Probing the distribution of gliadin proteins in dough and baked bread samples using conjugated quantum dots as a labeling tool

Gliadin;Quantum Dots (QDs);Antibody Conjugation and Confocal Laser Scanning Microscopy (CLSM)

Ansari, Shadi ; Kokini ; Jozef L.

关键词: Gliadin;    Quantum Dots (QDs);    Antibody Conjugation and Confocal Laser Scanning Microscopy (CLSM);   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/46838/Shadi_Ansari.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Quantum dots (QDs) technology is commonly used in medical application as a probefordiagnosticproceduresviaimagingmacroscopicandmicroscopicstructuresinlife sciences.Alsotheycanbeusedfordesigningofbiosensors.However, theapplicationofthis technologyisverynewinfoodscience .Inthisstudy,anovel applicationofQDsinfoodsciencewasinvestigated.QDswere conjugatedto gliadin antibodyandusedasafluorescentprobetotrackgliadinproteinindoughandbakedbread samples. The type and quantity of gluten proteins and their subfractions, gliadins and glutenins, are critical for baked product functionality. Gliadin proteins are also able to activate coeliac disease which causes severe damages to the digestive system. Therefore, it is important tounderstandhowgliadinsaredistributedindoughandtheeffectofbakingconditionson distributionofgliadininbakedbread.QDsconjugatedgliadinantibodywasspecifically boundtogliadintodetermineitsdistributioninthreedifferentsamplespreparedatvarious heating times. Dough, bread baked at 5 minutes and at 9 minutes were evaluated. Three different layers (i.e. top, center and bottom) were investigated.Toplayerinbakedbreadsmeansthelayerwhichisfar from the direct heat then center layer and closet layer to heat is bottom layer of baked breads. The conjugation process was through covalent linkage in presence of SMCC (Succinimidyl-4-(N-maleimidomethyl) cyclohexane-1-carboxylat) cross linker.Confocal laser scanning microscopy (CLSM) was used to image QDs conjugated with gliadin antibodies.The mean intensity of gliadin attached to quantum dots for each sample was calculated and plotted.CLSMimagesshowedsignificantchangesinthedistributionofgliadinwithbaking time compared wheat flour dough. Bread baked at 9 minutes shows the highest amount of fluorescent intensity from gliadin bound quantum dots in the top layer which is not in contact with the direct heat. Similar observation was made for bread baked at 5 minutes and both contained more gliadin than dough sample.However, the amount of gliadin in dough is more than that of bottom layers which receive more heat in both baked bread samples.Analysis of variance (ANOVA) was conducted to compare the mean fluorescence intensity of QDs bound to gliadin in different samples and sections. The ANOVA analysis of the overall data with probability of 99% (α=0.01) and95%(α=0.05)indicatedthatthemeanintensityvalueofgliadinchangeswasstatistically significant.