Application of Xanthan, Guar and Psyllium gum in Iranian yoghurt drink (doogh) to increase in stability by fluid gel technology

Doogh is a native fermented dairy drink in Iran and has an important share in beverage industry.Phase separation is an undeniable phenomenon which takes place in acidic dairy drinks involvingDoogh. In this study fluid gel technology was used to improve the stability and suspendingproperties. Guar gum, Xanthan gum and psylium gum were employed. Different gumsconcentrations (0.01, 0.03 and 0.05%w/w) and hydration temperature of hydrocolloids (70, 80 and 85)with total solids standardized as 5% (w/w) of final product were used. Hot hydrocolloid solutionswere added to partial diluted Doogh while shearing it to produce fluid gel. Flow behavior, particlesize distribution, microstructure and serum separation were measured. Guar causes a high apparentviscosity at low shear rates, with significant impact on the flow It changes in the microstructure andparticle size. Also, it reduced the volume of separated serum. Guar enhanced the stability throughnetwork formation and trapping of particles. Xanthan and psyllium also had an impact on the flowbehavior and properties of colloidal particles, but were less effective than Guar. Xanthan andPsyllium particles increase doogh stability with developing a repulsive force, but larger particleswere deposited. Yield stress was observed in the samples and the extrapolation method was basedon the amount of Herschel Blackley. In general, samples containing guar caused higher yield stress.

کلیدواژه ها:

doogh ، phase separation ، rheological properties ، hydrocolloid ، guar