There must be something in the processing of canned/tubed ginger & garlic puree's (other than garlic and ginger) that reduces both the flavour and aroma. I personally hate frying with either as it tends to spit like hell in hot oil. This I think is due to the additives and other impurities (vinegar?). Some brands are worse than others.
When I make a curry with processed purees, I now mix the puree into a the oil before adding to the hot pan which reduces the spitting (mess). If I use freshly made garlic or ginger paste this doesn't happen and I can add it directly to the hot oil .. so there must be a difference between the fresh and canned/tinned. It also smells different when cooking.
Many garlic pastes and purees use reconstituted garlic. I guess both taste and aroma is affected during the manufacturing process.
SnS