Study Of Properties And Molecular Interactions Of Chicken Myofibrillar Protein And Food Gums Mixed Gels

The properties of myofibrillar protein (MP), MP-Carrageenan (CAR), and MP-Gelatin and the molecular interactions such as electrostatic interactions, disulfide bonds, hydrophibic interactions and hydrogen bonds were investigated.Chapter two: The effects of MP concentration, pH and ionic strength (I) on textural properties and rheological properties of MP gels were studied by textural analyzer and rheometer. Results indicated, hardness, springness, G', G''increased with the MP concentration increased. The hardness and G', G''of MP were highest at pH6.0. Hardness, springness, G', G''increased when the ionic strength increased. MP concentration and ionic strength influenced hardness and springness of MP gels significantly.Chapter three: The addition of CAR increased the hardness, springness, G', G''of the MP samples. MP and the molecular interactions between MP and CAR were the main reason which caused G', G''increased. The hardness and G'increased as CAR concentration increased. The CAR concentration had little influence on springness of MP-CAR gels. The hardness of MP-CAR mixed gels was highest at pH6.0. G'of MP-CAR samples decreased as pH increased. The orthogonal test L9 (34) was adopted to seek the effects of concentration of CAR, pH, ionic strength, [K+] on gel hardness and springiness. The results showed that the factors which affected the hardness of the mixed gels were in the order of [K+], ionic strength, concentration of CAR and pH from major to minor. The factors which affected the springiness of mixed gels were in the order of [K+], concentration of CAR, pH and ionic strength. Concentration of CAR 33.33%, pH 6.0, I 0.2, [K+] 0.10mol/L is the optimal combination for hardness of MP-CAR mixed gels. Concentration of CAR 33.33%, pH 7.0, I 0.2, [K+] 0.10mol/L is the optimal combination for springness of MP-CAR mixed gels. Scanning electron micrograghs of MP gels and MP-CAR gels showed that CAR enhanced the structure of MP gels via clinging to the MP gel network.Chapter four: The molecular interactions in the formation of MP and MP-CAR gelation was investigated by determining the effects of the solvents on the properties of MP. The addition of DTT influenced formation of disulfide bond. And the changes of the properties of the MP gels and MP-CAR mixed gels were unobvious, so the disulfide bond have little effect on the formation of MP and MP-CAR gelation. Addition of SDS influenced hardness and springness of the gels significantly. So the hydrophobic interactions have given great contribution to the formation of MP and MP-CAR gelation. The addition of urea and GuHCl decreased hardness springiness and G'of the gels obviously. So the hydrogen bonds also have significant effect on the formation of MP and MP-CAR gelation. pH influenced the electrostatic interactions, and changed the properties of the gels. The effects of propanediol concentration on hardness on MP gels and MP-CAR mixed gels were investigated. The result showed that the influences of hydrophibic interactions were more important than hydrogen bonds during the formation of MP gels. But, hydrophibic interactions and hydrogen bonds both played an important part in MP-CAR gels.Chapter five: The properties of the MP-Gelatin were studied. The hardness of gelatin increased with the concentration of gelatin increased. The addition of gelatin decreased the hardness, but improved the springness. G'decreased when the concentration of gelatin increased. The hardness of MP-Gelatin increased and G'decreased as pH increased. The orthogonal test L9 (34) was adopted to seek the effects of concentration of gelatin, pH, ionic strength on gel hardness and springiness. The results showed that the factors which affected the hardness and springness of the mixed gels were in the order of concentration of gelatin, pH and ionic strength from major to minor. Concentration of gelatin 50%, pH 6.0, I 0.6 is the optimal combination for hardness of MP-gelatin mixed gels. Concentration of gelatin 50%, pH 7.0 and I 0.2 is the optimal combination for springness of MP-gelatin mixed gels.