CIDCA   05380
CENTRO DE INVESTIGACION Y DESARROLLO EN CRIOTECNOLOGIA DE ALIMENTOS
Unidad Ejecutora - UE
capítulos de libros
Título:
Hydrocolloids as o/w emulsion stabilizers: Effect of the structural features during storage.
Autor/es:
M. QUINTANA; G. LORENZO; N. ZARITZKY; A. CALIFANO
Libro:
Functional Properties of Food Components
Editorial:
Research Signpost
Referencias:
Lugar: Kerala; Año: 2007; p. 1 - 22
Resumen:
  Droplet size distribution, stability and rheology oflow-in-fat (35%) oil-in-water emulsions stabilizedwith 1 % w/w Tween 60, and i)5% potato starch (PS), ii) 5 % PS and 0.5 % xanthan gum (XG), and iii)1 % XG were studied during storage at 20‹C. Addition of 0.5M NaCl to the emulsions was analyzed in all the systems. Rheological properties of the corresponding continuous phases were also measured. In all cases Sauter diameter values between 10.2-12.8 ƒÊm were obtained; neither the presence of NaCl or storage time affected droplet size distribution. Microscopic observations revealed that all emulsions were flocculated. Objective stability tests based on the back scattered light profiles showed that emulsions containing PS + NaCl destabilized within 2 days, while the same emulsion without salt was stable up to 14 days. Emulsions containing XG or PS + XG, with or without NaCl showed a delay stage of phaseseparation which exceeded 6 months. Viscoelastic properties of the emulsions containing PS were modified because of changes in the microstructure of the aqueous phases and starch retrogradation. Although the systems exhibited weak gel-like properties, the addition of NaCl caused a decrease of GL and GLL in emulsions containing PS, attributed to the screening of the phosphate charges present in potato starch. Inclusion of salt did not affect emulsions stabilized only with XG. Both viscoelastic moduli GLand GLL of emulsions containing PS decreased during storage time while these phenomena were not observed in emulsions with only XG added.