Study On The Mechanism Of The Interaction Of Volatile Compounds With The Myofibrillar Proteins Of Beef Glycated

Flavor of food is an important consideration for consumers to purchase food.In real life,people often encounter problems with the loss of food flavor,especially in meat products.When the meat products are just processed,the flavor is rich and the aroma is tangy.However,as the standing time is extended,the flavor will be greatly reduced.This has seriously affected people’s demand for food.Numerous studies have shown that proteins can adsorb different kinds of flavor compounds under specific spatial conformations and structures,thereby changing the concentration of food headspace flavor compounds and affecting the sensory quality of foods.Maillard reactions inevitably occur during processing and storage of meat products.Myofibrillar protein(MP)is the main protein in meat proteins.Glycosylation of MP can improve its solubility,emulsifying properties and other functional properties,but whether it affects the ability of myofibrillar protein to adsorb flavor has not been proven.In this study,glycosylation of myofibrillar proteins was carried out under wet conditions to simulate the Maillard reaction in the process,and the effect of myofibrillar glycosylation on the adsorption capacity of flavors was studied by adding glucose or glucose.Amines,explore the effects of the type and amount of sugar on the physicochemical and structural properties of glycosylated myofibrillar proteins.The effects of myofibrillar glycosylation on the adsorption capacity of different flavors were analyzed by adding 14 typical meat flavors of alcohol,aldehyde,ketone and ester,and the possible mechanism of influence was analyzed.The main contents and results are as follows:(1)The degree of glycosylation of glucose was low.When the weight ratio of Myofibrillar protein(MP)and glucose(Glc)eached 1:6,the free amino group content was significantly lowered.This indicates a minimum ratio of glucose glycosylated myofibrillar protein is 1:6.No significant differences between the sample bands were observed in the SDS-PAGE map.As the amount of glucose added increases,the solubility of myofibrillar protein increases and the surface hydrophobicity decreases.Atomic force microscopy showed that the structure of MP became larger and denser after heating at 40 °C,indicating that thermal aggregation of MP occurred,and the structure of glycosylated myofibrillar proteins becomes small and dispersed,indicating that glucose glycosylation prevents the thermal aggregation of myofibrillar proteins to some extent.(2)Glycosylation of glucosamine has a different effect on myofibrillar proteins than glucose.When myofibrillar proteins and Glucosamine(Glc N)were reacted in a weight ratio of 1:1,the free amino group content was significantly lowered,and the degree of grafting reached 20.75%.As the amount of glucosamine added increases,the free amino group content decreases and the degree of grafting increases.When the ratio of MP to Glc N increased to 1:6,the free amino group content did not change significantly,and the degree of grafting tends to be stable,indicating that the reaction has reached saturation,and the continued addition of glucosamine will not continue glycosylation.In the SDS-PAGE map,the glycosylated sample became lighter at a band around 200 k Da,and a severe application band appeared at a higher molecular weight.The bands under non-reducing conditions are shallower and at the 200 k Da of the glycosylated sample almost disappear.The degree of glycosylation of glucosamine is higher than that of glucose,which may be related to the presence of primary amines at the C-2 position of glucosamine.Through LC-MS studies of the Lys-Glc N model system,it was found that glucosamine reacted with myofibrillar protein to release ammonia and water,while continuing the reaction in the form of Schiff base.As the amount of glucosamine added increased,the total sulfhydryl content of MP decreased significantly,indicating that glucosamine induced disulfide cross-linking of myofibrillar proteins.A large and aggregated structure of glucosamine glycosylated proteins was observed from an atomic force microscope,indicating that cross-linking of disulfide bonds leads to an increase in the molecular structure of the protein.As the amount of glucosamine added increases,the solubility decreases and the surface hydrophobicity increases.The fluorescence intensity of the glycosylated protein in the fluorescence spectrum was significantly reduced,and the maximum emission wavelength was significantly red-shifted,indicating that glucosamine glycosylation changed the tertiary structure of myofibrillar protein.(3)The adsorption capacity of myofibrillar proteins on 14 typical meat flavors of alcohols,aldehydes,ketones and esters was analyzed by GC-MS.The adsorption capacity of myofibrillar proteins for different flavor compounds is significantly different,and the adsorption capacity is followed by esters > aldehydes > ketones > alcohols.Glucose-glycosylated myofibrillar protein has no significant effect on the adsorption capacity of alcohol,aldehyde and ketone volatile flavors.Glucose glycosylation significantly enhances the ability of myofibrillar proteins to adsorb ethyl hexanoate and octyl acetate.Glucosamine glycosylation induces disulfide cross-linking of myofibrillar proteins,resulting in increased release of alcohol flavors.The decrease of sulfhydryl groups leads to a decrease in the adsorption capacity of myofibrillar protein to 2-methylbutanal,but has no significant effect on the adsorption capacity of hexanal and octanal,indicating that the adsorption sites of different aldehyde flavors are different,2-methyl Butyraldehyde is primarily bound to myofibrillar proteins via sulfhydryl groups.Glucosamine glycosylated myofibrillar protein had no significant effect on the adsorption capacity of ketone flavors.Glycosylation of glucosamine significantly enhances the ability of myofibrillar proteins to adsorb ethyl hexanoate and octyl acetate.