Effects Of Low NaCl On Gel Properties Of Grass Carp Myofibrillar Protein Mediated By MTGase During Heat And Cold Treatment

Our object of production and processing of surimi products from seawater resources to freshwater resources,due to the seawater resources is limited.However,the gel strength of freshwater surimi is weak,we need to add MTGase to improve gel strength.In addition,the consumers paid attention to health consciousness and disturbed by chronic disease problems,we study low salt gel products to reduce sodium intake meeting consumer lower levels in food market.This study uses grass carp(Ctenopharynodon idellus)to explore some salt substitutes(KCl,MgCl2 and CaCl2)of the myofibrillar protein(MP),and provide a theoretical basis and technical guidance for the production of good quality low sodium gel products.The main conclusions are the following:1.Effect of low sodium NaCl on gel physicochemical properties of MP during heating treatment mediated by MTGaseThe gel strength,water holding capacity(WHC),rheological properties,microstructure and heat stability of MP at different salt treatments(KCl,MgCl2 and CaCl2)was tested by the methods of texture profile analysis,centrifugation,rheological test,scanning electron microscope(SEM)and differential scanning calorimetry(DSC).The results showed KCl had the similar physicochemical gel properties with NaCl.It was worth noting that potassium salt,magnesium salt and calcium salt are beneficial to human body,can be used as nutritional additives or dietary supplements.Effect of partial substitution of NaCl on gel strength of MP as follows:KCl>MgCl2>CaCl2.Calcium salt and magnesium salt decreased the WHC.Other properties of substitutes of NaCl were similar to NaCl which could improve the gel characteristics.KCl have a better prospect in the development of low salt gel meat products.2.Effect of low sodium NaCl induced fish MP gel space conformation and chemical force during heating treatment mediated by MTGaseIn this experiment,3 kinds of neutral salts(KCl,MgCl2 and CaCl2)were tested by Raman spectroscopy and UV spectrophotometer for the space conformation and chemical force which including disulfide bonds,hydrophobic interactions,hydrogen bonding and electrostatic interactions.The results indicated that different NaCl substitutes had different effects on the forces and spatial structure of MP during gel process.KCl replaced NaCl with no significant changes on the gel properties.Effect of partial substitutes of NaCl on chemical forces of gel net structure of MP as follows:hydrophobic interaction>hydrogen bonding>disulfide bonds.Different treatments of partial substitutes of NaCl,chemical interactions were also different.3.Effects of low sodium NaCl on gel properties of MP during cold treatment mediated by MTGaseEffect of low sodium NaCl induced MP during cold-set treatment found that cold gelatin was a gentle process.The water distributions in gel system were related to the substitution of NaCl.There were no significant changes in gel whiteness during the cold-set gelatin.The gel strength of KCl and NaCl group was significantly higher than other groups,but all treatment groups were lower than the blank group.All of the samples increased with the storage time,gel strength increased gradually,NaCl and KCl group rheological properties were higher than other groups.The storage modulus was related to storage time.The absorption peaks of actin and myosin were changed significantly which indicated that proteins had denatured during cold-set gel process.Different substitution of NaCl had an effect on the space conformation of cold gelatin.