Thermal sensitivity of some plantain micronutrients during deep-fat frying

Potassium reduction in food by preparation technique for the dietetic management of patients with chronic kidney disease: a review

BACKGROUND

Chronic kidney disease patients often use food preparation techniques to reduce potassium intake. However, the most effective techniques have not yet been determined for all food groups. The present study aimed to analyse all of the available information on potassium reduction in the food and identify the best preparation techniques by comparing the trend of change in potassium level.

METHODS

Nine databases were searched from 1976 to May 2020, according to the PRISMA Statement. We included all articles reporting the amount of potassium before and after the application of food preparation techniques. Data were analysed using the Wilcoxon test and statistical simulation.

RESULTS

A wide variety of food and culinary processes was observed in the 65 included articles. Cooking in water, pressure cooking and cooking in a microwave oven reduced potassium levels in all food groups, particularly in cereals and derivatives, fruits and derivatives, meats and derivatives, legumes, and leafy and cruciferous vegetables. Soaking food significantly reduced the potassium content in tubers and roots and leafy and cruciferous vegetables. Steam cooking and dry heating cooking also reduced potassium, although at a level lower than the other techniques.

CONCLUSIONS

The present review shows that, in general, all food preparation techniques can reduce the potassium content, although cooking in water and soaking promotes a greater reduction; however, more studies with standardised techniques and complete data are necessary.

Overnight soaking or boiling of "Matooke" to reduce potassium content for patients with chronic kidney disease: does it really work?

BACKGROUND

There is an increase in number of patients with chronic kidney disease (CKD) in Uganda's health facilities looking for different options of preparing matooke (bananas), their staple food.

OBJECTIVE

To establish and evaluate an effective method of removing potassium from bananas (matooke).

METHODS

Bananas were sampled from 5 markets in Kampala, Uganda. Deionized water was used to soak the bananas and the potassium concentration was determined using an atomic absorption spectrophotometer in both the bananas and water after soaking for varying time intervals. We also determined the potassium concentrations in the bananas and the water after boiling the bananas at 200 degrees Celsius at intervals of 10 minutes (for 60 minutes).

RESULTS

The potassium concentration did not appear to change on soaking alone without boiling. However, on boiling, the concentration in the bananas decreased from about 1.4 ppm to approx. 1 ppm after 60 min; yet the concentration of potassium released into deionized water increased steadily from 0.0 ppm to about 1.2 ppm after 60 min of boiling.

CONCLUSION

This study demonstrates that boiling the bananas is a more effective way of removing the potassium from bananas than simply soaking them.

Kinetics of anthocyanin degradation and browning in reconstituted blackberry juice treated at high temperatures (100-180 degrees C)

Monomeric anthocyanin degradation and nonenzymatic browning (NEB) index have been determined in reconstituted blackberry juice heated at high temperature in a hermetically sealed cell. Statistical analysis demonstrated that, when the temperature range (100-180 degrees C) was divided into two subranges (100-140 and 140-180 degrees C) for anthocyanin degradation, reaction kinetics were well represented by two sequential first-order reactions. The activation energy for NEB from 100 to 180 degrees C (106 kJxmol(-1)) was slightly higher than the anthocyanin value at the lower temperature range (92 kJxmol(-1)), but was more than twice the value for the higher range (44 kJxmol(-1)). The reaction rate constant at 140 degrees C for anthocyanin degradation (3.5 x 10(-3) s(-1)) was two times that for the NEB index (1.6 x 10(-3) s(-1)). Hence, anthocyanin degradation was faster than the appearance of NEB products. The non-isothermal method developed allows estimating kinetic parameters and thereby generating temperature profiles of heat processes that would help preserve the nutritional properties of foods during high-temperature processes.