Author Archives: Filipe Antunes

Author: Filipe Antunes

Expert in food chemistry. PhD in Physical Chemistry. Professor at University of Coimbra, Portugal, consulting for international and national companies. CEO at DBox Portugal. Professional experience at Procter & Gamble (USA) and BASF (Germany). Head of 32 funded scientific projects in food coatings, nano and micro encapsulation, green chemistry and materials. Principal investigator at the COLLING group of the University of Coimbra. Holder of 19 international awards.

Food dispersions includes emulsions such as milk, cream, sauces, etc. The main characteristic of these foods is the presence of small particles, and the consequent high interfacial area between the particles and the continuous phase. The properties of food colloids are defined by the interactions among the particles.

Food emulsions consist of an oil phase containing hydrophobic compounds and an aqueous phase containing water-soluble compounds. One phase is dispersed into the other, defined as oil-in-water emulsions or water-in-oil emulsions, dependently if water or oil are the continuous phase, respectively. Emulsions are thermodynamically unstable, and phase separation can be deaccelerated or even prevented through kinetic factors. The origin of destabilization is based on gravitational force, attractive and repulsive forces among the particles, etc.

The destabilization can then be seen by creaming, flocculation, and coalescence. In addition to these, emulsion phase inversion and Ostwald ripening are phenomena that can happen in emulsions. Creaming is a phase separation caused by the upward migration of droplets due to density difference between phases. Flocculation is the aggregation of droplets due attractive forces. Coalescence is the merging of droplets.

The dispersion of water in oil for the production of mayonnaise is one of the most known examples of food emulsions.

Stokes Law and phase stability

Even in apparently stable systems, with a shelf life of several years, the number and size of droplets change with time. Stokes’ Law gives the creaming / sedimentation rate for an isolated, rigid, uncharged droplet: U=2/9 R2dρg/η. R stands for the radius, dρ for the density difference, g for gravity and η for viscosity. Creaming may be considered as negligible compared with Brownian motion when U is less than 1 mm/day. Stokes’ Law shows how to prevent or minimize creaming: i) Reduction of droplet size, for instance by the addition of considerable amounts of amphiphiles such as surfactants, or by the use of homogenizers at high operating pressure. ii) Reduction of density differences between the phases. Density difference between the oil phase and water phase is, depending on other factors, about 50 kgm-3. While the density of large droplets is similar to the oil phase, very small droplets have a density closer to that of the aqueous phase. iii) Tuning the viscosity of the continuous phase, by adding polymeric thickeners, for instance gums. iv) in the moon.


The way human beings feed themselves strongly influences their physical and emotional balance. Meat products are an excellent source of nutrients and are widely consumed around the world. However, these products are also susceptible to chemical and microbiological deterioration, which creates health risks.

Consumption of contaminated food and water kills 1.8 million people annually. In addition, each person is wasting an average of 150kg of food per year, also due to lack of food conservation.

Packaged meat products arrive at the consumer’s house in good food safety conditions. However, food contamination is a serious concern at the post-opening stage of the package. It is thus urgent to create more advanced solutions of food preservation, which reduce the contamination and increase the shelf-life after the package is opened.

Sliced charcuterie may have an extended shelf-life with the developed technology.

A new technology for the preservation of charcuterie

Researchers at the University of Coimbra, Portugal, and Primor Charcutaria Prima developed a research project to address this problem. New surfactant and polymer systems were developed to promote longer shelf life through the incorporation of consumer safe edible coatings in the meat. Furthermore, this coating prevents the use of the protective N2/CO2 atmosphere in the packaging, which leads to the reduction of the amount of plastic volume used in the packaging, yielding a better environmental impact.

The various types of performed assays included: chemical, physical and microbiological tests to identify coatings with improved bacterial elimination, light scattering and rheology tests to identify the best suited coatings for spray application, and electron microscopy to compare the level of meat degradation with and without coating. Color, taste, texture and odor were continuously monitored throughout the project. After the laboratory tests, the best performance coatings were applied in semi-industrial environment.

This new results will make available to consumers a new generation of preservation for fresh meat products.