How to extend the fragrance retention time of flavours?

Flavours, as an important additive, have a wide range of applications in the fields of food, medicine, cosmetics, leather, textile and paper making to beautify people’s lives.

 

The use of flavours in consumer products not only helps consumers to establish a pleasurable sensory experience, but also helps to build brand recognition of the product.

 

In practical application, volatility is the key to achieve the function of the flavour, which is also the defect of the flavour, the traditional flavour has a high volatility, volatile aromatic components are easily deteriorated and lost during the storage and manufacturing process, resulting in a poor fragrance retention effect, while the current consumer requirements for the length of the fragrance retention time is getting longer and longer and more demanding.

 

Therefore, to achieve a lasting perception of aromatic volatiles has become a challenging task, how to extend the fragrance of the fragrance time has become a hotspot of growing concern for businesses and researchers, especially in the toiletries market, long-lasting fragrance products are increasingly favoured by consumers, but how to achieve long-lasting fragrance, is still a technical challenge for the industry.

 

The easiest way to prolong fragrance retention is to increase the amount of fragrance used, but simply increasing the amount of fragrance often leads to an overly strong aroma, making consumers feel offended and uncomfortable.

 

Therefore, choosing the right fragrance and the right fragrance retention technology can have a better effect on the product.

 

In this paper, from the impact of fragrance strength factors, fragrance retention technology and other aspects of the current technology to enhance the retention of aroma progress.

 

1 The relationship between the molecular structure of spices and aroma

Spice is a volatile aromatic substances, the classical theory of spice chemistry that: the spice molecule needs to contain a stimulating sense of smell of the fragrance group.

 

The number of carbon atoms in the fragrance compound molecule, unsaturation, functional groups, substituents and isomerism and other factors will have an impact on the strength of the aroma, while the strength of the aroma will affect the duration of the fragrance, in general, the stronger the aroma of the longer the fragrance time will be longer.

 

Flavour developers can carry out the design, synthesis or formulation of fragrance according to the law of fragrance structure and fragrance aroma.

 

2 Fragrance carrier

As the volatile aromatic components of the spice in the storage and manufacturing process is easy to deteriorate and lost, so researchers will transfer it to the spice carrier, so that the spice attached to it, which not only increases the storage stability of the spice and can control the release rate of the spice to achieve the slow release as well as prolonging the fragrance of the spice to stay the purpose of time.

 

At present, the spice carrier is mainly divided into adsorption-type carrier, capsule-type carrier, matrix-type carrier.

 

3 Spice precursor

Fragrance precursor is a class of relative molecular mass, high boiling point of the material, less aromatic or no aroma itself, but after hydrolysis, light, oxidation, high temperature, enzyme catalysis or pH changes and other ways to stimulate the release of compounds with aroma fragrance.

 

Fragrance precursors have a great advantage in practical polymer applications due to their precise and controllable properties and high stability, which is another common method to achieve long-lasting fragrance retention in addition to microencapsulation in market applications. Fragrance precursors are divided into natural and artificial fragrance precursors.

 

4 Flavour fixatives

In a fragrance system, the fixative is a higher boiling point, lower vapour pressure, in very low concentrations still have the aroma of the compound, the fixative can make the head of the fragrance in a period of time to reduce the amount of volatility, the higher the boiling point of the fixative, the lower the vapour pressure, the head of the fragrance volatility will be less.

 

Flavouring agent can be divided into animal natural flavouring agent, plant natural flavouring agent and synthetic flavouring agent.

5 fragrance enhancer

Fragrance enhancers, also known as aromatics, is a chemical substance that can enhance or improve the aroma and odour of other substances and spices, itself does not necessarily present the aroma, and will not change the structure and composition of other aroma substances, but it can strengthen the human olfactory nerve stimulation, improve and enhance the sensitivity of the olfactory cells, and strengthen the transmission of aroma information.

 

The requirements for aroma enhancers are no destructive effect on the substances that need to be scented, long-lasting aroma, no irritation and toxicity, and low dosage. Fragrance enhancer can be a single compound or a mixture.

6 surfactant solubilising effect

Surfactants have a certain solubilising effect on fragrances, surfactants can reduce the volatility of fragrances by forming micelles with fragrance molecules.

 

It has been noted that the same perfume at the same dilution may have a very different perceived odour in different surfactant solutions. This is due to the fact that the solubilisation of the fragrance molecules in different surfactants is not the same, resulting in different volatility of the perfume.

7 Summary

There are various ways to prolong fragrance retention, including the selection of fragrance molecules, the application of fragrance carriers, the design of fragrance precursors, the use of fixatives and fragrance enhancers, and the use of surfactant solubilisation.

