[Determination of aluminum in foods]

In connection with studies on the changes of functional properties of food constituents (e. g. solubility of proteins) by means of aluminium compounds, the elaboration of an appropriate method for the quantitative determination of aluminium has been necessary. The organic samples are mineralized with 80% perchloric acid; in case of fat-containing foods, after fat removal. After reaction with aluminon (ammonium salt of aurin tricarboxylic acid), aluminium is determined photometrically at 530 nm. The limit of detection lies between 1 and 2 ppm; the recovery rate is 103%; the standard deviation is +/- 10%. The determination (without mineralization) requires about 1 hours. The authors analyzed, inter alia, milk (1.2--1.7 ppm A1), fat cheese (9 ppm), micora (4 ppm), aluminium-stabilized protein texturates (300--1500 ppm).