Oxygen barrier performance of whey-protein-coated plastic films as affected by temperature, relative humidity, base film and protein type

Impact of environmental storage conditions on properties and stability of a smart bilayer film

This study aimed to investigate the behavior of smart bilayer films under various temperature and relative humidity (RH). Smart bilayer films were fabricated using sodium alginate with incorporated butterfly pea anthocyanin and agar containing catechin-lysozyme. Cellulose nanospheres were added at concentrations of 0% and 10% w/w of the film and subjected to test at 4 °C and 25 °C, considering different RHs (0%, 50%, and 80%). The results showed that RH had a greater impact on the mechanical properties than temperature, leading to a decrease in tensile strength and an increase in elongation at break with higher RH. The films displayed increased strength but reduced flexibility at low temperatures. Oxygen permeability was negatively affected by increasing RH, while water vapor barrier properties were better at 25 °C than at 4 °C. In terms of color stability, the temperature played a more important role, with both types of smart bilayer films retaining their color stability throughout 14-day storage at 4 °C, even maintaining their ability to change color with pH. However, the films stored at 25 °C exhibited lower color stability and showed potential for color change with varying pH levels, but with lower intensity. The findings of this study demonstrate the significant impact of temperature and RH on the functional properties of smart bilayer films, with and without the addition of cellulose nanospheres. Such smart bilayer films have great potential for various applications, particularly in food packaging, where maintaining color, mechanical, and barrier properties under varying environmental conditions is crucial.

Active whey protein/hydroxypropyl methylcellulose edible films incorporated with cinnamaldehyde: Characterization, release kinetics and application to Mongolian cheese preservation

Edible films with modulated release of antimicrobial agents are important for food preservation. Herein, antimicrobial edible films were prepared using whey protein (WP) and hydroxypropyl methylcellulose (HM) as polymer matrix materials and cinnamaldehyde (CIN) as antimicrobial agent. The mass ratios of WP and HM were 100/0, 75/25, 50/50, 25/75 and 0/100. The release kinetics of CIN through the film was studied, applying the Fickian model, power law and Weibull model. The films were also characterized by physical and structural characteristics, and antibacterial activity. In comparison to other films, the CIN-loaded film with a WP/HM ratio of 50/50 had better moisture resistance, water vapor barrier properties and mechanical properties. High correlation factors were obtained by fitting the CIN release data with the power law (R2 > 0.96) and Weibull model (R2 > 0.97). The diffusion mechanism of CIN was pseudo-Fickian. The diffusion coefficients (D1 and D2) had a positive linear relationship with the HM ratio, suggesting that a high HM ratio was beneficial to the CIN release. Finally, the WH50-C film was successfully used to preserve Mongolian cheese. This research provides a new perspective on the design of active packaging film with sustained-release characteristics.

Biodegradable and gas barrier polylactic acid/star-shaped polycaprolactone blend films functionalized with a bio-sourced polyelectrolyte coating

This work aims at improving and disclosing new properties of films based on polylactic acid (PLA) and a star-shaped polycaprolactone (PCL). Indeed, previous works demonstrated that the presence of ad-hoc synthesized PCL, characterized by low molecular weight and carboxyl end groups (coded as PCL-COOH), improves the elongation at break of the films compared to that of neat PLA and increases their functionality. To further improve the properties of the system, alternating layers of chitosan (CH) and DNA were deposited on the surface applying a Layer-by-Layer (LbL) technique. This method was chosen because it allows the properties of the system to be modified without affecting the specific features of the bulk. In addition, the LbL technique is easily scalable and environmentally friendly because it is based on the use of an aqueous solution of two biomaterials, namely DNA and CH, which are not only derived from renewable sources but are also biocompatible and biodegradable. IR measurements on model silicon substrates subjected to the same treatment as the films, pointed out a linear growth of the proposed LbL assembly. Indeed, FE-SEM measurements highlighted the deposition of a uniform coating. The presence of the CH/DNA assembly reduced the oxygen permeability under both dry and humid (50% R.H.) conditions when compared to the uncoated film. In addition, the coating had no relevant effect on the hydrolytic and enzymatic degradation of the system, so that the biodegradability of the film was maintained.

