Henrique C. M., Teófilo R. F., Sabino L., Ferreira M. M. C.,
Cereda M. P., "Classification of Cassava Starch Films by Physicochemical
Properties and Water Vapor Permeability Quantification by FTIR and PLS",
J.
Food Sci., 72(4), E184-E189 (May 2007).
[Article]
Abstract.
Cassava starches are widely used in the production of biodegradable
films, but their resistance to humidity migration is very low. In this
work, commercial cassava starch films were studied and classified according
to their physicochemical properties. A nondestructive method for water
vapor permeability determination, which combines with infrared spectroscopy
and multivariate calibration, is also presented. The following commercial
cassava starches were studied: pregelatinized (amidomax 3550), carboxymethylated
starch (CMA) of low and high viscosities, and esterified starches. To make
the films, 2 different starch concentrations were evaluated, consisting
of water suspensions with 3% and 5% starch. The filmogenic solutions were
dried and characterized for their thickness, grammage, water vapor permeability,
water activity, tensile strength (deformation force), water solubility,
and puncture strength (deformation). The minimum thicknesses were 0.5 to
0.6 mm in pregelatinized starch films. The results were treated by means
of the following chemometric methods: principal component analysis (PCA)
and partial least squares (PLS) regression. PCA analysis on the physicochemical
properties of the films showed that the differences in concentration of
the dried material (3% and 5% starch) and also in the type of starch modification
were mainly related to the following properties: permeability, solubility,
and thickness. IR spectra collected in the region of 4000 to 600 cm-1
were used to build a PLS model with good predictive power for water vapor
permeability determination, with mean relative errors of 10.0% for cross-validation
and 7.8% for the prediction set.
Keywords.
Keywords Plus.