Search: highly fermented

The energy or caloric value of beer is calculated according to Council Directive 90/496/EEC and is based on the amount of protein, carbohydrate, alcohol, glycerin and organic acids. For performing the calculation, caloric values are attributed to 1 g of each of the following: 17 kJ (4 kcal) of protein or utilizable carbohydrate, 29 kJ (7 kcal) of ethanol, 13 kJ (3 kcal) of organic acid, and 10 kJ (2.4 kcal) of higher alcohols. (Fat is not included in the calculation for beer.)

Calculations made on this basis demand a significant amount of analytical effort.

A simpler approach, which also suffices for routine analysis, is the calculation from the alcohol content (A) and real extract (E_R) [1, 2]:

Fruit juices

The positive effect of fermented beverages on the human body has been known for centuries. Current beverage trends, like kvass (Russia) and kombucha (Asia), stem from traditions with roots deep in the past. They have always been consumed as healing beverages. Non-alcoholic forms of fermentation employ microorganisms, such as lactic and acetic acid bacteria. They produce organic acids like lactic acid and gluconic acid, which promote digestion and metabolism. Due for the most part to their slightly acidic flavor, these kinds of fermented beverages are popular with consumers as a healthy natural refreshment.

Malt, fruit juice and tea serve as a base for fermented beverages.

As a rule, fermented beverages contain 0.5 – 15 g/l D-gluconic acid.

D-gluconic acid is phosphorylated by adenosine 5'-triphosphate (ATP) in the presence of gluconate kinase to gluconate-6-phosphate

 D-Gluconate + ATP \(^{\underrightarrow{\text{gluconate kinase}}}\) D-gluconate-6-P + ADP

The enzyme 6-phosphogluconate dehydrogenase (6-PGDH) catalyzes the oxidation of gluconate-6-phosphate to ribulose-5-phosphate with nicotinamide adenine dinucleotide phosphate (NADP): 

D-Gluconate-6-phosphate + NADP⁺ \(^{\underrightarrow{6-PGDH}}\) ribulose-5-phosphate + NADPH + H⁺ + CO₂

The amount of NADPH formed during the reaction is proportional to the amount of D-gluconic acid.

Beer or wort is fully attenuated under agitation in an Erlenmeyer flask after yeast has been added. From the difference between the extract content prior to fermentation commencing (original gravity) and after fermentation is complete, the limit of attenuation is calculated.

Real extract minus apparent extract of the fully attenuated beer (from which the alcohol was removed) yields the value for “apparent attenuation”, because during the final stages of attenuation alcohol is produced.

The portion, which has actually been fermented, can be calculated through multiplication by the factor 0.81. This factor is related to the so-called attenuation quotient q [1].

The energy value or caloric value of beer is calculated according to Council Directive 90/496/EEC and is based upon the amount of protein, carbohydrate, alcohol, glycerin and organic acids. For performing the calculation, caloric values are attributed to 1 g of each of the following: 17 kJ (4 kcal) of protein or utilizable carbohydrate, 29 kJ (7 kcal) of ethanol, 13 kJ (3 kcal) of organic acid, and 10 kJ (2.4 kcal) of higher alcohols. (Fat is not included in the calculation for beer.)

The dextrin content is calculated through multiplication of the difference between the total glucose content and the fermentable extract by a factor of 0.915.

The carbohydrates are calculated as a sum of the fermentable extract as determined through an analytical method and through the calculated value for dextrins according to B-420.43.999 Berechnung der Dextrine.