Overview of the Cast Polyolefin Film Extrusion Technology for Multi-Layer Packaging Applications

The review article presents the technology of producing polyolefin-based films by extrusion casting. Due to the wide use of this type of film as packaging for food and other goods, obtaining films with favorable properties is still a challenge for many groups of producers in the plastics market. The feedblock process and multimanifold process are the main methods of producing multi-layer film. In the case of food films, appropriate barrier properties are required, as well as durability and puncture resistance also at low temperatures. On the other hand, in order to properly pack and present products, an appropriate degree of transparency must be maintained. Therefore, processing aids such as anti-slip, anti-block and release agents are commonly used. Other popular modifiers, such as waxes, fatty acid amides and mineral fillers-silica, talc or calcium carbonate-and their use in film extrusion are discussed. The article also presents common production problems and their prevention.

Effects of the Aging Period and Method on the Physicochemical, Microbiological and Rheological Characteristics of Two Cuts of Charolais Beef

Wet-aging (WA) and dry-aging (DA) methods are usually used in the beef industry to satisfy the consumers' tastes; however, these methods are not suitable for all anatomical cuts. In this study, WA and DA were applied to improve the quality of two cuts of Charolais beef (Longissimus dorsi and Semitendinosus). For 60 days (i.e., 2 days, 15 days, 30 days and 60 days of sampling), a physicochemical, rheological, and microbiological analysis were performed at WA (vacuum packed; temperature of 4 ± 1 °C) and at DA (air velocity of 0.5 m/s; temperature of 1 ± 1 °C; relative humidity of 78 ± 10%) conditions. The results showed that the aging method influenced the aging loss (higher in the DA), cooking loss (higher in the WA), malondialdehyde concentration (higher in the DA) and fatty acid profile (few changes). No differences in the drip loss and color were observed, which decreased after 30 days of aging. The WBSF and TPA test values changed with increasing an aging time showing that the aging improved the tenderness of meat regardless of the aging method. Moreover, the aging method does not influence the microbiological profile. In conclusion, both WA and DA enhanced the quality of the different beef cuts, suggesting that an optimal method-time and aging combination could be pursued to reach the consumers' preferences.

Effect of Ultrasound Treatment on Barrier Changes of Polymers before and after Exposure to Food Simulants

In this study, we investigated the impact of ultrasound treatment on barrier properties of linear low-density polyethylene (LLDPE) and acrylic/poly(vinylidene chloride) polypropylene (PPAcPVDC)-coated pouches intended for food packaging before and after exposure to food simulants. Packaging pouches were filled with two food simulants, namely ethanol (10% (v/v)) and acetic acid (3% (w/v)), in order to simulate food−packaging interaction and possible compound migration from packaging materials. Samples were subjected to an ultrasound water bath treatment for 5 min, 15 min, and 30 min at 60 °C (±2 °C) and with an amplitude of 100% as an equivalent to the heat-treatment conditions combined with an ultrasound effect. Furthermore, the effect of temperature on the polymer barrier (water vapour and oxygen permeability) properties was tested at 20 °C, 40 °C, and 60 °C. Results showed that PPAcPVDC possessed better properties of water vapour permeability and oxygen permeability properties to LLDPE. Statistical analyses showed a significant (p < 0.001) impact of ultrasound treatment on the overall migration value, regardless of the food simulant used.

