The packaging is a barrier against physical, chemical, and biological factors that can cause product degradation. It protects cosmetics (preventing contamination, moisture, light, and air, and providing integrity during transportation, storage, and handling) and is a powerful branding and marketing tool. The packaging must comply with various regulatory requirements and standards for product safety, labeling, and environmental sustainability. The size of the cosmetics packaging market was USD 55,729.9 million in 2023. It is projected to increase to approximately USD 58,070.6 million in 2024 and grow to USD 78,612.4 million by 2032, with a compound annual growth rate (CAGR) of 3.9% from 2024 to 2032. [
41]. The cosmetic packaging market continues its growth, driven by evolving consumer preferences, innovation in materials, and sustainable packaging solutions. Key drivers propelling market growth include the surge in beauty and personal care products, heightened emphasis on eco-friendly packaging, and the advent of premiumization in the cosmetics industry. Petrochemical plastics (i.e., PET (polyethylene terephthalate), PVC (polyvinylchloride), PS (polystyrene), and PA (polyamide) are usually used for cosmetic packaging since they are transparent, permeable, flexible, have good tensile strength, thermal efficiency, cost-effectiveness, and can be sterilized. However, the overuse of these materials is unsustainable and has been proven to have disastrous consequences for our planet. Plastics contribute to worldwide environmental pollution and threaten various life forms since they have a stable structure of carbon–carbon bonds [
42]. Synthetic plastics not only take centuries to break down, but they also seep into the environment. It has been estimated that 8 million metric tons of plastics end up in our oceans each year [
5]. Plastics disperse and gradually break down into micro- and nanoplastics when they enter the ocean. Various organisms, including marine mammals, fish, crustaceans, mollusks, zooplankton, and phytoplankton, consume these tiny particles. This ingestion can adversely affect their physiological processes [
43], impacting climate change and global warming since approximately 70% of the world’s oxygen is generated through photosynthesizing marine life forms such as seaweeds and microalgae [
44].
Furthermore, people ingest plastic particles by consuming land and sea-based food products, drinking water, and inhalation [
45]. This scenario has increased demand for alternative packaging solutions that are renewable, recyclable, easily degradable, and require little to no disposal. Edible packaging materials, a subset of bio-based and biodegradable materials, have been researched as an alternative to traditional cosmetic packaging due to their film-formation properties.
4.1. Edible Packaging
Edible packaging is an eco-friendly, safe, and functional solution that can be consumed with the product and decomposes faster than traditional packaging materials, significantly reducing the waste generated. Edible packaging provides a novel experience that can attract consumers looking for unique products, allowing brands to stand out in a crowded market with an eco-friendly image and increasing consumer engagement and loyalty. Edible packaging is based on biomolecular matrixes derived from plants, animals, or microorganisms. Common biomolecules include polysaccharides (i.e., cellulose, starch, and chitosan), proteins (i.e., casein, gelatin, and soy proteins), and lipids (i.e., paraffin, waxes, and oils) [
46] (
Figure 5). Biopolymers form a cohesive structure that incorporates active compounds (i.e., prebiotics, probiotics, vitamins, minerals), functional ingredients (i.e., antioxidants, antibrowning agents, and antimicrobials), and sensory enhancers (i.e., flavors, colors, and textures enhancers) [
13]. Edible packaging employs edible materials (i.e., capsules, pods, film, strips, powder, tablets, lip balms, lipsticks, sachets, and pouches) to package cosmetic products, offering a sustainable alternative to reduce plastic waste and the environmental impact of traditional cosmetics packaging and promote environmental responsibility in the beauty industry.
4.1.1. Edible Films or Strips
The materials used to create edible films can be grouped into three primary categories based on their source and production process: polymers that are directly extracted from biomass, such as polysaccharides and proteins; polymers that are produced through traditional chemical synthesis using renewable, bio-based monomers, like polylactic acid, and polymers that are produced by microorganisms or genetically modified bacteria [
47] (
Figure 6).
