title: Chitosan/pectin polyelectrolyte complex as a pH indicator.
abstract: A polyelectrolyte complex (PEC) matrix formed between chitosan and pectin was developed to entrap a bioactive compound (anthocyanin), obtaining an useful pH indicator device. Polysaccharides of opposite charges such as chitosan and pectin can have a very strong intermolecular interaction. The innovation lies in obtaining a new system based on natural and biodegradable compounds, which is simple to manufacture, to indicate variation in pH by visual changes in colour. This device has potential applications in food packaging. The PEC was studied using chitosan and pectin solutions at different pHs values (3.0, 4.0, 5.0 and 5.5) and pectin/chitosan molar ratios (1.0 to 10/1.0 to 5.0). PEC films were homogeneous and showed the highest yield (60.0%) at pH 5.5. Diffusion tests indicated efficient bioactive compound entrapment in the PEC matrix. Thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy indicate the compatibility between the polymers and bioactive compound.
authors.affiliation: UNICAMP-State University of Campinas, School of Chemical Engineering, Av. Albert Einstein, 500-CP, 13083-852 Campinas, SP, Brazil. Electronic address: viniciusbvm@feq.unicamp.br.
authors.forename: Vinicius Borges V
authors.initials: VB
authors.lastname: Maciel
authors.affiliation: UNIFESP-Federal University of São Paulo, Department of Exact and Earth Science, Rua São Nicolau, 210 Diadema, SP, Brazil. Electronic address: cristiana.yoshida@unifesp.br.
authors.forename: Cristiana M P
authors.initials: CM
authors.lastname: Yoshida
authors.affiliation: UNICAMP-State University of Campinas, School of Chemical Engineering, Av. Albert Einstein, 500-CP, 13083-852 Campinas, SP, Brazil. Electronic address: franco@feq.unicamp.br.
authors.forename: Telma Teixeira
authors.initials: TT
authors.lastname: Franco
mesh_terms: D048271:Chitosan / Q000737:chemistry*; D004573:Electrolytes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D010368:Pectins / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry
chemical_list: D004573:Electrolytes; D011108:Polymers; D010368:Pectins; D048271:Chitosan
keywords: Anthocyanin; Chitosan; Pectin; Polyelectrolyte complex; pH indicator