**5. Acknowledgments**

This work was supported by grants from Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT), Argentina, PICT 1085 (ANPCyT); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina, PIP 1735 (CONICET); and Universidad Nacional de La Plata (UNLP), Argentina, 11/X502 (UNLP).

M. C. Tomás is a member of the Career of Scientific and Technological Researcher of Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina. D. M. Cabezas is a recipient of a postdoctoral fellowship from Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). R. Madoery is a Scientific and Technological Researcher, and Professor at Universidad Nacional de Córdoba (UNC). B. W. K. Diehl is Director of Spectral Service GmbH, Cologne, Germany.

Sunflower lecithin and microbial PLA2 were provided by Vicentin S.A.I.C. and Danisco, respectively. Thorsten Buchen is acknowledged for his technical assistance.
