Detection and resource analysis of benzoic acids in milk by HPLC

Benzoic acid naturally presented in raw milk in a very low concentration.The benzoic acid content of milk was studied by HPLC,and the relationship of benzoic acid,milk acidity and hippuric acid was investigated in this paper.The results showed that the concentration of benzoic acid was lower than 1μg/mL,and the concentration of hippuric acid was 16.0μg/mL,when the acidity of raw milk was lower than 16°T.When the acidity of milk increased to 40°T,the concentration of benzoic acid increased to 1.65μg/mL,but the concentration of hippuric acid decreased to 12.91μg/mL.When milk acidity was 90°T,the concentration of benzoic acid reached to 9.09μg/mL,but hippuric acid could not be found in sour milk anymora.Sour milk had high benzoic acid content,and benzoic acid was converted by hippuric acid which naturally presented in milk.The milk powder showed the similar results.