Glucose fructose kit

In the wine industry, sugar concentration is determined to establish the technological maturity of grapes, to follow fermentation trends, to assess the effect of adding concentrated musts and to determine sugar residues. Furthermore, the dosage of sugars for refermentation is common practice in sparkling wine production. 
Glucose is the simple sugar most commonly found in grapes and is the elective substrate for the energy metabolism of yeasts and many other microorganisms. It differs from fructose in that it has an aldehydic function (more reactive) and a lower sweetening power as far as sensory analysis is concerned. It also represents the aglycone for many volatile aromatic compounds and anthocyanins. A few g/l of glucose in wine may represent the energy source for possible bacterial development; for stabilised and finished wines, it confers sweetness and roundness. Therefore in oenology it is more appropriate to discriminate simple sugars individually and the enzymatic method is identified as the official method for such determinations.
Glucose and fructose represent the fermentable sugars in must (on average 200 g/l), both of which are metabolised by yeast during alcoholic fermentation. The residual sugars give, in the order of a few g/l, sweetness to the product but at the same time represent the energy source for any undesirable bacterial development. In general, alcoholic fermentation is considered complete when the fermentable sugar content is less than 2 g/l.