What factors determine the carbohydrate content of coffee

What factors determine the content of carbohydrates in coffee

Low molecular weight sugars:

Sucrose is the most important free sugar in raw coffee beans, and its content varies according to variety, source and maturity. Generally speaking, Arabica coffee beans contain more sucrose than Robusta coffee beans, and other simple sugars, including reducing sugars, can also be detected in the extract of raw coffee beans. Raw coffee beans also contain glucose and fructose, the content of Arabica is lower than that of Robusta, and the total reducing sugar of Arabica is also lower than that of Robusta.

After roasting coffee beans, the changes of low molecular weight sugars vary according to the degree of roasting, the loss of sucrose is the fastest, the loss rate of light roasting is 97%, moderate roasting is 99%, heavy roasting is 100%. Others, such as glucose, fructose and arabinose, also have considerable losses.

Polysaccharides:

Polysaccharides are very important components in raw coffee beans, accounting for about 40% ~ 50% of dry matter. According to the type, there are polygalactose, polyicoses, polyarabinose and cellulose, which are the substances that make up the plastids of coffee beans and are related to the hardness of coffee beans.

After roasting, polysaccharides will still be preserved in a considerable amount. According to the data obtained from a study, it is found that there is not much difference among different roasting degrees, and the retention rate is between 70% and 75%, among which the retention rate of cellulose is the highest and that of polyarabinose is the lowest. In terms of extraction, some polysaccharides will be extracted, depending on the type of solvent. When extracted with water, more polysaccharides are extracted from arabinose, galactose and some mannose.

Organic acids:

When making coffee, the performance of acidity is very important. under good conditions and skills, a special taste with fresh acidity can be developed, which is a necessary condition for high-grade coffee. Generally speaking, the more deeply roasted coffee beans, the less sour development, or even none, and show another kind of pure coffee characteristics.

Non-volatile acids in raw Arabica coffee beans include citric acid, malic acid, oxalic acid and tartaric acid. After testing, a large number of volatile acids were not found. When raw coffee beans are roasted, the content of acid changes greatly, among which the change of volatile acid is the biggest. After roasting, the loss rate of acid in raw beans is about 15%, and what is more noteworthy is the chemical change of acid. Formic acid and acetic acid increased at the initial stage of roasting, and increased with the increase of roasting degree. Until the end of roasting, citric acid and malic acid showed a decreasing trend, while citric acid and malic acid decreased gradually to form their decomposition products.