Study On The Influence Of Germination Process On The Oat Protein And The Rheological Properties Of The Oat-wheat Mixing Dough

The malted oat was prepared using the native oat as the material in this study. Theprocess of the oat germination was studied, and the nutrient of the malted oat wasevaluated. Then the molecular weights, the amino acids composition and the secondarystructural characterization of the oat protein, e.g., oat isolated protein, albumin, globulin,prolamin and glutelin extrated from malted oat flour was investigated. Finally, the impactof germination process on the farinogram characteristics and pasting properties of theoat-wheat mixing dough was performed.The optimum conditions of the wheat germination process was carried out using thegermination rate as a index. Based on the L9（34）orthogonal and using the germination rateas a index, the conditions of the wheat germination process was obtaind as follows:steeping temperature21℃, steeping time16h, germination temperature20℃, andgermination time5h. The highest germination rate could up to65.33%.After germination, the SDF content increased from0.59%to2.86%, the TDF, IDF, Ca,Fe content increased，respectively increased63.19%,53.02%,13.33%and33.45%.But theprotein, fat, reducing suger, starch, β-glucan, Mg and VE content in malted oat is less thanunmalted oat.The free amino acid in malted oat decreased from7.60mg/g to5.50mg/g, lysine and theessential amino acids content in malted oat protein increased16.15%and8.27%respectively, the ratio of the essential amino acids and total amino acids (E/T) is alsoincrease. There is no significant difference between the molecular weights of malted oatprotein, four protein fractions of oat (albumin, globulin, prolamin and glutelin) andunmalted oat: the molecular weights of α subunits、α’ subunits、β subunits、A3and Axacidicsubunits, Bxand B4basic subunits of oat protein ranged from14.4KDa to66KDa; themolecular weights of Axacidic subunits and B4basic subunits of albumin ranged from14.4KDa to20KDa and27KDa to35KDa; the molecular weights of Axacidic subunits andB4basic subunits of globulin ranged from14.4KDa to35KDa; the molecular weights of Axacidic subunits and B4/Bxbasic subunits of prolamin and glutelin ranged from20KDa to35KDa. Malted oat protein have51.19%ordered structure, is higher than unmalted oatprotein, through the FTIR, we found that there is a little change in second structure ofmalted oat protein fractions: in albumin, the α-helix content decreased0.94%,β-sheetincreased5.94%,β-turn increased1.42%;in globulin,α-helix content increased13.55%,β-sheet increased26.35%, β-turn decreased20.77%; prolamin include23.77%random, thecontent of other structures are all decrease; in glutelin, α-helix content increased20.26%, β-sheet increased40.17%, β-turn decreased17.80%.The addition of malted oat flour increased the gelatinization properties of dough, butdecreased the farinograph properties of the dough made from mixed flour. If the addingamount is in15~30%, the water absorption and protein softness of malted oat mixed flourdough is higher than oat mixed flour dough, but if in0~15%additive amount, theexactly opposite results were founded. With the increase of adding amount, thedevelopment time, stability time, starch gelatinization viscosity and thermal stability ofmalted oat mixed flour dough is lower than oat mixed flour dough; malted oat mixed flourdough was harder to anabiosis.