NL2035677B1

NL2035677B1 - Melanoidin-coated mineral uv filter particles and methods for their preparation

Info

Publication number: NL2035677B1
Application number: NL2035677A
Authority: NL
Inventors: Akçay Adnan; Medina Juan; Aggenbach Keri; Rozene Vallespin Paloma
Original assignee: Kaffe Bueno Aps
Priority date: 2023-08-25
Filing date: 2023-08-25
Publication date: 2025-03-10
Also published as: WO2025045833A1

Abstract

37100 The present disclosure pertains to a process for the preparation of melanoidin—coated inorganic UV filter particles, using melanoidin and titaniumand/or zinc oxide particles as starting material and wherein either: A. a mixture of the titaniumand/or zinc oxide particles and melanoidin in water is ultrasonic treated, followed by spray drying the mixture to form melanoidin—coated titaniumand/or zinc oxide particles; B. the titaniumand/or zinc oxide particles are activated by acid treatment, followed by slow introduction of the melanoidin to the activated titanium—and/or zinc particles to form a melanoidin/titanium—and/or zinc oxide complex, and separation and drying of the resulting melanoidin—coated particles, or C. the titaniumand/or zinc oxide particles are subjected to high mechanical shear and heating, followed by introduction of the melanoidin through a nozzle and separation and drying of the resulting melanoidin—coated titanium—and/or zinc oxide particles. The disclosure is also directed to the resulting melanoidin—coated particles, sunscreen protection agents comprising said particles and compositions comprising said sunscreen protection agents.

Description

1 37100

MELANOIDIN-COATED MINERAL UV FILTER PARTICLES AND METHODS

FOR THEIR PREPARATION

Field

The present disclosure is in the field of melanoidin-coated mineral UV-such filter particles such as titanium- and/or zinc oxide particles and methods for preparing said melanoidin-coated mineral UV filter particles, their use as sunscreen protective agent and compositions comprising sald sunscreen protective agent.

Background

UV exposure is known to cause skin damage such as aging, sunburn and skin cancer. The danger of UVB region (280-320 nm) absorption has been well recognized for it can cause skin damage. Whereas UVA radiation (320-400 nm) is less recognized, it can also cause dermatological problems.

Therefore, protecting human skin from UVA radiation as well as UVB radiation has been an important issue and various materials are in demand for the effective skin protection from harmful UV radiation.

Sunscreen is an over-the-counter formula that easily protects human skin from UV radiation by application on the skin directly. Sunscreen can be classified into two main categories: organic sunscreens and inorganic sunscreens.

Organic sunscreens like oxybenzone and avobenzone protect skin by absorbing UV, however, organic sunscreens can cause health problems when it is applied on skin directly with high concentration.

2 37100

Inorganic sunscreens have been widely used due to their ability of reflecting and scattering UV radiation. Examples thereof are titanium oxide and zinc oxide. Titanium oxide has been used as UV blockers due to its excellent UV protection ability, photostability and relatively low dermatologic toxicity often in combination with Zinc Oxide which is also a known inorganic UV filter.

For instance, KR 100968715 relates to a cosmetic composition for sunscreen, and more particularly to a cosmetic composition for sunscreen containing an inorganic sunscreen as an active ingredient. The composition of the present invention does not contain an organic sunscreen but contains only an inorganic sunscreen. The cosmetic composition comprises titanium dioxide as an inorganic ultraviolet screening agent, and the inorganic ultraviolet ray shieiding agent is a mixture of neopentylglycol dihexancate, cyciomethicone, polvgiyceryl- and a blocking agent base.

However, crystalline TiO: which has photocatalytic activity can induce damage on human skin and this problem poses challenges to application of TiQ2 in cosmetic fields. Also, white cast phenomena of TiO: is one of the drawbacks that make wide application in cosmetics difficult that they tend to leave a white layer on human skin.

In order to overcome aforementioned disadvantages, various strategies have been developed such as application of TiO: in the purely rutile structure or surface coating of the

Tiz.

