), but this is beyond the rejection of the product. When measuring color parameters was observed that compared to untreated samples of pasteurized samples have a greater change in color saturation (ΔH), brightness, color (ΔL) and total color change (ΔE), while ultrasonically treated samples did not record significant changes.

• Keywords: ultrazvuk visoke snage; aromatski profil; senzorske karakteristike; GC/ MS metoda
• Keywords (english): high-power ultrasound; aromatic profile; sensory characteristics; GC/ MS method
• Language: croatian
• URN:NBN: urn:nbn:hr:159:261222
• Study programme: Title: Food Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka prehrambenog inženjerstva (magistar/magistra inženjer/inženjerka prehrambenog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-05-04 13:19:26