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Impact of Thiocyanate Salts on Physical, Thermal, and Rheological Properties of Zein Films
Author(s) -
Selling Gordon W.,
Maness Ashley,
Bean Scott,
Smith Brennan
Publication year - 2013
Publication title -
cereal chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.558
H-Index - 100
eISSN - 1943-3638
pISSN - 0009-0352
DOI - 10.1094/cchem-09-12-0123-r
Subject(s) - plasticizer , chemistry , elongation , differential scanning calorimetry , ultimate tensile strength , thiocyanate , glass transition , rheology , ammonium thiocyanate , ethylene glycol , salt (chemistry) , potassium thiocyanate , chemical engineering , sodium thiocyanate , nuclear chemistry , polymer chemistry , inorganic chemistry , organic chemistry , polymer , materials science , composite material , physics , engineering , thermodynamics
A new class of zein additives was investigated, thiocyanate salts. Ammonium, potassium, guanidine (GTC), and magnesium thiocyanate salts were added to solutions of zein in with various amounts of tri(ethylene glycol) (TEG), cast as films, and then tested to determine the impact that each salt had on properties. The presence of these salts affected solution rheology and intrinsic viscosity, demonstrating that the salts interacted with the protein. It was found that these salts acted as plasticizers, as they lowered the glass transition temperature of zein when evaluated with differential scanning calorimetry. In zein films in which TEG was present, these salts increased elongation and reduced tensile strength. However, unlike traditional plasticizers (such as TEG), when the salts were used as the only additive, elongation was not increased and tensile strength was not decreased. Of the salts tested, GTC in combination with TEG was found to increase elongation the most. The impact of salts on elongation was greatly affected by the relative humidity in which the samples were stored.