The Effect of Various Boiling Conditions on Reduction of Phosphorus and Protein in Meat

Abstract

Objective: Dietary phosphorus restriction and intake adequate amount of protein play a prominent role in control of hyperphosphatemia and prevention of protein-energy malnutrition for chronic kidney disease (CKD) and dialysis patients. To reduce dietary phosphorus intake, we focused on boiling, which can affect the bioavailability of nutrients by changing mineral solubility and breaking down food structure. The aim of this study was to assess the effect of boiling on the phosphorus and protein content of beef. We boiled beef in differing fluid mediums, varied the size of the meat, method of boiling and cooking time, and compared the effects on phosphorus reduction.

Design and methods: We evaluated the retention values of phosphorus, protein, and phosphorus to protein ratio in beef before and after boiling. We used differing fluid mediums (soft water, hard water, 5% solution of acetate, and 0.5% sodium bicarbonate water), varied the size of the meat (block, sliced, and cubed), different boiling methods (normal pan and pressure cooker [PC]), and different cooking time (10 and 30 minutes).

Results: The soft water sample had lower phosphorus to protein ratio compared with the hard water, 5% solution of acetate, and 0.5% sodium bicarbonate water sample. The phosphorus content of the sliced meat sample at 30 minutes was almost half the content of the uncut block of sample at 10 minutes. The block PC sample for 10 minutes had a phosphorus content almost equal to the block normal pan sample for 30 minutes. Moreover, the sliced PC sample at 30 minutes had the lowest phosphorus to protein ratio of all the samples.

Conclusions: Our results show that boiling with soft water, sliced food and a PC is the preferable cooking procedure for chronic kidney disease and dialysis patients because it allows for a reduction of the phosphorus content while preserving protein content, and it would bring the suppression of protein-energy malnutrition.