Effect Of High Pressure Processing On The Structural And Functional Properties Of Wheat Dough

High pressure processing(HPP)is a gentle,non-thermal physical processing technique,which acts on samples instantaneously and uniformly.HPP treatment can cause starch gelatinization and protein denaturation.At present,there are few studies on the effect of HPP on wheat dough.However,it is important to understand the mechanism of the structural and functional properties of wheat dough under HPP treatment and to expand the application of HPP in the food industry.In this study,we investigated the effect of HPP treatment at different pressure levels on the structural and functional properties of wheat dough with different moisture contents.The results are as follows:According to the results of differential scanning calorimetry(DSC),HPP treatment did not significantly affect the gelation behavior of the samples with 29%moisture content.With the increase of the moisture content and pressure level,the degree of gelatinization of samples increased gradually.Under the condition of 60%moisture content,the starch was completely gelatinized after 600 MPa treatment.After determined by Rapid Visco Analyzer(RVA),the RVA gelatinization curve of samples with low moisture content(29%and 33%)was not significantly affected by HPP treatment.With the further increase of moisture content,low pressure(100 and 200 MPa)treatments led to the increased viscosity,while with increasing pressure,the viscosity decreased.From the analysis of RVA results,it can be concluded that low pressure treatment loosened the starch granules and eventually leads to an increase in viscosity,while higher pressure treatment resulted in the gelatinization of starch and enhancing the shear resistance and inhibiting the retrogradation of the flour paste.HPP treatment also altered the texture characteristics of sample gels.When the moisture content reached a certain value(such as 43%),HPP can reduce the hardness,springiness,gumminess and chewiness of gels,and has the potential to improve the texture characteristics of food.By measuring the swelling power and the solubility,we found that with the increase of moisture content and pressure,the swelling power decreased and solubility increased.In addition,high pressure treatment can better maintain the morphology of starch particles by observing the scanning electron microscope(SEM)images.By the analysis of X-ray diffraction(XRD),it can be concluded that HPP destroyed the crystalline structure of sample and facilitated the formation of the amylose-lipid complex.According to the results of ATR-FTIR,the short-range ordered structure of samples decreased with increasing moisture content and pressure level.