Study On Effect Of Potato Flour On The Quality Of Frozen Dumplings

With high starch content and good freeze-thaw stability, potato flour can be widely used in frozen dumplings. This study researched the effects of potato flour on the quality of frozen dumplings, and changes of texture and quality during frozen storage by texture Analyzer, DSC, low-field NMR, dynamic rheometer, and scanning electron microscopy.First of all, we studied the effects of processing conditions on the quality of frozen dumplings and found that potato flour can significantly reduce the cracking rate of frozen dumplings, increased the toughness of dumpling skin and hardness of cooked dumpling skin, shear and extensibility decreased, cooking loss rate slightly higher. Obtained by orthogonal experiment, the optimal combination of process is: potato flour addition 15%, water 46%, and mixing time 10 min, salt addition 1.0%.Secondly, compared with wheat flour dumplings, the quality of potato flour dumplings was studied during frozen storage. Study has found that increasing in water loss rate of frozen potato flour dumplings is not obvious, and there is no change in cracking rate after long-term frozen storage; hardness of TPA, shear, and toughness increased gradually. Frozen water content was studied by DSC. It is turned out that with extension of frozen storage, frozen water content gradually increased, but the frozen water content of potato flour dumpling skin is always less than the wheat flour dumpling skin. The microstructure of frozen dumpling showed that gluten network structure of potato flour dumpling skin was destroyed in a lesser extent.There are two states of water in frozen dumpling skin by measuring transverse relaxation time T2 with NMR: intermediate water and free water, respectively. Relative area of intermediate water A21 increased, relative area of free water A22 reduced, and the water mobility of potato flour dumpling skin was less than wheat flour dumpling skin. Along with prolonged frozen storage time, wheat flour frozen dough's and potato flour frozen dough's storage modulus and viscous modulus decreased,while loss angle tangent increased. To sum up, during frozen storage, potato flour can inhibit the damage of internal structure of frozen dough.Finally, study on characteristics of wheat starch and potato starch showed that, compared with wheat starch, potato starch has a lower peak viscosity, lower gelatinization temperature. And holding capacity is much higher than wheat starch under non-freezing and freezing conditions, therefore potato starch has good freeze-thaw stability.