master's thesis
Effect of moisture content on properties of semolina extrudates

Ružica Vračević (2012)
Josip Juraj Strossmayer University of Osijek
FACULTY OF FOOD TECHNOLOGY
Department of Food Technologies
Sub-department of Carbohydrates Technology
Metadata
TitleUtjecaj vlažnosti pšenične krupice na svojstva ekstrudata
AuthorRužica Vračević
Mentor(s)Đurđica Ačkar (thesis advisor)
Abstract
Ekstruzija je suvremeni postupak obrade različitih vrsta sirovina i proizvodnje širokog spektra prehrambenih proizvoda, pri čemu se kao osnovna sirovina često koristi pšenična krupica. Cilj ovog rada bio je utvrditi utjecaj vlažnosti pšenične krupice na svojstva ekstrudata. Pšenična krupica (Griz) vlažnosti 15 % i 20 % ekstrudirana je na jednopužnom ekstruderu Do-Coder, Brabender 19/20 DN, GmbH, Duisburg, Njemačka pri temperaturnom profilu 135/170 °C, uz primjenu puža konfiguracije 4:1. Dobivenim ekstrudatima ispitana su fizikalna, termofizikalna, kemijska i reološka svojstva u odnosu na neekstrudirane uzorke. Istraživanjem je utvrđeno da je ekspanzijski omjer bio veći kod ekstruzije pri većem sadržaju vlage. Nasipna masa bila je veća kod ekstruzije pšenične krupice pri nižem sadržaju vlage. Uzorci ekstrudirani pri većoj vlažnosti imali su veću tvrdoću, dok sadržaj vlage nije imao utjecaja na lomljivost ekstrudata. Moć upijanja povećala se nakon ekstruzije, pri čemu je do većeg povećanja došlo kod pšenične krupice ekstrudirane pri većem sadržaju vlage. Ekstruzija je imala utjecaj na reološka svojstva pšenične krupice te je došlo do povećanja vrijednosti viskoznosti vrha, ali bez statistički značajne razlike između neekstrudiranih i ekstrudiranih uzoraka. Sadržaj masti se smanjio nakon procesa ekstruzije, ali na sadržaj pepela pšenične krupice ekstruzija nije imala utjecaj.
Keywordsextrusion grits wheat grits moisture content
Parallel title (English)Effect of moisture content on properties of semolina extrudates
Committee MembersDrago Šubarić
Đurđica Ačkar
Jurislav Babić
Mirela Kopjar
GranterJosip Juraj Strossmayer University of Osijek
FACULTY OF FOOD TECHNOLOGY
Lower level organizational unitsDepartment of Food Technologies
Sub-department of Carbohydrates Technology
PlaceOsijek
StateCroatia
Scientific field, discipline, subdisciplineBIOTECHNICAL SCIENCES
Food Technology
Engineering
Study programme typeuniversity
Study levelgraduate
Study programmeFood Engineering
Academic title abbreviationmag. ing. techn. aliment.
Genremaster's thesis
Language Croatian
Defense date2012-10-02
Parallel abstract (English)
a wide range of food products, where the wheat grits are often used as main raw materials. Aim of this study was to dermine the effect of moisture content on properties of semolina extrudates. Semolina (Griz) with 15% and 20% moisture content was extruded in a laboratory single screw extruder Do-Corder, Brabender 19/20 DN, GmbH, Duisburg, Germany at temperature profile 135/170 °C, using screw with compression ratio 4:1. Physical, thermophysical, chemical and rheological properties of the obtained extrudates were determined, and results were compared with control samples of non-extruded wheat grits. The results showed that the expansion ratio was higher when semolina with higher moisture content was extruded. Bulk density was higher at extruded semolina with lower moisture content. Samples extruded at higher moisture content had higher hardness, while moisture had no effect on fracturability of extrudates. Water absorbtion index increased after extrusion process, and this increase was higher when semolina was extruded at higher moisture content. Extrusion had the effect on the rheological properties of semolina, where the peak viscosity increased, but with no statistically significant differences between nonextruded and extruded samples. The fat content was reduced after extrusion, but no effect of extrusion on the ash content of semolina was observed.
Parallel keywords (Croatian)ekstruzija krupica pšenična krupica vlažnost
Resource typetext
Access conditionAccess restricted to students and staff of home institution
Terms of usehttp://rightsstatements.org/vocab/InC/1.0/
URN:NBNhttps://urn.nsk.hr/urn:nbn:hr:109:434870
CommitterSanda Hasenay