Review articlePotential use of polymers and their complexes as media for storage and delivery of fragrances
Graphical abstract
Introduction
Fragrances are used as one of the most indispensable ingredients in food and fabric industries. Controlled delivery of fragrant molecules has remained a research focus in the flavor and fragrance industry. To elongate the limited longevity of olfactive perception, the development of pro-perfumes or pro-fragrances has attracted attention over the years. Many volatile chemical compounds have been used as perfumes or deodorants in various consumer goods. Their volatility is essential to provide a pleasant olfactory response, while this property also can be a disadvantage.
For fragrances used in various products (e.g., cosmetics, fabrics, household goods, food, and personal care products), one of the main interests is to improve the delivery of imparted fragrant molecules with controlled release and long life [1,2]. There is also great interest in infusing scent into everyday materials such as fabrics or in turning liquid flavors into free-flowing powders so as to increase their shelf life in food products [3]. Most fragrance delivery systems have the drawbacks of premature evaporation and degradation during storage. Additionally, the lifespan of flavors is short, and their perception to the sensory system is also affected by external factors like heating, oxidation, or chemical interactions. The selection method for a particular fragrance delivery depends upon the nature of the consumer goods and the stimulus that triggers the release mechanism. Hence, for the selection of a particular method, a number of criteria need to be considered [4]. First, it is important to consider the targeted application of fragrances, e.g., food items and fabrics. Second, the required level of humidity in the product is also important, as this factor is directly related to the storage conditions. The third criterion is the reaction mechanism that will be used to trigger the release of molecules [5,6].
Constraints on the use of fragrances are commonly accompanied by environmental concerns on the large-scale production of non-biodegradable fragrances and toxicity associated with their release. The introduction of encapsulation technique opened up the way to avoid the problems of using such products which was not possible before because of their significantly low chemical stability (during processing, storage, or usage). In fact, a straightforward route exists to develop microencapsulated fragrance material(s) which can be adopted from the pre-existing methods in other fields of applications (e.g., foods and agriculture, pharmacy, or cosmetics). Nonetheless, industrial constraint (e.g., cost in use) is an important factor to consider in a cost-competitive market area as observed from various commercial products. As such, there are at least a few parameters that should be controlled during encapsulation process such as process retention, protection, deposition, triggered release, and sustained release of volatiles. To resolve problems associated with such variables, detailed evaluation is required to assess not only the interactions between the volatile ingredients and the carrier (or encapsulant material) but also the behavior of the selected material under several application conditions.
The selection of a particular delivery system depends not only on the nature of the product in which this delivery system is to be used but also on the kind of release mechanism that is actually required. In this respect, encapsulation should be the tool to make more efficient use of fragrances as slow or controlled delivery systems. Further, for the release mechanism of fragrance, a list of factors should be considered such as its initial loading in the polymer, solubility in the solvent, equilibrium partitioning between polymer and solvent (and any possible diffusional barriers). There are two major concerns regarding the development of fragrance delivery system such as the time required to produce a stable capsule and price of its constituents [4]. It appears that much work is still to be made in three major areas. Firstly, the retention of volatile components in carrier materials should be improved, especially in case of products that are subjected to drastic storage or handling conditions. Secondly, the potential of triggered and sustained release systems in terms of hedonic benefits should be investigated more in depth. Finally, the cost level of current delivery systems is still an issue in many fragrance applications. It is thus believed that progress in all of these areas will require a better understanding of the materials science aspects underlying encapsulation as well as a better integration of the delivery systems into the perfume/flavor creation process. In parallel with the continuing work on the common encapsulation technologies, it is desirable to pursue new developments to further advance from current scientific levels, especially in nanobiotechnology fields such as molecular recognition, new polymers, and novel composite materials.
In this article, current applications of various polymers and their complexes in fragrance delivery systems are briefly reviewed. Functionality and applicability of these polymers are highlighted in order to provide a comprehensive view on the development of these materials in perfume industry. Through the extensive survey on the literature, the perspectives of polymer-based active packaging options for various encapsulants are highlighted. Fragrance loading rate of various aromas under varying temperature and pH conditions have also been discussed in details. The practical tools for the identification of encapsulation media such as Scanning Electron Microscope and Transmission Electron Microscope have also been discussed to assess the mechanisms controlling the entrapment of fragrances in the encapsulant. As such, we provide a comprehensive review on the capture and controlled release of fragrances in various products and summarized information on effective options to control the fragrance release process, such as microencapsulation process using various polymers and their complexes. We discuss about various methods to control encapsulation via chemical and engineering processes. Different types of triggering mechanisms for the release of the loaded fragrant molecules in diverse encapsulating agents have been elaborated. Different types of polymeric materials developed for the micro- or nanoencapsulation of various fragrances are also described. The importance of polymeric materials has been reviewed with respect to their properties for encapsulation along with the associated scientific challenges in this research area.
