Food-Package-Processing relationships in emerging technologies: Ultrasound effects on polyamide multilayer packaging in contact with different food simulants.

In this study, the effect of ultrasound processing on the properties of two packages widely used in food products was evaluated: polyamide (PA) and polyethylene (PE) multilayer packaging. Packages composed of PE/PA/PE (Film A) and PE/PA/PE/PA/PE (Film B) were filled with aqueous and fatty food simulants and treated in an ultrasound water bath (frequency 25 kHz, volumetric power of 9.74 W/L, temperature of 25 °C, and time of 30 and 60 min). Materials were evaluated in term of structure and performance properties. Ultrasound did not or induced small changes in chemical groups, crystallinity, melting temperature, and tensile strength of the films. Film A showed a reduction in heat sealing tensile strength of 25% in the machine direction and 22% in the transverse direction. Film B showed a 20% increase of water vapor transmission rate after ultrasound processing. Although ultrasound had little impact on the properties of the evaluated materials, these modifications do not compromise the use of these packages for applications in ultrasound-processed foods. Therefore, the results indicate that ultrasound can be used as a food processing technology in multilayer PA and PE packaging.

Biopolymer-Based Films from Sodium Alginate and Citrus Pectin Reinforced with SiO2.

Blend films based on sodium alginate (SA) and citrus pectin (P) reinforced with different concentrations of SiO2 (0-10% w/w) were developed in this study. From the morphological (SEM) and structural (FT-IR) evaluation, it was verified that the incorporation of the reinforcing agent did not drastically modify the microstructure of the films, nor did new chemical bonds form. However, the XRD results suggested a slight reduction in the crystallinities of the blends by the incorporation of SiO2. Among the formulations prepared, the addition of a 5% reinforcing agent was responsible for the simultaneous improvement of mechanical and barrier properties. Comparing the control sample (SA/P) with the SA/P/5.0%SiO2 film, the tensile strength increased from 27.7 ± 3.7 to 40.6 ± 4.5 MPa, and the water-vapor transmission rate decreased from 319.8 ± 38.7 to 288.9 ± 23.5 g m-2 day-1. Therefore, SiO2, as a reinforcing agent in SA/P blends, represents a simple and effective strategy for improving the properties of biopolymer-based films in applications, such as packaging.

Improving the mechanical properties and thermal stability of sodium alginate/hydrolyzed collagen films through the incorporation of SiO2.

Biopolymer-based films have become leading alternatives to traditional fossil-based packaging plastics. Among the countless types of biopolymers with potential for such applications, films containing hydrolyzed collagen in their composition were scarcely explored. This study determined the effect of different loads of nano-SiO2 (0, 2, 6, 8 and 10% w/w of sodium alginate) in the sodium alginate (SA) and hydrolyzed collagen (HC) blend films in terms of structure, thickness, mechanical properties, and thermal stability. The results indicated an improvement in the general mechanical and thermal behavior. Tensile strength increased from 18.2 MPa (control sample) to 25.4 MPa for the SA/HC film incorporated with 10% nano-SiO2. In the same condition, the film's elongation at break improved impressively (from 19.5 to 35.8%). Thermal stability improved slightly for all proportions of nano-SiO2. Therefore, the addition of nano-SiO2 can be an easy and simple strategy to improve crucial properties of SA/HC blend films, increasing its performance for future application as sustainable packaging.

Effect of low concentrations of SiO2 nanoparticles on the physical and chemical properties of sodium alginate-based films.

This work investigated the effect of adding low concentrations of nano-SiO2 (0.5, 1.0 and 1.5%) in the properties of films based on sodium alginate, to identify lower thresholds in the proportion of the reinforcing agent. It was found that, even in the smallest proportion, thermal stability of the nanocomposites improved significantly (with degradation onset increased by almost 15% compared with the control film). The surface morphology showed pronounced roughness at nano-SiO2 concentrations greater than 1.0%, indicating agglomeration of part of the nanomaterial. Mechanical properties were reduced for the samples with concentrations equal to 1.0 and 1.5%, however, without significant differences between them. Conversely, water vapor and light barrier properties have not undergone significant changes in any formulation. Therefore, the use of 0.5% nano-SiO2 in alginate films would be an easy and economically interesting way to improve thermal stability, without significantly reducing mechanical properties of the pure material.

