Effect of roasting on Brown Coffee Powder

When roasted, raw beans contain sucrose and sugar to melt into caramel. It mainly affects the color of roasted coffee; the pentosan contained in coffee beans is partially degraded to produce uraldehyde during roasting, which makes roasted coffee have a special grain aroma. In the roasting process, the formation and decomposition of acids occur at the same time, about 7% of chlorogenic acid contained in raw beans is destroyed by 1/3 or even 1/2; acetic acid is lost, its content is nearly 0.4%; this makes the pH value of coffee powder about 5.1, add 1 gram, make sour taste softer and taste less salty. In the roasting process, the nonvolatile components of coffee are converted into volatile components, such as fatty acids and lipids decomposed into aliphatic hydrocarbons, N-methyl nicotinic acid inner salts converted into nitrogen-containing compounds, high terpenes decomposed into monoterpenes, etc. This gives roasted coffee a special flavor.

Raw beans contain about 13% protein, peanuts contain about 27% protein, egg protein 13%-15%, due to the effect of high heat protein structure changes, such as peptide hydrolysis, amino bond denaturation and the formation of new covalent isopeptide bonds, hydrolysis release methyl sulfate and methyl mercaptan. Fragrance is better. Due to high temperature, moisture content, salt, pH value, add eggs will immediately solidify, roast coffee beans must be quickly stirred, so that add eggs less and smaller lumps.

Aroma produced by roasted peanuts contains carbonyl compounds. Special aroma components include pentapyrazine compounds and N-methyl pyrrole. Among them, a-arachidin provides special aroma for fried peanuts. Peanut contains 47% peanut oil, is a non-drying oil, the most difficult polymerization, does not affect the color of coffee.

Volatile substances and other substances produced in the roasting process of peanuts and eggs make up for the defect that there is no specific flavor after roasting of a single variety of coffee, so that the flavor of coffee is mellow and thick.