Formulation, structuring foodHervé This

4 September 2013

Let's begin by a simple definition :

Formulation is a technological activity (remember that there is a difference between quantitative science and technology: science means looking for the mechanisms of phenomena, whereas technology means improving technique using science; both are "research", contrary to technique). Its goal is : designing and making products, for the craft or for the industry.

As using the most advances results of quantitative sciences can lead to new applications, formulation is improved when it's based on physical, chemical, biological knowledge, and the most advanced knowledge you use, the more advanced the innovation. In other words: if you use old knowleldge, the probability that innovation was already made from it is high, but on the contrary nobody did application if you use a freshly produced scientific results. As a conclusion, engineers working in formulation should know the most advanced results of sciences. And this is the key for competitivity, and commercial success as well (look at the computer industry!).

As a consequence, learning formulation means : 1. learning to look for fresh scientific results2. learning to understand fresh scientific results3. learning to decide which are the useful scientific results4. learning to make new products from new scientific results.

But... what is formulation?

It is the activity of creatin, design, fabrication of prototypes, for commercial products which have a use value. A formulated product is obtained by the association of various raw materials, either synthetized or extracted from natural products. Among the various materials used for formulation, there are: - some which have the main function of the product- formulation auxiliaries, which have secondary functions, such as making the production easier (surfactants for emulsions, for example), or making a longer shelflife (preservation agents, for example).

Formulation is important for all industries transforming materials, from making raw materials up to finalindustries, directly in contact with consumers (industry or public), which can make ready to use formulated products. Material, environment, biology... are concerned by formulation because active matter for synthesis are concerned. "Chemical specialties" are marketed on the basis of the functional properties taht they tive to final mixtures (giving odor, taste, color, thickening agents, filming agents, filtering ultraviolet radiations,hydration of the skin...) rather than molecular criteria (molecular structure, purity, etc.). More recently, the word "formulation" was introducte in the industry circles for describing the action of

creating and designing a cosmetic product, a perfume, paintings and coats, plastic material, and even in the food industry. Formulation today is one of the most important branches of the industry for life and environment. It encompasses the whole set of knowledge, and practical know how necessary for the design of products.

Formulation is a key activity for the industries!

Formulation is a key activity for the industry, because the whole industry is using formulation methods. Often formulation is giving the use value in the industry of food, cosmetic, pharmacy, paintings and coats, varnishes, soaps...Formulated product are, as said, often made from raw material either synthetized or of natural origin. But whatever the origin, these raw materials are either active principles (think of digitaline, in heart drugs for example) or conditioning/packaging elements (we include here active packaging). Active principles are the main products having the main use announced for the products, and formulation auxiliaries are having secondary functions, such as making the production easier. For example : - in a drug, there are active principles, - in a perfume, the active compounds are odorants compounts, in a solvent which is the equavalent of thecapsule, pill, etc of drugs- a food, there are "bioactive" compounds (they have receptors, either for sensory effects or for nutrition), as well as a "matrix", in which the bioactive compounds are partly trapped.

In France, the Nomenclature d'Activités Française (NAF) is grouping formulation industries with pharmacy (drugs), phytochemistry (plant caring products, cosmetics, perfumes, hygiena products, soaps, detergents, home caring products, products for photography, data storing devices, varnishes, inks, paintings, coats, lubricants, adhesives, explosives). However other industries of material transformationswhich don't belong to these fields (fuels, papers, rubbes, cements, glass, ceramics...) are also formulatingthe product they sell. For example : icy sugar makers (sucrose agregates of diameter smaller than 0.1 mm) coat the sucrose crystals with anti-motting agents, in order to make the dispersion easier (silica, starch).

