Study On The Physicochemical Properties During The Lye Macerating Of Tripe

Tripe contain a variety of nutrients,protein content of about 14.5%,collagen is the main protein components,easy digestion and absorption by human body.The current research on tripe mainly focuses on tenderizing water retention,swelling process optimization,freshness preservation,quality control,etc.There are very few studies on the changes in the physicochemical properties of the tripe,the physicochemical properties of the tripe protein during the lye macerating.Therefore,the experiment has studied the changes in the physicochemical properties of the tripe during the lye macerating,the structural characteristics of tripe collagen,and the changes in the structure of tripe collagen under different lye macerating conditions(lye macerating temperature,NaOH mass concentration,lye macerating time).In order to provide theoretical basis for the processing of tripe.the main research results are as follows:(1)The protein content of fresh tripe and salted tripe respectively were 14.62 g/100 g and 29.65g/100 g,respectively;the pH values respectively were 6.81 and 6.76.(2)The experiment uses salted tripe as raw material to analyze the changes in physicochemical properties during lye macerating(raw materials,pre-cooking,swelling,and water retention).The results showed that during the lye macerating of tripe,the shear force value,hardness value,elasticity value,chewiness value,insoluble collagen content gradually decreased(p<0.05),soluble collagen protein content,and collagen solubility gradually increase(p<0.05),the microstructure appears to be broken,broken,stretched,and loose.Lye macerating conditions have a significant impact on the physicochemical properties of salted tripe(p<0.05).The content of total collagen in50 °C treatment group was significantly lower than that in other groups(P < 0.05),the weight gain rate of tripe in 50 °C treatment group was significantly higher than that in other groups(P < 0.05).The weight gain rate of tripe in 5 g/L treatment group was significantly higher than that in other groups(P < 0.05).The content of total collagen in 30 min treatment group was significantly lower than that in other groups(P < 0.05),the weight gain rate of tripe in 30 min treatment group was significantly higher than that in other groups(P < 0.05).(3)In this study,the enzyme-soluble collagen was extracted from the raw materials of fresh and salted tripe.The structure of tripe collagen was characterized by SDS-PAGE gel electrophoresis,ultra violet spectrum(UV),amino acid analyzer,fluorescence spectrum,fourier transform infrared spectroscopy(FTIR)and Scanning electron microscopy(SEM).The results showed that the collagen in tripe was mainly composed of type ? collagenous protein,and the collagen from fresh and salted tripe was different,the fresh collagen retained the more complete triple helix structure.Compared with fresh tripe,salted tripe of collagen mass of fraction of glycine content fell by 8.73%;the maximum absorption wavelength of ultraviolet spectrum is redshifted by 2 nm,the absorption peak intensity increased;the maximum emission wavelength of fluorescence spectrum was blue shifted by 2 nm,the absorption peak intensity decreased;the absorption peaks in the A,B,?,?,and ? regions of the amides were blue shifted,the content of ?-fold was decreased,and the contents of irregular curl,?-helix and ?-rotation were increased;In the microstructure,the folding structure is reduced,the pores are increased,the crushing effect is obvious,and the disorder degree is deepened.(4)To study the effect of different lye macerating temperatures(40,45,50,55,60 °C)on the structure of salted tripe collagen.The results showed that different lye macerating temperature treatments had a significant effect on the collagen structure of salted tripe(p<0.05).With the increase of lye macerating temperature,the UV absorption peaks blue shift to different degrees,and the absorption peak intensity first decreases,then increases and then decreases.In the secondary structure,the peak positions of the amide A,B,?,?,and ? regions are slightly shifted,and the peak intensity of the amide ? region is reduced to varying degrees;the hydrogen bond interaction between the collagen molecules and the collagen subunits in the 45 °C treatment group The C=O,N-H,and C-N bonds in the base structure changed significantly;the irregular coils and ?-helices and other parts accounted for a smaller range of changes,and the ?-sheets and ?-turns were transformed into each other.In the tertiary structure,the maximum emission wavelength first shifts red and then blue,and the fluorescence intensity gradually decreases;the surface hydrophobicity first increases and then decreases(p<0.05).The microstructure manifests itself as the curling,fragmentation,and aggregation of collagen molecules,and finally the fragmented and ball-andstick-like structures are formed.Therefore,the collagen in the 40 °C treatment group has been denatured.With the increase of lye macerating temperature,the conformation of collagen and the "microenvironment" of amino acid residues have changed,and the secondary structure,tertiary structure,and microstructure have also changed.The degree of degeneration gradually deepened.(5)To study the effect of different NaOH mass concentrations(3,4,5,6,7 g/L)on the structure of salted tripe collagen.The results showed that treatments with different NaOH mass concentrations had a significant effect on the collagen structure of salted tripe(p<0.05).With the increase of the NaOH concentration concentration,the ultraviolet absorption peaks have different degrees of blue shift,and the absorption peak intensity first increases and then decreases.In the secondary structure,the peak positions of the amide A,B,?,?,and ? regions shifted slightly,and the peak intensity of the amide ? region gradually weakened;C=O,N-H,C-N in the collagen subunit structure of the 4 g/L treatment group The bond has changed significantly,the hydrogen bond interaction and hydrophobic interaction between the collagen molecules in the 5 g/L treatment group have been significantly changed;the ?-sheet and ?-helix under the treatment of lower alkali concentration(3 ? 5 g/L)And the proportion of ?-turns and other parts increased.Under higher alkali concentration(5 ? 7 g/L),the proportions of ?-sheets,?-helices and ?-turns became stable,and the proportions of irregular coiled structures began rise.In the tertiary structure,when the NaOH mass concentration ? 4 g/L,the surface hydrophobicity first increases and then decreases(p<0.05);when the NaOH mass concentration ? 5 g/L,the active sulfhydryl content first increases and then decreases(p<0.05).The microstructure shows collagen fragmentation and aggregation.Low alkali concentration treatment mainly produces rod-shaped collagen structure,and high alkali concentration treatment mainly produces porous collagen structure.Therefore,with the increase of NaOH mass concentration,the conformation of collagen and the "microenvironment" of amino acid residues change,the secondary structure,tertiary structure,microstructure,etc.also change,and the degree of collagen degeneration gradually deepens.(6)To study the effect of different lye macerating time(20,25,30,35,40 min)on the structure of salted tripe collagen.The results showed that different lye macerating time treatments had significant effects on the collagen structure of salted tripe(p<0.05).With the increase of processing time,the UV absorption peaks have different degrees of blue shift(except for the 25 min treatment group),and the absorption peak intensity first increases,then decreases and then increases.In the secondary structure,the peak positions of the amide A,B,?,?,and ? regions changed,and the interaction force between the collagen molecules changed;the hydrogen bond interaction between the collagen molecules in the 30 min treatment group changed,and the collagen The change of C=O bond in the protein subunit structure tends to be stable;the irregularly coiled part transforms into ?-sheet,?-helix,?-turn and other parts,and finally tends to be stable(lye macerating time ?30 min).In the tertiary structure,the fluorescence intensity gradually decreases,the surface hydrophobicity shows a dynamic cycle that first increases and then decreases(p<0.05).In the microstructure,collagen molecules curl,shrink,cross-link,break,break,and aggregate to form fragmented and rodshaped collagen structures.Therefore,as the lye macerating time increases,the conformation of collagen and the "microenvironment" of amino acid residues change,and the secondary structure,tertiary structure,microstructure,etc.also change,and the degree of collagen degeneration gradually deepens.