Effects Of High Hydrostatic Pressure Treated Starches On Aeration Properties Of Gluten Free Model Dough

Maize,potato and sweet potato starches are important and commonly used raw materials in food industry of the world,e.g.the application in gluten-free food.However,the structure and properties of native starch restricts its application potential.As a non-thermal physical modification technique,high hydrostatic pressure?HHP?has been successfully used to extend the shelf life of fresh and processed food products with minimum impact on its sensory,nutritional values and aroma compounds,and has achieved a considerable attention to the researchers and food industries.However,no comparative study on the effects of HHP treatment on characteristic of maize,potato and sweet potato starches is available,as well as the application of HHP treated starches in gluten-free model dough.In this study,the effects of high hydrostatic pressure on physicochemical,thermal and structural properties of maize,potato and sweet potato starches were studied.On this basis,effects of HHP treated starches and different sugars on thermomechanical,rheological and microstructural properties of gluten-free model dough were investigated,thus to reveal the possible effect mechanism of HHP treated starches on aeration properties of gluten free model dough.The specific research results are as follows:?1?HHP treatment?100,300 and 500 MPa for 15 and 30 min at 25°C?showed significant influences on physicochemical,thermal and structural properties of maize,potato and sweet potato starches?20%,w/w?.Amylose and damaged starch contents of all three starches were increased,but their solubility and swelling power were decreased after HHP treatment.Thermal properties of maize starch were significantly different with those of potato and sweet potato starches.Maize starch treated at 500 MPa was completely gelatinized with larger particle sizes,and exhibited different pasting properties than potato and sweet potato starches.Crystalline pattern of maize and potato starches was changed from A to B and B to B+V at500 MPa respectively,whereas that of sweet potato starch was still C-type.HHP modified starches might be taken into consideration for starch-based food with high quality.?2?In order to improve the aeration properties of the dough,HHP?100,300 and 500 MPa for 30 min at 25°C?treated maize,potato and sweet potato starches were selected for the preparation of starch-HPMC-egg white protein?EWP?model dough.The starch-HPMC-EWP model dough with 500 MPa treated maize,potato and sweet potato starches showed significantly higher water absorption,dough development time and dough stability,and higher storage modulus?G??,loss modulus?G???and complex shear modulus,suggesting the formation of stable network structure.Maximum dough height,maximum gaseous height,total gas production and retention capacity of the dough prepared with 500 MPa treated potato and sweet potato starches were significantly increased,while that with 500 MPa treated maize starch were decreased,and this could be attributed to the complete loss of granular structure of maize starch treated at 500 MPa.Compared with fermentation time 0 min,the relaxation time T₂₂ of the model dough with corn starch?300 MPa?,potato starch?500 MPa?and sweet potato starch?500 MPa?were significantly increased at fermentation time 60 min,indicating that the proportion of weakly bound water in the dough increased with the fermentation,which was beneficial to the dough gas holding.Uniform and continuous network structure was observed in all starch model dough at fermentation time 60 min.?3?On this basis,the effects of different sugars?sucrose,trehalose,maltose and xylose?on the rheology,water mobility and microstructure of starch-HPMC-EWP model dough prepared with HHP treated maize starch?300 MPa?,potato starch?500 MPa?and sweet potato starch?500 MPa?were studied.The doughs with the incorporation of trehalose showed higher G?and G??,but lower maximum creep compliance and degree of dependence of G?on frequency sweep than maltose,sucrose and xylose,suggesting the formation of more stable network with stronger deformation resistance.The addition of trehalose and maltose significantly increased the maximum gaseous height,total gas production and total gas retention of the model dough.Compared with fermentation time 0 min,the relaxation time T₂₂ and T₂₃of the maize starch model dough with trehalose were increased,while those of potato and sweet potato starch model dough were decreased at fermentation time 60 min,indicating that the proportion of weakly bound water and free water were changed with the fermentation,which affected the dough gas holding capacity.Uniform and continuous network structure was observed in all starch model dough at fermentation time 60 min.Thus,there is a great potential for HHP treated maize,potato and sweet potato starches used in the new formulations development of gluten-free dough the incorporation of trehalose or maltose.