Elemental Studies On The Effect Phonton On Steamed Bread Preservation

To study the role of photon on preservation of steamed bread,fresh steamed bread were selected as the material in this thesis.The effect of preservation was researched by the TA-XT.Plus texture analyzer and sensory evaluation.Differential Scanning Calorimeter(DSC),Rapid Viscosity Analyzer(RVA),Scanning Electron Microscope(SEM),Fourier Deconvolution Infrared Spectroscopy(FTIR)and Nuclear Magnetic Resonance(NMR)were used to research the effects of photon on component and structure of steamed bread.And the mechanism was discussed by through synthetic analyses,which were used to provide theoretical references for the role of photon on preservation of flour products.Firstly,the study was on the base of water loss rate change and sensory evaluation results during the storage combined with the TA-XT.Plus texture analyzer.the result show that the water loss rate of steamed bread of photon groups was lower than the control group.Otherwise,the sensory score were higher than it,and the specific volume of steamed bread,whiteness,hardness,springiness,resilience,cohesiveness of steamed bread were better that in control group.This suggested that the photon possess certain effects to preservation of steamed bread.Secondly,the varieties of microstructure of steamed bread were studied by the SEM.The result show that starch granules were separated from protein netwok structure.Furthermore,the microstructure of steamed breads of the photon group was more complete.That illustrated the photon could inhibition damage of protein network.Thirdly,the thermodynamics characteristics and the viscosity characteristic of the steamed breads were determined using Differential Scanning Calorimeter and Rapid Viscosity.Found the retrogradation of steamed bread in photon group was lower than the control group.Meanwhile,the effect of-photon on amyloplastic of steamed bread was studied during storage.The photon had function in delaying attenuating aging with affecting the composition and structure of starch,extending the shelf life of steamed bread.Finally,the mechanism of the effect photon on steamed bread was researched with FTIR and NMR technology.Results indicate that ?-sheet of protein secondary structure had a downside and ?-turn gradually increasing trend,but changes trend of control group were more significant.H1049/1022 and H990/1022 ratio presented with increase,which is lower than the control group.The T2 relaxation time of the photon group was lower according to the NMR results.The comprehensive analysis indicated that the steamed bread was lost part of moisture with increasing storage time.The photon could reduce the size of the water cluster so that forge the formation of hydrogen bond between water molecules and starch.Moisture was held up in system by hydrogen bond of water molecules combined with starch.This improved the hydraulic and reduced the components of starch gelatinization and the starch aging.Moreover,this promoted the combination of protein and starch.Then these could increase steamed bread for the binding capacity of free water,delaying the aging of the steamed bread.