Utjecaj blanširanja i depektinizacije na iskorištenje i pektinske tvari u proizvodnji soka od jagode

undergraduate thesis

• Title (english): Influence of blanching and pectolitic enzymes addition on the pectin substances and yield in producing strawberry juices
• Author: Silvija Novak
• Mentor: Branka Levaj (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Food Engineering); (Laboratory for Technology of Fruits and Vegetables Preservation and Processing); Zagreb
• Defense date and country: 2009-09, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Rad predstavlja rezultate istraživanja o tome kako blanširanje i depektinizacija utječu na iskorištenje i pektinske tvari u proizvodnji bistrih i mutnih sokova od jagode sorte Alba. Proizvodnja soka je provedena sa i bez prethodnog blanširanja kaše. Također sa i bez depektinizacije blaširane i neblanširane kaše prije prešanja i dobivenih sokova nakon prešanja. Spektrofotometrijski su određeni udjeli pojedinih pektinskih frakcija u uzorcima izuzetim tijekom proizvodnje mutnog soka od jagode. Tijekom proizvodnje praćeno je i kako primjenjeni postupci utječu na ukupno iskorištenje. Na osnovu dobivenih rezultata zaključuje se da se u blanširanoj pulpi smanjio udio pektinske frakcije topljive u vodi, a povećao udio pektinske frakcije topljive u lužini dok je količina frakcije topljive u oksalatu ostala nepromijenjena. Matični sokovi dobiveni iz blanširane pulpe imaju niži udio svih pektinskih frakcija i ukupnih pektina u odnosu na matične sokove dobivene bez blanširanja. U mutnim sokovima (gotovom proizvodu) najzastupljenija je pektinska frakcija topljiva u vodi. Uglavnom svi mutni sokovi imaju manje svih pektinskih frakcija i ukupnih pektina u odnosu na matične sokove. Blanširanje i depektinizacija kaše povećavaju iskorištenje na prešanju.

Abstract (english)

Strawberry, Fragaria annanasa cv. Alba, was used to produce clear and cloudy juices. The process of juice producing was taken with and without blanching mash. Also with and without adding pectolitic enzymes in blanched mash and mash which was not blanched before pressing. Furthermore, after pressing enzymes were added to produce clear juices. Colorimetric determination of the amount of pectin fractions (soluble in water, in oxalate, in alkali) in samples were taken during cloudy juice making. During the process of juice making it was followed how a particular treatment influenced the total yield. Based on the results the following conclusion was arisen: in blanched pulp water-soluble fraction was reduced, alkali-soluble fraction was increased and oxalate-soluble fraction was not changed in comparison to pulp before blanching. The juices produced by pressing blanched pulp had lower level of all pectin fractions and the amount of total pectin than the juices produced without blanching. In cloudy juices (final products) the water-soluble fraction was represented the most. All cloudy juices had lower level of all pectin fractions and the amount of total pectin than juices after press. Blanching mash and adding pectolitic enzymes in mash increase yield on pressing.

• Keywords: sok od jagode; pektinske tvari; blanširanje; depektinizacija; iskorištenje
• Keywords (english): strawberry juice; pectin substances; blanching; pectolitic enzymes; yield
• Language: croatian
• URN:NBN: urn:nbn:hr:159:478314
• Study programme: Title: Food Technology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka prehrambene tehnologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka prehrambene tehnologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-08-31 12:44:52