A Review on the Commonly Used Methods for Analysis of Physical Properties of Food Materials

The chemical composition of any food material can be analyzed well by employing various analytical techniques. The physical properties of food are no less important than chemical composition as results obtained from authentic measurement data are able to provide detailed information about the food. Several techniques have been used for years for this purpose but most of them are destructive in nature. The aim of this present study is to identify the emerging techniques that have been used by different researchers for the analysis of the physical characteristics of food. It is highly recommended to practice novel methods as these are non-destructive, extremely sophisticated, and provide results closer to true quantitative values. The physical properties are classified into different groups based on their characteristics. The concise view of conventional techniques mostly used to analyze food material are documented in this work.

Valorization and Application of Fruit and Vegetable Wastes and By-Products for Food Packaging Materials

The important roles of food packaging are food protection and preservation during processing, transportation, and storage. Food can be altered biologically, chemically, and physically if the packaging is unsuitable or mechanically damaged. Furthermore, packaging is an important marketing and communication tool to consumers. Due to the worldwide problem of environmental pollution by microplastics and the large amounts of unused food wastes and by-products from the food industry, it is important to find more environmentally friendly alternatives. Edible and functional food packaging may be a suitable alternative to reduce food waste and avoid the use of non-degradable plastics. In the present review, the production and assessment of edible food packaging from food waste as well as fruit and vegetable by-products and their applications are demonstrated. Innovative food packaging made of biopolymers and biocomposites, as well as active packaging, intelligent packaging, edible films, and coatings are covered.

Effects of Compostable Packaging and Perforation Rates on Cucumber Quality during Extended Shelf Life and Simulated Farm-to-Fork Supply-Chain Conditions

Cucumbers are highly perishable and suffer from moisture loss, shriveling, yellowing, peel damage, and decay. Plastic packaging helps to preserve cucumber quality, but harms the environment. We examined the use of compostable modified atmosphere packaging (MAP) with different perforation rates as a possible replacement for conventional plastic packaging materials. The results indicate that all of the tested types of packaging reduced cucumber weight loss and shriveling. However, compostable MAP with micro-perforations that created a modified atmosphere of between 16-18% O₂ and 3-5% CO₂ most effectively preserved cucumber quality, as demonstrated by reduced peel pitting, the reduced appearance of warts and the inhibition of yellowing and decay development. Overall, micro-perforated compostable packaging extended the storage life of cucumbers under both extended shelf conditions and simulated farm-to-fork supply-chain conditions and thus may serve as a replacement for the plastic packaging currently used to preserve the postharvest quality of cucumbers.

Improving gelatin-based emulsion films with cold plasma using different gases

In this research, the effects of cold plasma treatment on the properties of gelatin-based emulsion films (GEFs) using different gases were investigated. The gases used include O2, N2, air, Ar, and ethanol-argon (EtOH-Ar). Surface hydrophobicity, morphology, water vapor permeability (WVP), and mechanical, thermal, and antifungal properties after plasma application on the film were analyzed. The results revealed that surface hydrophilicity significantly increased after cold plasma, while the contact angle significantly decreased (p < .05). Furthermore, atomic force microscopy results showed that the argon gas plasma significantly increased roughness of the GEFs surface. Besides, plasma did not decrease WVP. Different gases had no significant effect on the mechanical properties of the GEFs (p > .05). Oxygen permeability after plasma application was significantly different from the control sample; consequently, the permeability after plasma application decreased and the lowest level 55.7 (cm3μm m-2 day-1 Pa-1) was seen for oxygen gas. Plasma treatment caused etching effects and lessened the surface moisture of the polymer film. Antimicrobial activity was observed in the cold plasma-treated samples, especially under air and nitrogen atmosphere. Cold plasma treatment is an effective method for surface modification, expanding the application of emulsion films in the packing industry with improved performance properties.

