Electrospinning of soy protein isolate and poly(lactic acid) ultrafine fibers for controlled release of allyl isothiocyanate
In this project, electrospinning technique was investigated to produce ultrafine soy protein isolate (SPI) and poly(lactic acid) (PLA) fibers. SPI fibers (~200 nm) were produced by electrospinning denatured protein (10-15% wt/wt) in aqueous solution (pH 12, 60 °C) in the presence of poly(ethylene oxide) (0.6-0.8% wt/wt) and Triton X-100 (0.5-1% wt/wt). In contrast, PLA fibers (~4 [mu]m) were spun from polymer (10% wt/wt) dissolved in a mixture of chloroform and dimethylformamide DMF (90:10). Fiber morphology can be manipulated readily by changing the fiber-forming formulation. An antimicrobial agent, allyl isothiocyanate (AITC), was incorporated in SPI and PLA electrospun fibers by direct addition of the antimicrobial into the fiber-forming solution. AITC concentration significantly affected the fiber morphology. AITC loss was reduced when cyclodextrins were used as a secondary carrier. Exposing these fibers to elevated humidity (>50% RH) triggered the release of AITC, with concomitant change in visual appearance and fiber micro-morphology. Preliminary studies showed that electrospun SPI fibers with AITC prevented mold growth on bread, indicating promising active and smart packaging applications.