PHYSICOCHEMICAL CHARACTERIZATION OF STARCH BASED FILMS

BERTUZZI, MARÍA ALEJANDRA; ARMADA, MARGARITA; GOTTIFREDI, JUAN CARLOS

JOURNAL OF FOOD ENGINEERING

Elsevier

Año: 2007 vol. 82 p. 17 - 25

0260-8774

In the present paper, the physic and chemical characterization of high amylose corn starch (HACS) based film, through determination of film solubility in water, water sorption isotherms, opacity and crystallinity of films and the rheological behavior of film forming suspensions is reported. Effects of film composition and preparation method on film properties were investigated to identify HACS film elaboration conditions to improve film properties. Film forming suspensions show pseudoplastic and thixotropic behavior. Apparent viscosity of film forming gel increases exponentially with HACS concentration and Arrhenius law adequately represents variation with temperature. Alkaline treatment time of HACS previous to gelatinization, also affects film properties. It was found that film solubility and opacity decrease while crystallinity increases although it reaches an asymptotic value after treatment time of 60 minutes. Glycerol content also affect opacity and water sorption. Glycerol content should never overcome 30% to obtain acceptable quality films. Higher concentrations conduce to a looser network, as a result opacity and water sorption increase.