Mineral losses in hot water- and microwave-blanched green and dry white beans

Abstract

The effect of microwave and conventional hot-water blanching upon selected mineral (calcium, copper, iron, potassium, magnesium, manganese, sodium, zinc) losses in green and dry white beans (Phaseolus vulgaris) was studied. The mineral content was determined by atomic absorption spectrophotometry. Microwave blanching resulted in significantly greater losses of calcium, magnesium and potassium, but in significantly greater manganese retention in dry white beans. Neither method resulted in significant mineral changes in green white beans. In practical terms, the microwave blanching treatment did not have the expected performance in relation to mineral retention when compared to the traditional hot-water blanching, thus suggesting that it may not be a viable alternative blanching method under all circumstances.