The Effect of Whey Protein-Based Edible Coatings Incorporated with Lemon and Lemongrass Essential Oils on the Quality Attributes of Fresh-Cut Pears during Storage

Biocomposite Active Whey Protein Films with Thyme Reinforced by Electrospun Polylactic Acid Fiber Mat

Electrospinning is a versatile technique for obtaining nano/micro fibers which are able to significantly change the active properties of composite materials and bring in new dimensions to agri-food applications. Composite bio-based packaging materials obtained from whey proteins, functionalized with thyme essential oil (TEO) and reinforced by electrospun polylactic acid (PLA) fibers, represent a promising solution for developing new active food packaging using environmentally friendly materials. The aim of this study is to obtain and characterize one-side-active composite films covered with a PLA fiber mat: (i) WF/G1, WF/G2, and WF/G3 resulting from electrospinning with one needle at different electrospinning times of 90, 150, and 210 min, respectively, and (ii) WF/G4 obtained with two face-to-face needles after 210 min of electrospinning. While TEO bioactivity is mainly related to its antimicrobial and antioxidant properties, the PLA fiber mat uplifted the composite mechanical and barrier properties of films. The bi-layer films obtained were characterized by SEM, showing the distribution of the electrospun fiber mat and an increased thickness of the PLA layer from WF/G1 to WF/G4, while FTIR spectra showed the structural vibrations of the functional groups. The experimental results show that WF/G4 have a FTIR fingerprint resembling PLA, retained ~50% of the volatile compounds present in the uncovered film (WF/TEO), while it only had 1.41 ± 0.14 (%) of the permeability to octanol of the WF/G1 film. WF/G4 exhibited 33.73% of the WVP of WF/G1 and displayed the highest tensile strength, about 2.70 times higher than WF/TEO. All films studied revealed similar antimicrobial effect against Bacillus cereus, Geotrichum candidum, and Rhodotorula glutinis and good antiradical activity, thus demonstrating good prospects to be applied as food packaging materials. WF/G composite materials are good candidates to be used as bioactive flavoring primary packaging in hard cheese making.

Natural biopolymers in edible coatings: Applications in food preservation

Edible coatings are revolutionizing food preservation by offering a sustainable and effective solution to key industry challenges. Made from natural biopolymers such as proteins, polysaccharides, and lipids, these coatings form a thin, edible layer on food surfaces. This barrier reduces moisture loss, protects against oxidative damage, and limits microbial growth, thereby extending shelf life while preserving food quality. Enhanced with natural additives like essential oils and antioxidants, these coatings offer antimicrobial benefits and contribute to health. Applications span from fresh produce, where they control respiration and moisture, to meat, dairy, and bakery products, maintaining sensory and nutritional properties. Innovations in coating technologies-such as composite materials, nano-emulsions, and bio-nanocomposites-are improving their mechanical strength, barrier properties, and compatibility with other preservation methods like modified atmosphere packaging. Although challenges remain in cost, consumer acceptance, and regulation, edible coatings represent a significant stride towards sustainable food systems and reduced dependence on synthetic packaging.

Edible Coating for Fresh-Cut Fruit and Vegetable Preservation: Biomaterials, Functional Ingredients, and Joint Non-Thermal Technology

This paper reviews recent advances in fresh-cut fruit and vegetable preservation from the perspective of biomacromolecule-based edible coating. Biomaterials include proteins, polysaccharides, and their complexes. Compared to a single material, the better preservation effect was presented by complexes. The functional ingredients applied in the edible coating are essential oils/other plant extracts, metals/metal oxides, and organic acids, the purposes of the addition of which are the improvement of antioxidant and antimicrobial activities and/or the mechanical properties of the coating. The application of edible coating with other preservation technologies is an emerging method, mainly including pulsed light, short-wave ultraviolet, modified atmosphere packaging, ozonation, and γ-irradiation. In the future, it is crucial to design coating formulations based on preservation goals and sensory characteristics. The combination of non-thermal preservation technology and edible coating needs to be strengthened in research on food preservation. The application of AI tools for edible coating-based preservation should also be focused on. In conclusion, edible coating-based preservation is promising for the development of fresh-cut fruits and vegetables.