Bio-Based Packaging: Materials, Modifications, Industrial Applications and Sustainability

Environmental impacts and consumer concerns have necessitated the study of bio-based materials as alternatives to petrochemicals for packaging applications. The purpose of this review is to summarize synthetic and non-synthetic materials feasible for packaging and textile applications, routes of upscaling, (industrial) applications, evaluation of sustainability, and end-of-life options. The outlined bio-based materials include polylactic acid, polyethylene furanoate, polybutylene succinate, and non-synthetically produced polymers such as polyhydrodyalkanoate, cellulose, starch, proteins, lipids, and waxes. Further emphasis is placed on modification techniques (coating and surface modification), biocomposites, multilayers, and additives used to adjust properties especially for barriers to gas and moisture and to tune their biodegradability. Overall, this review provides a holistic view of bio-based packaging material including processing, and an evaluation of the sustainability of and options for recycling. Thus, this review contributes to increasing the knowledge of available sustainable bio-based packaging material and enhancing the transfer of scientific results into applications.

Materiality of Edible Film Packaging in Muscle Foods: A Worthwhile Conception

Muscle foods are extremely extensive food products that are relished throughout the world. They are known for their exclusive nutritional content and bio-availability however, at the same time, they also provide apposite media for the growth of pathogenic and spoilage microorganisms. Packaging seems to be a substantial approach to overcome this problem, but most of the packaging involves the usage of non-biodegradable and non-renewable material like plastic, nylon, polyester, etc. The alarming situation caused by synthetic material has been realized worldwide and several scientists, agencies, and the food industry are working globally to explore materials that are derived from the natural source. Biodegradable films are an excellent alternative to conventional plastics. These biodegradable films and coatings are derived from various biological sources and are receiving considerable importance in recent years. Different meat and meat product needs specific packaging condition and these active, composite bio-based films are having a wide potential in the meat sector. This review gathers the research and findings over the period of time-related to biodegradable edible film applied to muscle foods.

Development of emulsion films based on bovine gelatin-nano chitin-nano ZnO for cake packaging

This research extends the effect of packaging with bovine gelatin, gelatin nanocomposite (GN), gelatin emulsion (GE), two layers gelatin nanocomposite and gelatin emulsion (GNE), and polyethylene (PE) films on sponge cake properties during storage at 25°C and 55 ± 2% RH. In this regard, water vapor permeability (WVP) and oxygen permeability (OP) of films were compared. Then, moisture content, acidity, peroxide value, texture profile, organoleptic properties, and fungal growth of packed cakes were determined. Results showed that the addition of nanoparticles could reduce the water vapor permeability from 9.680 ± 0.460 × 10-10 (g m/sm-2Pa-1) for net gelatin film to 6.067 ± 0.337 × 10-10 (g m/sm-2 Pa-1) for gelatin nanocomposite film and oxygen permeability from 39.262 (cm3μm/ m2dkPa) for net gelatin film to 29.645 (cm3μm m-2 dkPa) for nanocomposite film. However, GNE films had the highest barrier properties. Results of acidity and peroxide values of cakes admitted the sufficiency of GNE films for sponge cakes packaging. In addition, antifungal properties of nanoparticles led to less fungal growth on cakes packed in GNE films. The cakes packed in GNE films own more organoleptic and texture acceptability than the ones packed in other films. Generally, according to the results GNE films are acceptable for packaging of sponge cakes which contain no preservative because this packaging can prevent fungal growth for a longer time and even more can maintain the cake chemical and organoleptic quality.

Application of edible coatings on fresh and minimally processed fruits: a review

Purpose

This paper aims to update with information about edible coating on minimally processed and fresh fruits, focussing on the composition, active ingredients, antimicrobial concentration and their effect on ripening rate, phytonutrients retention and shelf-life of fruits. In future, the data will be helpful for the processors to select the best coating material and its effective concentration for different fresh and minimally processed fruits.

Design/methodology/approach

Major scientific information was collected from Scopus, Web of Science, Mendeley and Google Scholar. Several key words such as postharvest, edible coating, phytonutrients, shelf-life enhancement, bioactive compounds, minimally processed fruits and antimicrobial compounds were used to find the data. Relevant information was collected by using 90 recent research and review articles.

