The secret is the Maillard reaction! In 1912, Louis-Camille Maillard discovered that bread crust, coffee beans, beer and roasted meat all turned brown because of a chemical reaction between sugars and proteins they contained. But the reaction produced not only brown pigments, but it also produced flavours. Indeed, chemists soon made the first artificial flavour, that of maple syrup, by combining the amino acid serine with glucose.
If you want a tasty stew, brown the meat in hot oil to which a little flour has been added before adding any liquid. The Maillard reaction requires a high temperature, one that cannot be achieved if the stew ingredients are just plopped into the water. But, and isn’t there always a “but?” Heating sugars and protein also produces acrylamide, a carcinogen. However, in this case, the high heat is applied for a short time so the amount of acrylamide formed would be insignificant. In any case, acrylamide cannot be avoided. It is found in coffee, cereals, bread, chips and French fries.