Now, let's talk about the color of alkaline pyrogallol. Pyrogallol is a yellow to white crystalline powder that is water-soluble and easily oxidized to darker colors. When pyrogallol is mixed with an alkaline solution, it turns dark brown or black due to the rapid oxidation of pyrogallol to polymeric products.
These polymeric products are known as melanoidins, which are a group of brownish pigments formed from the reaction between reducing sugars and amino compounds. The formation of melanoidins is a complex process that involves a series of chemical reactions, including the Maillard reaction, caramelization, and degradation of amino acids.
The Maillard reaction is a browning reaction that occurs when amino groups react with reducing sugars at high temperatures. The reaction produces a complex mixture of molecules, including melanoidins, which give the characteristic color and flavor to baked goods, roasted coffee, and grilled meats.
Caramelization is a non-enzymatic browning reaction that occurs when sugar is heated to high temperatures. The reaction produces a mixture of caramel-like compounds, including caramelans and caramelens, which contribute to the brown color and sweet taste of caramelized foods.
In summary, the color of alkaline pyrogallol is dark brown or black due to the formation of melanoidins, which are a group of brownish pigments formed from the reaction between reducing sugars and amino compounds. The formation of melanoidins is a complex process that involves a series of chemical reactions, including the Maillard reaction, caramelization, and degradation of amino acids.