TBHQ, which stands for “tertiary-butyl hydroquinone”, is both used as a preservative and antioxidant in fats and oils to protect against oxidative deterioration or rancidity, and therefore extend storage stability. This ingredient is fat-soluble and especially effective for unsaturated vegetable oils with the European food additive number E319.
http://www.chinafooding.com/Tert-Butylhydroquinone-TBHQ
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