A term for: When a taste or smell of a product is being concealed by another product

Solution 1:

Dominate

Usage:

Use in high concentrations causes the syrup flavour to dominate other flavours. Syrup tends to mask delicate flavours such as vanilla.

Reference, example found in Google Books: 'The Complete Technology Book on Flavoured Ice Cream' ASIA PACIFIC BUSINESS PRESS Inc., Jan 1, 2006

Credit goes to Jason Bassford in the comments