Quality changes of donuts as influenced by leavening agent and hydrocolloid coatings

Abstract

The effect of two edible coatings, methylcellulose (MC) and gum tragacanth (GT) in<br><br>combination with two kinds of leavening agents, yeast and baking powder were<br><br>examined on quality properties of donuts. Dough surface were coated with hydrocolloid<br><br>solutions (1% w/w) then fried at 150C. GT and MC coatings significantly<br><br>(P &lt; 0.05) reduced oil uptake up to 33.00 and 24.74%, respectively. Fermented<br><br>donuts had significantly lower oil content than cake donut, which is about 9.96%,<br><br>while coating and leavening agent had no significant (P &gt; 0.05) effect on moisture<br><br>content of fried donuts.Crust color increasedwith frying time and density decreased<br><br>during first minuets of frying time. Results of sensory evaluation showed there was<br><br>no significant difference between coated and uncoated donuts. However, yeastraised<br><br>samples significantly (P &lt; 0.05) had highest score on the appearance, porosity<br><br>and uniformity of pores in comparison with cake donuts.