期刊
FOOD HYDROCOLLOIDS
卷 113, 期 -, 页码 -出版社
ELSEVIER SCI LTD
DOI: 10.1016/j.foodhyd.2020.106424
关键词
Gelatin; Cellulose nanocrystal; Electrostatic interaction; Mechanical properties
资金
- Pulp and Paper Science and Graphic Arts (LGP2) that is part of the LabEx Tec 21 [ANR11-LABX-0030]
- PolyNat Carnot Institute [ANR-16-CARN-0025-0]
- Plant Macromolecule Research Center (CERMAV)
- Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior - Brasil (CAPES) [001]
- CNPq
- SISNANO (MCTI)
- FINEP
- Embrapa AgroNano research network (Embrapa)
- Sao Paulo Research Foundation (FAPESP) [2016/03080-2, 2018/00278-2]
Adjusting pH, CNCs content, and film-forming drying temperature is an effective strategy for improving the physical properties of Gel/CNCs films. Electrostatic attractive forces can reduce water vapor permeability, while the formation of complex coacervates may decrease mechanical properties.
Cellulose nanocrystals (CNCs)-reinforced gelatin (Gel) films are appealing candidates for biodegradable packaging. However, tailoring the physical properties of Gel/CNCs films by control of pH and film-forming drying temperature continues unstudied. Here, we described the influence of pH on the physical properties of Gel/CNCs films covering different CNCs contents. The interactions between CNCs and Gel were studied by assessing the zeta-potential of Gel/CNCs suspensions under acidic (pH 3), Gel isoelectric point (pI, pH 6) and alkaline (pH 8) conditions. pH 3 promotes the electrostatic attraction, while pH 8 favors the electrostatic repulsion in the Gel-CNCs pair, increasing the suspension viscosity in both cases. The addition of 0.5 wt% CNCs decreased the water vapor permeability (WVP) of the Gel/CNCs films by 68% under electrostatic attractive forces and by 39% at the gelatin pI. The addition of 5 wt% CNCs at pH 3 resulted in the formation of complex coacervates, which decreased the mechanical properties and increased the WVP of Gel/CNCs films. Increasing pH above the Gel pI remarkedly increased the gelatin renaturation as triple helices, which was found to be key for increasing by 152% and 56% the Young's modulus and tensile strength, respectively, of the Gel/CNCs films with 0.5 wt% CNCsFilm-forming drying temperatures had an inverse effect on the triple helix content, and, consequently, on the physical properties of the Gel/CNCs films. These findings denote that modulating pH, CNCs amount, and drying temperature is a suitable strategy for tailoring the properties of nanocellulose-reinforced gelatin films for an extended range of food packaging applications.
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