Effect Of Gelatin On The Quality Of Dough And Its Fermented Products

Collagen has rich physiological functions,gelatin is the hydrolysate of collagen.Because it contains a large number of hydrophilic groups such as hydroxyl,carboxyl and amino groups,it shows gelation,thickening,emulsification,stability and other functional properties,so it is widely used in the field of food,medicine and cosmetics.This thesis mainly studies the effect of gelatin on the texture of wheat dough and the quality of its fermented products,steamed bread and bread,and explores the interaction between gelatin and gluten from the perspective of microstructure.1 Gelatin improves the texture of the dough.The results were as follows: the optimal addition of low gluten meal unfermented fish skin gelatin was 4 %;the optimal addition of fermented fish skin gelatin and beef bone gelatin were 4 %and 2 %,respectively.The optimum addition of medium gluten meal,unfermented and fermented fish skin gelatin were1 %and 4 %,respectively.The optimum addition amount of high-gluten flour unleavened dough,cowhide and fish skin is 1 %,and the optimum addition amount of fermented dough is 1 %and 1.5 %,respectively.Generally speaking,the gelatin from fish skin has great influence on the hardness,adhesiveness and chewiness of dough,while the gelatin from cow skin and bone has good elasticity,cohesiveness and resilience.This paper further studied the effect of gelatin on the rheological properties of fermented dough.The results showed that the storage modulus and loss modulus of the dough after adding gelatin were both greater than the respective blank control group,but the loss tangent value tan ? was smaller than the respective blanks.This shows that the addition of gelatin can increase the viscoelasticity of the dough.Gelatin is not simply filled in the gluten network structure,but has a complex interaction with the gluten protein in the dough,and the mixing system of the dough gradually changes from viscosity to the main.Mainly for elasticity,the degree of molecular cross-linking polymerization in the mixed system gradually increases,and the stability of the dough is enhanced.This is consistent with the results of the laser confocal microstructure of the dough.After gelatin is added,the holes in the network structure are reduced,starch and gelatin are evenly filled in the network structure,and the network structure of the dough becomes dense and continuous.2 In addition,the effects of gelatin addition on the quality of steamed bread were studied by measuring the texture,sensory evaluation,nutritional evaluation and flavor analysis of steamed bread,and the microstructure and antioxidant activity of flour products were further discussed.The results are as follows:When the gelatin content was 3 %,the hardness of steamed bread decreased significantly,the specific volume and sensory score increased significantly(P<0.05),and the internal structure of steamed bread was uniform and showed good luster.The results of nutritional evaluation showed that the protein content of steamed bread with gelatin was significantly increased by 18 %(P<0.05),the essential amino acid and total amino acid content were significantly increased by 46 % and 57 %(P<0.05),the first limiting amino acid lysine score was increased by 52 %,and the total essential amino acid score was increased by 22 %.GC-MS detected a total of 24 flavor substances.After adding gelatin,alcohols and aldehydes in steamed bread were significantly reduced,and esters,alkanes and aromatic heterocyclic amines increased by 40.60%,48.6% and 34.00% respectively.However,the overall flavor of steamed bread did not change significantly in terms of sensory evaluation.FTIR results showed that: compared with the blank group,?-helix only changed in dough;?-fold content only increased significantly in steamed bread(P<0.05);while ?-turn content decreased in varying degrees(P<0.05),This shows that gelatin changes the protein secondary structure of the dough and the finished product.3 This paper also discussed the influence of the amount of gelatin on the texture,sensory evaluation,and nutritional evaluation of the bread,and further studied the microstructure and antioxidant activity.The results are as follows:When the gelatin content was 1.5 %,the sensory score and specific volume of bread reached the optimal value.With the increase of gelatin content,the crust was more black red than the bread core,indicating that Maillard reaction was more intense.Nutritional evaluation results showed that: compared with the blank group,after adding gelatin,the protein content in bread increased by 7.11%,the essential amino acid and total amino acid content were significantly increased by 23.3% and 20.2%,the first limiting amino acid lysine The acid score increased by 7.85%,and the total amino acid score increased by 18.74%(P<0.05).A total of 22 flavor substances were detected by GC-MS,and the two types of bread shared 16 substances.In addition,after adding gelatin,the content of alcohols and esters in bread decreased by 31.7% and 14.0%,aldehydes increased significantly,and the contents of alkanes and aromatic heterocyclic amines increased by 10.7% and 7.8%,respectively.However,the overall flavor of bread did not change significantly in terms of sensory evaluation.FTIR results showed that gelatin changed the secondary structure of the protein.Among them,compared with the blank group,only the bread group had a significant increase in?-sheet content by 4.20%.The ?-turn content in the unfermented,fermented,and bread groups decreased significantly by 5.52%,6.35%,and 6.76%,respectively.Increased by2.67%,5.13% and 2.78%(P<0.05).In addition,collagen peptides aggravated the occurrence of bread Maillard reaction.In conclusion,gelatin significantly improved the texture of dough and the quality characteristics of fermented products,and the nutritional value was significantly improved.