Active pullulan-based coatings incorporated with Auricularia auricular extracts for preserving potato fresh-cuts

In the present study, Auricularia auricular polysaccharides (AAP) and Auricularia auricular proteins (AAPR) obtained from the waste products of Auricularia auricular were incorporated into pullulan (PUL) to obtain active packaging films/coatings. Results showed that incorporating AAP/AAPR into PUL-based films decreased their transparency, but increased the compactness, thermal stability, antioxidant, and antimicrobial properties. Adding 2% PUL films with 10%:10% of AAP/AAPR exhibiting good mechanical properties were applied to fresh-cut potatoes to avoid spoilage during eight days of storage, with significantly decreased in browning index, weight loss, microbial growth prevention and the total soluble solids was maintained. These results substantiated that pullulan containing AAP/AAPR as an active film/coating with antioxidant and antimicrobial properties has significant potential for maintaining safety and quality of fresh-cut potatoes and extending their shelf life.

Development of a novel, sustainable, cellulose-based food packaging material and its application for pears

This study aimed to develop a cellulose-based active food packaging material using paper, a biodegradable, sustainable, recyclable, renewable, and relatively low-cost material. For electrospray coating, fulvic acid (FA), which has antioxidant and antimicrobial properties, and sericin (S) were used as an active agent and a carrier medium, respectively. Solutions prepared at various concentrations and ratios of FA and S were analyzed, the properties of the active packaging material were examined, and the effect on the quality of pears was studied. The optimum conditions of electrospraying for minimum droplet size and maximum antibacterial effect were 0.8 g/mL concentration of solutions, 1:1 FA:S ratio, 20 kV voltage, 0.75 mL/h flow rate, and 23 cm collector-needle tip distance. FA had static, lethal, and inhibitory effects on Pseudomonas syringae and P. digitatum, the common pathogenic microorganisms on pears. The antioxidant activity of FA was higher than that of S (872.96 mM vs. 239.36 mM). At the end of the 90-day storage period, pears stored in the active packaging material at 7 °C and 90% RH showed better preserved color and texture, matured later, had a lower antimicrobial load, and were more appreciated in sensory evaluation than other samples.

Edible Coatings as a Natural Packaging System to Improve Fruit and Vegetable Shelf Life and Quality

In the past years, consumers have increased their interest in buying healthier food products, rejecting those products with more additives and giving preference to the fresh ones. Moreover, the current environmental situation has made society more aware of the importance of reducing the production of plastic and food waste. In this way and considering the food industry's need to reduce food spoilage along the food chain, edible coatings have been considered eco-friendly food packaging that can replace traditional plastic packaging, providing an improvement in the product's shelf life. Edible coatings are thin layers applied straight onto the food material's surface that are made of biopolymers that usually incorporate other elements, such as nanoparticles or essential oils, to improve their physicochemical properties. These materials must provide a barrier that can prevent the passage of water vapor and other gasses, microbial growth, moisture loss, and oxidation so shelf life can be extended. The aim of this review was to compile the current data available to give a global vision of the formulation process and the different ways to improve the characteristics of the coats applied to both fruits and vegetables. In this way, the suitability of compounds in by-products produced in the food industry chain were also considered for edible coating production.

