Of course, there are the labels on the back. These long lists of ingredients, most of which mean nothing. And the nutritional tables, which compile the intake for the body. But nothing, nowhere on the know-how, the processes, the recipe. If there is one secret that the food industry jealously guards, it is what happens in its kitchens, these opaque rooms without clerks or shots, where machines transform foodstuffs.
To produce millions of low-cost, identical meals, which remain soft, juicy, tender, despite weeks of sleeping on supermarket shelves, food manufacturers have their tricks, which few are willing to reveal in broad daylight: Like an oil operator, they “crack” the raw materials at their disposal (wheat, corn, milk, etc.), extract and separate their components, modify their shape and nature. Until changing their molecular structure.
Intense, large-scale processes. Didier Majou, member of the Academy of Agriculture, speaks more of “food chemistry laboratories”. “From one grain of corn, we can produce more than 300 different products. It’s heavy industry, which requires a lot of investment and know-how, there are few players on the market” , warns the one who heads Actia, a network of technical institutes in the agri-food industry.
“Food chemistry”
Among the most processed products is starch, an element found in corn, wheat, potatoes or peas. In flour or starch, it thickens and gels – this is the secret of all good artisanal sauces. But in this minimally processed form, this powder forms lumps and its effect does not last. To prevent the sauces from separating, and speed up their preparation in the huge tanks where they are mixed, manufacturers have a technique. “They change the molecular structure of starch, thanks to chemical or biological processes,” explains Catherine Renard, research director at the National Institute of Agronomic Research (INRAE). This gives this “modified starch” that is found among the ingredients of many food products. A business where France is the leader.
A dozen starch modifications are authorized in Europe. Most are obtained by macerate in acid baths. These corrosive liquids, sometimes flammable, eat away at the bonds between molecules. “Acetylated” starch, for example, was immersed in acetic acid, the highly concentrated vinegar acid. This gives it a greater absorption capacity. If we then pour adipic acid, present in beets and also in the nylon industry, it is transformed a second time, into acetylated distarch adipate. And it swells less.
Manufacturers apply these chemical improvements to everything. They have enabled numerous innovations and the appearance of new products. “At the start, the industry did not make soft cakes, for example, because they dried in a few days, like at home,” explains Catherine Renard. To preserve softness, manufacturers add “stabilizers,” another line of additives, which help keep products moist by strengthening the bonds with water.
Acid baths
Using the same principle, factories modify fats to increase their emulsifying power and their ability to bind liquids. Otherwise, no mayonnaises or salad dressings. At home, the oil and vinegar end up separating, it’s less salesy. “In nature, certain fats form triglycerides: a glycerol molecule linked to three fatty acids. Manufacturers separate them to obtain mono and diglycerides of fatty acids. Smaller, more unstable particles, which attach more easily and sustainably to liquids”, describes Adem Gharsallaoui, professor at Lyon 1 University.
Fat can also be “hydrogenated”. “We inject hydrogen, we heat to hundreds of degrees, we add chemical catalysts and we thus manage to modify the nature of the bonds between the fatty acids,” continues Adem Gharsallaoui. This modification allows the fat to be preserved in solid form, like butter which does not. Enough to prevent the spreads from being too runny when it is hot. “But it also risks blocking the arteries because they form crystals more easily,” adds Adem Gharsallaoui.
Other production lines are responsible for exploiting the 2,000 components of milk. This is the case of Ingredia, a French giant whose processing site is based in Hauts-de-France, in Saint Pol sur Ternoise. “For us, 10% of our turnover comes from sales of bottles of milk. The rest is the extraction of ingredients, which cheesemakers or industrial chocolatiers, among others, order from us,” explains Sandrine Delory. , director of the cooperative. In its warehouses spread over 22 hectares, 400 million liters are processed each year.
When our investigation was announced, the cooperative insisted: even if, in these kitchens, the hum of the machines has replaced the arguments between brigades, these methods are “gentle and natural”. “We use small coffee filters, which are much more technical,” summarizes Sandrine Delory. “Our desire is not to do chemistry, but to use all the richness of milk to avoid waste and promote this living and fragile product on which it is difficult to obtain a margin and which deteriorates very much. quickly,” continues the manager.
Pre-chewed ingredients?
The company also uses enzymes, a so-called “organic” processing tool. These proteins, found in the mouth and stomach, break the chains of molecules, giving them new properties. The method, called “enzymatic hydrolysis”, allows the firm to obtain milk protein hydrolyzate. A patented “bioactive”, used to increase protein content. It also helps slow the absorption of certain ingredients – which makes it an additive of choice for athletes, the elderly or pre-diabetics.
These reactions must be stopped at the right time, to prevent the product from spinning: “You then have to heat it very hard, then get rid of the enzymes, by spinning the mixture very quickly in a centrifuge, a sort of giant salad spinner”, adds Catherine Renard, from INRAE. This same hydrolysis, carried out on starch, makes it possible to obtain the famous glucose syrup, one of the best known and most criticized processed ingredients. Shelled in this way, this sugar is accused of being “pre-chewed”, and of causing insulin to rise too quickly in the blood – which increases the risk of diabetes.
Among the additives with surprising origins, xanthan gum is in the lead. Less known than the cochineal, the worm causing red dyes, this thickener is produced from bacteria in culture, Xanthomonas campestris. These microorganisms are responsible for black rot on cabbage leaves. Their ‘slime’ produces a sort of gelatin, which must then be purified using isopropanol for example, a toxic solvent used in the manufacture of ink or varnish, which is then eliminated.
Molasses exploding
Manufacturers don’t just process additives. To give breakfast cereals, chips and snacks these attractive shapes, they grind wheat or potatoes into a molasses. This is then injected into a tube, in which an endless screw turns. The mixture is heated and pressurized. The water inside remains liquid well after 100°C. When the product comes out of the machine, it vaporizes suddenly and causes the dough to swell.
The technique, called “expansion cooking”, makes it possible to impose very varied shapes, otherwise impossible to obtain. But this can degrade the ingredients and taste. In this case, and to go quickly, manufacturers then add flavorings, natural or synthetic – also ultra-processed. To make industrial sausages, or nuggets, an extruder is preferred: the meat is pushed cold against a stopper and comes out as a mush, which is also easier to shape.
All these transformations allow the appearance of a host of new products on the shelves. But also give a false impression of abundance, regrets INRAE researcher Anthony Fardet. He was one of the first to document the harmful effects of processed food. “More and more, the industrial kitchen resembles a Lego game. We assemble hyper-standardized bricks that are much less rich and diverse than the raw materials used.” And slip: “Certain products are processed for the sole purpose of inflating nutri-scores”. Nothing is lost, nothing is created.
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