August 15/Mysore, India/Food Hydrocolloids -- In "Effect of hydrocolloids on the rheological, microscopic, mass transfer characteristics during frying and quality characterisitcs of puri," appearing online ahead of print in the journal Food Hydrocolloids, K.R. Parimalaa and M.L. Sudha of the Baking & Confectionery Technology Department Central Food Technological Research Institute, Mysore, CSIR, India, studied the effect of various hydrocolloids on puri from whole-wheat flour.

Effect of hydrocolloids such as guar gum (GG), arabic gum (AG), carrageenan (CG), locust bean gum (LBG), xanthan gum (XN), hydroxypropyl methylcellulose (HPMC) and carboxymethylcellulose (CMC) at 0.5% w/w level on rheological and quality parameters of puri from whole wheat flour was studied. Hydrocolloids like CMC, XN and HPMC increased the water absorption of puri dough, while it decreased in all other samples. The dough development time and mixing tolerance index values increased, while dough stability did not get affected. On addition of hydrocolloid, there was a reduction in the pasting temperature, while the peak viscosity, hot paste viscosity and cold paste viscosity values increased. Hardness, cohesiveness and adhesiveness properties of the puri dough increased with the addition of hydrocolloids. All the hydrocolloids used in general helped in retention of moisture in the puri and hence remained softer and pliable, while there was a significant reduction in the oil content of puri samples containing hydrocolloids. Among the different hydrocolloids used, addition of guar gum at 0.5% w/w level led to puris having improved quality characteristics to a greater extent with respect to moisture retention, lowering of oil content upon frying with softer and pliable texture and better keeping quality. The mass transfer studies confirmed that the mass transfer co-efficient values for moisture loss and oil uptake was lower in puris with guar gum than control.