The Role of Texture and Sensorial Experience in Cosmetics with Bio-based Options

TAGS:  Skin Care    Sustainability / Natural Cosmetics   

Product benefits ensure customer loyalty in the long run, but sensory appeal sells the product. Cosmetic products must please the senses of a consumer to positively influence their buying decision.

• An attractive packaging or product color can please the sense of sight.
• The product fragrance can please the sense of smell if it ties in well with the positioning of the product.
• The feel and texture of the product can also trigger various sensations and reactions.

The product texture must reinforce the claims made on the product label. The first touch should produce a sensation that promises quality, efficacy, and luxury. Some cosmetic formulators focus more on the visual and olfactory appeal of the product, as compared to texture. The first impression made by the product texture plays an important role in the selection of personal care products.

Let’s deep dive into the science of product texture and how you can achieve required texture using different ingredients.

How product texture enhances overall product feel?

Product texture is also important in creating a perception of quality and efficacy. Beyond perception, texture also contributes to product benefits, such as moisturizing properties. Cosmetic formulators must, therefore, evaluate the effect of each ingredient on the product texture and build their formulation such that the final texture is in harmony with the marketing brief.

Skin care products, in particular, are judged by their texture. To achieve the right texture, formulators must have a thorough understanding of emulsion technology. Texture is characterized, not only by the physical and rheological properties of the emulsion, but also by how the skin feels during and after product application. Consumers may characterize texture as a property that makes the product easy to pick up, creamy, spreadable, stringy or firm. They may also classify the texture of a product by the smooth, soft, greasy or sticky feel it leaves on their skin.

In order to meet the targeted rheological properties and to achieve a texture having a favorable consumer appeal, formulators of cosmetics and personal care products must find the optimal combination of emulsifiers, thickeners, emollients and other additives.

Cosmetics Emulsions and Role of Emulsifiers

Most skin care products, including creams and lotions, are generally formulated as emulsions. An emulsion is a mixture of two normally immiscible liquids combined such that very fine droplets of one liquid are dispersed in the other. An emulsifier is an additive that encourages suspension of the droplets of one liquid in another. A stabilizer helps maintain the emulsified state once it has been achieved. Emulsions in skin care products can be classified as:

• Water-in-oil emulsions or
• Oil-in-water emulsions

The most commonly used emulsion type in skin care formulations is oil-in-water. This means that small droplets of oil are suspended in the water phase. Since the external phase is water, these emulsions feel less greasy as compared to water in oil emulsions. The figure below illustrates how an emulsifier helps combine two immiscible liquids to form an oil-in-water emulsion.


A pickering emulsion is a special type of emulsion that is stabilized by solid particles adsorbed onto the interface between the two phases. These particles reduce the surface energy allowing the two phases to mix. The figure below shows how pickering emulsions are stabilized by solid particles at the interface.

Adding Texture to Emulsions by Incorporating Thickeners

Texture is added to emulsions by incorporating thickeners that modify the product rheology. Thickeners modify the viscosity of a product to make it easier to apply and more appealing to the consumer. They can be used to give the product more firmness, integrity of shape, spreadability, resilience, cohesiveness, and compressibility. Various types of thickeners are available to formulators (discussed below), with each type having its own advantages and drawbacks.

Lipid Thickeners

Lipid thickeners are solids at room temperature and must be liquefied for incorporation into emulsions. The natural thickness of these materials helps thicken the formula to which they are added. Some commonly used lipid thickeners are: Carnauba Wax Cetyl Alcohol Stearyl Alcohol, and Stearic acid

Naturally-derived Thickeners

These thickeners are derived from natural products. They work by absorbing water to swell up thereby increasing the viscosity. Such thickeners are suitable for formulas that contain a high-level of water. Unfortunately, natural thickeners can produce inconsistent results. They may also cloud clear formulas and leave a sticky feel on the skin. Some examples of naturally derived thickeners include: Xanthan gum Guar gum Locust bean gum Cellulose derivatives, and Gelatin

Mineral Thickeners

Mineral thickeners are powdered minerals that absorb water and oils to increase viscosity. They can be used in both oil as well as water-based formulations. Mineral thickeners can lose their thickening properties at higher pH. In addition, high shear may also cause the viscosity to break down. Some examples of mineral thickeners include: Silica Bentonite, and Magnesium Aluminum Silicate

Synthetic Thickeners

Synthetic thickeners are chemical ingredients that help increase viscosity. The most common examples are Carbomers. The thickener swells by absorbing water to form a clear gel. It produces a desirable non-sticky feel on the skin. The viscosity of Carbomers is pH dependent which limits their use in certain formulations. Their synthetic nature also makes them undesirable for bio-based or natural products.

