The Studies Of Frozen Storage On Gluten Properties And Mechanism Of Dehydration

The effects of frozen storage on the functional properties, microstructure and structurecharacteristics of frozen wet wheat gluten were studied systematically in this paper. Therelationships between the performance, structure of wheat gluen and dehydration of frozenwet wheat gluten in frozen storage was discussed. The main contents were described asfollows:Frozen wet wheat gluten was treated after frozen storage in order to study the effects offrozen storage time, freeze–thaw cycles and temperature fluctuations on the functionalproperties of wheat gluten. After frozen storage for120d and five freeze–thaw cycles, theresults showed that the solubility of frozen wheat gluten decreased from2.19mg/mL to1.48mg/mL and2.14mg/mL, water–holding capacity from1.92g water/g sample to1.62g gwater/g sample and1.17g water/g sample, emulsifying capacity from59.84%to52.33%and50.61%, foamability from139%to39%and25%and foam stability from62.87%to35.61%和26.6%; The oil–holding capacity of frozen wheat gluten was increased from1.18g oil/gsample to1.57g oil/g sample and2.05g oil/g sample and emulsion stability of frozen wheatgluten were improved from54.5%to62.25%and58.76%; After increased temperaturefluctuations, the solubility, water–holding capacity, emulsifying capacity, foamability andfoam stability of frozen wheat gluten decreased firstly and then decreased, while theoil–holding capacity and emulsion stability of frozen wheat gluten showed reverse tendency.The effects of frozen storage on the property of water and thermal stability, particle sizedistribution and network structure of wheat gluten was investigated by Differential ScanningCalorimetry(DSC), Zeta potential and laser particle size analyzer, Scanning ElectronMicroscopy (SEM) in this chapter. After frozen storage for120d, the results showed that thepercentage of freezable water was increased from59.2%to64.4%and the denaturationtemperature (Td) and the denaturation enthalpy（ΔH）of wheat gluten first decreased and thenincreased with the passage of time; the particle size of wheat gluten was increased and thenetwork of wheat gluten which appeared to be thin, rough and loose was destroyed in frozenstorage; with freeze–thaw cycles and temperature fluctuations, the denaturation temperaturesof wheat gluten was increased, while the denaturation enthalpy decreased.The effects of frozen storage on the surface hydrophobicity, disulfide bond, secondarystructure, molecular weight and subunits of wheat gluten was researched by ANS Fluorescentprobe technology, Ellman，s reagent colorimetric method, Fourier Transform Infrared Spectroscopy(FTIR), High Performance Liquid Chromatography (HPLC) and SDS–PAGEtechnology in this chapter. After frozen storage for120d, the results showed as follows: thevalue of surface hydrophobicity of wheat gluten was enhanced; the amount of disulfide bondwas reduced; as the frozen storage time increased, the content of β–sheets and β–turns wasfirst increased and then decreased and the amount of α–helixes and random coil was firstdecreased and then increased in the secondary structure of wheat gluten at the same time,while the amount of α–helixes and random coil was increased and the content of β–sheets andβ–turns decreased after freeze–thaw cycles and temperature fluctuations; the molecular ofwheat gluten was increased in some degree, while the dissociation of part of high molecularweight subunits of wheat gluten was observed and the number of lower molecular weightsubunits was increased.The important reasons for dehydration of frozen dough was the effect of frozen storageon structure of wheat gluten and water molecular properties.