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Study on Glycosylation Modification of Tilapia Myofibrillar Protein

Author: ChenXin
Tutor: HuangHe
School: Guangdong Ocean University
Course: Of Food Science
Keywords: Tilapia Myofibrillar protein Glycosylation modified Solubility Emulsification Thermal stability
CLC: TS254.1
Type: Master's thesis
Year: 2010
Downloads: 130
Quote: 1
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Abstract

This study to improve the perspective of tilapia meat protein features, the choice of glucose, lactose, dextran, chitosan and carboxymethyl cellulose sodium as a the glycosyl donor on tilapia myofibrillar protein dry heat sugar base of modified explore the impact of the myofibril protein solubility, emulsifying properties and thermal stability of the sugar the type and degree of modification, to optimize the process conditions of the glycosylation modified tilapia myofibrillar protein, as aquatic protein modification, and the development of new high quality protein resources to provide a better theoretical basis. Main results are as follows: 1, in the ratio of sugar to protein of 1:1 (w / w), relative humidity of 65% under the conditions of temperature 50 ℃ With the extension of the reaction time (0-120 h), the glycosylation change The increase in the degree of solubility, emulsification and heat stability of the reaction product has a different degree of improvement. By contrast, the reaction of small molecules of glucose and lactose myofibrillar protein dry heat faster, the solubility was increased and then decreased with the prolongation of the reaction time, the reaction products of thermal stability and emulsifying resistance improvement is not obvious; slower molecular weight of chitosan, sodium carboxymethyl cellulose, and dextran and protein dry heat reaction, the extent of reaction is easier to control in the early stages of the Maillard reaction, whereby The thermal stability of the product obtained, solubility and good emulsifying properties. In the experiment range, the improving effect of sodium carboxymethylcellulose myofibrillar protein solubility is preferably improved more significantly, and in a low ionic strength solution; dextran do glycosyl donor myofibrillar The the protein emulsifying activity and emulsion stability improvement is the most obvious; sodium carboxymethyl cellulose myofibrillar protein thermal stability improvement is most significant. 2, SDS-PAGE analysis further shows that the small molecule of glucose and lactose myofibrillar protein response speed, small molecule reducing sugars and myofibrillar protein molecules covalently bound, with the extension of reaction time, the mobility rate increases with significantly extending the reaction time becomes slow, gradually increasing the molecular weight of the reaction product; dextran, chitosan and sodium carboxymethyl cellulose and myofibrillar protein, the reaction rate is slower, and the reaction is easier to control in the United States in the early stages of the Maillard reaction. With the extension of reaction time, little change in the rate of mobility, molecular weight did not change significantly myofibrillar protein bands by SDS-PAGE results show only. Therefore, in the process of dry heat glycosylation reactions, it is necessary to select the appropriate sugar, and the strict control of the degree of reaction, the protein with a reducing sugar group must be controlled in the early stages of the Maillard reaction. Comprehensive analysis of the glucan glycosyl donor myofibrillar protein emulsified improve glycosyl donor myofibrillar protein solubility and thermal stability, improved sodium carboxymethyl cellulose. 3 glucan as glycosyl donor, emulsifying activity and emulsion stability of the reaction products of tilapia myofibrillar protein - glucan dry heat indicators on the basis of single factor experiments, response surface analysis emulsifying activity index optimized process conditions: reaction time 30.62h, reaction temperature 72.02 ℃, relative humidity of 65% dextran myofibrillar protein than 3.3:1; Under these conditions, the dry heat reaction products emulsion stability index of 1.908 ± 0.013, 31.545 ± 0.4, the thermal stability of (43.53 ± 0.55)%, the solubility in 0.1mol / L NaCl solution (44.13 ± 0.81)%, in 0.1mol / L NaCl the solubility in the solution (63.13 ± 1.29)%, and the degree of grafting (23.2 ± 0.3)%, quadratic model prediction of the response surface with the corresponding value was no significant difference, experimental optimization of process parameters is feasible. 4, Sephacryl S-200 gel column chromatography to optimize process conditions prepared tilapia myofibrillar protein - the glucan dry hot reaction products were separated from the eluent at 490nm and 280nm overlapping absorption peaks at Its content analysis, in the glycosylation reaction process, the glucan is in excess, and initially inferred reaction glycoprotein collected eluent of 10-25, after dialysis and lyophilization of infrared spectra analysis, the change of the characteristic absorption peak further glucan and myofibrillar protein faint dry heat Maillard reaction is likely to occur. 5, sodium carboxymethyl cellulose glycosyl donor, solubility and thermal stability of the reaction products of tilapia myofibrillar protein - sodium carboxymethyl cellulose dry heat indexes in the basis of single-factor test on optimization by response surface methodology the modified optimum conditions: reaction time 23.94 h, reaction temperature 52.45 ℃, relative humidity of 65%, sugar and protein than 1.4:1; Under these conditions, the dry The thermal reaction in 0.1mol / L NaCl solution, the solubility of (82.13 ± 0.32)% (88.77 ± 0.21)% solubility in 0.5mol / L NaCl solution, thermal stability (82.2 ± 0.75) %, emulsifying activity index is 0.895 ± 0.01, emulsion stability index was 12.3 ± 0.4, protein grafting degree (28.2 ± 0.3)%, no significant difference in predictive value and the corresponding response surface quadratic model, experimental optimization of process parameters feasible.

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