 

The molecular structure of flavouring molecules has been thoroughly studied, and suitable flavourings can be selected according to different systems;

 

Fragrance carrier is divided into adsorption-type carrier, capsule-type carrier and matrix-type carrier, is currently the most widely used method to achieve long-lasting fragrance, especially capsule-type carrier, capsule-type carrier according to the wall material is divided into natural polymer capsule, synthetic polymer capsule and inorganic capsule, natural and synthetic polymers are more widely used materials, inorganic capsule is limited to the use of calcium carbonate and silicon dioxide class materials;

 

Fragrance precursor including natural fragrance precursor and artificial fragrance precursor, artificial fragrance precursor design with ingenuity exists, in the mild environmental conditions can be achieved under the chemical bond breakage so that the slow release of fragrances, but also to achieve the long-lasting fragrance is one of the important means;

 

Flavouring agents are necessary for the preparation of a perfume and can reduce the volatility of other fragrances;

 

Flavour enhancers are currently used more in the food industry and can play a role in increasing flavour and aroma;

 

In addition, the solubilising effect of some surfactants on fragrances can also be used to achieve the effect of prolonged fragrance retention.

 

Fragrance technology in many areas have common places, summing up these technical methods can play a reference and inspiration for the development of long-lasting fragrance retention technology for daily-use chemicals after.

 

In recent years, the gross domestic product (GDP) has continued to grow at a rapid pace, surpassing a number of countries one after another until today it ranks second in the world. With the synchronous change is that the quality of life of domestic consumers is also undergoing radical changes, the quality of life increasingly demanding. As one of the products essential to the daily life of consumers, the quality of daily chemical products to improve the quality of upgrading is also in full swing.

The development of daily chemical products industry, from the initial category of relatively single product to meet the primary needs of consumers, and gradually evolved to meet the needs of different customer groups and the emergence of a variety of product forms, showing such as safety, functionality, green, customised and other points of the development trend in tandem.

 

Taking detergents as an example, traditional detergents such as washing powder and soap are mainly used for cleaning, which can basically meet the needs of consumers to clean the surface stains of fabrics completely. However, after washing, the clothes emit the smell of the detergent itself, which does not give the user a pleasant mood.

 

With the gradual improvement of living standards, consumer demand for laundry products is no longer limited to the simple function of removing stains, but has higher requirements. Scented detergents have emerged in this context, the use of products with different fragrances can give consumers a different experience, so the market is highly favoured by consumers.

After the first generation of washing products, its fragrance is relatively simple, usually only has a single fragrance, the fragrance stays for a shorter period of time.

 

With the people’s living standards in recent years from subsistence gradually towards well-off, consumers subsequently higher level of demand is to use the product after the hope that the scent can be retained for a long time.

 

Will have a different aroma of the flavour through different technical means and microencapsulation technology to fully fit, organically integrated into the upgraded products again, these products can better meet the needs of consumers lasting fragrance.

 

This kind of products with long-lasting fragrance effect, in the industry is usually called “scent retention agent”, commonly known as “clothing perfume”. In the market, the solid form of scent beads is more common, but there are also some liquid products scent retention liquid.

According to the statistics of Ali’s “2020 Washing Market Consumption Trend” report, the compound growth rate of the fragrance beads is more than 100%, which is close to the hot laundry gel beads in the market in recent years, and is far ahead of the traditional laundry detergent, clothing care agent and other products. On the platform of Jingdong Mall alone, there are as many as 268 brands of scent-retention beads on sale (November 2022 data).

The base of the scent beads is usually polyethylene glycol (PEG), and the effective substance for the release of fragrance is the flavouring agent, which can regulate the speed of the release of the flavouring agent, and ultimately achieve a long-lasting scent effect.

 

For example, a patent has been granted to stay in the fragrance beads PEG-8000 as a matrix, the content of about 80%; flavour microcapsules as a fragrance agent, the amount of addition of 0.2% to 30%.

 

Another related patent adds limonene, phenylethanol, belladonna aldehyde, benzyl acetate, rose ether, patchouli oil and other different substances as the effective substances for aroma release, with an additive amount of 0.1%~15%; and the additive amount of the aroma fixing agent is about 25%.

According to the preferences of different consumers, the flavour of the scent beads varies, but can be broadly divided into the top note (also known as the “head”, “top”, etc.), the middle note (also known as the “body”), the middle note (also known as the “body”), the middle note (also known as the “body”), the middle note (also known as the “body”) and the middle note. “middle notes”, etc.), after-tones (also known as “base”, “tail”, “bottom”, etc.).

 

For example, the top notes of a brand of scent beads include mint, lemon, freesia, green tea, lavender, orange, etc., the middle notes include fig, rose, lily of the valley, jasmine, etc., and the bottom notes include sandalwood, amber, ambergris, ambergris, cedar and patchouli.

