Effect Of Parvalbumin Of Mandarin Fish Under Microwave Field Maillard Reaction

Mandarin fish(Siniperca chuaisi),also known as Osmanthus fish,is one of the most four famous freshwater fish in China and is also an important freshwater economic fish species in East Asia.It has been popular with people since ancient times,with its meat delicious,less thorny,innocent and nutritious.Since fish is one of the common allergens,which often cause itching,rashes,etc.,it prevents allergic people from taking good quality protein from mandarin fish and other fish.In this study,Microwave oven,a common kitchen tool,was used to simulate the daily cooking process of fish.The mandarin fish was mixed with glucose,maltose and sucrose in three different concentrations of sugar solution.Then it heated by microwave in different heating time for Maillard reaction.The parvalbumin in treated mandarin fish was extracted and analyzed by LC-MS/MS,ELISA and in vitro digestion experiment.By using the raw fish meat,we can better simulate the process in the home cooking and food processing industries and understand the changes in the properties of the fish in the entire Maillard reaction process.It provides basic data for the subsequent research on reducing immunogenicity by introducing microwave treatment technology into fish processing products.The results of this study are as follows:(1)The effects of different factors on Maillard reaction were determined by orthogonal experiment: The effects of sugar type,sugar concentration and microwave heating time on browning degree were investigated.The optimum conditions were obtained as follows: reaction sugar was glucose,microwave heating time was 15 min,and sugar concentration had no effect on browning degree within the concentration range of this experiment.Referring to the orthogonal experimental group,the electric heating control group and the blank control group(Native)were designed.The Maillard reaction degree of all the experimental groups was analyzed by 420 nm absorbance analysis and acrylamide gel electrophoresis,and the Maillard reaction degree of G3(glucose,1.5 mol/L,15 min)and M2(maltose,1mol/L,15 min)group was the highest.The corresponding parvalbumin bands were the most migratory.(2)Analysis of glycation sites and glycation groups of microalbumin after Maillard reaction: Firstly,the amino acid sequences of untreated parvalbumin of Siniperca chuatsi were determined by LC-MS/MS,and the complete amino acid sequences of two subtypes PV-I and PV-II of parvaalbumin of mandarin fish were obtained by mass spectrometry and Uniprot database searching.The glycation sites of the corresponding albumins of the two groups with the highest Maillard reaction were analyzed,and a manual method was established to compare the glycosylation sites of G3 and M2.The modified groups found in G3(glucose,1.5 mol/L,15 min)and M2(maltose,1 mol/L,15 min)parvalbumin were formyl(Frm),carboxymethyl(Cmc),glucose(G)and arginine(Arg)by Analyst TF 1.7.1 software and Pak View 2.2.In addition,one unreported group were found in M2.The modified group was *(M=97.03).We speculated that this was a sulfate radical.LC-MS/MS results showed that there were eleven different glycated site and five glycated groups in parvalbumin of Mandarin fish after saccharification,which might destroy the conserved region structure and block the binding of predicted epitopes to IgE,thus affecting the allergenicity of parvalbumin.This provided a theoretical basis for the changes of immunological properties of glycosylated parvalbumin.(3)Effects of microwave heating on antigenicity and digestibility of parvalbumin in Mandarin fish: Parvalbumin was isolated and purified from Mandarin eel,and polyclonal antibody was prepared in New Zealand white rabbit.The titer of antibody in serum was over 32000.Indirect competitive ELISA was used to analyze G3(glucose,1.5 mol/L,15 min),M2(maltose,1 mol/L,15 min),S1(sucrose,0.5 mol/L,15 min),G-Heating(glucose,1.5 mol/L,15 min),M-Heating(maltose,1 mol/L,15 min),S-Heating(sucrose,1.5 mol/L,15 min)in microwave group.The results showed that Maillard reaction could reduce the antigenicity of parvalbumin.Microwave heating is more conducive to reducing the antigenicity of parvalbumin than electric oven heating.In microwave-assisted glucose-maillard reaction system,the antigenicity of parvalbumin is the lowest.Compared with untreated parvalbumin,the antigenicity of G3 decreased by 66.03%.The digestive resistance of G3,G-Heating,M2,M-Heating,S1,S-Heating and blank group Native was evaluated by simulated gastric digestion in vitro.The results showed that microwave-assisted glycation of parvalbumin was easier to digest.It can be inferred that the microwave-heating Maillard reaction can better reduce the antigenicity of the parvalbumin compared with the electric furnace heating,thereby reducing the immunogenicity of the parvalbumin.In the in vitro gastric digestion experiment,the results showed that the microwave-heating Maillard reaction can increase the digestibility of the parvalalbumin of the mandarin fish.