Films based on biopolymers are created using solutions that contain three primary components: the biopolymer, a plasticizer, and a solvent. The characteristics of the resulting film are influenced by both the inherent properties of the film components and external processing factors. Protein films offer mechanical stability, polysaccharides are used to manage oxygen and other gas transmissions, and fats are employed to minimize water transmission [
48]. It is important to note that only protein films supply nitrogen during their degradation, serving as fertilizers, a benefit not provided by films that do not contain protein [
49]. Polysaccharides are carbohydrate macromolecules composed of two or more monosaccharides connected with glycosidic linkages through condensation reactions, insoluble in alcohol and nonpolar solvents, typically white in color, tasteless, and seldom crystalline. Thanks to their adaptable biocompatibility and various functionalities, they stand out among edible polymers [
50]. Starch, pectin, carrageenans, alginates, xanthan gum, and cellulose derivatives are edible polysaccharides used in cosmetics [
51,
52,
53].
Fruit pectin [
54] or agar [
55] can be used for facial masks, exfoliating pads, or individual make-up wipes. These films dissolve upon contact with water, releasing the product and eliminating the need for additional packaging waste. They possess thermal characteristics, barrier attributes, and mechanical properties. Thermal analysis helps understand how a material behaves under varying rates of cooling or heating or in an inert, reducing, or oxidizing atmosphere. This understanding allows prediction of how a protein package might behave during different processing stages, such as freezing or cooking. During these stages, proteins denature, dissociate, and realign, allowing protein molecules to combine and cross-link through specific linkages. In the context of packaging materials, a critical piece of information is the glass transition temperature (Tg, the temperature range at which a glassy material transitions into a rubbery state, decreasing the Young’s modulus).
The term “glass transition” describes the reversible shift in the physical characteristics of specific materials when they undergo a particular range of temperature changes. Biopolymer-based films exhibit brittleness at lower temperatures. However, as the temperature increases and reaches the glass transition point, these materials transform and exhibit ductility.
Above Tg, the polymeric materials are in a soft, rubbery state, which has barrier properties, while below Tg, polymers are in a glassy state with low permeability. The Tg values are also vital for determining the compression molding and extrusion temperatures. Tg generally increases with stiff chains and bonds, cross-linking between chains, bulky side groups, and the degree of crystallinity. Conversely, Tg decreases when the quantity of low-molecular-weight plasticizers increases [
56]. Barrier properties are crucial in determining a product’s shelf life and/or packaging, and they are linked to the product’s requirements and final use. The primary agents studied in packaging applications are water vapor and oxygen, as they can permeate from the internal/external environment through the polymer, leading to ongoing changes in product quality and shelf life. Biopolymer-based films typically have a high inclination towards water vapor permeability (WVP), making the solubility and diffusivity of water molecules critical factors in controlling permeability within the polymeric matrix. WVP coefficients indicate the amount of water vapor that passes through a unit area of the packaging material in a given time (kg mm
−2 s
−1 Pa
−1) and quantify water vapor permeability [
57]. The polymers influence the mechanical properties. The tensile test measures the tension force in Pascal (MPa), the percentage of elongation at break (%), and the elastic modulus in Pascal (GPa). It provides insights into the material’s flexibility, hardness, and elongation and helps to predict how the packaging behaves during handling and storage [
58].
4.1.2. Polysaccharide-Based Edible Films
Polysaccharide-based edible films have good gas oil and lipid barrier performance but are vulnerable to humidity and have low water resistance. Cellulose, alginate, and pectin are the leading polysaccharides used. The key advantages of polysaccharides are availability, abundance, nontoxicity, thermo-processability, and low cost. Cellulose requires a chemical alteration, which involves replacing the numerous hydroxyl functions with acetate or methyl groups before being used for packaging purposes. As a result of this modification, the material becomes more straightforward to process and convert into films due to the reduction in the physical system and the quantity of hydrogen bonds. Various cellulose materials can be produced following this chemical adjustment, each with specific mechanical strength characteristics, solubility, and barrier efficiency against oxygen and lipids. The most frequently used materials, known for their excellent film-forming properties, include hydroxypropyl methylcellulose, methylcellulose, hydroxypropyl cellulose, and carboxymethyl cellulose [
59]. Alginates are obtained from brown seaweeds; they have good oxygen and water barrier qualities, antioxidant properties, flexibility, and absorbency ability [
60]. Edible films made from pectin are used in solution-cast or compression-molded self-standing films [
61], extruded casings [
62], or edible coatings [
63].
