Rheology and microstructure of myofibrillar protein-starch composite gels: Comparison of native and modified starches.

Composite gels were prepared from 2% myofibrillar protein (MP) imbedded with native starch (potato or tapioca starch) or their modified starches in 0.6 M NaCl at pH 6.2. The role of native starch (potato or tapioca) and their modified counterparts in the rheology and microstructure of MP gels was evaluated. Dynamic rheological testing with temperature sweeping (20-80 °C) showed substantial increases in the storage modulus (G') of the MP sols/gels with the addition of starch. The increase in G' was inversely related to the pasting temperature of specific starch types. The strength and water-holding capacity (WHC) of the MP composite gels containing esterified starches were superior to those containing native or cross-linked esterified starches. Microstructural analysis showed that the "packing effect" of potato starch (PS) on MP gels was more remarkable than that of tapioca starch (TS) because of the larger granule size of the PS. However, esterified TS (ETS) and native TS made the greatest contribution to the WHC of the MP gels at 80 °C.