HFCS is made by enzymatically converting glucose in corn syrup to fructose, so it stands to reason that the product can have any glucose:fructose ratio needed. Since humans categorically taste fructose as sweeter than glucose, it makes sense that HFCS is tuned differently for different applications and in situations where the ratio is very far away from 1:1 I do contend that HFCS could taste different than sucrose. Perhaps it was unwise for me to assume that most HFCS used is close to the 1:1 ratio of sucrose.
"High fructose" corn syrup is "high" in fructose relative to normal corn syrup. Table sugar is naturally high in fructose already. The corn syrup you're suggesting is used in baked goods has less fructose than table sugar does.
Sucrose is a disaccharide formed from a glucose and a fructose molecule bound with an oxygen atom. in the presence of an acid (or in your stomach when you eat it) it will undergo hydrolysis and disassociate into its component sugars. Sucrose and high fructose corn syrup made in the same 1:1 ratio are from a practical standpoint, identical.
Table sugar is 50% fructose. That’s just basic chemistry, sucrose is a disaccharide that is trivially cleaved upon ingestion. I am confused by your confusion. How high does it need to be to be “high”?
You’re right, and I learned something. Sucrose breaks down into a 50/50 mix of glucose and fructose in the gut. It’s not 50% fructose until you eat it though…
HFCS is 42% fructose if it's in food, and 55% if it's in a can of soda, and in that can of soda sucrose is dissociated into glucose and fructose within something like a week of being canned, because the acid in the beverage breaks the bond too. There is simply no useful distinction to make between sucrose and HFCS.
High fructose corn syrup is called that because normal corn syrup has essentially no fructose, unlike table sugar.
HFCS used in soda is 55% fructose. HFCS used in e.g. baked goods is usually 42% fructose, so it can have lower fructose levels than sugar.