Physical chemistry for formulation

Before, it was said that the industries concerned with formulation are diverse. However all theses activities are using the same kind of physical and chemical skills. Physics and physical chemistry have different approaches, but engineers for formulation have to use the knowledge of the two disciplines, as well as biology, botany, etc. at different times of the design and tests of products. Or course, special knowledge of analysis (physical, chemical) and methodology are needed, so that one can ensure that the formulated products have the intended function. En conclusion, engineers will be competent only if they are trained to the most advanced methods and knowledge, in these fields. They have to get: 1. Theoretical tools1.1. General physical descriptions: Chemistry of solutionsStructure of condensed matterDiffusion and transports (heat, matter...)Thermodynamics (in particular phase transition)Out of equilibrium thermodynamics (for metastability)Soft matter (order parameters, methods for study, colloïdal and disperse systems, vectorization)

Supramolecular assembliesHydrodynamics

1.2 General chemical descriptions: Various classes of organic compoundsBiomoleculesChemical analysisChemometricsChemical processes and molecular interactionsRelationship structure/property

1.3 General technologyBibliographyTechnology transfer.

2. Tools for design and characterization2.2. Levels of designMacroscopicMicroscopicNanoscopicMolecular2.3. Characterization tools- HPLC and LC-MS-GC-MS- UV vis, IR- RMN- EC- viscosimetry, texturometry- microscopy (optical, electronic, near field, atomic...)

3. General toolsLinguistic skillsCommunicationComputing

One example of formulation: an "eclipsa dish"

Here, the goal is to show how a clear method can help innovation in the food field. This example sticks only to design. For industrial aspects, this design work should of course be followed by implementation, making prototypes, analysis and characterization of prototypes, etc. The example was achieved in 1998, when there was a great sun eclipsa over Europe. Let's decide to make an "eclipsa dish".

First, we shall define the goal. Eclipsa dish : what does it mean ? An eclipsa is a phenomenon when the appearance of the sun is changing, because the moon is moving between the sun and the earth, hiding partly our star. In practice, one can see the light disk sligthly cut, as the world is shadowing, with some coolness of the air, and then the environment is normal again. Each step can be the opportunity of a technology transfer : - a white disk being darkened on an edge- cooling-light disappearance before reapparition

Of course, the idea is not to make the real changes, but to transfer toward the food field.

1. First we want that the visual aspect of the disk represents the eclipsa. Let's think to a white disk with an edge colored in black : this is very easy. Colored in black? For food, one solution could be to use squid ink (either you make it from squids, or you buy the ink in food shops). But also the juice of plants can turn from green to black when plant tissues are cut, so that they release both phenolics and enzymes of the polyphenol oxidase kind, which make dark melanoidins. Or we could use caramel, or Maillard products.

A white disk? Again, it's good if you know how to cool: you can cut a disk in dough, such as lasagna, forexample. But of course you could also use titanium oxide in order to make material appear white, as do pastry chefs. Let's decide for dough, as it contains starch, which is useful because when it is heated, it can release glucose, which is good for well being. In order to make such a dough (for 4 people), you could use a culinary recipe: mixe in a vessel 200 g flour, 2 egg yolks, 1 spoon of olive oil, 5 g salt. You knead, and when the dough is homogeneous, you make it flat in a thin layer (3 mm) and using a plate (diameter 15 cm) put on top, you cut around and make 8 disks. Then you cook the disks in boiling water with salt for about 3 min. You cool the disks under cold water. Then you paint the dark disk on 4 of the 8 disks.

Now for the visual presentation, it's done.

2. The main point is the "eclipsa of flavour". How to make it? We shall prepare an ingredient deprieving it of what it has as an important componant. For example, garlic is thought to make an "heavy" breath... but if you peel garlic cloves (about 20) and if you boil them 6 times with fresh water each time, starting from cold water, then the cloves will have lost their heavy odor, keeping only taste.

3. Coolness: we have to play with temperatures. Of course, the disks will be better when hot, but what if we put something cold between 2 hot disks ? Let's decide for langoustine, big shrimps. Heat oil, then putthe shrimps, salt, pepper. Make it smoke, and shells have to become brown. Then stop heating, and wait for cooking. Remove the shels, and keep the meat in a fridge. In a pan, put the shells, with heads, with onions and one sliced carrots (of course, after washing and peeling). Cook more, then reduce the intensity of the heating system, add pastis, flamb and add 0.5 L of white wine. Cook for 30 min, then filter, in order to recover as much liquid as possible. In a small pan put some butter (about 10 g) and 40 g of flour, heat until browning, and add the liquid, as well as 100 g of butter. Here is the sauce. In order to make the dish, you shall heat the disks in an oven, and put on plates one disk, some shrimps (cold), some garlic purée, hot sauce, and the other disks of dough (the one with colored edge), also hot.