Physical and Chemical Properties of Vegetable Films Based on Pumpkin Purée and Biopolymers of Plant and Animal Origin

Highly methylated apple pectin (HMAP) and pork gelatin (PGEL) have been proposed as gelling agents for pumpkin purée-based films. Therefore, this research aimed to develop and evaluate the physiochemical properties of composite vegetable films. Granulometric analysis of film-forming solutions showed a bimodal particle size distribution, with two peaks near 25 µm and close to 100 µm in the volume distribution. The diameter D_4.3, which is very sensitive to the presence of large particles, was only about 80 µm. Taking into account the possibility of creating a polymer matrix from pumpkin purée, its chemical characteristic was determined. The content of water-soluble pectin was about 0.2 g/100 g fresh mass, starch at the level of 5.5 g/100 g fresh mass, and protein at the level of about 1.4 g/100 g fresh mass. Glucose, fructose, and sucrose, the content of which ranged from about 1 to 1.4 g/100 g fresh mass, were responsible for the plasticizing effect of the purée. All of the tested composite films, based on selected hydrocolloids with the addition of pumpkin purée, were characterized by good mechanical strength, and the obtained parameters ranged from about 7 to over 10 MPa. Differential scanning calorimetry (DSC) analysis determined that the gelatin melting point ranged from over 57 to about 67 °C, depending on the hydrocolloid concentration. The modulated differential scanning calorimetry (MDSC) analysis results exhibited remarkably low glass transition temperature (Tg) values, ranging from -34.6 to -46.5 °C. These materials are not in a glassy state at room temperature (~25 °C). It was shown that the character of the pure components affected the phenomenon of water diffusion in the tested films, depending on the humidity of the surrounding environment. Gelatin-based films were more sensitive to water vapor than pectin ones, resulting in higher water uptake over time. The nature of the changes in water content as a function of its activity indicates that composite gelatin films, with the addition of pumpkin purée, are characterized by a greater ability to adsorb moisture from the surrounding environment compared to pectin films. In addition, it was observed that the nature of the changes in water vapor adsorption in the case of protein films is different in the first hours of adsorption than in the case of pectin films, and changes significantly after 10 h of the film staying in an environment with relative humidity RH = 75.3%. The obtained results showed that pumpkin purée is a valuable plant material, which can form continuous films with the addition of gelling agents; however, practical application as edible sheets or wraps for food products needs to be preceded with additional research on its stability and interactions between films and food ingredients.

Characterization of Synthetic Polymer Coated with Biopolymer Layer with Natural Orange Peel Extract Aimed for Food Packaging

This research was aimed to make biolayer coatings enriched with orange peel essential oil (OPEO) on synthetic laminate, oriented poly(ethylene-terephthalate)/polypropylene (PET-O/PP). Coating materials were taken from biobased and renewable waste sources, and the developed formulation was targeted for food packaging. The developed materials were characterized for their barrier (O₂, CO₂, and water vapour), optical (colour, opacity), surface (inventory of peaks by FTIR), and antimicrobial activity. Furthermore, the overall migration from a base layer (PET-O/PP) in an acetic acid (3% HAc) and ethanol aqueous solution (20% EtOH) were measured. The antimicrobial activity of chitosan (Chi)-coated films was assessed against Escherichia coli. Permeation of the uncoated samples (base layer, PET-O/PP) increased with the temperature increase (from 20 °C to 40 °C and 60 °C). Films with Chi-coatings were a better barrier to gases than the control (PET-O/PP) measured at 20 °C. The addition of 1% (w/v) OPEO to the Chi-coating layer showed a permeance decrease of 67% for CO₂ and 48% for O₂. The overall migrations from PET-O/PP in 3% HAc and 20% EtOH were 1.8 and 2.3 mg/dm², respectively. Analysis of spectral bands did not indicate any surface structural changes after exposure to food simulants. Water vapour transmission rate values were increased for Chi-coated samples compared to the control. The total colour difference showed a slight colour change for all coated samples (ΔE > 2). No significant changes in light transmission at 600 nm for samples containing 1% and 2% OLEO were observed. The addition of 4% (w/v) OPEO was not enough to obtain a bacteriostatic effect, so future research is needed.

