Studies And Effects Of Glycation On The Gel Properties And Volatile Flavor Characteristics Of Silver Carp Mince

China is a large country in freshwater fish breeding,but the processing efficiency of cultured freshwater fish is generally not high at present.To solve this predicament and promote healthy development of freshwater fish farming industry,it is necessary to develop high-value-added fish products.However,soft texture and intense fishy smell are not conducive to deep processing of cultured freshwater fish.At present,there is no method or technology to improve both texture and aroma of freshwater fish meat products.In this paper,protein glycation modification technology was introduced.The effects and mechanisms of glycation on gel properties and volatile flavor characteristics of silver carp mince(SCM)were investigated.New fish products were developed based on glycation technology.This study will provide a theoretical basis and technical reference for developing high quality protein products and improving the added value of freshwater fish.The specific research contents are as follows:(1)The effect of glycation with different monosaccharides(glucose,L-arabinose,and xylose)on the p H,color,texture,water retention,water distribution,protein structures,microstructure,and volatile flavor of silver carp mince(SCM).The results showed that glycation decreased the p H and increased the Browning degree,texture properties,and water holding capacity(WHC).Low field nuclear magnetic resonance(LF-NMR)showed that glycation increased the water content in the SCM gel and enhanced the binding degree of proteins to immobile water.Raman spectroscopy could be used as a rapid and nondestructive technique for glycated protein structure identification.Raman spectroscopy showed that glycation increased the surface hydrophobicity of proteins and promoted the formation of disulfide bonds.Scanning electron microscope(SEM)showed that glycation was beneficial to the formation of uniform and dense network gel structure of SCM.E-nose and GC-IMS showed that glycation promoted Maillard reaction and lipid oxidation.The 10 VFCs were significantly different and were expected to be potential markers to distinguish samples.Sensory evaluation showed that glycation reduced the fishy smell of SCM gel and increased the meaty,toasty,and burnt smell.These results indicated that glycation is an effective gel texture and aroma enhancement technique for developing freshwater fish products.This research provided a better understanding of the mechanism of glycation enhancing the gel texture and aroma of SCM and a theoretical basis and technical support for applying glycation in the food industry and developing ready-to-eat fish products.(2)The changes in the degree of grafting,chemical composition,p H,color,texture,total amino acid composition,and volatile flavor compounds of SCM with or without glucose were studied at different heating times.The results showed that the addition of glucose could promote the glycation reaction rate of SCM.The texture of SCM-G heated for 120 min was better than others.Lysine and cysteine were the main amino acids involved in glycation.Glycation enhanced the overall aroma of SCM by accelerating lipid oxidation and Strecker degradation.The greater glycation extent,the greater contribution of key aroma active compounds to the overall aroma.In addition,principal component analysis(PCA)suggested that the changes in volatile flavor might be greatly related to p H value.In conclusion,these results suggested that glycation enhanced the texture and volatile flavor of SCM during thermal processing and could be used as a texture and aroma enhancement technique for developing protein nutrition food with good flavor of low-value fish.(3)The browning index(BI),sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE),Fourier transform infrared spectroscopy(FTIR),total amino acid composition,chemical score,protein digestibility,and reductive power of digested products were determined.The correlation between the degree of glycation,protein structure,and protein nutritional quality was analyzed.The results showed that the BI value of SCM-G increased with the increase of heating time.Myosin heavy chain(MHC),myosin light chain(MLC),tropomyosin,and actin were the main protein reactants for glycation.Glycation led to the expansion of the secondary structure of SCM proteins.Glycation reduced lysine and cysteine content but did not change the first limiting amino acid(Val)in SCM.The essential amino acid content of glycated SCM remained consistent with the amino acid nutritional requirements for children and above recommended by FAO/WHO.In addition,glycation did not change protein digestibility but increased the reducing power of digested products with increasing DG.These results provided a theoretical basis for applying glycation in food processing industry and developing aquatic products with high nutritional value.(4)The effect of different levels of L-arabinose addition on the sensory quality and digestibility of silver carp sausage by testing color,texture,smell,taste,sensory score,and digestibility.The results showed that the L* value of fish sausage decreased with the increase of L-arabinose,while a* value,b* value,and BI increased.In addition,the hardness,springiness,and chewiness of fish sausage reached the maximum when adding 2% L-arabinos.E-nose and E-tongue showed that L-arabinose enhanced the aroma and taste profiles.Sensory evaluation found that fish sausage with 2% Larabinose had the highest overall acceptability.Moreover,2% arabinose maintained the protein digestibility of fish sausage intact.This study suggested a promising potential for applying glycation in aquatic product processing and developing nutritious readyto-eat fish products using L-arabinose.