EFFECT OF GLYCEROL ON PHYSICAL PROPERTIES OF CASSAVA STARCH FILMS

• Published in: Journal of food processing and preservation Vol. 34; no. s2; pp. 401 - 410
• Main Authors: BERGO, P, SOBRAL, P.J.A, PRISON, J.M
• Format: Journal Article
• Language: English
• Published: Malden, USA Malden, USA : Blackwell Publishing Inc 01-05-2010; Blackwell Publishing Inc
• ISSN: 0145-8892; 1745-4549
• DOI: 10.1111/j.1745-4549.2008.00282.x

In this work, the effect of glycerol on the physical properties of edible films were identified by X-ray diffraction (XRD), differential scanning calorimetry (DSC), infrared (FTIR) and microwave spectroscopy. According to XRD diffractograms, films with 0 and 15% glycerol displayed an amorphous character, and a tendency to semicrystallization, for films with 30% and 45% glycerol. From DSC thermograms, the glass transition (Tg) of the films decreased with glycerol content. However, two Tgs were observed for samples with 30% and 45% glycerol, due to a phase separation. The intensity and positions of the peaks in FTIR fingerprint region presented slight variations due to new interactions arising between glycerol and biopolymer. Microwave measurements were sensitive to moisture content in the films, due to hydrophilic nature of the glycerol. The effect of plasticizer plays, then, an important rule on the physical and functional properties of these films, for applications in food technology. Edible and/or biodegradable films are thin materials used mainly in food recovering, food packaging and other applications, in substitution of the films obtained by synthetic ways. In view of these applications, these films must satisfy some of the exigencies in order to increase the food shelf-life, or in other words, they must be flexible, transparent, resistant to some gases such as oxygen, as well as resistant to water vapor. The addition of plasticizers alters the functional properties of the films. Thus, the physical characterization of these films becomes fundamental in order to increase their potential use in industry.