Structure development studies of soft gels using a dynamic U- tube rheometer of novel design

The process of structure formation of a series of food gels was studied using a patented U-tube rheometer of novel design. The instrument has been especially designed and developed to determine the shear moduli of very weak and syneresing gels, particle contained gels and foams. The rheometer is fully automatic and operates in both static and oscillating modes. The performance of the instrument was assessed by monitoring the development of the shear modulus in relation to time of gelatinised maize starch aqueous dispersions ranging in starch concentration from 6% to 12% (dry basis), gelatine gels with gelatine concentrations ranging from 2% to 12%(dry basis) as well as of native set yogurt and kefir gels. An important asset of the design is that it allows measurements to be performed on liquids as thin as water yet having the maximum strain within the limit of linear viscoelasticity. This allows a gel formation process to be monitored right from the start when the sample is still in the state of a liquid up to the point of the formation of a true gel. Another important asset of the instrument is the modular design of the sample holder allowing easy access for cleaning which moreover is fully detachable from the main body of the instrument so the sample it contains can be pretreated in an environment (heating or freezing) other than that it will eventually be measured.