Preparation and characterization of whey protein isolate films reinforced with porous silica coated titania nanoparticles

Abstract

Whey protein isolate (WPI) films embedded with TiO2@@SiO2 (porous silica (SiO2) coated titania (TiO2)) nanoparticles for improved mechanical properties were prepared by solution casting. A WPI solution of 1.5 wt% TiO2@@SiO2 nanoparticles was subjected to sonication at amplitudes of 0, 16, 80 and 160 μm prior to casting in order to improve the film forming properties of protein and to obtain a uniform distribution of nanoparticles in the WPI films. The physical and mechanical properties of the films were determined by dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and tensile testing. Water vapor permeability (WVP) measurements revealed that the water vapor transmission rates are slightly influenced by sonication conditions and nanoparticle loading. The DMA results showed that, at high sonication levels, addition of nanoparticles prevented protein agglomeration. The thermal stability of the materials revealed the presence of 3-4 degradation stages in oxidizing the protein films. The addition of nanoparticles strengthens the WPI film, as evidenced by tensile stress analysis. Sonication improved nanoparticle distribution in film matrix; such films can potentially become effective packaging materials to enhance food quality and safety. AbstractWhey protein isolate (WPI) films embedded with TiO 2 @@SiO 2 (porous silica (SiO 2 ) coated titania (TiO 2 )) nanoparticles for improved mechanical properties were prepared by solution casting. A WPI solution of 1.5 wt% TiO 2 @@SiO 2 nanoparticles was subjected to sonication at amplitudes of 0, 16, 80 and 160 μm prior to casting in order to improve the film forming properties of protein and to obtain a uniform distribution of nanoparticles in the WPI films. The physical and mechanical properties of the films were determined by dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and tensile testing. Water vapor permeability (WVP) measurements revealed that the water vapor transmission rates are slightly influenced by sonication conditions and nanoparticle loading. The DMA results showed that, at high sonication levels, addition of nanoparticles prevented protein agglomeration. The thermal stability of the materials revealed the presence of 3-4 degradation stages in oxidizing the protein films. The addition of nanoparticles strengthens the WPI film, as evidenced by tensile stress analysis. Sonication improved nanoparticle distribution in film matrix; such films can potentially become effective packaging materials to enhance food quality and safety.

Improvement of barrier and mechanical properties of whey protein isolate based food packaging films by incorporation of zein nanoparticles as a novel bionanocomposite

“…Zhou et al (2009) used 4% TiO 2 and observed a 70% decrease in WVP while Zolfi et al (2014) and Li et al (2011) observed 14% and 9.4% decreases by adding 5% and 1% TiO 2 , respectively. Kadam et al (2013) and Sothornvit et al (2009) did not obtain any gain in the barrier property of the WPI film after adding silica coated TiO 2 and clay nanoparticles, respectively. Zolfi et al (2014) reported that WVP decreased by 57% with 5% clay addition while Sothornvit, et.…”

“…With the addition of titania, Zhou et al (2009) andLi et al (2011) reached a maximum strength of 2.38 MPa (41% increment with respect to pure WPI film) and 10.2 MPa (67% increment), respectively. To achieve a homogeneous distribution of the nanoparticles, Kadam et al (2013) coated titania with silica, however, they observed only a slight increase in tensile strength from 1.03 to 1.18 MPa (15% increment). Zolfi et al (2014), Wakai and Almenar (2015) and Azevedo et al (2015) measured maximum tensile strengths of~11 MPa (57% increment with respect to pure WPI film), 2.3 MPa (16% increment) and 5.42 MPa (49% increment), respectively.…”

“…Zhou, Wang, and Gunasekaran (2009) reported that small amounts of TiO 2 (<1%) addition significantly improved the tensile properties of WPI film, on the other hand had a negative effect on the moisture barrier properties. Kadam et al (2013) coated TiO 2 nanoparticles with a layer of silica and applied sonication to the film forming solution prior to casting to prevent aggregation of the particles. Combination of sonication and silica coating contributed to enhancing tensile stress at break and Young modulus values, however, this strategy did not alter the moisture barrier properties and caused 50% reduction in elongation of the films.…”

Improvement of Food Packaging-Related Properties of Whey Protein Isolate-Based Nanocomposite Films and Coatings by Addition of Montmorillonite Nanoplatelets

“…Hence, among other biopolymers (Park et al, 2002;Petersson and Oksman, 2006;Almasi et al, 2010), whey protein-based nanocomposites have become a promising field of interest in recent years (Hedenqvist et al, 2006;Zhou et al, 2009;Sothornvit et al, 2010;Li et al, 2011;Kadam et al, 2013;Zolfi et al, 2014;Azevedo et al, 2015;Wakai and Almenar, 2015;Hassannia-Kolaee et al, 2016a,b;Oymaci and Altinkaya, 2016). Previous research on whey protein isolate (WPI) nanocomposites demonstrated that the barrier and mechanical properties of these materials improved with increasing nanofiller loadings (Sothornvit et al, 2010;Zolfi et al, 2014;Azevedo et al, 2015;Hassannia-Kolaee et al, 2016a;Oymaci and Altinkaya, 2016;Zink et al, 2016).…”

Microstructure and Antimicrobial Functionality of Nano-Enhanced Protein-Based Biopolymers

“…Nanofillers (e.g., nanoclays) have been used to strengthen whey protein polymer matrices (Zhao et al, 2008). In an earlier report, we demonstrated that the mechanical properties of WPI and corn zein films could be improved by using porous silica (SiO 2 ) coated titania (TiO 2 ) nanoparticles as nanoenhancers (TiO 2 @@SiO 2 ) (Kadam et al, 2013).…”