Titre :
|
Effect of freezing rate and frozen storage on starch-sucrose-hydrocolloid systems
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Auteurs :
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C. Ferrero ;
N. Zaritzky
|
Type de document :
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article/chapitre/communication
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Année de publication :
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2000
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Format :
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p. 2149-2158
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Langues:
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= Anglais
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Catégories :
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GENIE DES PROCEDES FRIGORIFIQUES
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Mots-clés:
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VITESSE DE CONGELATION
;
AMIDON
;
RHEOLOGIE
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Résumé :
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Model food systems based on starch (100 g kg), sucrose (150 g kg) and water (750 g kg) with and without the addition of a low proportion of hydrocolloid (xanthan gum, guar gum or sodium alginate) were gelatinised, frozen at different rates and stored to analyse textural changes by oscillatory rheometry. Differential scanning calorimetry (DSC) was used to analyse gelatinisation, amylopectin retrogradation and glass transition temperatures. Sucrose had a significant effect on the increase in the gelatinisation temperature as well as on the decrease observed in glass transition values. The onset temperature of the second step of the glass transition, corresponding to the heat capacity change close to ice melting (denoted Tg in the present work), ranged between -23.0 and -22.2°C. Rheological viscoelastic tests showed an increase in the dynamic moduli G and G' after slow freezing and during storage at -19°C (T > Tg) in starch-sucrose systems that is related to sponge formation due to amylose retrogradation. DSC studies confirmed that also amylopectin retrogradation occurs during storage; however, samples containing gums did not develop the spongy appearance.
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Source :
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Journal of the science of food and agriculture, vol.80, n°14
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