Structure and Functionality of Whey Protein Concentrate-Based Products with Different Water Contents

Abstract

Properties of different heated mixtures of whey protein concentrate, starch, gelatin, and sucrose with different water contents were studied. The water activity of samples was determined. The structural properties were analyzed by confocal laser scanning microscopy, solubility assays in different extraction solutions, polyacrylamide gel electrophoresis, and differential scanning calorimetry. Color, texture, and water-holding capacity of samples were also determined. Results show that a certain water content it is needed to form a structure with solid characteristics in these mixtures. The temperature for starch gelatinization is lower than the temperature for whey proteins denaturation, but when sucrose is present, whey proteins are denatured, before the gelatinization of starch. Sucrose is major contributor to the adhesiveness of the samples and to the decrease of their water activity. Also, sucrose decreases the firmness and cohesiveness of the samples. The main component that contributes to the browning of the samples during the heat treatment is whey protein concentrate, whereas starch is the main component responsible for the water-holding capacity in these samples. Gelatin does not modify appreciably the properties of the mixtures in the proportion used in these assays.