Gianfranco Risuleo

By Claudio De Seta, Nicola Calandrella, Valerio Berardi, Antonio Mazzarelli, Gianfranco Scarsella and Gianfranco Risuleo

Part of the book: Glaucoma

By Nicola Calandrella, Simona Giorgini and Gianfranco Risuleo

Part of the book: Glaucoma

By Camillo La Mesa and Gianfranco Risuleo

The role that some forces exert on food colloid stability is discussed. The focus is on the combination of different energy terms, determining particle-particle attraction or repulsion. The forces are relevant in dispersion stabilization and macroscopic phase separation. The observed features depend on the energies at work and colloid concentration. Examples deal with food manipulations giving cheese, yogurt, and mayonnaise. All products result from the overlapping of forces jointly leading to aggregation or phase separation in foods. The combination of attractive, van der Waals (vdW), and repulsive, double-layer (DL) forces results in the dominance of aggregation or dispersion modes, depending on the particle concentration, on the force amplitude, and on their decay length. DL and vdW forces are at the basis of Derjaguin-Landau-Verwey-Overbeek (DLVO) theory on colloid stability. That approach is modified when these forces, jointly operating in bio-based colloids, overlap with steric stabilization and depletion modes. Steric effects can be strongly dispersive even at high ionic strength, despite this is rather counterintuitive, when depletion ones favor the nucleation in a single phase.

Part of the book: Some New Aspects of Colloidal Systems in Foods