Document IIF

Effet du processus de congélation du sorbet sur la température d'étirage et la dimension des cristaux de glace, à l'aide des mesures en ligne obtenues par la méthode de réflectance des rayons concentrés (FBRM).

Effect of sorbet freezing process on draw temperature and ice crystal size using focused beam reflectance method (FBRM) online measurements.

Résumé

During sorbet and ice-cream manufacturing, a narrow ice crystal size distribution with a small mean size is desirable, in order to get a smooth texture in the final product. We studied the influence of the mix-flow rate, the evaporation temperature of the refrigerant fluid, the dasher speed and the draw temperature and on the ice crystal size during sorbet freezing, in order to identify optimal operating conditions. We used the focused beam reflectance method (FBRM) to follow the evolution of the ice crystal size. The FBRM probe, provides accurate and repeatable information about the chord length distribution (CLD) of ice crystals. With this probe it is possible to follow the development of the ice crystals online in sorbets or slurries containing up to 40% of ice. The effect of refrigerant-fluid temperature was very important; by decreasing refrigerant temperature we reduce significantly the ice-crystal size and we obtain lower draw temperature as expected. High dasher speeds slightly decrease the ice crystal chord length, due to the attrition of the bigger ice crystals, which produces new smaller ice nuclei by secondary nucleation. Also, an increase of the dasher speed slightly warms the product, due to the dissipation of frictional energy into the product. As expected, low mix-flow rates result in lower draw temperatures because the product remains longer in contact with the freezer wall, extracting thus more heat from the product. Nevertheless, the mix flow rate did not show a significant effect on the ice crystal size.

Documents disponibles

Format PDF

Pages : 7 p.

Disponible

  • Prix public

    20 €

  • Prix membre*

    Gratuit

* meilleur tarif applicable selon le type d'adhésion (voir le détail des avantages des adhésions individuelles et collectives)

Détails

  • Titre original : Effect of sorbet freezing process on draw temperature and ice crystal size using focused beam reflectance method (FBRM) online measurements.
  • Identifiant de la fiche : 30001054
  • Source : Proceedings of the 23rd IIR International Congress of Refrigeration: Prague, Czech Republic, August 21-26, 2011. Overarching theme: Refrigeration for Sustainable Development.
  • Date d'édition : 21/08/2011

Liens


Voir d'autres communications du même compte rendu (569)
Voir le compte rendu de la conférence