Improvement Of Baking Qualities Of Whole Wheat Saltine Crackers And Determination Of The Mechanism Of Water Migration

Whole wheat flour is riched in protein, dietary fiber, vitamin, minerals, polyphenol, andphytochemicas. In recent years, with the whole wheat food go into the customers’ heartsdeeply, the whole wheat crackers becoming a novel products as nutrient, health, convenientare accepted by more and more people. In this study, the formula and processing craft ofproducing whole wheat saltine crackers and barley saltine crackers were optimized,respectively. Also, the stack weight, stack height, specific volume, and breaking strength weremeasured to evaluate the baking quality of end products. The results of quality evaluation ofwhole wheat saltine crackers showed that the whole wheat flour had a detrimental effect onthe baking quality attributes of whole wheat saltine crackers, especially in reducing the ovenspring of the end products. Therefore, the endoxylanases, vital wheat gluten, and arabic gumwere utilized to improve the baking quality of whole wheat saltine crackers; arabic gum, guargum, and xanthan gum were employed to modify the baking quality of barley saltine crackers.In addition, the effects of these modifiers on the physicochemical characteristics andrheological properties of whole wheat flour were observed. Finally, the low-field nuclearmagnetic resonance was performed to determine the water migration in whole wheat doughsystem. The LF-NMR data proved that the mechanism of resulting in inferior baking qualityof whole wheat saltine crackers was the water competition between arabinoxylans matrix andgluten-starch network in whole wheat dough system. The gluten network was unable to formdue to lack of water, which led to reduce the puffiness of whole wheat saltine crackers sincethe weak gas retention ability of dough.The stack weight, stack height, specific volume, and breaking strength of whole wheatsaltine crackers were all reduced with increased the addition levels of whole wheat flour. Thestack weight and breaking strength were increased, and the stack height and specific volumeof barley saltine crackers were reduced with increased the addition levels of whole barleyflour. With increasing the addition levels of whole wheat flour, the water absorption of wholewheat cracker flour, the P and P/Lvalues, G′′modulus of whole wheat dough, and proteinweakening were all increased, and L and W values, G′modulus were reduced. Besides, thegeltinization rate and retrogradation rate of starch were reduced by the whole wheat flour.The W-SRC, Suc-SRC, P, and P/L values were reduced, and L value of whole wheatflour was increased with the presence of endoxylanases. With increased addition levels ofarabic gum, the SRC values, P, W and P/L values were reduced, and L value of whole wheatflour was enhanced. The P, L, W values of whole wheat dough and the stack weight, stackheight, specific volume, and breaking strength of whole wheat saltine crackers were allincreased with the presence of vital wheat gluten. The G′and G′′moduli of whole wheatdough were increased with increased addition levels of endoxylanases, vital wheat gluten, andarabic gum. The stack height and specific volume of whole wheat saltine crackers wereincreased with increased addition levels of endoxylanases and arabic gum. The optimum of combined modifiers of whole wheat saltine crackers is:0.035%endoxylanased,1.5%vitalwheat gluten, and1.5%arabic gum.Arabic gum reduced the SRC, P, W values, and protein weakening of barley cracker flour,and increased the L and P/L values of barley cracker flour and stack height and specificvolume of barley saltine crackers. The SRC, P, P/L values of barley cracker flour wereincreased, L and W values of barley cracker dough and stack height and specific volume ofbarley saltine crackers were reduced with the presence of guar gum and xanthan gum. Thegeltinization rate and retrogradation rate of starch in barley cracker flour were all reduced bythe arabic gum, guar gum, and xanthan gum.With increased the particle size of whole wheat flour, the dilute and shearing effects onwheat gluten network were enhanced. The content of α-helix， β-sheet， β-turn, andβ-anti-parallel of whole wheat dough were reduced, and the content of random coil wasincreased. In T2relaxation time distribution curve, peak T21represents the water absorption ofAX matrix, T22represents the water absorption by gluten-starch network, and T23is free water.The RT21of whole wheat dough was reduced, and RT22was increased by the endoxylanasesand arabic gum. RT23changed insignificantly. After dough resting, the peak T21and T22wereshifed left with the presence of endoxylanases and arabic gum. Resultes of Low field-NMRshowed that the water was migrated from arabinoxylanas matrix into gluten-starch networkunder the action of endoxylanases and arabic gum.