Regarding the lasting fragrance, there is no widely accepted evaluation method, mainly by the manufacturer’s self-declaration, different companies give different views.

 

Some companies claim to be able to stay 24 h, some companies claim to be able to stay 7 d, and some companies claim that their scent retention time can be as long as 180 d.

Fragrance retention beads are new products that have emerged in the market in recent years, which can bring different feelings to consumers and create a pleasant mood.

 

However, in the context of rapid development, many products are substandard, which brings great trouble to consumers and introduces a lot of uncertainty to the healthy and sustainable development of the industry.

 

Some producers have developed corporate standards for internal use for the purpose of self-control of product quality.

 

In order to regulate the quality of such products, there is an urgent need to formulate industry standards or national standards at a higher level for such products.

In July 2022, the Ministry of Industry and Information Technology (MIIT) approved the development of a recommended industry standard for “Fragrance Retaining Agent for Laundry”, with a project plan number of 2022-0866T-QB and a development cycle of 24 months.

 

During the drafting process of this standard, high-frequency indicators such as moisture and volatile matter content, pH value, etc. in the above enterprise standards were suggested to be included. At the same time, sufficient attention should be paid to the dissolution performance that affects the use effect.

 

The evaluation method of fragrance retention effect is not involved in the above enterprise standards, and the establishment of this method is very necessary, especially the evaluation method that can quantitatively reflect the effect of long-lasting fragrance retention.

Although the establishment of the method is difficult due to the complexity of the effective fragrance components and the uncertainty brought by the fixative, the research and development of the method is urgent from the point of view of the development of the industry.

 

The objective of this standard is to standardise the product quality of scent retention agents for garments, to screen out poor quality products from the market, to reduce the operational risk of compliant suppliers and to ensure consumer protection.

Want your clothes to smell good for a long time? These technologies turn laundry detergent into a “treasure trove of scents”.

The aroma upgrade of laundry detergent is driving the high-end process of the laundry detergent category, and the different fragrance types and long-lasting scent is an important selling point of the hot-selling laundry detergent products, and many of the hot-selling products create different fragrances and long-lasting scent effects.

 

However, it is difficult to achieve long-lasting fragrance in laundry detergent, because laundry detergent is a water-soluble system and fragrance is oil-soluble. In laundry detergent, fragrance is solubilised into the micelles of the surfactant, but in the actual washing process, with the destruction of the micellar structure of the fragrance without solubilising the system, the fragrance can easily be washed away by the water in the process of washing, and cannot be adhered to the clothes to achieve long-lasting fragrance.

 

Through literature search, several fragrance retention methods available in the market.

Porous material adsorption of fragrance. This technology has poor fragrance closure and low fragrance retention strength.

 

Microcapsule slow release technology. The use of polymer insoluble wall material, closed flavour to improve the effect of fragrance, this technology can be adjusted to leave the intensity of the fragrance and fragrance time is generally longer.

Substrate combination. Flavour and polymer materials combined together, through some environmental factors to release the flavour, so as to achieve the effect of retention of fragrance, this technology is generally longer retention time.

Mixed technical means to improve the time of retention of flavour. Various fragrance slow-release technology is constantly updated, the major international flavour and fragrance suppliers to put forward a number of extremely fine differentiation of microencapsulated flavour technology.

Microcapsule fragrance technology by adding microcapsule fragrance in the laundry liquid system can better achieve the purpose of fragrance retention, in the normal washing of clothing, microcapsule fragrance will be retained by the clothing fibres, so as to residual in the clothing, when people wear clothing, residual in the clothing on the microcapsule fragrance in the friction and other external factors will gradually rupture, the release of fragrance, so as to achieve the effect of long-lasting fragrance retention.

 

Increasing the dosage of common flavour in laundry detergent has obvious effect on immediate fragrance retention, but not on long-lasting fragrance retention.

However, the long-lasting fragrance retention effect was not obvious.

 

Increasing the amount of microencapsulated flavour in laundry detergent has a more obvious effect on the long-lasting fragrance retention of clothes.

 

Consumers will consider both the immediate fragrance retention effect during washing and the long-lasting fragrance retention effect after washing when purchasing scented laundry detergents.

 

When both common flavour and microencapsulated flavour are added to the laundry detergent base (dosage: 0.2% common flavour + 0.08% microencapsulated flavour), the stability of the laundry detergent base meets the requirements of the QCQ.

The stability of the laundry detergent matrix meets the requirements of QB/T 1224 liquid detergents for clothes.

And we can get the laundry detergent with good fragrance retention effect, which can satisfy the consumers’ demand for the fragrance retention of laundry detergent.