Study of Brazilian beans: protein extraction and hydrolysis followed by phenylalanine removal.

摘要

Beans occupy an important place in the diet of Brazilian people, but their use by phenylketonurics is forbidden. This study aimed to reduce the phenylalanine (Phe) contents of bean (Phaseolus vulgaris) protein extracts, using activated carbon as a Phe adsorbent. Effects of initial pH, enzyme:substrate ratio, temp., type of proteinase and protein:activated carbon ratio were determined. Efficiency of Phe removal was assessed by 2nd derivative spectrophotometry. Phe removal varied from 25.4 to 87.9% and the final Phe content from 433.7 to 2679.8 mg Phe 100 g--1 hydrolysate. Use of a proteinase from Papaya carica led to the highest percentage of Phe removal (81.5%), and optimal values for enzyme:substrate ratio, protein:activated carbon ratio and temp. were 10:100, 1:88 and 50 degrees C, respectively. A pH of 8.4 was selected, since no adjustment was needed in order to initiate the hydrolytic reaction.