Avaliação das condições de melhor estabilidade térmica para a recuperação da bromelina a partir de resíduos do abacaxi

Abstract

Aiming the bromelain recovery from industrialization residues of pineapple (pérola variety), we assessed the better pH conditions in which the enzyme is more stable over time, and under several temperatures. The assays were carried out measuring the enzymatic activity of the pure bromelain and of the extract of fruit residues, using casein as substrate. The extract was obtained by crushing the peel and core of the fruit. The activity was expressed as mmol tyrosina (L min.-1) through the absorbance at 280 nm of aromatic amino acids generated from the casein hydrolysis. Two pH ranges were studied: 5.5 to 6.5 and 3.3 to 3.5 and temperatures from 25 to 62°C. The inactivation parameter (ki) was determined plotting the activity as a function of time for each temperature. The thermal decomposition showed to be of first order and the activation energy higher for the fruit enzyme than the purified bromelain when the pH ranged from 3.3 to 3.5. A pH between 5.5 and 6.5 should be applied in order to recover the enzyme from the fruit residues, due to the negligible thermal decomposition in the studied temperature range (up to 62°C).