Effect of drying conditions and plasticizer type on some physical and mechanical properties of amaranth flour films

Abstract

a b s t r a c tIn this work we studied the influence of the drying temperature and relative humidity on the solubility, mechanical properties, water vapor permeability (WVP), and drying time of amaranth flour films plasticized with glycerol or sorbitol. The effect of drying temperature and relative humidity on the mechanical properties of the film is a function of the plasticizer type. In the presence of glycerol, tougher flour films are obtained at a lower drying rate, but an inverse behavior is observed for the films plasticized with sorbitol. The drying conditions do not have a significant effect on WVP compared with sorbitol-plasticized samples, the water sorption isotherm shows that the glycerol-plasticized flour films are able to retain more water at equilibrium at all the studied temperatures. The lower moisture content, WVP and drying time achieved for these films in all the drying conditions indicate better interaction of sorbitol with the starch and protein macromolecules present in the amaranth flour. The optimized drying conditions are 50 C and 76.2% RH, and 35 C and 70.3% RH for the films plasticized with glycerol and sorbitol, respectively.

Effect of Plasticizer Type and Concentration on Tensile, Thermal and Barrier Properties of Biodegradable Films Based on Sugar Palm (Arenga pinnata) Starch

“…The tensile strength values of plasticized SPS films were higher than the reported values for films of corn starch with glycerol and stearic acid [69], corn starch with glycerol and xylitol [62], corn starch with glycerol alone [70], glycerol plasticized rice starch [71], amaranth flour plasticized with sorbitol or glycerol [68], cassava starch with glycerol [72], cush-cush yam starch [73], and pea starch with glycerol [74]. On the other hand, their tensile strength values were lower than LDPE and polystyrene [63].…”

“…This tendency can be ascribed to the smaller molar mass of glycerol (92.0928 g/mol; sorbitol 182 g/mol) which facilitate easy interaction between glycerol-starch molecular chains. Tapia-Blácido et al [68] also testified that glycerol is a more effective plasticizer for most edible films. [68] and Tapia-Blácido et al [50], who reported that sorbitol plasticized flour films are more resistant to breakage than films plasticized with glycerol at constant proportions.…”

“…Tapia-Blácido et al [68] also testified that glycerol is a more effective plasticizer for most edible films. [68] and Tapia-Blácido et al [50], who reported that sorbitol plasticized flour films are more resistant to breakage than films plasticized with glycerol at constant proportions. Interestingly, GS-plasticized films exhibited a tensile strength between individual G-and S-plasticized films.…”

Design and characterization of mucoadhesive hydroxypropyl cellulose oral films

“…Significant difference was not found between the tensile strengths during the storage. HPC described as having less water affinity in the literature [70] and this behaviour of filmforming polymer was evidenced with tensile strength measurement, because the Gly content of the films dramatically decreased the tensile strength of films via increasing of water absorption which is also written in the literature [85][86][87].…”

“…Például β 1 -receptor stimuláció a nyálmirigy megnagyobbodását idézi elő, míg a metoprolol (β 1 antagonista) csökkenti a mirigyállo-mány méretét [86,87]. A nyálmirigy állomány megnagyobbodását okozó hatóanyagok a VII.…”