Microwave transmittance in gelatin-based films

Abstract

Biopolymers are alternative materials used in the production of edible and/or biodegradable films. A very important restriction factor concerning the films is their sensitivity to environmental conditions, such as temperature and relative humidity. The production of films based on gelatin and polyvinyl alcohol blends can be an alternative solution in order to reduce the sensitivity to the humidity. Thus, the aim of this work was to apply the microwave transmittance technique to measure qualitative effects of the presence of glycerol and polyvinyl alcohol on the moisture content of gelatin-based films. The results show that the films with glycerol, conditioned for one week in NaBr, revealed visible changes between 11 and 13 GHz as the plasticizer concentration increased. For gelatin films containing PVA, the results revealed very low microwave insertion losses. Thus, this behaviour was attributed to the presence of water molecules in gelatin films.

Acetylated Distarch Phosphate/Chitosan Films Reinforced with Sodium Laurate‐Modified Nano‐TiO2: Effects of Sodium Laurate Concentration

“…All the films exhibit strong absorption peaks between 3200 and 3400 cm −1 owing to the stretching vibrations of –OH and N–H, and at 2925 and 2851 cm −1 owing to the stretching vibration of the saturated C–H (Ahmad, Nirmal, Danish, Chuprom, & Jafarzedeh, ). The peaks at 1039 cm −1 mainly arose as a result of the possible interactions between the plasticizer and film structure (Bergo et al., ). With the addition of TiO 2 and TiO 2 ‐SLx, the intensity of the peaks of the ADSP/CS‐TiO 2 ‐SLx films at 2925 and 2851 cm −1 increased relative to those of the ADSP/CS film.…”

Phase transitions in biodegradable films based on blends of gelatin and poly (vinyl alcohol)

“…Among these alternatives, the mixing of these biopolymers with the poly (vinyl alcohol) (PvA) has gained interest in the last years. The PvA is a synthetic, hydrophilic and biodegradable polymer (MATSuMurA et al, 1999) which has been used in studies on the development and characterization of films, such as PvA/wheat (DIChArry et al, 2006), PvA/collagen hydrolysate (SArTI; SCANDolA, 1995;AleXy et al, 2003), and PvA/gelatin (ChIellINI et al, 2001a,b,c;berGo et al, 2006;MArIA et al, 2008;MeNDIeTA-TAboADA et al, 2008;SIlvA et al, 2008;MorAeS et al, 2008;CArvAlho et al, 2009), among others.…”

“…Therefore, gelatin has been widely used as a single biopolymer in studies on edible and/or biodegradable films (lIM;MINe;TuNG, 1999;MeNeGAllI et al, 1999;SobrAl, 1999;SobrAl et al, 2001;GroSSo, 2004;vANIN et al, 2005;ThoMAZINe;SobrAl, 2005;yAKIMeTS et al, 2005;berGo; moisture content = 9.3%) donated by Gelita South America (Sao Paulo, brazil), and the poly (vinyl alcohol) (PvA) with two hydrolysis degrees (hD) (Celvol-418, hD = 91.8%; Celvol-350, hD = 98.6%) donated by Celanese (Dallas, uSA). The studied plasticizers were glycerol (Synth, brazil) and sorbitol (Nuclear, brazil).…”

Gamma-Irradiated Gelatin-Based Films Modified by HEMA for Medical Application

“…[1] Consequently, biodegradable film preparation including pure gelatin [2][3][4][5][6][7] or gelatin blended with other biopolymers, [8,9] followed by a casting method, and film characterization have been investigated. It is commonly used in the food, cosmetics, and photographic industries for its gel-forming abilities, nontoxicity, and low production cost.…”