Whey-based polymeric films for food packaging applications: a review of recent trends

The food industry is always looking for new strategies to extend the shelf life of food. In recent years, the focus has been on edible films and coatings. These play an essential role in the quality, safety, transport, storage, and display of a wide variety of fresh and processed foods and contribute to environmental sustainability. In this sense, this study aimed to carry out a bibliometric analysis and literature review on the production of whey-based films for application in food packaging. Whey-based films have different characteristics when compared to other biopolymers, such as antimicrobial and immunomodulatory capacity. A wide variety of compounds were found that can be incorporated into whey films, aiming to overcome their limitations related to high solubility and low mechanical properties. These compounds range from plasticizing agents, secondary biomacromolecules added to balance the polymer matrix (gelatin, starch, chitosan), and bioactive agents (essential oils, pigments extracted from plants, and other antimicrobial agents). The most cited foods as application matrix were meat (fish, chicken, ham, and beef), in addition to different types of cheese. Edible and biodegradable films have the potential to replace synthetic polymers, combining social, environmental, and economic aspects. The biggest challenge on a large scale is the stability of physical, chemical, and biological properties during application. © 2022 Society of Chemical Industry.

Use of whey protein as a natural polymer for the encapsulation of plant biocontrol bacteria: A review

Climate changes, drought, the salinity of water and soil, the emergence of new breeds of pests and pathogens, the industrialization of countries, and environmental contamination are among the factors limiting the production of agricultural products. The use of chemicals (in the form of fertilizers, pesticides and fungicides) to enhance products against biotic and abiotic stresses has limitations. To eliminate the effects of agricultural chemicals, synthetic agrochemicals should be replaced with natural substances and useful microorganisms. To be more effective and efficient, plant biocontrol bacteria need a coating layer around themselves to protect them from adverse conditions. Whey protein, a valuable by-product of the cheese industry, is one of the important natural polymers. Due to its high protein content, safety, and biodegradability, whey can have many applications in agriculture and encapsulation of bacteria to resist pests and plant diseases. This compound is a rich source of amino acids that can activate plant defense systems and defense enzymes. Considering the amazing potentialities of formulation whey protein, this review attends to the efficiency of whey protein as coating layers on fruit and vegetables and in the packaging system to increase the shelf life of agricultural products against phytopathogens.

Strategies for Exploiting Milk Protein Properties in Making Films and Coatings for Food Packaging: A Review

Biopolymers of different natures (carbohydrates, proteins, etc.) recovered from by-products of industrial processes are increasingly being studied to obtain biomaterials as alternatives to conventional plastics, thus contributing to the implementation of a circular economy. The food industry generates huge amounts of by-products and waste, including unsold food products that reach the end of their shelf life and are no longer usable in the food chain. Milk proteins can be easily separated from dairy waste and adapted into effective bio-based polymeric materials. Firstly, this review describes the relevant properties of milk proteins and the approaches to modifying them for subsequent use. Then, we provide an overview of recent studies on the development of films and coatings based on milk proteins and, where available, their applications in food packaging. Comparisons among published studies were made based on the formulation as well as production conditions and technologies. The role of different additives and modifiers tested for the performances of films and coatings, such as water vapor permeability, tensile strength, and elongation at break, were reviewed. This review also outlines the limitations of milk-protein-based materials, such as moisture sensitivity and brittleness. Overall, milk proteins hold great potential as a sustainable alternative to petroleum-based polymers. However, their use in food packaging materials at an industrial level remains problematic.

Milk protein-based active edible packaging for food applications: An eco-friendly approach

Whey and casein proteins, in particular, have shown considerable promise in replacing fossil-based plastics in a variety of food applications, such as for O₂ susceptible foods, thereby, rendering milk proteins certainly one of the most quality-assured biopolymers in the packaging discipline. Properties like excellent gas barrier properties, proficiency to develop self-supporting films, adequate availability, and superb biodegradability have aroused great attention toward whey and other milk proteins in recent years. High thermal stability, non-toxicity, the ability to form strong inter cross-links, and micelle formation, all these attributes make it a suitable material for outstanding biodegradability. The unique structural and functional properties of milk proteins make them a suitable candidate for tailoring novel active package techniques for satisfying the needs of the food and nutraceutical industries. Milk proteins, especially whey proteins, serve as excellent carriers of various ingredients which are incorporated in films/coatings to strengthen barrier properties and enhance functional properties viz. antioxidant and antimicrobial. In this review, the latest techniques pertaining to the conceptualization of active package models/ systems using milk proteins have been discussed. Physical and other functional properties of milk protein-based active packaging systems are also reviewed. This review provides an overview of recent applications of milk protein-sourced active edible packages in the food packaging business.

