title: Chemical treatment and characterization of soybean straw and soybean protein isolate/straw composite films.
abstract: This work investigated changes in the chemical composition and structure of soybean straw (SS) treated with alkali (NaOH 5% and 17.5%) and bleached with hydrogen peroxide (H2O2) or sodium hypochlorite (NaOCl). Removal of the amorphous constituents increased the degree of crystallinity and the content of cellulose fibers particularly after reaction with high concentrations of alkali. Treatment with NaOH 17.5% contributed to the allomorph transition from cellulose I to II regardless of the bleaching agent, but H2O2as bleaching agent promoted more effective delignification. This work also evaluated the potential use of treated and non-treated SS as reinforcement filler in soy protein isolate film (SPI). Films added with treated SS presented higher mechanical resistance, lower elongation at break, and lower solubility in water. Addition of non-treated SS did not affect the properties of the SPI film significantly. The low solubility and the reasonable water vapor permeability of the composite films make them suitable packaging materials for fresh fruit and vegetables.
authors.affiliation: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Bandeirantes Avenue 3900, CEP 14040-901, Ribeirão Preto, SP, Brazil; Departamento de Engenharia de Alimentos, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, Rua Duque de Caxias Norte 225, CEP 13635-900, Pirassununga, SP, Brazil. Electronic address: mmartelli@usp.br.
authors.forename: Milena
authors.initials: M
authors.lastname: Martelli-Tosi
authors.affiliation: Embrapa Instrumentação, National Nanotechnology Laboratory for Agriculture, Rua XV de Novembro, 1452, CEP 13561-206, São Carlos, SP, Brazil.
authors.forename: Odílio B G
authors.initials: OBG
authors.lastname: Assis
authors.affiliation: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Bandeirantes Avenue 3900, CEP 14040-901, Ribeirão Preto, SP, Brazil.
authors.forename: Natália C
authors.initials: NC
authors.lastname: Silva
authors.affiliation: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Bandeirantes Avenue 3900, CEP 14040-901, Ribeirão Preto, SP, Brazil.
authors.forename: Bruno S
authors.initials: BS
authors.lastname: Esposto
authors.affiliation: Embrapa Instrumentação, National Nanotechnology Laboratory for Agriculture, Rua XV de Novembro, 1452, CEP 13561-206, São Carlos, SP, Brazil.
authors.forename: Maria Alice
authors.initials: MA
authors.lastname: Martins
authors.affiliation: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Bandeirantes Avenue 3900, CEP 14040-901, Ribeirão Preto, SP, Brazil.
authors.forename: Delia R
authors.initials: DR
authors.lastname: Tapia-Blácido
mesh_terms: D002482:Cellulose; D018857:Food Packaging; D005519:Food Preservation; D006861:Hydrogen Peroxide; D010539:Permeability; D012973:Sodium Hypochlorite; D030262:Soybean Proteins / Q000737:chemistry*; D013025:Glycine max; D013718:Tensile Strength
chemical_list: D030262:Soybean Proteins; D002482:Cellulose; D006861:Hydrogen Peroxide; D012973:Sodium Hypochlorite
keywords: Chemical treatment; Composite films; Mechanical properties; Microfiber morphology; Soybean straw; Structure characterization