Avaliação do efeito do pH na adsorção de proteínas do leite em bagaço de cana-de-açúcar

Abstract

The adsorption is a common operation in the industries and has as objective the separation and purification of chemical compounds, being, therefore, a mass transfer process. Thus, adsorption is understood as an operation where there is the enrichment of a certain compound (adsorvate) in the surface region of a material (adsorbent). Recent research shows the increasing use of plant residues as adsorbents. Among these residues, sugarcane bagasse, due to its high availability and high surface area, is an excellent candidate for adsorption operations. The treatment of whey is of interest, as this mixture has a high polluting potential and is rich in proteins. Today, 50% of whey is used in the food industry, but there is still in Brazil its disposal as effluent. The main proteins present in the whey, known as homo proteins, are BSA (bovine serum albumin) and alpha-lactalbumin (α-La) and beta-lactoglobulin (β-Lg). The objective of this work is to evaluate the effect of pH of the solution on the adsorption capacity of these proteins in sugarcane bagasse. 100% Whey Protein solutions, buffered with citric acid and sodium citrate based buffer, at different pH (4.0, 4.5, 5.0, 5.5) were used to construct the curves of calibration. The results show that the pH of the solution influences the calibration curve which indicates variation in protein conformation. The pH of the solution was also shown to be a fundamental variable in the adsorption of milk proteins in sugar cane bagasse.