Antioxidant of propyl gallate

The gallates used as food antioxidants include propyl, octyl and dodecyl esters of gallic acid. Propyl gallate (n-propyl-3,4,5-trihydroxybenzoate) is used in vegetable oils and butter. It is also used as antioxidant in ethers, emulsions, waxes and transformer oils.

This antioxidant is used to prevent rancidity in meat products such as rendered fats or pork sausage.

Structure of propyl gallate

It is an effective antioxidant for shelf-life improvement of vegetable oils at usages levels of 100 to 200 ppm, or the FDA and USDA permitted levels; however, its usage is hampered by solubility problems, discoloration and poor heat stability.

Propyl gallate is less soluble in fats and oils than BHA and BHT and has significant solubility in water. The low oil solubility of propyl gallate makes this antioxidant difficult to incorporate into fats and oils and its solubility in water makes it more likely to complex with iron and iron salts, which causes dark discoloration in some applications.
Antioxidant of propyl gallate