Influence of Different Commercial Modified Cassava Starches on the Physicochemical Properties of Thermoplastic Edible Films Obtained by Flat‐Die Extrusion

Abstract

Starch constitutes a promising resource for biodegradable packaging, but it presents several processing drawbacks when using conventional industrial equipment, such as flat‐die extrusion. This work demonstrates that the replacement of native cassava starch (NS) with commercial hydrolyzed (HS) or carboxymethyl (CMS) starches diminishes the amount of energy required to process starch granules into thermoplastic films by extrusion. Homogeneous films with starch‐glycerol interaction improvements are obtained when using HS or CMS instead of NS. HS films exhibit the lowest crystallinity and the highest susceptibility to water among the studied systems. Likewise, CMS films maximize Vh crystalline structure fraction and present higher Young's modulus and stress at break, and lower water vapor permeability values. In order to combine the positive properties and to overcome the limitations of each modified starch, blend films from HS:CMS (50:50 wt%) are also developed and investigated. Phase separation is observed in this system, and there are no improvements in the overall properties. The results of this investigation show that employing commercial CMS, even in very low carboxymethylation degree represents a successful strategy to improve mechanical and barrier properties of flat‐die extruded films, while HS can be used to obtain water‐soluble films for specific applications.

Effect of TiO2 Nanoparticles and Extrusion Process on the Physicochemical Properties of Biodegradable and Active Cassava Starch Nanocomposites

“…The relative intensity of the peak at 18° decreased while that of the peaks corresponding to the Vh-type structure at 19.6° increased in S 120 samples compared to S 80 ( Figure 4 ). These results are due to a better starch processing in S 120 and thus to the possible greater interaction between starch and glycerol, suggesting that more glycerol molecules are within the helical structure of the starch in this film [ 33 , 53 ]. As a consequence, lower RC values were obtained for the films processed at 120 rpm ( Table 1 ).…”

“…The temperature profile employed was set at 80 °C/100 °C/110 °C/120 °C/130 °C/140 °C/140 °C/140 °C/130 °C/120 °C for both screw speeds. This temperature profile was chosen considering that in previous works a lower temperature profile was employed at 80 rpm or 120 rpm, which led to some broken starch granules [ 32 , 33 ]. From extrusion process a large thread was obtained that was stabilized in a desiccator at room temperature and relative humidity (RH) of 57% given by a saturated solution of sodium bromide (NaBr).…”

“…Water vapor permeability (WVP) of developed films was determined according to ASTM E-96 procedure with the following modifications [ 33 , 40 ]: Film samples were placed in acrylic permeation cells, with an exposed circular area of 3.8 × 10 −4 m 2 , previously filled with CaCl 2 . Cells were conditioned in desiccators at RH of 75% (NaCl) and stored at room temperature to simulate a humidity-controlled chamber.…”

Effect of Wheat and Oat Bran on the Physicochemical Properties of Edible Starch‐Based Films Obtained by Extrusion for Food Packaging Applications

“…[ 9–12 ] However, one of the most difficult challenges in the research of starch‐based materials has been to make them competitive and to be able to produce them using industrial‐scale process techniques, such as the extrusion. [ 13–15 ]…”

“…[9][10][11][12] However, one of the most difficult challenges in the research of starch-based materials has been to make them competitive and to be able to produce them using industrial-scale process techniques, such as the extrusion. [13][14][15] One strategy to enhance the competition of starch films has been to improve their mechanical resistance through the use of edible nano/micro particles, [16][17][18] but also to enrich them by granting certain functionality. In particular, bran has been highly promoted for different types of diets due to its high content of nutrients and health benefits.…”