Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Nutrition, Dietetics, and Food Sciences

Department name when degree awarded

Nutrition and Food Sciences

Committee Chair(s)

Deloy Hendricks


Deloy Hendricks


Compliance with the strict dietary regimen for the dialysis patient can be very challenging. Many foods are limited from the diet of a renal patient because of the high potassium content. The physiological consequences of failure to follow a diet prescription can be fatal for the dialysis patient. In an effort to improve patient compliance with nutritional protocols, several potato cooking methods and centrifugation of tomato sauce were investigated for their effects in reducing potassium content.

All methods with a 24-hour soak were found to be significant in reducing potassium content of potatoes (P < 0.05). However, some of the methods in which the potatoes were not soaked were also found to be effective in reducing potassium content. Slice thickness and volume of cooking water used were found to be two important factors in determining potassium loss. The 4-mm sliced potatoes, which had a mean potassium value of 84 mg/100 g, lost more potassium than the 8-mm potatoes with a mean potassium value of 182 mg/100 g (P < 0.05). Furthermore, the potatoes cooked in 10 times the amount of water lost more potassium (124 mg/100 g) than those cooked in only 5 times the amount of water (148 mg/100 g) (P < .005). Soaking in cold versus hot water, agitation of the soak water, or the addition of chemical chelators to the soak water were not shown to be any more effective in reducing the potassium content than the other methods. Sensory data indicated that participants did not have a strong taste preference for potatoes cooked by any one particular method (P < 0.05).

Centrifugation of tomato sauce, and retention of the solids were found to be effective methods for reducing the potassium content of tomato sauce. There was, however, a significant difference (P < 0.05) in the participants' taste preference for the tomato sauce that was centrifuged one time versus the tomato sauce that had been centrifuged twice.

The results of this study are significant because they suggest that there are more effective, alternative methods for preparing potatoes and tomato sauce than those that are currently being used. This would suggest an increased likelihood for patient adherence to nutritional recommendations.