Different temperature treatment effects on the changes of the functional properties of beans (phaseolus)
2013
Strauta, L., Latvia Univ. of Agriculture, Jelgava (Latvia) | Muizniece-Brasava, S., Latvia Univ. of Agriculture, Jelgava (Latvia)
The experiment was carried out in the Latvia University of Agriculture. The objectives of this research were to study changes of bean (Phaseolus) protein fractions occurring under the thermal treatment conditions and determine the critical temperature for Maillard reactions in beans. In these reactions lignified protein is made from amino acids and sugars, and it decreases the nutrition value of the food. If lignified protein exceeds 50% of crude protein content in food, then food is considered unsuitable for daily diet. In this experiment beans were milled and then heated at 50 ± 3 °C, 75 ± 3 °C, 100 ± 3 °C, 125 ± 3 °C and 150 ± 3 °C temperature in the drying oven for 20 h. As a control sample non heated beans were used, and they all were kept in a plastic jar at room temperature (20 ± 1 °C). Dry matter, crude protein, starch, sugar and lignified protein content were determined in heated beans and control samples. No significant changes of crude protein content were observed due to thermal treatment. It was from 24.3 ± 0.3 g 100 g-1 of dry matter. Similarly, no significant changes were observed in starch content, as it stayed averagely 47.1 ± 0.2 g 100 g-1 of dry matter. Medium high correlation was observed (0.64) between lignified protein content and sugar content for in different temperature treated beans. Lignified protein showed exponential growth if the samples were heated at a temperature of 100 ± 3 °C and higher, giving exponential change.
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