Findings

The main findings of this comprehensive review are to improve the quality of fruits, to meet the next-generation food security needs. However, in the process of achieving the goal of improving quality of food produce, embrace of synthetic, non-biodegradable packaging materials have increased, creating serious pollution problem. Amidst several alternatives for replacement of synthetic packaging, the option of biodegradable films and coatings showed promising results.

Originality/value

The paper represents recent information about the edible coating used for the enhancement of shelf-life of fresh and minimally processed fruits.

The Drop-in-Drop Encapsulation in Chitosan and Sodium Alginate as a Method of Prolonging the Quality of Linseed Oil

Nowadays, the encapsulation of sensitive products by various techniques has become popular as a promising preservation method. In particular, this applies to oils with a high content of unsaturated fatty acids and a high susceptibility to deterioration. This work presents the possibility of using a chitosan and sodium alginate in the form of a hydrogel membrane to protect food ingredients such as linseed oil, which is stored in an aquatic environment. The obtained results showed the high efficiency of the coaxial method encapsulation, which did not affect the quality of the oil measured after encapsulation. The greatest protective effect was observed in the linseed oil⁻chitosan membrane system, in which the primary and secondary oxidation products content were 88% and 32% lower than in the control sample, respectively. The smallest changes of the fatty acid profile, conjugated dienes, and trienes were observed in the chitosan capsules with linseed oil compared to the control sample.

Reinforced cassava starch based edible film incorporated with essential oil and sodium bentonite nanoclay as food packaging material

Biodegradable packaging in food materials is a green technology based novel approach to replace the synthetic and conventional packaging systems. This study is aimed to formulate the biodegradable cassava starch based films incorporated with cinnamon essential oil and sodium bentonite clay nanoparticles. The films were characterized for their application as a packaging material for meatballs. The cassava starch films incorporated with sodium bentonite and cinnamon oil showed significant antibacterial potential against all test bacteria; Escherichia coli, Salmonella typhimurium and Staphylococcus aureus. Antibacterial effect of films increased significantly when the concentration of cinnamon oil was increased. The cassava starch film incorporated with 0.75% (w/w) sodium bentonite, 2% (w/w) glycerol and 2.5% (w/w) cinnamon oil was selected based on physical, mechanical and antibacterial potential to evaluate shelf life of meatballs. The meatballs stored at ambient temperature in cassava starch film incorporated with cinnamon oil and nanoclay, significantly inhibited the microbial growth till 96 h below the FDA limits (10⁶ CFU/g) in foods compared to control films that exceeded above the limit within 48 h. Hence cassava starch based film incorporated with essential oils and clay nanoparticles can be an alternate approach as a packaging material for food industries to prolong the shelf life of products.

Physical, Chemical and Biochemical Modifications of Protein-Based Films and Coatings: An Extensive Review

Protein-based films and coatings are an interesting alternative to traditional petroleum-based materials. However, their mechanical and barrier properties need to be enhanced in order to match those of the latter. Physical, chemical, and biochemical methods can be used for this purpose. The aim of this article is to provide an overview of the effects of various treatments on whey, soy, and wheat gluten protein-based films and coatings. These three protein sources have been chosen since they are among the most abundantly used and are well described in the literature. Similar behavior might be expected for other protein sources. Most of the modifications are still not fully understood at a fundamental level, but all the methods discussed change the properties of the proteins and resulting products. Mastering these modifications is an important step towards the industrial implementation of protein-based films.

