Thermoplastic starch plasticized with alginate-glycerol mixtures: Melt-processing evaluation and film properties.
Corn starch melt-processing in the presence of a commonly used plasticizer mixture (water/glycerol) and a non-conventional alternative (alginate/glycerol) was evaluated. All assayed formulations were successfully processed by melt-mixing and injected in circular probes. It was determined that all samples presented a typical viscoelastic behavior, observing a decrease in storage and loss modulus with water and alginate concentration, which facilitated samples processability. Concerning to thermal stability, it was not affected neither for water nor alginate presence. From injected probes, flexible films were obtained by thermo-compression. Films with the highest assayed water content presented a sticky appearance, whereas those containing alginate were non-tacky. Plasticizing action of water and alginate was evidenced by the occurrence of homogeneous fracture surfaces, without the presence of unmelted starch granules. Besides, the shift of glass transition temperature to lower values also corroborated the plasticizing effect of both additives. In conclusion, obtained results demonstrated the well-plasticizing action of sodium alginate on starch matrix, turning this additive into a promissory alternative to replace water during melt-processing of thermoplastic corn-starch.
Planta Piloto de Ingeniería Química (PLAPIQUI), Departamento de Ingeniería Química, Universidad Nacional del Sur (UNS), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino "La Carrindanga" km 7, 8000 Bahía Blanca, Argentina; Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA), Universidad Nacional de La Plata, CONICET, 47 y 115, 1900 La Plata, Argentina. Electronic address: ovlopez75@yahoo.com.ar.
Olivia V
OV
López
Planta Piloto de Ingeniería Química (PLAPIQUI), Departamento de Ingeniería Química, Universidad Nacional del Sur (UNS), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino "La Carrindanga" km 7, 8000 Bahía Blanca, Argentina.
Mario D
MD
Ninago
Planta Piloto de Ingeniería Química (PLAPIQUI), Departamento de Ingeniería Química, Universidad Nacional del Sur (UNS), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino "La Carrindanga" km 7, 8000 Bahía Blanca, Argentina.
M M Soledad
MM
Lencina
Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA), Universidad Nacional de La Plata, CONICET, 47 y 115, 1900 La Plata, Argentina.
María A
MA
García
Departamento de Química, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahía Blanca, Argentina.
Noemí A
NA
Andreucetti
Planta Piloto de Ingeniería Química (PLAPIQUI), Departamento de Ingeniería Química, Universidad Nacional del Sur (UNS), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino "La Carrindanga" km 7, 8000 Bahía Blanca, Argentina.
Andrés E
AE
Ciolino
Planta Piloto de Ingeniería Química (PLAPIQUI), Departamento de Ingeniería Química, Universidad Nacional del Sur (UNS), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Camino "La Carrindanga" km 7, 8000 Bahía Blanca, Argentina.
Marcelo A
MA
Villar
D000464:Alginates / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D005990:Glycerol / Q000737:chemistry*; D006603:Hexuronic Acids / Q000737:chemistry; D010968:Plasticizers / Q000737:chemistry*; D013213:Starch / Q000737:chemistry*; D044366:Transition Temperature; D014867:Water / Q000737:chemistry; D003313:Zea mays / Q000737:chemistry*
D000464:Alginates; D006603:Hexuronic Acids; D010968:Plasticizers; D014867:Water; D020723:Glucuronic Acid; D013213:Starch; D005990:Glycerol
Corn starch; Melt-processing; Plasticizers; Sodium alginate