Probiotic Technology for Skin Moisturization

New Upcycled Ingredient Based on Probiotic Technology for Skin Moisturization

Abstract

Based on a probiotic fermentation technology, Symrise has developed a new postbiotic ingredient for skincare application. This fermented ingredient has been proven to moisturize the skin and at the same time improve the skin texture.

In addition to standard corneometric measurements, the skin surface changes induced by this new ingredient have been evaluated using high quality digital imaging system, and a smart visualization of product performance for hands skin moisturization has been developed.

Introduction

Hydration has been a key cosmetics concern at the core of marketing claims since decades. Especially, hand skin dehydration is a common concern for many women,
men, and children during wintertime or when using aggressive hygiene procedures.

Here, a new sustainable cosmetic ingredient for skin care, created by upcycling valuable side-streams from Lactobacillus probiotics manufacturing, is investigated for hand skin moisturization.

Moisturization evaluation is commonly limited to the stratum corneum water content measurement. However, objective moisturizing benefit needs to be considered with a more holistic approach.

Indeed, the skin surface changes occurring after using a moisturizing product are of high importance in the user satisfaction (increased suppleness, decreased roughness, leading to soothing sensations and lesser discomfort).

To bring value to the investigation of the moisturizing properties of the postbiotic ingredient, a combinatory protocol was used, mixing standardized corneometric measurement of the stratum corneum and the capture and analysis of digital macro images of the same areas using a new camera, developed to provide high resolution images, 3D reconstruction of the skin surface pattern and objective parameters to follow-up under the effect of a moisturizer.

The skin microrelief pattern evolves with intrinsic (age, dryness1,2) and extrinsic factors (UV exposure, relative humidity)3-5 and reflects the functional state of the skin.6-8 We present here the results of such investigation, applied to the hand and forearm skin, and combined with corneometric measurements.

Besides, the moisturizing effect of the product to the hands was modelized using a method of continuous color mapping that helped to display the differences objectively and successfully between investigational ingredient formula and placebo.

Materials and Methods

The in vivo study was performed in winter, in Paris, with a panel of 13 healthy female and male subjects from 22 to 53 years old. Cosmetic O/W emulsions containing 5, 10 and 20% of the studied cosmetic ingredient (INCI: Lactobacillus Ferment, Lactic Acid, Pentylene Glycol, Sodium Benzoate, 1,2-Hexanediol, Caprylyl Glycol) have been evaluated in comparison to a placebo.

The ingredient is a postbiotic coming from an upcycling process starting from the fermentation of selected Lactobacillus strains, identified as beneficial for the skin and already used in the food and healthcare industries (Symrise AG, Holzminden, Germany and Probi AB, Lund, Sweden) (Fig. 1).

From this process, the biomass (probiotics) and the supernatant (fermentation broth) are obtained. The biomass is used in consumer healthcare and food industries, but the supernatant is usually discarded.

It contains micronutrients both allowing the growth of health-associated bacteria strains and produced by Lactobacilli (amino acids, proteins, minerals, and organic acids). The potential of this supernatant for skincare applications has been identified for strong moisturization benefit, and it is now valorized in this new ingredient.

For the first part of the study, the formula containing 20% of the studied ingredient and the placebo were applied randomly on two defined areas on the back part of the volunteers’ hands. For the second part of the study, the formulas containing 5% and 10% of the studied ingredient and the placebo were applied randomly on defined areas on the subjects’ inner forearms.

The stratum corneum capacitance was measured on the different defined locations on the hands and the forearms, before application of cosmetic formulas, then 1 hour later.

Image acquisitions were performed on the same locations than the capacitance measurements, before application and after 4 hours, with a macro camera (SkinCam®, Newtone Technologies, Lyon, France). To measure skin surface pattern characteristics, 3D depth maps were computed from 2D images of the skin surface (Fig. 2).9-11

Roughness parameter Spa, the arithmetic average variation of surface amplitudes on the entire surface, was studied. Other roughness parameters were also studied: the mean depth and the mean area of furrows, and the mean height and the mean area of ridges.

Results

Corneometric measurements confirmed the moisturizing effect of the postbiotic ingredient versus placebo as soon as after 1 hour after application. On the hand, the moisture increase reached +44.09%, a statistically higher evolution than the one registered on the hand treated with the placebo.

On the forearms the moisturizing effect of the ingredient was also shown, with a respective increase of 19.45% and 21.90% when treated with the emulsions containing 5% and 10% (Fig. 3).

Besides, statistically significant benefit of the ingredient on the skin surface pattern was registered versus placebo, 4 hours after the application, based on roughness and microrelief pattern parameters (Fig. 4 and 5).

Particularly Spa parameter, reflecting the roughness showed a decrease, proving a smoothing effect, whereas, on the contrary, this parameter increases overtime on the skin treated with placebo.

The placebo did not counterbalance the natural evolution of the skin surface roughness whereas the formula containing the ingredient did. The benefit of the fermented ingredient is also statistically proven versus placebo on the mean ridges height parameter.

This result confirms the effect measured over the whole analyzed skin surface and brings a new element of understanding of the intrinsic evolution of the micro-relief pattern under the effect of the ingredient. There again the placebo showed opposite evolution over time.

These results show complementary information given by each of the investigational methods. Corneometric measurement helped highlighting the immediate effect of the formula containing the fermented ingredient with improvement after one hour of the stratum corneum water content. Image analysis contributed to proving the durable effect of the formula containing the new ingredient versus placebo on the skin surface texture quality.

To visualize the corneometric values evolution a unique developed algorithm was used, enabling to project moisturizing results on a 3D whole hand skin model. Corneometric average values obtained in two locations of each hand was turned into colors based on a grey to blue color bar (from the lowest measured capacitance values to the highest measured values).

These color levels were mapped on a 3D hand model, in each of the measured areas and then interpolated to cover the entire hand back skin and reflect a holistic interpretation of these results (Fig. 6).

Conclusion

Thanks to this new combining approach, the postbiotic ingredient performance for skin moisturization has been demonstrated both on the moisture contents in the stratum corneum and on skin microrelief patterns quality.

Interestingly each approach brought complementary information in terms of benefit for the skin and also showed efficacy at different time points. The postbiotic ingredient has been proven to bring immediate moisturization to the skin, but also to smooth the skin and evens its texture.

This study shows the positive impact of postbiotics on skin moisturization and the importance of such ingredients for skincare.

The joint research between Symrise and Probi, focusing on probiotic Lactobacillus strains, allows Symrise to determine how to best integrate new scientific data into innovative cosmetic products. Symrise benefits from the fact that the Swedish manufacturer can access an enormous database of bacterial strains and supply large quantities of probiotics at a consistently high quality.

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Authors

Léa Schmidt, Mickael Larnicol – Symrise SAS, France

Joachim Hans – Symrise AG, Germany

Translation and Compilation

Tuğba Bayazıt – Application Technologist / Team Leader AMET Symrise