Textural and structural breakdown properties of selected hydrocolloid gels

Abstract

Textural and structural breakdown properties of bovine serum albumin (BSA), starch, gelatin, and gellan gels were investigated using texture profile (TPA) and multiple extrusion cell (MEC) analyses, respectively. TPA was conducted under ambient conditions whereas MEC analysis was performed at 37°C with addition of artificial saliva. Each type of gel exhibited distinct textural characteristics and breakdown behaviours. Soft and hard starch gels could not be distinguished using the TPA parameters, however the force and work needed to rupture these gels differed significantly (P<0.05) during MEC analysis. BSA gel was the hardest, strongest, most elastic and required the highest amount of energy during the extrusion cycles as compared to other gels. Although the amounts of work done for BSA and starch gels during extrusions were similar, the breakdown of starch gel was faster due to the action of α-amylase in the artificial saliva. Gelatin gel was several times harder than gellan gel, but its breakdown was the fastest due to its susceptibility to melt at 37°C. TPA parameters provided information on textural properties of gels. However, MEC analysis provided additional information on the structural breakdown behaviours of the gels in conditions that resemble oral processing.