INVESTIGADORES
CABEZAS Dario Marcelino
congresos y reuniones científicas
Título:
Fractionation of Sunflower Lecithin. Characterization and Emulsifying Properties
Autor/es:
CABEZAS, D.M.; TOMÁS, M. C.
Lugar:
St. Louis, Missouri (USA)
Reunión:
Congreso; 97th AOCS Annual Meeting & Expo; 2006
Institución organizadora:
American Oil Chemists' Society (AOCS)
Resumen:
Native and modified lecithins are used in a wide range of food applications
(emulsifiers, dispersing agents). Phospholipids present interesting surface
properties, which enable them to achieve emulsion stability in diverse food
products (mayonnaise, salad dressings).
The main aim of this work was to study the fractionation process of
sunflower lecithin investigating the effect of the emulsifying properties of different
fractions on the stability of oil in water (O/W) emulsions.
Sunflower lecithin -provided by a local oil industry- was treated with
absolute ethanol (ethanol / gum ratio 3:1, 65°C, 1h, moderate agitation) obtaining
an enriched PC and PI/PE fractions, respectively. Furthermore, both of them were
purified with the addition of acetone to remove the residual oil and dried.
Phospholipid composition of different samples were determined by HPLCELSD
with a previous purification step by SPE.
Oil in water (O/W) (30:70 w/w) emulsions were prepared in an Ultraturrax
T25 homogeneizer (10,000 rpm, 1 min) using sunflower oil and different sunflower
lecithin fractions (PC, PI/PE and deoiled lecithin) in a range of 0 - 2% respect to
water phase.
Optical characterization of dispersions was carried out using a vertical scan
analyzer (Quick Scan), obtaining the corresponding differential Transmission and
Backscattering profiles. The mechanisms of destabilization and the corresponding
kinetics involved -in each case- were determined.
The results obtained showed that PC enriched fraction contained 85% PC,
10% PE and 5% PI while PI/PE fraction presented 37% PC, 23% PE and 40% PI.
All emulsions presented a destabilization process by a creaming process
followed by coalescence in some cases. Also, changes in emulsion stability were
observed as a function of the type of the emulsifier agent assayed and its
concentration.
Emulsions with 0.1 to 0.5% PI/PE fraction showed a rapid destabilization
process. At higher concentration, it was recorded a higher level of initial
backscattering than those corresponding to samples previously mentioned, with a
decline of the creaming rate and an increase in emulsion stability.
PC enriched fraction exhibited the most efficient role as emulsifier agent in
comparison with deoiled sunflower lecithin and PI/PE fraction at all concentrations
used, mainly at low concentration levels.
These results provide interesting information for further developments in the food industry.