Section snippets
Mechanisms of encapsulation and release of fragrances
The encapsulation process is useful in improving the properties and usability of several industrial and commercial products, such as fragrances, self-healing materials, nutrients, and drugs. Fragrances and flavors have a limited lifetime as their constituents evaporate and degrade before or during use [7,8]. Flavors and fragrances have widely been applied in many fields (e.g., food, medicine, papermaking, textiles, leather, cosmetics, and tobacco). The encapsulation process basically functions
Materials for encapsulation
Various high strength materials with biodegradable and biocompatible polymeric shells are used for encapsulation. However, many of the reported fragrance-entrapping molecules are unstable due to their reactive functionalities, e.g., aldehyde, ketone, and terpenes. Thus, various other materials, such as chitosan [19], cyclodextrins [20], and polymers [21], have been explored as alternatives. Porous materials, such as zeolites, are also studied in fragrance delivery systems. Various natural or
Types of fragrances loaded
Aroma compounds, also called odorants, aromas, or fragrances, are chemical compounds producing a smell or odor. These compounds are produced by volatilizing chemical constituents, even at very low concentrations. The use of fragrances has become very frequent in homes as well as for personal care. The fragrances commonly used in daily life include those that mimic the aroma of flowers (e.g., rose, vanillin, tuberose, lavender, and jasmine). Upon their release, the fragrant molecules interact
Performance of encapsulation materials and media
Encapsulation is a process of capturing various compounds into a coating material. The effect of the aroma can be prolonged if fragrances and flavors are encapsulated with the aid of various media (e.g., polymers). Fragrance agents can be encapsulated in various polymers, biomolecules, minerals, and porous materials (e.g., zeolites and MOFs). The different forms of a fragrance-capturing polymer may take the shape of nanoparticles, capsules, micelles, inclusion complexes, or emulsions, which are
Critical assessment of polymeric materials in fragrance delivery
Fragrances with attractive aromas may exert sensitizing effects on our emotional cognizance. They are used in many household and personal care products, such as toiletries, air fresheners, and cosmetics. The optimized utility of fragrances depends upon two critical factors of volatility and long-term stability. Although the volatile nature of fragrance is of paramount importance to achieve a desired sensory response, it results in an undesired loss if stored over a long duration. This limiting
Conclusion
This review was carried out to provide an overview of the prospective applications of polymeric complexes for the storage and delivery of fragrances on the commercial scale. Fragrance chemicals have widespread applications in various goods of consumer importance (e.g., food, wine, spices, perfumes, laundry detergents, fabric softeners, soaps, detergents, and personal care products) owing to their soothing effects on human behavior. Chemically, fragrances are organic compounds with highly
Acknowledgments
Rajnish Kaur acknowledges the SERB-DST, India (Ref No.: PDF/2016/001870) for her research grant. This study was supported by a grant from the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT, & Future Planning (Grant No: 2016R1E1A1A01940995). This research was also supported partially by the R&D Center for Green Patrol Technologies through the R&D for Global Top Environmental Technologies funded by the Ministry of Environment (MOE), Republic of Korea.
References (93)
- et al.
Physical approaches for the delivery of active ingredients in foods
Trends Food Sci. Technol.
(2006) - et al.
Preparation and characterization of polysulfone microcapsules for perfume release
Chem. Eng. J.
(2012) - et al.
Stimuli-responsive polymeric nanocarriers for the controlled transport of active compounds: concepts and applications
Adv. Drug Deliv. Rev.
(2012) - et al.
Properties and controlled release of chitosan microencapsulated limonene oil
Rev. Bras
(2014) - et al.
Polymers for flexible displays: from material selection to device applications
Prog. Polym. Sci.
(2008) - et al.
Emerging methods for the fabrication of polymer capsules
Adv. Colloid Interf. Sci.
(2014) - et al.
Influence of operating conditions on the surface morphology of microcapsules prepared by in situ polymerization
Colloids Surf. A Physicochem. Eng. Asp.
(2010) - et al.
Fabrication and performances of microencapsulated paraffin composites with polymethylmethacrylate shell based on ultraviolet irradiation-initiated
Mater. Chem. Phys.
(2012) - et al.
Microencapsulated n-octadecane with different methylmethacrylate-based copolymer shells as phase change materials for thermal energy storage
Energy
(2012) - et al.
Biology and applications of olfactory sensing system: a review
Sensors Actuators B Chem.
(2012)
Geraniol—a review of a commercially important fragrance material
S. Afr. J. Bot.
Occurrence and fate of synthetic musk compounds in water environment
Water Res.
