Inhibition of Lysinoalanine Formation and Spinnability of Low Protein Concentration Dope

Abstract

A large amount of lysinoalanine (LAL) was found in the spun fiber of soy protein. Thus its inhibition was attempted in preparing dope and spun fiber, and the spinnability of the dope was studied.
The amount of LAL increased with increasing protein concentration. LAL formation was directly proportional to the protein concentration, which might be attributed to the increased frictional heat generated by the high viscosity of the dope.
LAL formation could be controlled in low protein concentration dope, but it resulted in a reduction of the viscoelastic value of the dope. When there was less than 14% protein, the dope could not be spun at 50°C, whereas it showed good spinnability when applied in low temperature process. In the case of 14% protein, dope prepared with 0.4_??_0.7% NaOH showed excellent spinnability (spun at a rate of more than 35m/min). Dope prepared with 0.1% NaOH (pH 8.5) could also be spun at a rate of 20m/min. Low temperature and low alkali treated fibers prepared from 14% protein showed decreased LAL formation.