Inhomogeneity Of Glycation Of Ovalbumin In Microwave Field

With the development of economy and society and the continuous improvement of people's living standards,people's requirements for food have gradually changed from the initial satiety and maintenance of their living conditions to the development of safe nutrition,inspiration from diet and psychological needs.Therefore,higher and higher requirements have been put forward for food industry and processing technology.In recent years,protein glycosylation modification based on Maillard reaction has gradually become a hot spot to improve the functional properties of protein and improve the flavor of products.However,the preparation of flavor products and modified products based on glycosylation reaction is mainly conducted by conduction heating,which is time-consuming,high temperature,long production cycle and high energy consumption The advantages of energy saving and environmental protection have gradually attracted the attention of food researchers at home and abroad,and become a new technology to promote the glycosylation of food protein.Microwave heating can improve the quality and efficiency of protein glycosylation.However,the uneven distribution of microwave in the process of microwave heating will lead to uneven heating,resulting in local hot spots and cold spots,which will affect the quality and stability of products.Moreover,there are few studies on the non-uniformity of protein glycosylation reaction in microwave field,lack of qualitative and quantitative analysis and related theories of non-uniform products,which need to be further studied,To guide the application of microwave heating technology in food glycosylation modification and quality improvement,and provide theoretical guidance for the research and development of new uniform microwave processing equipment.In this paper,the effects of microwave heating inhomogeneity on the reaction products,structural properties and sensitization of ovalbumin and glucose were studied.The molecular mechanism of microwave heating inhomogeneity in anhydrous state was revealed by mass spectrometry and molecular docking.The main conclusions are as follows(1)Microwave accelerated the glycosylation reaction.The molecular weight of ovalbumin after microwave glycosylation increased significantly,and the free amino content also decreased significantly.The tertiary structure of ovalbumin unfolds,the secondary structure changes,and the spatial structure of ovalbumin becomes loose.The structure of sample No.3,which is farthest from the magnetron,changes the most.(2)The content of lysine in ovalbumin was mainly decreased by microwave glycosylation.The fructosamine produced in this process was not stable.The content of hydroxymethyl furfural,carbonyl and carboxymethyl lysine in sample 3 farthest from magnetron was the highest.The content of acrylamide in No.5 sample nearest to magnetron tube was the highest,but the content of acrylamide in all samples was far lower than the toxic dose,and 4-methylimidazole was not detected in the samples.(3)After microwave glycosylation,the foaming and emulsifying properties of ovalbumin decreased to some extent,and the sample No.3,which was farthest from the magnetron tube,was most seriously damaged.The rheological behavior of the modified ovalbumin was also changed,the antioxidant capacity was significantly improved,and the denaturation temperature was also increased.The sample No.3which is farthest from magnetron has the strongest antioxidant capacity,but the denaturation temperature is the lowest.In conclusion,most of the functional properties of glycosylated ova were improved,and the heterogeneity was also reflected in each sample.(4)Microwave glycosylated ovalbumin is easy to be hydrolyzed by pepsin,but not by trypsin.After digestion,the ion chelating ability of microwave glycosylated ovalbumin was improved in varying degrees,and the ion chelating ability of sample 3which was farthest from magnetron was the worst.After digestion,the microwave glycosylated ovalbumin still has good antioxidant activity,and the sample No.3which is farthest from the magnetron tube has the strongest antioxidant activity after digestion.In general,the digestibility of ovalbumin was not affected by microwave glycosylation.(5)Microwave glycosylation could not reduce the antigenicity of ovalbumin,but the antigenicity of ovalbumin decreased significantly after digestion,and the antigenicity of sample 3 which was farthest from magnetron tube was the lowest.3,2,5,3,2,5 glycosylation sites were detected in samples 1,2,3,4,5,6,respectively.K323 and K227 were the two sites prone to glycosylation.Microwave can induce glucose molecules to enter the hydrophobic interior of ovalbumin.