Analysis of odour compounds from scented consumer products using gas chromatography-mass spectrometry and gas chromatography-olfactometry
Anal. Chim. Acta
Quantitative structure–property relationship analysis for the retention index of fragrance-like compounds on a polar stationary phase
J. Chromatogr. A
High loading fragrance encapsulation based on a polymer-blend: preparation and release behavior
Int. J. Pharm.
Preparation of poly (methyl methacrylate) microcapsule with encapsulated jasmine oil
Energy Procedia
Sustained-release properties of cotton fabrics impregnated with nanotuberose fragrance
J. Appl. Polym. Sci.
Novel biocompatible nanocapsules for slow release of fragrances on the human skin
New Biotechnol.
Encapsulation of a fragrance molecule in zeolite X
Microporous Mesoporous Mater.
Carrageenan for encapsulation and immobilization of flavor, fragrance, probiotics, and enzymes: a review
J. Carbohydr. Chem.
Chitosan as a bioactive polymer: processing, properties and applications
Int. J. Biol. Macromol.
Antimicrobial behavior of ion-exchanged zeolite X containing fragrance
Microporous Mesoporous Mater.
Microencapsulation with chitosan by spray drying for industry applications – a review
Trends Food Sci. Technol.
Sol–gel microencapsulation of odorants and flavors: opening the route to sustainable fragrances and aromas
Chem. Soc. Rev.
Facile synthesis of thermal-responsive P (NIPAM-S)/SiO 2 hybrid hollow spheres and their controllable release properties for fragrance
Polym. Chem.
Beauty game changers
Household Pers. Prod. Ind.
Micro/nanoencapsulation of essential oils and fragrances: focus on perfumed, antimicrobial, mosquito-repellent and medical textiles
J. Microencapsul.
Encapsulated recyclable porous materials: an effective moisture-triggered fragrance release system
Chem. Commun.
Encapsulation of aroma
Recent developments in microencapsulation of food ingredients
Dry. Technol.
Flavor encapsulation
Food Rev. Int.
Encapsulation Processes, Food Powders: Physical Properties, Processing, and Functionality
Flavors & fragrance delivery systems
CHIMIA Int. J. Chem.
Liquid-Core Microcapsules: A Mechanism for the Recovery and Purification of Selected Molecules in Different Environments
Encapsulation of fragrances and flavours: a way to control odour and aroma in consumer products
Overview of controlled release mechanisms
Encapsulation of lemon oil by paste method using β-cyclodextrin: encapsulation efficiency and profile of oil volatiles
J. Agric. Food Chem.
Encapsulation using hyperbranched polymers: from research and technologies to emerging applications
Ind. Eng. Chem. Res.
Properties of Polymers: Their Correlation With Chemical Structure; Their Numerical Estimation and Prediction From Additive Group Contributions
Electrical Properties of Polymers
Triggered release from polymer capsules
Macromolecules
Monodisperse polymer capsules: tailoring size, shell thickness, and hydrophobic cargo loading via emulsion templating
Adv. Funct. Mater.
Different techniques for preparation of polymeric nanoparticles-a review
Asian J. Pharm. Clin. Res.
Polymer microcapsules with programmable active release
J. Am. Chem. Soc.
Cited by (86)
Potential use of Thai mango (Mangifera indica Linn. cultivar Chok-Anan) seed porous starch for retention of aroma compounds from coffee extract
2024, International Journal of Biological MacromoleculesPore engineering of micro/mesoporous nanomaterials for encapsulation, controlled release and variegated applications of essential oils
2024, Journal of Controlled ReleaseA comprehensive study on flavor/cyclodextrin inclusion complexes
2023, Colloids and Surfaces A: Physicochemical and Engineering AspectsA review on the efficacy of essential oils and their nanoencapsulated formulations against aflatoxins contamination of major cereals with emphasis on mode of action
2023, Biocatalysis and Agricultural BiotechnologyVisible light-based polymerization of poly (methyl methacrylate) encapsulated fragrances used for fabric softener applications
2023, Industrial Crops and ProductsStimulus responsive microcapsules and their aromatic applications
2022, Journal of Controlled ReleaseCitation Excerpt :Fragrances, also known as odorants, refer to compounds capable of producing volatile chemical constituents with an aroma or fragrance. Since aromatic molecules can interact with human olfactory receptors after release, bring pleasant smell and taste, and can endow consumer goods with excellent additional commercial value, fragrances and flavors have a wide range of applications in cosmetics, food, medicine, tobacco, textiles, leather, and paper [1,2]. According to the source and production method, aroma molecules can be classified as natural, natural identical or synthetic compounds.
- 1
These authors are considered as co-first authors because they contributed equally to this work.