Application Of Glycation Of Different Disaccharides In Modification Of Ovalbumin

Eggs are a very important raw material in the food industry and one of the important food sources for humans.Eggs are cheap,but their nutritional value is very high.There are rich types of protein.In addition to protein,it also includes lipids such as lecithin,thiamine,riboflavin,vitamins A,B,D,E and other vitamins,as well as calcium,phosphorus,potassium,sodium,magnesium,and iron.,Zinc and other minerals.Many nutrients in eggs are easily digested,absorbed and utilized.However,eggs can cause severe allergic reactions,especially in infants and children.The clinical manifestations are mainly skin rash,urticaria,angioedema,etc.Due to the diversification of current foods and complex food components,it will inevitably bring hidden dangers to patients with egg allergies.This will bring great pain to patients,so it is urgent to find a safe and reliable method to reduce sensitization.Maillard reaction(MR)is one of the most common and important chemical reactions in food processing and storage.Previous studies have shown that glycosylation based on Maillard reaction can significantly improve the functional properties of proteins.At the same time,it is a potential method to reduce sensitization.Previous studies have found that the main factors affecting glycosylation rate and degree of glycosylation include external conditions such as reaction time,temperature,and relative humidity,and internal conditions such as the type or configuration of sugars can also significantly affect the glycosylation reaction.Disaccharides are the simplest oligosaccharides,formed by the condensation of two monosaccharides.Compared with monosaccharides,the glycosylation reaction of disaccharides is less prone to browning and has more functional properties;it is less prone to phase separation than polysaccharides.Therefore,this thesis takes the main allergenic protein in eggs: ovalbumin as the main research object,and studies six different configurations of disaccharide glycosylation modification on OVA structure,functional properties,allergenicity and glycosylation sites Impact.The main conclusions are as follows:1.Different disaccharide glycation modified OVA will increase the molecular weight of OVA,modify the primary structure.The glycation activity of disaccharides of different configurations is significantly different,which is in dry heat.Under the conditions,the degree of activity of glycation reaction with OVA is OVA-Mel>OVACel>OVA-Mal>OVA-Lac>OVA-Tur>OVA-Iso;we find through endogenous fluorescence,ultraviolet,circular dichroic and infrared.The glycation of different disaccharides can change the structure of OVA significantly.2.The glycation of different configurations of disaccharides can significantly improve the antioxidant capacity of OVA.The approximate order of the glycation modification of the six disaccharides on the antioxidant activity of OVA is: OVAMel>OVA-Tur>OVA-Cel>OVA-Mal ? OVA-Lac>OVA-Iso.Glycation of different disaccharides can also improve the emulsification ability of OVA.3.After glycation of different configuration disaccharides to modify OVA,the content of carbonyl compounds,5-hydroxymethyl furfural and melanoidin in the system are significantly increased,of which OVA-Mel and OVA-Tur generates the largest amount.Although the degree of glycation of OVA-Tur is not high,it has undergone severe browning,and the content of the final product is the highest.We believe that a serious caramelization reaction occurs while Tur is glycosylated.4.We used indirect competitive ELISA to detect the influence of different disaccharide glycation modifications on OVA sensitization.The results showed that in addition to OVA-Tur and OVA-Iso,the Ig G and Ig E binding capacity of other samples were all There was a significant decrease(P<0.05),and OVA-Iso and OVA-Tur were not significantly different from natural OVA or even increased.The binding ability of Ig G and Ig E have the same changing trend.The samples are sorted according to the binding ability: OVA-Mel<OVA-Cel<OVA-Lac<OVA-Mal<OVA-Iso<OVA-Tur.5.In the six samples of OVA-Mel,OVA-Cel,OVA-Mal,OVA-Lac,OVA-Tur and OVA-Iso,we have identified 16,14,11,11,9 and 7 glycation sites,respectively.Point,the DSP value of each site is different,indicating that different configurations of disaccharides have different glycation activities.6.Through single factor and orthogonal experiments,the optimal preparation process of melibiose for preparing hypoallergenic OVA was determined: the ratio of protein/melibiose was 1:1,the p H was 9.0,and the reaction time was 9 h.Under these conditions,glycation OVA has the best desensitization effect.