4.1.3. Proteins-Based Edible Films
Edible protein films are obtained from proteins in plants and animals (
Table 4). The advantages of proteins over polysaccharides are their abundance, high nutritional value, remarkable ability to form films, gas barrier properties against odor, oxygen, and carbon dioxide, and mechanical properties [
64]. Their flexibility is enhanced with the presence of numerous hydrophilic substances such as sorbitol and glycerin. However, changes in the moisture content of the surrounding environment can negatively impact their mechanical properties and water vapor permeability due to their natural hydrophilicity and consequent high biodegradability. Applying cross-linking, which can be either chemical or physical, can potentially improve these characteristics [
65]. Collagen-based edible film is a protective layer, preventing the movement of oxygen, moisture, and solutes. It contributes to the product’s structural integrity and allows vapor permeability. Additionally, such films inhibit fat oxidation, discoloration, and microbial growth, thereby preserving the product’s sensory attributes [
66].
Gelatin is obtained through the partial hydrolysis and heat treatment of collagen. The chemical composition of gelatin is closely related to that of collagen. Hydrolysis breaks down the natural molecular bonds between individual collagen strands into a more easily rearranged form. As a result, gelatin is a combination of single or multiple-stranded polypeptides, each with an extended left-handed helix conformation and containing between 50 and 1000 amino acids. The molecular weights can range from 3 to 200 kDa, influenced by the type of raw material used and the specific handling conditions [
67]. Two gelatin varieties are typically produced: type A (from acid hydrolysis) and type B (from alkaline hydrolysis) [
68]. Gelatin is rich in glycine residues, which comprise nearly one-third of its structure and are arranged in every third residue. It also contains proline and 4-hydroxyproline residues. A typical gelatin structure is -Ala-Gly-Pro-Arg-Gly-Glu-4Hyp-Gly-Pro-. The estimated composition of amino acids in gelatin can fluctuate, particularly among the minor constituents, based on the source of the raw material and the processing method used [
69]. Gelatin-based films are an excellent barrier against oxygen but have a high sensitivity to moisture that decreases their thermomechanical and barrier properties. A potential solution to this issue is to combine a gelatin-based film with a moisture-resistant biodegradable polymer through a process known as laminating or coextrusion, which is commonly used in film packaging. This process optimizes multilayered structures based on the specific packaging requirements and conditions [
70].
Zein possesses excellent film characteristics, including a water-repelling nature (despite having high levels of nonpolar amino acid groups), potential antimicrobial and antioxidant activities, adhesive film-forming capability, and exceptional resistance to both moisture and oxygen. The Food and Drug Administration (FDA) recognizes zein as a safe material for use in food systems. The disadvantages of zein-based film are its tendency to break easily and its poor processability, mechanical properties, elongation at break, and thermal properties [
71].
Films derived from whey proteins are known for their viscosity and stretchability. They exhibit a strong barrier against oxygen and aromas thanks to their densely packed, orderly network structure and low solubility. However, due to the high content of hydrophilic amino acids in whey protein, products made solely from whey protein materials may have subpar mechanical strength and vapor-barrier properties. Plasticizers, antimicrobial agents, or antioxidants can bolster their mechanical strength and augment their functional properties. The high cost of whey proteins limits their use in this sector [
72].