Nano Coating of Aloe-Gel Incorporation Additives to Maintain the Quality of Freshly Cut Fruits

The edible coating is an environmentally friendly technology that is applied to fresh-cut fruit products. One of the natural ingredients that are potentially applicable is aloe-gel because it contains several functional components. The main advantage of aloe-coating is that additives can be incorporated into the polymer matrix to enhance its properties. Additives tend to improve the safety, nutritional, and sensory attributes of fresh fruits, but in some cases, aloe-coating does not work. Furthermore, particle size determines the effectiveness of the process on fresh-cut fruits. Aloe-gel nano-coating can be used to overcome the difficulty of adhesion on the surface of fresh-cut fruits. However, quality criteria for fresh cut fruit coated with aloe-gel nano-coating must be strictly defined. The fruit to be processed must be of minimal quality so that discoloration, loss of firmness, spoilage ratio, and fruit weight loss can be minimized. This study aims to discuss the use of nano-coating aloe-gel incorporated with additional ingredients to maintain the quality of fresh-cut fruits. It also examined the recent advances in preparation, extraction, stabilization, and application methods in fresh fruits.

Preparation of Silver Antibacterial Agents with Different Forms and Their Effects on the Properties of Water-Based Primer on Tilia europaea Surface

Micron silver particles prepared by the chemical reduction method, urea formaldehyde resin-coated nano-silver solution microcapsules, and nano-silver solution were used as three kinds of antibacterial agents. These were added to a water-based primer on the surface of Tilia europaea in contents of 1.0%, 4.0%, 7.0%, 10.0%, 13.0%, and 16.0%. In order to achieve the best comprehensive performance of the water-based primer, the mechanical, optical, and antibacterial properties of the three antibacterial coatings with different contents of silver antibacterial agents were explored. It was concluded that when the antibacterial agent content was 4.0%, the color difference, impact resistance, adhesion, and gloss of water-based primer on the Tilia europaea surface were better. When the antibacterial agent content added was 16.0%, the antibacterial properties of the three groups of coatings improved to 94.89%, 81.75%, and 83.98%, respectively. The results provide a research idea for the preparation of antibacterial coatings on the surface of wood furniture.

Application of Whey Protein-Based Edible Films and Coatings in Food Industries: An Updated Overview

The recent surge in environmental awareness and consumer demand for stable, healthy, and safe foods has led the packaging and food sectors to focus on developing edible packaging materials to reduce waste. Edible films and coatings as a modern sustainable packaging solution offer significant potential to serve as a functional barrier between the food and environment ensuring food safety and quality. Whey protein is one of the most promising edible biopolymers in the food packaging industry that has recently gained much attention for its abundant nature, safety, and biodegradability and as an ecofriendly alternative of synthetic polymers. Whey protein isolate and whey protein concentrate are the two major forms of whey protein involved in the formation of edible films and coatings. An edible whey film is a dry, highly interacting polymer network with a three-dimensional gel-type structure. Films/coatings made from whey proteins are colorless, odorless, flexible, and transparent with outstanding mechanical and barrier properties compared with polysaccharide and other-protein polymers. They have high water vapor permeability, low tensile strength, and excellent oxygen permeability compared with other protein films. Whey protein-based films/coatings have been successfully demonstrated in certain foods as vehicles of active ingredients (antimicrobials, antioxidants, probiotics, etc.), without considerably altering the desired properties of packaging films that adds value for subsequent industrial applications. This review provides an overview of the recent advances on the formation and processing technologies of whey protein-based edible films/coatings, the incorporation of additives/active ingredients for improvement, their technological properties, and potential applications in food packaging.