I'm not sure what you are asking, but i hope this provides what you want to know. Sucrose (aka cane sugar) is made up of a double molecule of glucose and fructose. So it is 50% fructose and 50% glucose. Glucose is the universal fuel that most living creatures use to supply their bodies with energy. Fructose is the bad guy, as you know from your reading of David's books.

Dextrose is a commercial name for glucose. Most of the "good" sugar in the home brew section of the supermarket is called dextrose. When buying it just watch out for unusual additives to the glucose as some of them are not suitable.

i hope this answers your question. if not please try again.