4. We can improve all this, with a real flavour disappearing, before coming back. Let's not forget that we are physical chemists: we would like to change the perception of one or many odorant or taste compounds. But we know that these compounds are perceived when they are released bythe food. Release is easy when odorant compounds are pure. It is slowed down when the compounds are dissolved in a solvent: oil, for example. Making an emulsion of the compounds is also changing the release: hydrophobic compounds, for exemple, will be dissolved in oil, and oil droplets dispersed in water. So that odorant compounds cannot leave easily the system. And when we add proteins, around theoil droplets, the release is even slower. Finally when such an emulsion is "hidden" in a system, the release will be even slower. The practice, now: let's use an odorant compound, or rather (it's easier) a mixture of odorant compounds with high volatility, so that the odorant compounds are immediately release, when the food we be put in the mouth ; the same compounds will be trapped as said before, so that they will be released also, but much later.

For example, let's grind some basil leaves, and put the "juice" on top of the upper hot disk. Methylchavicol and linalol which make the main part of the odor will be released immediately. Now let's grind other leaves of basil in a mortar with pestle, with oil (a solvent for the odorant componds). The let's use some shrimp fond, with a gelatine sheep dissolved in it, and let's make an emulsion using the basil oil. When this emulsion is made, let's put it in the middle of the shrimps (cut into two parts). The emulsion will make a gel, in which the emulsion will be trapped !

Finally, let's remark that in the previous description, we dipped toward the proposal of a solution, and weforgot to be systematic. In particular, we did not consider prototyping, we did not discuss the important issues of production (energy, time, raw materials...) or marketing (microbiology, stability in time during storing, preferences, regulations...). Another way of thinking could be : - distinguish first active principles, using the knowledge of the various receptors : odor, taste, trigeminal,tactile, temperature- then discuss the "galenic"- etc.

The DSF

Stricto sensu formulation is an activity of production of systems (for example, a dish has a good odor of basil), and not only description. However the two activities are linked: in order to be able to predict the possibilities for bioactivity, ofr example, you have to be able to understand the chemical as well as the physical organization of systems. We need, in particular, to: - know the structure of systems at all interesting scales- understant the chemical and physical laws applying during the production of prototypes. DSF, the formalism for disperse systems, is a tool for the two activities. We shall not consider it in details, but we shall consider an example.

1. Let's simply look to a formulated system (here food) :

The "reference size" it about 10 cm (the plate). At this scale, you can distinguish parts, from bottom to top:- a plate- a disk of sauce- some plant tissue- a lower part, yellow- un upper prat, white- a sauce on top. Using the beautiful method which consists in giving names to objects, we could write: S : sauceC: creamY: yellow massG: green vegetablesP: plate.

of":

Here, D2 tell you that it is a slice, a sheet, a layer.. D3 tells you about a 3-dimensional objet.

2. Let us now use a magnifying glass, in order to make the various part appear so big that they are out of focus. The reference size is now determined by the magnification. At this scale, nothing new. Let us thenmake it appear even bigger, and look at the scale of 1 mm. Nothing new again. But when the visible objects have a diameter of 0.1 mm, then a microscope can show interesting things such as:

Here you see droplets of hydrophobic material (it's oil) dispersed in a continuous phase made of water and gelatine. Let's call O the hydrophobic phase, W the aqueous solution and S the solid network of gelatine. In order to describe the presence of two continuous phases, let's use the symbol x, so that the oildroplets are dispersed (symbol /) at random in the continuous SxW phase. Some conclusions can now be drawn

This is the main idea of DSF: describe systems formally.