Study On The Extraction And Characteristics Of Myofibrillar Protein From Abalone (Haliotis Discus Hannai Ino)

Abalone (Haliotis discus hannai Ino), belonging to Mollusk, Gastropoda, is one of the most precious marine food in China. In the present study, abalone was studied as object and the extensive information on the physicochemical properties of myofibrillar proteins extracted from abalone was investigated during thermal treatment.The objective of present study was to obtain extensive information on the composition and its solution turbidity and solubility of myofibrillar protein extracted from abalone. The electrophoretic patterns indicated that abalone myofibrillar protein mainly contained myosin (201 kDa), paramyosin (96 kDa), actin (46 kDa) and tropomyosin (38 kDa). The turbidity increased but the solubility decreased with the increase of temperature, particularly from 40 to 50℃. The turbidity decreased but the solubility increased significantly at pH between 5.5 and 6.0 and with the increase of ionic strength from 0.2 to 0.4 mol/L.The surface hydrophobicity of abalone myofibrillar protein was calculated from the determined fluorescence intensity using 1-anilinonaphthalene-8-sulfonic acid (ANS) as the probe. The results indicated that the surface hydrophobicity significantly increased from 30 to 80℃, and then remained unchanged with increased temperature to 90℃. The a helix content of abalone myofibrillar protein was determined by circular dichroism analysis. The results indicated that the α-helix content decreased substantially from 40 to 90℃, which resulting in 56% of the α-helix unfolded. The total sulfhydryl content of abalone myofibrillar protein was determined by colorimetric assay using Ellman’s reagent. The results showed that the total sulfhydryl content remained constant until 60℃, and then decreased rapidly with increased temperature to 90℃. Therefore, as a conclusion, the myofibrillar protein from abalone underwent aggregation with alterations of tertiary and quaternary structures, unfolding of the secondary structures and formation of disulfide bonds during thermal treatment.Meanwhile, the effect of protein content, heating temperature and time on the water holding capacity (WHC) was also studied. The results displayed that 1) the WHC increased with the increase of protein content; 2) the higher WHC appeared when the heating temperature were at 40℃ and 50℃, especially at 50℃ for 10 min.The heat-induced dissociation of abalone myofibrillar protein was also examined by the method of SDS-PAGE. The results showed 1) the most extensive dissociation occurred at 45℃, and no apparent dissociation occurred above 55℃; 2) the myofibrillar protein dissociated sufficiently after treated at 50℃ for 5 min, and at a much lower extent for longer than 30 min; 3) the increasing of the amount of ATP can induce dissociation of myofibrillar protein.