Yep. You can use NMR spectroscopy to detect the molecular structure of the sugars (in wine and fruit juice) and they are quite different. So different that it is possible to find the region of origin or the grape variety. See this PDF of the wine screener.A dealer on Audiogon once tried to make a wine analogy to me about audio measurements. He said that wines are all the same chemically, but taste different. This (the chemical part) is, of course, completely false.
This method has been used to detect economic subsidy fraud committed by spanish orange juice makers. They imported cheap oranges from South America and labeled the bottles as Spanish to get economic subsidy from the EU.
As a side note: Imagine someone measuring hundreds of wine bottles to build up a data base of NMR spectra for the purpose of detecting the grape variety, the region of origin, and others. The method requires about 10 ml per bottle. So every day we were greeted with a bunch of opened bottles to get rid of...