Avaliação da redução de potássio em hortaliças submetidas a diferentes métodos de cocção para possível utilização na dietoterapia renal

Abstract

Objective: This study assessed the concentration of potassium in raw and macerated raw vegetables and vegetables cooked by different methods - boiling, microwave and pressure-cooking - to verify if maceration and different cooking methods can effectively reduce the concentration of this mineral. Methods: This experiment had a random 3x5 factorial design (3 vegetables x 5 procedures) and the analyses were repeated 3 times. Flame photometry was used to determine potassium concentration in raw, soaked, boiled, microwaved and pressure-cooked potatoes, carrots and broccoli. Results: Potassium concentration in soaked (232.2mg/g), boiled (197.3mg/g), microwaved (170mg/g) and pressure-cooked (187.2mg/g) potatoes and soaked (315.0mg/g), boiled (309.9mg/g), microwaved (243.3mg/g) and pressure-cooked (210.6mg/g) carrots did not differ significantly. On the other hand, potassium concentration in microwaved (280.1mg/g) and pressure-cooked (167.3mg/g) broccoli was significantly different from that found in soaked and boiled broccoli. Therefore, microwaving and pressure-cooking reduce the potassium concentration in broccoli more effectively. Conclusion: Maceration and the different cooking methods were effective in reducing the concentration of potassium in the studied vegetables. However, other factors such as cooking length, temperature, type of container and microwave frequency and power level may also affect potassium concentration.