Fermentation focus: Unlocking bio-potencies of tea leaves, honey and kombucha for functional skin care

01 Jun 2023 --- Fermented beauty ingredients are a consistently expanding class of sustainable and high functional solutions. PersonalCareInsights explores new developments in the space, which showcase the skin boosting properties of fermented tea leaves from Thailand, berries and fruits naturally processed in kombucha, and the fermented honey of a rare and ancient bee species.

The first spotlighted ingredient – a bio-extract of the Thailand-native Miang tea plant (Camellia sinensis var. assamica) – exhibited its abilities when fermented together with a blend of lactic acid probiotics.

The study, published in Cosmetics, helps identify the most effective fermentation time and dose of bio-extract, while also suggesting improvements in bioactive compounds for use in skin care formulations.

“Biotechnology, cosmetics and aesthetic remedies are now inextricably intertwined due to the production of alternative, more effective and safer active ingredients,” highlight the scientists. “Additionally, there has been an increase in demand for natural cosmetic ingredients across the globe.”

Fermented tea leaves, mediated by probiotics, can enhance the bioavailability of compounds.According to Innova Market Insights data, the use of fermented ingredients in personal care products is increasing across all beauty categories, especially in facial skin care. Products with fermented ingredients are most often labeled as promoting better skin care absorption and skin barrier support, alongside sustainability and clean label claims.

Rich in bioactive compounds
Miang tea is commercially cultivated as a resource in northern Thailand. The activities of white, green and black Miang tea were investigated in the new study.

Findings of the research offer evidence that fermenting these tea leaves, mediated by probiotics, can enhance the bioavailability of compounds, transform bioactive compounds and decrease chemical solvent use for sustainability.

“Tea and its extracts have historically been used as essential ingredients in cosmetic manufacturing,” highlight the study researchers. “Many benefits are available, owing to their functional components such as flavonoids, amino acids, caffeine, theaflavins and catechins.”

“These substances, however, can not readily be absorbed or immediately used by the human body.”

Tea’s biotransformation during fermentation has notably exhibited the potential to be used in skin treatment and prevention of disease, as through this process its complex molecules are broken down into simpler sizes.

The lactic acid bacteria strains Lacticaseibacillus rhamnosus, Lactiplantibacillus plantarum and Saccharomyces cerevisiae were used as mixed probiotic starter cultures in the study.

With these strained, the activities of the Miang tea bio-extracts – including ferric reducing antioxidant power, lipid peroxidation, nitric oxide inhibition, tyrosinase inhibition, collagenase inhibition (MMP-1 and MMP-2) and antimicrobial activity – were found to be “considerable” after seven days of fermentation time.

Additionally, phenolic antioxidant compounds (gallic acid, epigallocatechin gallate, caffeic acid, caffeine and p-coumaric acid) – which are known to alleviate skin inflammation – were identified. 

Formulation benefits of lactic acid 
The substances produced by lactic acid bacteria during the fermentation of tea produce a variety of positive effects on the skin, including regulating pH, protecting against UV damage, reducing inflammation, protecting against harmful bacteria and supporting healthy skin cells.

Blackcurrant ferments produced using kombucha has been found to offer a significant content of active compounds for skin care.Lactic acid is the most well-known compound produced by lactic acid bacteria. It can help regulate the skin’s pH, exfoliate dead skin cells and promote the growth of healthy skin cells. 

When applied in the fermentation of tea leaves, lactic acid bacteria produce hydrogen peroxide. This compound has antibacterial properties and can help reduce inflammation on the skin. 

Lactic acid bacteria can also produce short-chain fatty acids, such as butyric acid and propionic acid, producing anti-inflammatory effects on the skin.

These results will be used for testing on human participants in further work.

Kombucha for the skin
The fruits of blackcurrant (R. nigrum L.), black chokeberry (A. melanocarpa Michx.) and billberry (V. myrtillus L.) are well-known natural plant materials with proven antioxidant activity. A separate study published recently in the journal MDPI examined the antioxidant properties of these plants’ extracts and ferments obtained during their fermentation using microorganisms in kombucha.

The results of the research indicate that these plant extracts and their kombucha ferments offer a significant content of biologically active compounds, such as polyphenolic compounds belonging to phenolic acids (benzoic and cinnamic acid derivatives), tannins (gallic and ellagic acid deisins) and flavonoids (anthocyanins, flavonols, and flavanols responsible for antioxidant activity, among others). 

In vitro studies using skin cells – fibroblasts and keratinocytes – as well as S. cerevisiae yeast have shown that the kombucha ferments possess a free radical scavenging capacity after ten to 20 days. 

Mibelle Biochemistry has produced an active ingredient elixir obtained by fermenting the honey of a rare and ancient bee species.Furthermore, both extracts and ferments have been shown to have a positive effect on skin cell health and metabolism.

What’s brewing in fermentation?
The number of launches with fermented ingredients has grown considerably in the last five years. The most popular ingredients are fermented green and black tea, probiotics or fermented mushrooms.

One of the first prominent fermentation-based cosmetic ingredients was Pitera by Procter & Gamble’s Japanese SKII. According to the International Nomenclature of Cosmetics Ingredients, Pitera is actually Galactomyces ferment filtrate. After realizing that the hands of elderly women working at a sake brewery were soft and youthful-looking, researchers at the company started examining the potential of yeast fermentation byproducts as potent anti-aging ingredients.

Ingredient supplier Mibelle Biochemistry is another specialist that has recently harnessed fermentation to develop its Black BeeOme ingredient. The active ingredient is an elixir obtained by fermenting the honey of a rare and ancient bee species.

Black BeeOme is designed to restore individual skin microflora after stress, resulting in healthy, exceptionally clear and pure skin. VinUp-Lift is another Mibelle Biochemistry product that undergoes a fermentation process during the production of the ice wine, when sugar is broken down and new metabolic products are created.

PersonalCareInsights recently caught up with Mibelle Biochemistry along other skin care suppliers in a Special Report to explore the benefits of fermented ingredients for the skin microbiome, while further discussing how precision fermentation yields rare and “endangered” molecules.

By Benjamin Ferrer