Ionic Thickeners

Ionic salts, such as NaCl, can be used to thicken anionic surfactant solutions. The use of these thickeners, however, is limited to specific applications.

Sustainable Bio-based Thickeners – Performance & Environmental Benefits

The cosmetics market is fast adopting the concept of ‘Green beauty’. The term refers to the use of bio-based feedstock for the production of safe and effective ingredients. In addition to having an environment-friendly production process, these ingredients must also be safe and healthy.

Bio-based products are generally perceived by consumers as friendlier to their skin. This perception has increased demand for bio-based cosmetic products. Consumers rely on various ecolabels to make healthy and environmentally responsible buying decisions. These ecolabels have stringent requirements that necessitate use of natural, plant-based products.

Furthermore, regulatory requirements in various markets are increasingly focused on replacement of questionable ingredients with safer bio-based alternatives. In this context, it is important for cosmetic formulators to ensure that each ingredient in their formulation is safe and preferably bio-based.

TEXTURLUX® Bio-based Thickeners

Primient offers a range of personal care additives under its brand TEXTURLUX®. All TEXTURLUX® products are fabricated by raw materials that are waxy corn sourced 100% with a sustainable agriculture program. TEXTURLUX® products are derived natural ingredient (>94%) based on ISO 16128. TEXTURLUX® products are cold processable to save energy. The TEXTURLUX® range includes several variants that give personal care product formulators a variety of bio-based options for adding texture to their products and providing the solution for their process challenges.

Product Name	INCI Name	Sustainability	Clarity (@same concentration)	Process Tolerance	Dispersibility	Usage
TEXTURLUX® Rheo	Hydroxypropyl Starch Phosphate	waxy corn1; derived natural2 >95%; cold processable; Readily biodegradable	+	+++	++++	1-10%
TEXTURLUX® Hold	Hydroxypropyl Starch Phosphate	waxy corn1; derived natural2 >94%; cold processable; Readily biodegradable	+	+++	+++	1-10%
TEXTURLUX® Feel	Hydroxypropyl Starch Phosphate	waxy corn1; derived natural2 >96%; cold processable; Readily biodegradable	+++	++	++	1-10%
Notes: Based on waxy corn sourced 100% through a farming program, which is benchmarked against recognized sustainability standards. According to ISO16128 ++++ very high or easy; +++ high; ++ medium; + low

Download Case Study
Cold Process Creams Done Right, Finally –
with TEXTURLUX® Personal Care Additives

TEXTURLUX® products can help formulators achieve a wide range of desired textures. A science based texture map tool and a sensory model have been developed to help predict product texture based on swelling power and concentration. (See figures below)



As a typical example, TEXTURLUX® Rheo is a starch-based thickener that is natural, and biodegradable with 95% bio-based content. It is safe and biocompatible with no toxic side effects. TEXTURLUX® Rheo is very versatile and can be used to modify the product texture in a variety of ways; it helps tailor product properties to meet formulation challenges. Rheo is as a primary viscosity builder and an emulsion stabilizer. It can transform a thin lotion into a rich and luxurious cream. TEXTURLUX® Rheo increases product viscosity without giving it a sticky, slimy, stringy or jelly-like consistency.

TEXTURLUX® Rheo – Feature & Benefits

TEXTURLUX® Rheo has been designed to provide good process tolerance in a variety of cosmetic applications. Its versatile nature and following excellent properties maximize texture development and build viscosity at the appropriate time during processing and packaging.

TEXTURLUX® Rheo has outstanding dispersibility in cold water. It does not require heating or premixing before addition. The thickener can be added to the oil or aqueous phase. It can also be post-added to optimize the product texture at the end of the production process.

Role of Viscosity & pH

The figure below shows that TEXTURLUX® Rheo acts quickly and reaches a stable viscosity in about 40 minutes. The percentage of thickener can be varied to achieve the desired viscosity.



The figure below shows that addition of 3-6% TEXTURLUX® Rheo is sufficient to meet the requirements of most cosmetic applications.



TEXTURLUX® Rheo is stable in a wide pH range from very acidic to highly alkaline. The recommended application range is 3 to 9. The figure below shows that a 5% TEXTURLUX® Rheo aqueous dispersion maintains the viscosity of the dispersion in a wide pH range.

Improving Spreadability and Smoothness

TEXTURLUX® Rheo has good rheological properties with respect to shear thinning and immediate recovery as shown in figure below. These properties improve spreadability and smoothness in cosmetic products.



