noun
adulterant
uh-DUL-ter-unt/əˈdʌltərənt/
A substance added to another that reduces its purity or quality.
The sawdust becomes an adulterant when it is mixed into the flour.

Etymology
The participial form of adulterare describes something that corrupts or falsifies. Used as a noun, it identifies the substance doing the corrupting: an improper addition that lowers purity.
In context
the fraud often involves expensive products like saffron for instance that's why the spice is regularly examined by chemists adulterant such as chalk powder or starch are added to bulk up the product
More examples
- Inspectors test the spice powder for cheap adulterants.
- The added water acts as an adulterant in the milk.
- The report identifies the adulterant that reduced the product's quality.
Forms
adulterant · adulterants
adulterate verb — To make impure by adding inferior material.
Similar words
- contaminant
- May enter accidentally rather than being deliberately mixed in.
- additive
- Can improve a product rather than reduce its purity.