Optimization of the Physical, Optical and Mechanical Properties of Composite Edible Films of Gelatin, Whey Protein and Chitosan.

Daniel Arizmendi-Cotero,María Dolores Hernández-Navarro,Octavio Dublán-García,Selene Elizabeth Herrera-Vázquez,Hariz Islas-Flores,Ninfa Ramírez-Durán,Leobardo Manuel Gómez-Oliván

doi:10.3390/molecules27030869

Daniel Arizmendi-Cotero, María Dolores Hernández-Navarro + Show 5 more

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https://doi.org/10.3390/molecules27030869

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Abstract

The aim of this work was to evaluate the effect of the concentration of gelatin (G) (3–6 g), whey protein (W) (2.5–7.5 g) and chitosan (C) (0.5–2.5 g) on the physical, optical and mechanical properties of composite edible films (CEFs) using the response surface methodology (RSM), as well as optimizing the formulation for the packaging of foods. The results of the study were evaluated via first- and second-order multiple regression analysis to obtain the determination coefficient values with a good fit (R ˃ 0.90) for each of the response variables, except for the values of solubility and b*. The individual linear effect of the independent variables (the concentrations of gelatin, whey protein and chitosan) significantly affected (p ≤ 0.05) the water vapor permeability (WVP), strength and solubility of the edible films. The WVP of the edible films varied from 0.90 to 1.62 × 10−11 g.m/Pa.s.m2, the resistance to traction varied from 0.47 MPa to 3.03 MPa and the solubility varied from 51.06% to 87%. The optimized values indicated that the CEF prepared with a quantity of 4 g, 5 g and 3 g of gelatin, whey protein and chitosan, respectively, provided the CEF with a smooth, continuous and transparent surface, with L values that resulted in a light-yellow hue, a lower WVP, a maximum strength (resistance to traction) and a lower solubility. The results revealed that the optimized formulation of the CEF of G–W–C allowed a good validation of the prediction model and could be applied, in an effective manner, to the food packaging industry, which could help in mitigating the environmental issues associated with synthetic packaging materials.

Highlights

The most widely used materials for packaging food, cosmetics and pharmaceutical products are synthetic plastics [1,2] due to their low production cost, light weight and excellent protection that they provide to the packaged product [3]
Among the materials obtained from agroindustrial by-products, which are employed in the elaboration of edible packaging, extruded corn, post-extraction rapeseed meal, dried fruit pomace and microcrystalline cellulose (MCC), whey protein, gelatin, chitosan, soy protein and zein can be found, among others [8,9,10,11,12,13,14]
The influence of the concentrations of gelatin (G), whey protein (W) and chitosan (C) over the physical (T, moisture content (MC), water absorption capacity (WAC), S, water vapor permeability (WVP)), optical (L*, a* and b*) and mechanical (YM, ST, E) properties of the composite edible films (CEFs) was analyzed through the surface response methodology using the Box–Behnken design

Summary

Introduction

The most widely used materials for packaging food, cosmetics and pharmaceutical products are synthetic plastics [1,2] due to their low production cost, light weight and excellent protection that they provide to the packaged product [3]. There is an urgent need driven by both the industry and consumers to develop environmentally friendly, renewable, naturally derived polymeric materials involving processes that are profitable and minimize pollution and environmental emissions [5,6] These sorts of natural polymers include polysaccharides, proteins and lipids that have become alternative eco-friendly material for potential elaboration in various applications, such as packaging, paper coating, biomedical, food science and agriculture [2], as well as edible films [7]. Its helicoidal triple structure is characterized by repeated sequence chains of amino acid triplets (glicine-X-proline, where X represents alanine, lysine, arginine, methionine or valine) [15] This protein has a wide range of applications in the food industry due to its abundance and its functional properties as a thickener, foaming agent, stabilizer, its capacity to form biodegradable films and as a micro-encapsulating agent [10]. Gelatin films have been applied to a variety of foods to extend their shelf life [16,17]

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