Effects Of High Hydrostatic Pressure Treated Starch On The Rheological Properties Of Starch-gluten And Starch-HPMC Doughs

In this study,five different botanical starches of wheat?WS?,corn?CS?,tapioca?TS?,sweet potato?SS?and potato starch?PS?were independently mixed into starch–gluten?gluten-containing?and starch–HPMC?gluten-free?model doughs respectively.Effects of the five different botanical starches on the rheological properties of the model doughs including gas production and retention capacities,viscoelasticity and retrogradation rate were determined.After a comparative study,among the five different botanical starches,PS-gluten and PS-HPMC doughs showed the worst rheological properties.In order to improve the rheological properties,high hydrostatic pressure?HHP?technique was used to treat PS.Effects of different pressure?200-500 MPa?on the physicochemical and structural properties of the PS were determined,and effects of different HHP treated PS on the rheological properties of PS–gluten and PS–HPMC model doughs were analysed.It was found that HHP treated PS improved the rheological properties of PS-gluten and PS-HPMC doughs.Furthermore,the structure and moisture distribution of the model doughs were analysed to explore the influence mechanism of different HHP treated PS on the rheological properties of the dough.At last,the 500 MPa treated PS was used to prepare PS–gluten and PS–HPMC doughs,and salt and sucrose were added to the model doughs in different levels to clear the the influence mechanism of different food ingredients on the rheological properties of the PS-gluten and PS-HPMC doughs.The results are as follows:?1?The rheological properties of the starch–gluten and starch–HPMC model doughs were significantly affected by starches from different botanical sources.Model doughs made with WS had the highest water absorption(W_abs=66.8%[72.90%]),recovery capacity(J_e/J_max=67.93Pa^-1[31.79Pa^-1]),gas production and retention capacities?V_T=500mL[424mL],RC=87.6%[98.5%]?,and the lowest deformation resistance(J_max=1.93Pa^-1[67.83 Pa^-1]).However,model doughs made with PS had the longest dough development time?DDT=12.67min[1.33min]?,mechanical agitation resistance?C₁-C₂=0.76N·m[0.39N·m]?,deformation resistance(J_max=1.25Pa^-1[7.31 Pa^-1])and retrogradation rate?C₅-C₄=2.65N·m[2.79N·m]?,and the lowest gas production,retention and recovery capacities(V_T=85mL[38mL],RC=82.1%[97.0%],J_e/J_max=54.97%[19.33%]).Interaction between WS and gluten was the strongest in the gluten model doughs?z?=0.128?,however,interaction between PS and gluten was the weakest?z?=0.160?.In HPMC model doughs,interaction between WS and HPMC was the weakest,while interaction between PS and HPMC was the strongest.During heating,model doughs made with WS showed the maximum degree of structure hardening,while model doughs made with PS showed the minimum degree of structure hardening.In general,among all the model doughs,PS–gluten and PS–HPMC model doughs showed the worst rheological properties.?2?In order to improve the rheological properties of the dough,HHP?200-500 MPa?was used to treat PS.HHP treatment destroyed the crystalline structure,which made the PS granules swell without changing amylose and amylopectine content.Different HHP treated PS had obvious effect on the rheologcial properties of the PS–gluten and PS–HPMC model doughs,which increased the water absorption,mechanical agitation resistance,deformation resistance,gas production and retention capacities,and decreased the retrogradation rate.HHP treated PS increased the water mobility,increased bound water content?from 15.95%to 20.71%?.HHP treatment may contribute to amylose dissolution from PS granules,interfering with the formation of the gluten network structure but increasing hydrogen interactions in starch-starch and starch-gluten of the PS-gluten doughs,which decreased the stability but increased the strength of the PS-gluten doughs?z?increased from 0.190 to 0.213?.For the PS-HPMC doughs,competitive hydration between amylose and HPMC decreased the hydrogen interactions in starch-starch and starch-HPMC,decreasing the stability and strength of the PS-HPMC doughs?z?decreased from 0.199 to 0.229?.?3?Different Na Cl additions exerted different influence on the gluten-containing and gluten-free doughs,which were made with 500 MPa HHP treated PS.Along with the NaCl addition increased from1.5%to 4.5%,model doughs showed longer dough development time,higher retrogradation rate and gas production capacity,but lower mechanical agitation resistance,deformation resistance and recovery.For the PS-gluten doughs,low salt additions??2.5%?made increased the stability of the dough?z?decreased from 0.156 to 0.150?,while high salt additions?>2.5%?decreased the stability of the dough?z?increased to 0.165?.For PS-HPMC doughs,low salt additions??1.5%?increased hydrogen interactions and stability of the dough?z?decreased from 0.221 to 0.152?,while high salt additions?>1.5%?reduced the hydrogen interactions and stability of the dough?z?increased to 0.214?.During heating,NaCl addition increased the degree of the structure hardening,delayed the gelatinization of the model doughs.?4?Different sucrose additions exerted different influence on the gluten-containing and gluten-free doughs,which were made with 500 MPa HHP treated PS.Along with the sucrose addition increased from 2%to 8%,the retrogradation rate and gas production capacity increased significantly,while the mechanical agitation resistance,deformation resistance,recovery and gas retention capacity decreased.Sucrose addition had little effect on the water absorption and dough development time of the PS–gluten model doughs,whereas the water absorption?from 73.0%to 74.5%?and dough development time?from2.25min to 3.80min?of the PS–HPMC model doughs increased significantly.Sucrose addition produced another free water with higher degree of mobility,and along with the increase of the sucrose addition,the mobility of the higher free water decreased(A₂₃3 from 0%to 0.28%).Sucrose decreased the stability of the PS-gluten dough?z?decreased from 0.221 to 0.187?,whereas increased the stability of the PS-HPMC dough.During heating,sucrose addition increased the viscosity of the model doughs,delayed the gelatinization,and increased the degree of the structure hardening of the PS–gluten model doughs,whereas decreased the degree of the structure hardening of the PS–HPMC model doughs.