Preparation and characterization of bionanocomposite films reinforced with nano kaolin

Effects of nano-kaolin incorporation into semolina films on the physical, mechanical, thermal, barrier and antimicrobial properties of the resulting bio-nanocomposite films were investigated. The properties included crystal structure (by X-ray diffraction), mechanical resistance, color, Fourier transform infrared spectra, decomposition temperature, water-vapor permeability (WVP), oxygen permeability (OP), and antimicrobial activity against Staphylococcus aureus and Escherichia coli. Kaolin was incorporated into biofilms at various amounts (1, 2, 3, 4, and 5 %, w/w total solid). All films were plasticized with 50 % (w/w total solid) combination of sorbitol/glycerol at 3:1 ratio. The incorporation of nanokaolin into semolina films decreased OP and WVP. The moisture content and water solubility of the films were found to decrease by nanokaolin reinforcement, and mechanical properties of films were improved by increasing nanokaolin concentration. Tensile strength and Young's modulus increased from 3.41 to 5.44 MPa and from 63.12 to 136.18, respectively, and elongation-at-break decreased. The films did not exhibit UV absorption. In conclusion, nanokaolin incorporation enhanced the barrier and mechanical properties of semolina films, indicating the potential application of these bio-nanocomposites in food-product packaging.

Preparation of Modified Films with Protein from Grouper Fish

A protein concentrate (PC) was obtained from Grouper fish skin and it was used to prepare films with different amounts of sorbitol and glycerol as plasticizers. The best performing films regarding resistance were then modified with various concentrations of CaCl₂, CaSO₄ (calcium salts), and glucono-δ-lactone (GDL) with the purpose of improving their mechanical and barrier properties. These films were characterized by determining their mechanical properties and permeability to water vapor and oxygen. Formulations with 5% (w/v) protein and 75% sorbitol and 4% (w/v) protein with a mixture of 15% glycerol and 15% sorbitol produced adequate films. Calcium salts and GDL increased the tensile fracture stress but reduced the fracture strain and decreased water vapor permeability compared with control films. The films prepared represent an attractive alternative for being used as food packaging materials.

Properties of poly(lactide)-whey protein isolate laminated films

BACKGROUND

This study aims to examine the feasibility of a novel multi-layer barrier film made entirely from biopolymers, which can be disposed after use in an economically and ecologically acceptable way, by employing mechanical strength and moisture barrier of poly(lactide) (PLA) films and oxygen barrier enhancement of whey protein isolate (WPI) films. The effect of glycerol was also determined. The three-layer films, PLA/WPI/PLA, were compared with those made of linear low-density polyethylene films (LLDPE/WPI/LLDPE). Composite structures of three-layer films obtained by a simple casting method using denatured WPI solution plasticised with glycerol (GLY) at three different ratios of GLY:WPI (1:4, 1:2.5 and 1:1.5). The WPI solution was applied between two base layers of corona-treated PLA or LLDPE films.

RESULT

The multi-layer films showed good appearance with no noticeably visible change and good adhesion of layers. PLA enhanced tensile strength of the composite structure. Oxygen permeability of the multi-layer films was significantly lower than the base films. The water vapour permeability of the structure relied mainly on the base films. The plasticiser content did not significantly affect the properties of the multi-layer structures.

CONCLUSION

Results suggested that WPI could work successfully as an alternative oxygen barrier layer of multi-layer structures.

Characterization ofJatropha curcasL. Protein Cast Films with respect to Packaging Relevant Properties

There is increasing research ongoing towards the substitution of petrochemical based plastics by more sustainable raw materials, especially in the field of bioplastics. Proteins of different types such as whey, casein, gelatine, or zein show potential beyond the food and feed industry as, for instance, the application in packaging. Protein based coatings provide different packaging relevant properties such as barrier against permanent gases, certain water vapour barrier, and mechanical resistance. The aim of this study was to explore the potential for packaging applications of proteins fromJatropha curcasL. and to compare the performance with literature data on cast films from whey protein isolate. As a by-product from oil extraction, high amounts ofJatrophameal are obtained requiring a concept for its sustainable utilization.Jatrophaseed cake includes up to 40% (w/w) of protein which is currently not utilized. The present study provides new data on the potential ofJatrophaprotein for packaging applications. It was shown thatJatrophaprotein cast films show suitable barrier and mechanical properties depending on the extraction and purification method as well as on the plasticiser content. Based on these findingsJatrophaproteins own potential to be utilized as coating material for food packaging applications.