Usporedba fizikalnih svojstava različitih veličina čestica šećera i stevije - Stevia rebaudiana (Bertoni)

master's thesis

• Title (english): Physical properties comparison of different sugar and stevia - Stevia rebaudiana (Bertoni) particle sugar
• Author: Tea Dozan
• Mentor: Ingrid Bauman (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Process Engineering); (Section for Fundamental Engineering); Zagreb
• Defense date and country: 2014-09-30, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Šećer, kao važan sastojak većine prehrambenih proizvoda, utječe na protočnost i reološka svojstva konačnih proizvoda. Kao zamjena za šećer, u današnje se vrijeme sve više prepoznaje potencijal biljke Stevia rebaudiana (Bertoni), čiji se glikozidi intenzivno koriste kao sladilo s niskom kalorijskom vrijednosti. U ovom istraživanju, saharoza u kristalnom obliku i suhi listovi Stevia rebaudiane (Bertoni) su mljeveni na željenu veličinu čestica, te su frakcije razdvojene prosijavanjem. Dobivene frakcije su analizirane kako bi se odredila fizikalna svojstva dobivenih prahova – raspodjela veličine čestica, svojstva tečenja, nasipna gustoća, rekonstitucijska svojstva, te se pomoću Spearmanovih koeficijenata i simboličkog algoritma dobili modeli međusobno zavisnih varijabli. Zeleni prah stevije pokazuje bolja svojstva tečenja u dinamičkim uvjetima, dok u testovima provedenim u statičkim uvjetima pokazuje lošija svojstva. Rezultati imaju značaj u primjeni zelenog praha biljke Stevia rebaudiana (Bertoni) te mogu služiti kao indikatori za poboljšanje efikasnosti procesa u kojima se šećer ili stevija koriste kao praškaste sirovine.

Abstract (english)

Sugar, as an important component of most food products is affecting the flow and rheological properties of the final products. At the present time, plant Stevia rebaudiana (Bertoni) is recognized with high potential as sugar substitute, whose glycosides are used extensively as a sweetener with a low calorific value. In this study, sucrose in crystal form and dry leaves of Stevia rebaudiana (Bertoni) were milled to desired particle sizes, and the fractions were separated by sieving. The obtained fractions were analyzed to determine the physical properties of the obtained powders - the particle size distribution, flow properties, bulk density and reconstitution properties. Using Spearman's coefficients and symbolic algorithm, were obtained models of interdependent variables. Green stevia powder showed better flow in dynamic conditions, while in tests conducted under static conditions showed worse characteristics. The results have significance in the application of green powder of Stevia rebaudiana (Bertoni) and can serve as an indicators for improving the efficiency of processes that use sugar or stevia powder as a raw material.

• Keywords: Šećer; Stevia rebaudiana (Bertoni); prahovi; fizikalna svojstva; veličina čestica
• Keywords (english): Sugar; Stevia rebaudiana (Bertoni); powders; physical properties; particle size
• Language: croatian
• URN:NBN: urn:nbn:hr:159:273603
• Study programme: Title: Food Safety Management; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka upravljanja sigurnošću hrane (magistar/magistra inženjer/inženjerka upravljanja sigurnošću hrane)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-05-02 11:22:23