Optimization of the conditions for producing soy protein isolate films

  • Isabela dos Santos Paglione Programa de Pós-graduação em Tecnologia de Alimentos (PPGTAL), Universidade Tecnológica Federal do Paraná, Avenida dos Pioneiros 3131, CEP 86036-370, Londrina, Paraná, Brazil
  • Marcella Vitoria Galindo Departamento Acadêmico de Alimentos (DAALM), Universidade Tecnológica Federal do Paraná, Londrina, Paraná, Brazil
  • Karen Cristine de Souza Programa de Pós-graduação em Tecnologia de Alimentos (PPGTAL), Universidade Tecnológica Federal do Paraná, Avenida dos Pioneiros 3131, CEP 86036-370, Londrina, Paraná, Brazil
  • Fabio Yamashita Programa de Pós-graduação em Ciência de Alimentos, Universidade Estadual de Londrina, Londrina, Paraná, Brazil
  • Carlos Raimundo Ferreira Grosso, Lyssa Setsuko Sakanaka, Marianne Ayumi Shirai Programa de Pós-graduação em Tecnologia de Alimentos (PPGTAL), Universidade Tecnológica Federal do Paraná, Avenida dos Pioneiros 3131, CEP 86036-370, Londrina, Paraná, Brazil

Abstract

The soy protein isolate (SPI) is a biopolymer highlighted as a raw material for producing films and demands the investigation of the processing conditions that make it possible to obtain a film with adequate functional properties. The objective of this work was to evaluate the effect of the pH and concentration of SPI on the mechanical properties, water vapor permeability, solubility, and color of the SPI films produced by casting using a central composite rotational design (CCRD). In general, the films presented a yellow coloration with a continuous aspect, good handling, and no apparent glycerol migration. The linear effect of pH positively influenced the tensile strength (TS) and elongation at break (ELO) of the film (p <0.05) but negatively influence the solubility (SOL) and color parameter L* for which we obtained lower values ​​of SOL and L* at a high pH. This possibly occurred because of the denaturation of the soy proteins at an alkaline pH, far from the isoelectric point, resulting in their unfolding and solubilization which facilitated the interaction between the chains, forming a more compact structure. Considering the optimization by the desirability function, to obtain a film with high TS and ELO and low SOL, it is necessary to use 7.56 g/100 g of SPI film-forming solution and to adjust the film-producing solution to pH 10.54.

Keywords: central composite rotational design, biopolymers, mechanical properties, solubility, desirability
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How to Cite
Paglione, I. dos S., M. V. Galindo, K. C. de Souza, F. Yamashita, and C. R. F. G. L. Setsuko Sakanaka, Marianne Ayumi Shirai. “Optimization of the Conditions for Producing Soy Protein Isolate Films”. Emirates Journal of Food and Agriculture, Vol. 31, no. 4, May 2019, pp. 297-03, doi:https://doi.org/10.9755/ejfa.2019.v31.i4.1933. Accessed 18 July 2019.
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Research Article