The effect of storage time on structural characteristics and rheological behavior of praline system (Bachelor thesis)

Νίκου, Αικατερίνη/ Nikou, Aikaterini

A series of praline samples were prepared in this work, aiming to study the praline structural changes during storage for a period of six weeks at room temperature. The prepared praline samples were varied in their composition. The samples were measured, immediately after their preparation as well as after a period of three and six weeks respectively. Moreover, the effect of moisture content was investigated in a reference sample (coded 29SAD3) stored at environments with different relative humidity values (11, 44, 48, 64, 75 and 84%). The methods employed for the examination of the samples included rheological measurements (extensional viscosity using lubricated squeeze flow viscosimetry, dynamic measurements under controlled shear strain and creep tests) as well as Differential Scanning Calorimetry (DSC). The results showed that the effect of aging on the rheological parameters could be attributed to the transformation of a sugar fraction from crystalline to glassy, together with the formation of new bonds in the praline matrix, due to Brownian motion and to hazel nut presence which has a high fat content. Besides, the dynamic measurements in the heat scanning mode revealed that apart from the temperature values of melting of the lipid polymorphs another temperature value was recorded which was attributed to the glass transition temperature (Tg) of sucrose. The Tg range was recorded from 40 to 60oC
Institution and School/Department of submitter: Σχολή Τεχνολογίας Γεωπονίας & Τεχνολογίας Τροφίμων & Διατροφής / Τμήμα Τεχνολογίας Τροφίμων
Subject classification: Πραλίνα -- Αποθήκευση
Praline -- Storage
Keywords: χρόνος αποθήκευσης;storage time;δομικά χαρακτηριστικά;structural characteristics;ρεολογία;rheology;συστήματα;systems;δυναμικές μετρήσεις;dynamic measurements
Description: Μεταπτυχιακή διατριβή - Σχολή Τεχνολόγων Γεωπόνων & Τεχνολογίας Τροφίμων & Διατροφής - Τμήμα Τεχνολογίας Τροφίμων, 2016 (α/α 8351)
Appears in Collections:Μεταπτυχιακές Διατριβές

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