Study On The Effect Of Properties Of The Wheat Gluten Modiifed By Chitosan-acetic Acid

The wheat glutent was choosed as raw material, and the effect of the solubility of thewheat glutent modified by chitosan-acetic acid was studyed in this paper, also the ortherfunctional properties of the wheat protein were discussed, at last the secondary structureand the thermodynamic property of the wheat protein were analysised by Fourier TransformInfrared Spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC), the maincontents are as follows:1.The effect of temperature and time interactions on the solubility of wheat glutenThe wheat glutent was choosed as raw materia, study the effect of the solubility ofwheat gluten under the different heating temperature and stirring time. The results showedthat at the same temperature, when the mixing time changed from10min to50min,duringthis time the solubility of wheat gluten kept a rising trend; When the mixing time arrived to50min,the solubility of wheat gluten reached to the maximum; When the mixing time wenton, the solubility of wheat gluten began to have a downward trend. Under the same mixingtime, when the heating temperature changed from30℃to70℃,during this heatingtemperature the solubility of wheat gluten kept a rising trend;When the heating temperaturearrived to70℃, the solubility of wheat gluten reached to a maximum;When the temperatureexceeded70℃, the solubility of wheat gluten began to have a downward trend. And by theslope of the solubility curve can be seen, the heating temperature on the degree of influenceof the wheat gluten was greater than the mixing time of its impact. Therefore, the optimalconditions for modifying as follows: temperature70℃, mixing time50min.2.The effect of acetic acid and stirring timeon the solubility of wheat glutenUnder the heating temperature of70℃,study the effect of the pH and the mixing timeon the solubility of wheat gluten extracted from flours. The results showed that under thesame pH of acetic acid, when the mixing time changed from10min to50min, the solubilityof wheat gluten kept a rising trend; When the mixing time arrived to50min,the solubility ofwheat gluten reached to the maximum; When the mixing time went on, the solubility ofwheat gluten began to have a downward trend. During the same mixing time, the solubilityof the wheat gluten protein turned the worst when the pH of the acetic acid was2; Duringthe case of pH3、4、5、6, at the first time the solubility of wheat gluten kept a rising trend,asthe time went on the solubility of wheat gluten turned to be a downward trend, and when the pH of acetic acid was3the solubility of wheat gluten turned the best; And And by the slopeof the solubility curve can be seen that the pH of acetic acid value affected the solubility ofthe wheat gluten far more than the mixing time. Therefore pH3of acetic acid should be animportant control factor in the wheat gluten modifying. And then the mixing time wasdetermined to50min.3.The effect of Chitosan-acetic acid and heating temperature on the solubility ofwheat glutenUnder the conditions the pH of3、the mixing time of50min, study the effect of thesolubility of wheat gluten under the different content of chitosan and the different heatingtemperature.The results showed that in the case of the same chitosan addition, when theheating temperature changed from30℃to70℃,during this heating temperature thesolubility of wheat gluten kept a rising trend;When the heating temperature arrived to70℃,the solubility of wheat gluten reached to a maximum;When the temperature exceeded70℃,the solubility of wheat gluten began to have a downward trend.Under the same heatingtemperature, when the content of chitosan added from0%to0.1%(of wheat gluten dryweight),he solubility of wheat gluten kept a rising trend; When the content of chitosanreachde to0.1%, the solubility of wheat gluten got the maximum; When the content ofchitosan kept adding over0.1%,the solubility of wheat gluten began to have a downwardtrend.Therefore, the best modified conditions were dertermined for the heating temperatureof70℃, the content of chitosan of0.1%(of wheat gluten dry weight).4.The effect of the other functional properties of the wheat gluten protein afftermodifiedThe wheat protein modified by acetic acid and chitosan-acetic acid both had beenlargerly improved such as emulsification and emulsion stability、foaming stability、waterholding capacity.And the gluten protein modified by chitosan-acetic acid> the glutenproteinacetic modified by acetic acid> the original wheat gluten; Yet the foaming propertiesand oil holding capacity of the modified gluten protein decreased in some extent; Inhydrolysis, under the conditions the pH of3the gluten protein modified by acetic acid andthe gluten protein modified by chitosan-acetic acid was higher than the wheat glutenmodified by0.01mol/L hydrochloric acid. It showed that under the acetic acid the wheatgluten had been hydrolied, and the wheat gulent partly became into the amino acid.5.The effect of the modified wheat gluten’s structural changes The effects of the changes on the structure of the gluten protein were investigated byFourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry(DSC).The results showed that the secondary structure of the wheat protein had beenchanged besides α-Helix、β-sheet、β-Turn、Random coil.And the denaturation temperature(Td) and the denaturation enthalpy （ΔH） of wheat gluten had already beenchanged.Therefore the thermal stability and hydropHobictiy of the wheat protein had alsobeen changed.