The Effect Of Transglutaminase On Gel Properties Of Myofibrillar Proteins Of Jumbo Squid(Dosidicus Gigas)

To a great extent, texture of meat products was dependent on the gelationcharacteristics of myofibrillar protein. As the muscle of jumbo squid has high proteaseactivity, which causes degradation of myosin, it has been characterized by a lowgel-forming capacity. The aim of this study was to improve the gel properties of themuscle of jumbo squid by adding transglutaminase (TGase).The effect of TGase on the gel properties, including the concentration of TGase,reaction temperature,reaction time and pH were studied. Meanwhile, the mechanismof how the TGase improve gel properties was probed by using SDS-PAGE andobserving with ESEM. At last, the conditions for strengthening the gel properties ofjumbo squid were optimized through Response surface method (RSM). The resultsare shown as follows:1. The concentration of TGase has significant effect on the hardness andspringiness of myofibrils (p＜0.05). The hardness reaches the maximum when theconcentration reaches 1%, and the springiness reaches the maximum when theconcentration reaches 0.5%. With the increase of TGase concentration, the strength ofboth MHC and PA decline and the three dimensional network structures becomedenser and evener.2. Reaction time of TGase has significant effect of the hardness and springinessof gel properties ((p＜0.05). The hardness reaches the maximum when the reactiontime reaches 2 hours. The springiness only increases significantly in the first half hourand shows no change in the rest of time. The strength of both MHC and PA decrease with the time, and the three dimensional network structures become denser andevener.3. Reaction temperature of TGase has significant effect on the hardness andspringiness of gel properties (p＜0.05). Both badness and springiness increasesignificantly at 20～40℃, and get the maximum number at 40℃, decreasesignificantly at 40～60℃. SDS-PAGE is closely related to the texture properties. Inmicrostructure, the porosity and uniformity of gel structure are satisfying at 40℃,while the gel structure is rough and. porosity is worse at 20℃and 60℃.4. pH has significant effect on the hardness and springiness of gel properties((p＜0.05). Both hadness and springiness get the maximum number at pH 7.0. Any pHnumber above or below 7.0 would let hardness and springiness drop sharply. Themicrostructures at pH5.0 and pH 7.0 have no obvious difference. There is no obviousnetwork structure at pH9.0.5. The conditions for strengthening the gel properties of jumbo squid wereoptimized through RSM. The best condition for hardness is 1.07% of TGaseconcentration, 42.1℃of temperature and 2.18 hours, all of which makes the hardness434.2 accordingly. The best condition for springiness is 0.765% of TGaseconcentration, 44.3℃of temperature and 1.61 hours, all of which makes thespringiness 0.973 accordingly.