Protein insolubilization and starch gelantinization of mechanically deboned chicken meat and cornstarch during twin-screw extrusion

Using high-temperature, short-time, twin-screw extrusion, 0.9% NaCl-soluble protein extractability and starch gelatinization of mechanically deboned chicken meat and 15% cornstarch (MDC-CS) extrudates were determined as a function of position in the extruder barrel. There were slight changes in total solids, protein, and fat in MDC-CS extrudates sampled in different sections of the barrel. Protein extractability decreased and starch gelatinization increased as the product moved through the barrel. A maximum of 75.4% gelatinized starch was measured in sampling Location 3 at 112 C. Protein extractability decreased from 100% at the feed port to 58.1% in sampling Location 2 at 103 C. Minimum protein extractability of 5.6% occurred at the die. The number of extractable protein bands decreased as the product moved through the barrel. Results indicated it is possible to identify changes in protein extractability and CS gelatinization as the product passes through the extruder barrel. The observations made in the current study may be helpful in establishing extrusion conditions to promote optimum protein denaturation and starch gelatinization in a particular barrel location for desired product texture and quality