Marcos V. Lorevice

Recent Advances on Edible Films Based on Fruits and Vegetables—A Review

Food packaging materials are traditionally expected to contain foodstuffs and protect them from deteriorating agents. Although petroleum-derived polymers have been widely used for this purpose, the rising concern with their nonrenewable and/or nonbiodegradable nature paves the route for the development of greener alternatives, including polysaccharides and polypeptides. The use of these food-grade biomacromolecules, in addition to fruits and vegetables, provides edible packaging with suitable physical-mechanical properties as well as unique sensory and nutritional characteristics. This text reviews the chronological development pathway of films based on fruit and vegetable purees, pomaces, and extracts. Recent advances are extensively reviewed with an emphasis on the role that each film component plays in the resulting materials, whose production methods are examined from a technical standpoint and essential properties are compiled and contrasted to their conventional, synthetic counterparts. Finally, this comprehensive review discusses advantages and limitations of edible films based on fruits and vegetables.

Nanocompósito de polpa de mamão e nanopartículas de quitosana para aplicação em embalagens

Nanocomposite materials have been incorporated into biopolymers, (e.g. hydroxypropyl methylcellulose), to improve their physical and chemical properties and enable them to be applied in food packaging, especially for their biodegradable and renewable properties. With this addition, fruit puree has been incorporated into the films to confer nutritional properties besides color and flavor. Chitosan is of interest in the packaging field since it is a biodegradable, bioabsorbable, antimicrobial agent. Furthermore, chitosan nanoparticles have been widely explored for their interesting properties and potential applications in food packaging. This work was divided into two stages: (1) chitosan nanoparticle synthesis; (2) addition of nanoparticles into HPMC and papaya puree films. Addition of chitosan nanoparticles to HPMC and papaya puree films improved film properties: mechanical, thermal and water vapor barrier. We have developed a novel nanomaterial with great potential for application in packaging to prolong the shelf life of food.

Hydrophobic edible films made up of tomato cutin and pectin

Cutin is the biopolyester that protects the extracellular layer of terrestrial plants against dehydration and environmental stresses. In this work, cutin was extracted from tomato processing waste and cast into edible films having pectin as a binding agent. The influences of cutin/pectin ratio (50/50 and 25/75), film-forming suspension pH, and casting method on phase dispersion, water resistance and affinity, and thermal and mechanical properties of films were investigated. Dynamic light scattering and scanning electron microscopy revealed that cutin phase aggregation was reduced by simply increasing pH. The 50/50 films obtained by casting neutral-pH suspensions presented uniform cutin dispersion within the pectin matrix. Consequently, these films exhibited lower water uptake and solubility than their acidic counterparts. The cutin/pectin films developed here were shown to mimic tomato peel itself with respect to mechanical strength and thermal stability. Such behavior was found to be virtually independent of pH and casting method.

On the effects of hydroxyl substitution degree and molecular weight on mechanical and water barrier properties of hydroxypropyl methylcellulose films

In line with the increasing demand for sustainable packaging materials, this contribution aimed to investigate the film-forming properties of hydroxypropyl methylcellulose (HPMC) to correlate its chemical structure with film properties. The roles played by substitution degree (SD) and molecular weight (Mw) on the mechanical and water barrier properties of HPMC films were elucidated. Rheological, thermal, and structural experiments supported such correlations. SD was shown to markedly affect film affinity and barrier to moisture, glass transition, resistance, and extensibility, as hydroxyl substitution lessens the occurrence of polar groups. Mw affected mostly the rheological and mechanical properties of HPMC-based materials. Methocel® E4 M led to films featuring the greatest tensile strength (ca., 67 MPa), stiffness (ca., 1.8 GPa), and extensibility (ca., 17%) and the lowest permeability to water vapor (ca., 0.9 g mm kPa-1 h-1 m-2). These properties, which arise from its longer and less polar chains, are desirable for food packaging materials.