4.1.4. Lipid-Based Edible Films
Lipids have a low molecular weight and polarity; therefore, they provide moisture-barrier properties but cannot be applied alone as films. Lipids commonly utilized in lipid-based edible films are mono-, di-, and tri-acylglycerols, free fatty acids, phospholipids, waxes (i.e., beeswax, candle wax, and carnauba wax), and resins (i.e., shellac resin, turpentine, and coumarin resin) (
Table 6) [
73]. Lipid films lack flexibility and transparency. Lipid molecules can be layered with a lipid hydrocolloid film coating through lamination to enhance their relatively low mechanical strength. Alternatively, they can be mixed with hydrophilic materials to form an emulsion complex. Despite having satisfactory mechanical properties and simple structures for their production and use, emulsion films are less effective than laminated films due to inadequate lipid dispersion. The complexity of producing multilayer films increases with the number of coatings used. Edible shellac has been used to coat fresh products and confections [
74].
4.1.5. Antioxidant-Based Edible Films
Developing edible packaging enriched with natural antioxidants is gaining significant attention [
83,
84]. This innovative approach enhances the cosmeceutical attributes of products, extends their longevity via minimizing weight reduction, and ensures the preservation of their freshness and sensory characteristics. It also safeguards the products from changes induced through light exposure, provides adaptability, and protects against moisture [
85]. The efficacy of antioxidants as a packaging component is contingent on an appropriate choice of antioxidant (i.e., concentration and stability), the formulation of the packaging, the conditions under which it is stored, and the attributes of the end product. It is crucial to consider the properties of antioxidants during the packaging formulation process, particularly their miscibility, interaction, and solid and off-putting sensory characteristics (such as color, taste, and smell) that negatively impact a consumer’s acceptance of the product [
86]. When incorporating antioxidants into edible films, it is vital to highlight the preference for naturally derived antioxidants. Adherence to governing bodies’ regulations and each country’s safety/quality standards is crucial, especially considering that edible packaging forms an essential component of the consumable portion (
Table 7) [
87].
Chitosan edible films are a superior packaging option for cosmetics. They have non-toxic nature, biodegradability, ability as a thickening agent, and antifungal, antioxidant, and moisturizing properties. This biomaterial can scavenge free radicals and chelate metal ions, thereby extending the shelf life of cosmetics [
88,
89].
The potential of edible packages can be enhanced through combining chitosan with essential oils (containing cinnamaldehyde, eugenol, rosemary, and thymol) [
90,
91], glutathione, vitamin E, vitamin C, α-carotene, phenolic acids, flavonoids, antioxidant biopeptides, and selenium, which can impart antioxidant properties to the films [
3,
92].
Table 7.
Some patents in which antioxidants have been used to prepare edible films.
Table 7.
Some patents in which antioxidants have been used to prepare edible films.
Patent Application | Patent Number | Plant-Based Ingredients | Details of the Invention | References |
---|
Taste-masking compositions and edible forms thereof | CA2834231A1 | Chitosan, carboxymethylcellulose, methylcellulose, hydroxypropylmethylcellulose, locust bean gum, guar gum, carrageenan, xanthum gum, pullulan, pectins, and gum arabic | This patent illustrates edible films that mask the taste of products (cosmetics). | [93] |
Methods and compositions for the treatment of skin | US9499419B2 | Chitosan and chitin | This patent concerns formulations designed to treat and improve skin conditions such as acne, rosacea, and wrinkles. Various factors, including photodamage, aging, hormonal imbalances, hyper-pigmentation, melasma, and keratosis, can cause these conditions. | [94] |
4.1.6. Edible Sachets or Pouches
Edible sachets or pouches made from edible films or coatings can be used for samples or single-use portions of moisturizers, hair masks, or facial cleansers. Consumers can tear open the sachet, apply the product, and dispose of the packaging by eating or composting it.
Notpla, a startup focused on sustainability, has introduced a novel packaging solution made from seaweed and plants to replace traditional plastic. This packaging was created by the branding agency Superunion. The material used by Notpla naturally decomposes in four to six weeks. It has been utilized in many ways, including thin films, coatings for takeaway containers, and condiment packets [
95].
Xampla is a startup originating from the University of Cambridge. The startup offers high-quality plant-protein packaging (i.e., edible sachets, microcapsules, and coatings) that can prolong the shelf life of products [
96].