Abstract: Starch-protein composites were prepared by separately adding different levels (0%, 4%, 6%, 8%, 10%, and 12%) of native corn starch (NCS), acetylated distarch phosphate (ADP), acetylated distarch adipate (ADA) and starch acetate (SA) to myofibrillar protein (MP) solution, and their rheological properties, gel strength, water-holding capacity and nuclear magnetic resonance (NMR) water relaxation time were measured. The results showed that the addition of starches significantly increased the storage modulus (G′) of MP, which began to increase at around 42 ℃. At this time MP began to form a gel, and the addition of modified starches significantly delayed the denaturation of MP (43–46 ℃). The gel strength of starch-protein composites reached its maximum when the addition level of modified starches was 8%, while NCS had no significant effect on the gel strength of MP (P > 0.05). The WHC of starch-protein composite gels with modified starches was about 13% higher than that with NCS (P < 0.05), and the best WHC occurred with the addition of SA and ADA. NMR analysis showed that the T2 relaxation time decreased with increasing level of modified starches, and T22 moved in the direction of fast relaxation, which indicates that the addition of modified starches reduced the mobility of water molecules. Therefore, among the modified starches, ADA has the most significant effect on the rheological properties, gel strength, WHC and moisture migration of MP. An appropriate amount (no greater than 10%) of modified starches can significantly improve the G’, gel strength and WHC of MP and decrease the water migration rate.

Key words: starch, myofibrillar proteins, rheological properties, gel strength, moisture migration