TEXTURLUX® Rheo has a short texture in aqueous systems. The figure below shows a microscopy image of TEXTURLUX® Rheo in water; the short texture provides good spreadability with low stickiness.

Compatibility with Salt Actives, Cationics, Surfactants & Clays

TEXTURLUX® is also compatible with salt-based active ingredients. It tolerates electrolytes very well and maintains its viscosity in emulsions with salt levels of up to 20%. The figure below shows that a 5% TEXTURLUX® Rheo aqueous dispersion maintains stable viscosity with up to 20% content of sodium chloride and calcium chloride salts.



TEXTURLUX® Rheo is compatible with cationic ingredients. Its viscosity can vary with different cationic ingredients or materials. The figure below shows the viscosity of 4% TEXTURLUX® Rheo in 0.5% Quat (10rpm) with various cationic ingredients or materials.


TEXTURLUX® Rheo is also compatible with anionic surfactants and non-ionic surfactants. Its viscosity can be influenced by surfactants. The figure below shows the viscosity of 5% TEXTURLUX® Rheo in aqueous + surfactant dispersions (20rpm).


TEXTURLUX® Rheo is also compatible with clay. Its viscosity is not influenced by clay. The figure below shows the viscosity of 5% TEXTURLUX® Rheo in aqueous dispersion with Bentonite and Kaolin clay (20rpm). Here, the viscosity of system is simply addition of the viscosity of TEXTURLUX® Rheo and clay.

Temperature Stability in Emulsions

TEXTURLUX® Rheo shows good stability in emulsion, in a wide temperature range from -20°C up to 50°C. There is a small percentage change in the viscosity of 4% TEXTURLUX® Rheo dispersion in a cream (20rpm), after the emulsion is frozen and after heating to 50°C (See figure below).

Foam Enhancing Properties

TEXTURLUX® Rheo has foam enhancing properties which can help increase the foam volume in certain applications. The figure below compares the foam volume produced by a sulfur-free foaming cleanser with and without 0.2% TEXTURLUX® Rheo. The foaming volume with TEXTURLUX® Rheo is significantly enhanced due to the additive.



The performance benefits of TEXTURLUX® Rheo can be summarized as follows:

• Natural, Sustainable, domestically produced, Non-GMO available
• Emulsion thickener with excellent aesthetics
• Emulsion stabilization properties
• Can be added to oil or aqueous phase
• Outstanding dispersibility in cold water
• Does not require premixing
• Works in a wide pH range
• Extensive tolerance to electrolytes
• Good rheological properties
• Can be added before or after emulsion is formed
• Excellent Freeze-thaw stability
• Foam enhancing properties

Diverse Applications of TEXTURLUX® Rheo

TEXTURLUX® Rheo is a versatile thickener which can be used to impart a variety of textures to different personal care formulations. It has been designed to provide optimal process tolerance for maximum texture development. It enhances the stability of emulsions and builds viscosity at the appropriate time during processing and packaging.

TEXTURLUX® Rheo finds application in formulating skin creams & lotions including:

• Daily facial moisturizers
• Night creams
• Body lotions
• Sunscreens, and
• Hand creams

It is also suitable for use in antiperspirants, deodorants, bath & shower products, conditioners, hair dye, shampoos, and styling products. TEXTURLUX® Rheo works well in emulsions, sprays and gels making it a suitable additive for a wide range of cosmetics and personal care products.

Conclusion

TEXTURLUX® bio-based solutions offer numerous advantages to cosmetic formulators. They can be used to produce a variety of textures, from milky to creamy, with ease of processing, which can be predicted by texture map and sensory model.

TEXTURLUX® Rheo has outstanding dispersibility in cold water and works in a wide pH range (3-9). Its shear thinning property helps achieve good smoothness and spreadability. TEXTURLUX® Rheo has excellent salt tolerance and is compatible with surfactants and clays. Its short texture reduces stickiness and provides good pick-up. The excellent freeze-thaw stability of TEXTURLUX® Rheo increases the shelf life of the end product.

TEXTURLUX® also has foam enhancing properties that can help increase the foam volume in foaming products. The viscosity of TEXTURLUX® emulsions can be predicted using phase volume and swelling power which can help formulators achieve their desired texture. Most importantly, TEXTURLUX® is safe, sustainable and bio-based. It is an ideal additive for formulators looking to produce natural products that meet green label requirements.

TEXTURLUX® Bio-based Solutions by Primient

View all the commercially available TEXTURLUX® bio-based ingredients used to formulate cosmetic products, analyze technical data of each product, get technical assistance or request samples.




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