Study On Effect Of Alternating Magnetic Field On The Quality Of Grass Carp Fillts And Beef During Cold Storage

Meat is perishable,so meat preservation has always been a very challenging problem for the food industry,where the challenge is to ensure food safety while maintaining its organoleptic qualities.Conventional refrigeration techniques may cause some undesirable sensory changes in meat products,but the magnetic field is a mild physical field with no contact,strong penetration,and good biocompatibility.This paper takes fresh grass carp and beef as the research objects to study the quality changes under conventional refrigeration conditions and the effect of 2 mT alternating magnetic field on its preservation,aiming to provide a high-quality refrigeration system for meat including fish and beef.A new method was used to study the preservation mechanism of alternating magnetic fields from the aspects of storage characteristics,flavor and sensory quality,and protein changes,so as to provide a theoretical basis for the application of alternating magnetic fields in meat preservation.First,the effects of 2 mT alternating magnetic field on the storage characteristics of refrigerated grass carp fillets and beef were investigated.The results showed that,compared with conventional refrigeration,alternating magnetic field of 2 mT could inhibit the refrigerated grass carp fillets and beef in microbial breeding,TVB-N content and TBARS value increasing,p H changing,characteristic putrefamine producing and drip and cooking losing.Besides,the colour of grass carp fillets and beef were better maintained.The total number of colonies and TVB-N content of grass carp fillets and beef samples in conventional refrigeration exceeded the thresholds on the 5th and 8th days,respectively,and the samples in the alternating magnetic field only exceeded the thresholds on the 8th and 13th days.The alternating magnetic field could inhibit lipid oxidation.After 13 days of storage,the TBARS value of grass carp fillets and beef refrigerated in the alternating magnetic field were respectively 28.86%and 26.24%lower than those in the conventional refrigeration group.In addition,the alternating magnetic field can delay the migration of semi-bound water in grass carp and beef to free water,reduce drip loss and maintain water holding capacity.Second,the effect of 2 mT alternating magnetic field on the flavor and sensory quality of refrigerated grass carp fillets and beef was studied.The results showed that the alternating magnetic field could delay the conversion of some free amino acids in refrigerated grass carp and beef to biogenic amines,inhibit the accumulation of bitter free amino acids,prevent the loss of umami free amino acids,delay the reduction of hydrolyzed amino acids,and maintain the nutrition of meat.To a certain extent,the alternating magnetic field can inhibit the generation of aldehydes,delay lipid oxidation,and maintain the flavor;retain the content of alcohols and inhibit the generation of ketones produced by complex biochemical reactions.In addition,the alternating magnetic field maintained the organoleptic qualities of refrigerated grass carp fillets and beef.Finally,the effect of 2 mT alternating magnetic field on the changes of refrigerated grass carp fillets and beef protein was studied.The results show that the alternating magnetic field can delay the protein oxidation of grass carp and beef to a certain extent,and stabilize the spatial structure of the protein.The alternating magnetic field could delay the decrease of total sulfhydryl content and Ca²⁺-ATPase activity,and the increase of carbonyl content and surface hydrophobicity.In addition,the alternating magnetic field can maintain the total content ofα-helix andβ-sheet of the protein,prevent the transition toβ-turn and random coil,and delay the decrease of fluorescence intensity...