People are much more aware of the dangers and ageing effects of too much sun. But this still does not dissuade us from wanting a golden glow to make us feel healthier and look slimmer.
From the 1970s streaky orange fake tans, the market has moved on rapidly to be able to satisfy consumers who want a tan but without the sun. Today, the sunbed backlash regarding the damage associated with UV tanning has increased the need for great artificial tanners. In the same way, the sun care market is currently targeting men with less greasy formulations, gradual tan and more masculine scents. Moreover, there is now no reason why a tan cannot be enjoyed all year round to give its wearers a midwinter wellbeing boost. Subtle colours and extra moisturisers help to make the winter tanners not only easy but also less drying. However, one of the main reasons that put people off using fake tanners is the smell associated with the tanning process. Actually, many of the products tend to be fragranced with quite substantive fragrances in an attempt to cover the malodour generated. Fruity florals or fruity gourmandes are the most popular area as they lend a cosmetic feel which can help to reinforce any claims of skincare benefits. Technology is now moving this area forward to ensure fragrances can help mask the unpleasant smells.
Biological context
Self tan products use the Maillard reaction, discovered by Louis Camille Maillard in 1912, responsible for many of the colour and flavour changes that happen to food during cooking, e.g. the caramelisation of sugar, and browning during roasting. The main self-tanning ingredient used is dihydroxyacetone (DHA), a small carbohydrate (C3) often derived from plant sources such as sugar beet, sugar cane and sugar wheat and produced by fermentation. The generated melanoidin pigments are similar to melanin, the natural brown pigment produced during UV ray exposure. Some of the other products generated during the DHA skin reaction have a significant odour associated with them, which many people find quite unpleasant. To deal with this issue, Soliance got involved in an active partner approach with CPL Aromas to create Vegetan FL Creation, a creative DHA solution that softens the self tanning odour. CPL Aromas is an international fragrance house, headquartered in the UK. The company has used very sensitive thermal desorption equipment to measure and identify the creation of these malodours in situ, and then used Aromaguard technology to create the fragrance that specifically works against the actual malodours generated during the self tanning process, while at the same time having no effect on the DHA skin colouring process. In turn, Soliance has combined all of its formulation expertise to subtly blend the Aromaguard fragrance with Vegetan FL, the liquid form of DHA approved by ECOCERT. Vegetan FL is produced through a highly efficient biotechnological process using fermentation and bioconversion. It is biobased from renewable and vegetable raw materials coming from agricultural crops. Furthermore, the surfactants used in the premix are alkyl polypentosides, also bio-based from vegetable raw materials.
Technology
Thermal desorption
Thermal desorption is a relatively new analytical technology that enables the quantitative measuring of fragrances and their components. It works in combination with headspace sampling technology and is a very flexible system that allows testing in the lab or out in the field and the analysing of materials that are very sensitive and have been difficult to analyse previously. Thermal desorption identifies any organic compound with a volatility inferior to bp 500°C by standard gas chromatography. Then the resultant traces are identified by mass spectrometry. The odour can be sampled by various means:
• Direct air sampling.
• Sorbent tubes.
• Direct desorption of materials.
• Sorbent Bar Solid Phase Extraction (SBSPE).
Headspace sampling
Protocol: A background odour map of the hand being used for testing was taken by placing a new and unopened plastic bag around the hand and sealing it at the opened end. A thermal desorption tube containing sorbent (Tenax/Carbograph), was then placed through the bag. A small hand-held pump then pulled the air through the tube at 50 mL/min for one hour (from T0). Small holes were made in the front of the bag to continue the air flow through the system, and prevent a vacuum. The components present on the hand are first identified by GC/MS. After one hour sampling, the tube was removed and placed in the thermal desorption unit. A self tan base was then applied to the hand and the bag was resealed. The same tube was placed in the bag again, and sampled using the pump for two hours. The tube was removed and desorbed again. After 3.5 hours from the start, the tube was placed back in the bag and sampled for one hour. The key components generated during the Maillard reaction are finally identified.
Aromaguard fragrance
Once identified, these key malodour molecules are then targeted by CPL’s Aromaguard fragrance technology (now referred to as ‘the odour suppressor’) to either remove or reduce their levels, or if it is not possible, to modify their perception during the smelling process. Based on the chemistry of these molecules and the CPL’s raw materials knowledge, fragrances are created:
• By using materials to reduce or eliminate the created malodour molecules.
• By using materials that work with the malodour molecules identified to create an overall fragrance impression.
The developed fragrances are re-tested by thermal desorption to try to get a fingerprint picture of the identified components until a physical reduction in key malodour generators.
Overlay for self tanning odour
From the Headspace sampling and the skin analysis, the key volatile components causing the main odour problem were identified. The following test looks specifically at the effect of the selected odour suppressor fragrance on them.
Protocol: Thermal desorption combined with the Headspace sampling is effectuated prior to application and after application of a self tan lotion containing 5% DHA with or without the selected odour suppressor fragrance. The components are identified by GC/MS, and the difference of malodour abundance is compared versus the unfragranced lotion. The selected odour suppressor fragrance has a significant reduction in the level of malodour. It is accompanied by the appearance of high molecular weight non-volatile components.
In vivo tests
Counteraction performance
Protocol: The malodour counteraction performance is evaluated by a panel of 12 experts. They blind test on the forearms two lotions with or without the odour suppressor fragrance and scored the malodour perception on a 10 points scale at different times after application. 0: no malodour, 2: very slight malodour, 4: noticeable malodour, 6: strong malodour, 8: very strong malodour, 10: overpowering malodour. The malodour perception is strongly reduced with odour suppressor fragrance technology.
Kinetic of coloration
Protocol: A panel of 12 volunteers applied on the one inner forearm a lotion with 11% Vegetan FL Creation (now referred to as ‘the novel self tanner’) and on the other inner forearm a lotion with 11% Vegetan FL (now referred to as ‘the original self tanner’) as positive reference. Colour intensity was assessed by using a chromameter CR200 (Observer 2, Illuminant D65) and measured at 3 hrs, 6 hrs, 24 hrs, 48 hrs, 72 hrs and 96 hrs after lotions applications (over five days). The results are statistically treated by using Student t-test paired. There is no significant difference of colour apparition and saturation on the skin between the lotion formulated with the novel self tan lotion and the lotion formulated with liquid DHA.
Olfactory study
Protocol: Two experts of the formulation department have smelt the panelist’s forearms to determine whether the novel self tan minimises or not the smell of DHA on the skin. Three possibilities are considered:
• In favour of the novel self tanner (1 point).
• In favour of the original self tanner alone (0 point).
• In favour of both (0 point).
Thus, only answers in favour of the novel self tanner are acceptable as evidence of an improvement (considering as malodours, the released smell during the Maillard Reaction). The result confirms that for 100% of volunteers, the unpleasant smell is definitely softened by the novel self tanner.
Conclusion
Vegetan FL Creation was borne from the synergetic know-how between CPL Aroma and Soliance to soften the malodours of the DHA application. The self-tanning process and the odours covering properties of the subtle blend have been demonstrated by different in vivo tests. This formulator-friendly premix including surfactants and solubiliser offers key advantages as it is stable, ready to use and easy to incorporate in cold phase. Vegetan FL Creation is particularly well-suited to face and body creams, lotions, spray, gels, mousses and wipes for both professional or consumer use. The recommended dose is between 2% and 15%.
