Effects of Polysaccharide Hydrocolloids on Dough Characteristics of Quick-frozen Raw-dough Sticks and the Quality of Deep-fried Dough Sticks

To systematically study the effects of seven common polysaccharide hydrocolloids （kappa-carrageenan (KC), Konjac glucomannan (KGM), sodium alginate (SA), arabic gum (GA), hydroxypropyl methylcellulose (HPMC), xanthan gum (XG), guar gum (GG)）on the properties of doughs in the production of quick-frozen dough sticks and the quality of deep-fried dough sticks before and after raw-dough quick-freezing, OPLS-DA cluster analysis, Pearson correlation were adopted to perform comprehensive analysis for physical, physicochemical and sensory properties. The research results revealed that polysaccharide hydrocolloids had significant effects on the hardness of kneaded dough (r=0.62, P=0.020<0.05) and cohesion (r=−0.48, P=0.023<0.05) of the fermented dough, but, there was no significant correlation between both properties (r=−0.27, P=0.22>0.05). Adding GA presented the greatest effect on the elasticity of fermented dough (P<0.05). Polysaccharide hydrocolloids significantly affected the crispiness (r=−0.43, P=0.044<0.05), cohesion (r=0.51, P=0.015<0.05) and taste (r=0.46, P=0.032<0.05) of deep-fried dough sticks. Significant correlations were found among the indicators of deep-fried dough sticks (P<0.05), and KGM, HPMC, GG, GA, KC, XG and SA had significant effects on the appearance and the taste (P<0.05). The indicators examined interacted with each other (P<0.05), and specific volume was related to the organizational structure (r=0.51, P=0.016<0.05), which was representative for evaluating the quality of deep-fried dough sticks. Based on cluster analysis, quick-frozen deep-fried dough sticks were divided into four categories (groups), 1.0% KGM, 1.0% KC, 1.0% GA, and 1.0% HPMC showed the largest specific volumes in their own groups (P<0.05). Before and after raw-dough quick-freezing, the specific volume of deep-fried dough sticks was not consistent (P<0.05), and that with KGM was significantly increased after quick freezing (P<0.05). Therefore, polysaccharide hydrophilic glue mainly affects the dough elasticity in the dough making process when quick-frozen deep-fried dough sticks green bodies were made and changes occur in the dough interior during the quick-frozen process, thus affecting the quality of deep-fried dough sticks.