On the determination of phosphorus in some processed fruit products by wet-digestion and dry-ashing methods ? a preliminary report

Abstract

Although wet-digestion and dry-ashing procedures are sometimes classified on the basis of their applicability to plant or animal materials, it is shown that different materials depending on their composition behave differently on oxidation by these procedures. Predigestion with concentrated nitric acid appears to give higher values of phosphorus in tomato pastes than the other conventional digestion procedures. An optimum nitric acid predigestion time appears possible for the pastes. For orange juices the level of phosphorus estimated is essentially independent of the oxidation procedure. Addition of ash-aid does not have any significant effect on the level of phosphorus obtained for these samples by dry ashing.