Essential oils as additives in active starch-based food packaging films: A review.

The production of sustainable food packaging from renewable sources represents a prominent alternative to the use of petrochemical-based plastics. For example, starch remains one of the more closely studied replacement options due to its broad availability, low cost and significant advances in improving properties. In this context, essential oils as additives fulfil a key role in the manufacture of renewable active packaging with superior performances. In this review, a comprehensive summary of the impact of adding essential oils to the starch-based films is provided. After a brief introduction to the fundamental concepts related to starch and essential oils, details on the most recent advances in obtaining active starch-based films are presented. Subsequently, the effects of essential oils addition on the structure-property relationships (from physicochemical to antimicrobial ones) are thoroughly addressed. Finally, applications and challenges to the widespread use of essential oils are critically discussed.

Furcellaran: An innovative biopolymer in the production of films and coatings.

Seaweed is a prominent source of polysaccharides with extraction processes properly established, allowing to employ them in several areas. Among all the types of biopolymers obtained from seaweed, furcellaran has gained notoriety in recent years. This is due to its abundance, water solubility and outstanding film-forming abilities. Despite still being little studied, in several works, remarkable advances in terms of improving properties of furcellaran-based films have been described in the literature. However, there are still numerous research opportunities to be explored regarding the improvement of material properties. Therefore, the objective of this review is to highlight the innovative method in preparation, characterization and performance of furcellaran-based films as food packaging. This is the first study in which current results in the area are presented. Initially, it concerns biopolymer chemical and extraction insights. In addition, a comprehensive description of the advances in film properties is outlined (from mechanical to active/intelligent responses). Ultimately, challenges and future prospects are also discussed.

Kefiran-based films: Fundamental concepts, formulation strategies and properties.

Concerns about plastic pollution have driven research into novel bio-derived and biodegradable polymers with improved properties. Among the various classes of biopolymers studied, kefiran films only have gained emphasis in recent years. Its film-forming ability and outstanding biological activities illustrate its potential for active packaging applications. However, despite recent advances, the key challenge is still associated with obtaining high water vapor barrier and better mechanical properties. In that fashion, this review highlights for the first time the cutting-edge advances in the preparation, characterization and enhancement of the packaging performance of kefiran-based films. The fundamental concepts of the biopolymer production and chemical analysis are previously outlined to direct the reader to the structure-property relationship. In addition, this research critically discusses the current challenges and prospects toward better material properties.

Effect of high-pressure processing on characteristics of flexible packaging for foods and beverages.

High-pressure processing is an emerging food preservation technology that causes minimal product quality loss: Food packaged and high-pressure processed keep most of their nutritional qualities, in addition to extending their shelf life. However, the selection of packaging materials suitable for this technology becomes extremely important, since processing can cause changes in the visual aspects and in the physicochemical and mechanical properties of the materials, compromising the shelf life and safety of high-pressure processed foods somehow. Some studies have evaluated the effect of this technology on the properties and the migration and diffusion potential of intentional substances and of polymeric components in some flexible multilayer laminated packaging. Within this context, an important and relevant issue for industrial applications is knowing the possible effects of the parameters of high-pressure treatments, in low and high temperature, on the structure and morphology of materials that, in turn, can determine the relevant effects on the mechanical, barrier, and thermal properties and the migration and diffusion potential of intentional and non-intentional substances. Our study aims to make a literature review on the requirements of flexible packaging materials that can be used in high-pressure processing and the state of the art and the knowledge of the effects of different processing conditions on their properties.