For instance, US 2008/0020054 relates to cosmetic and dermatological preparations for protecting human skin and

3 37100 hair against UV radiation, comprising surface-coated titanium dioxide particles which are transparent in the visible region and have a crystallite size of from 10 to 20 nm and a specific surface area of from 90 to 110 m 2 /g, wherein the surface coating of the titanium dioxide particles comprises a multicoating of a) aluminum oxide and b) methicone or a copolymer of methicone and dimethicone or a multicoating of a) aluminum oxide, b) methicone or a copolymer of methicone and dimethicone and c) silicon dioxide.

EP 3029095 is directed to the use of subpigmentary titanium dioxide, which is obtained in a Synrutil process and due to impurities has a beige-brown-gray or slightly yellowish color, as an absorber for UV radiation in coatings, especially in wood preservatives, in plastics and cosmetics.

Also JP H08143438 describes the preparation of rutile titanium oxide particles so as to avoid leaving a white layer on the skin.

Journal of Industrial and Engineering Chemistry (2020) published 2-3-2020, describes melanoidin-coated titaniumoxide particles. The titanium oxide coated particles are prepared by treating titanium isopropoxide with dihydroxy acetone (DHA) to prepare TiO; microspheres.

Said microspheres are subsequently carboxylated with chloroacetic acid. The carboxylated particles are then esterified with DHA. The terminal acid groups of the DHA are subsequently treated with arginine to prepare the melanoidin coating. Here the melanoidin-coated titanium oxide is prepared by forming the melanoidin in situ on the titanium oxide particle.

4 37100

Despite the various publications describing titanium oxide particles for use as sunscreen protective agents, the prior art products and their preparation processes leave much to be desired. There is a need for sunscreen protection agents that provide protection to both UVB and UVA radiation, do not pose a threat with respect to its photocatalytic activity and does not leave a white layer on the skin.

Further, sunscreen protection agents with these properties are desired that can be prepared in an environmentally sustainable, economically viable and practical and reproducible way.

Summary

The present disclosure provides a process for the preparation of melanoidin-coated inorganic UV filter particles that is inexpensive and elegant in its simplicity, efficiency and costs. It provides stable melanoidin-coated titanium- and/or zinc particles of homogeneous particle size with suitable UV-absorbing properties.

The present disclosure pertains to a method for the preparation of melanoidin-coated inorganic UV filter particles, using melanoidin and titanium- and/or zinc oxide particles as starting material and wherein either:

A. a mixture of the titanium- and/or zinc oxide particles and melanoidin in water is ultrasonic treated, followed by spray drying the mixture to form melanoidin-coated titanium- and/or zinc oxide particles;

B. the titanium- and/or zinc oxide particles are activated by acid treatment, followed by slow introduction of the melanoidin to the activated titanium- and/or zinc oxide particles to form a melanoidin/titanium- and/or zinc oxide complex, and separation and drying of the resulting melanoidin-coated particles, or

C. the titanium- and/or zinc oxide particles are 5 subjected to high mechanical shear and heating, followed by introduction of the melancidin through a nozzle and separation and drying of the resulting melanoidin-coated titanium- and/or zinc oxide particles.

Preferably, the inorganic UV filter particles comprise titanium oxide as their main oxide.

Preferably the acid used for the acid treatment of method B is carboxylic acid having 1-4 carbon atoms, more preferably the carboxylic acid is acetic acid.

In one embodiment the mechanical high shear of method C is conducted by exerting an ultrasonic treatment at a temperature of between 15-100 °C.

Preferably the melanoidin used to coat the titanium- and/or zinc oxide has been extracted from food waste material such as spent coffee and cocoa- and beer- production side products.

Preferably a fractionized melanoidin is used having a molecular weight (Mw) of between above 50 KDa. More preferably a molecular weight between 50 to 200 KDa, most preferable a range between 80 and 150 kDA, is used.

The present description also pertains to melanoidin-coated titanium- and/or zinc oxide particles obtainable by the processes according to the invention.

6 37100

The description is also directed to a sunscreen protection agent comprising the melanoidin-coated titanium- and/or zinc oxide particles according to the description and compositions comprising said the sunscreen protection agent.

Figure 1 gives the absorption spectrum of the melanoidin- coated particles according to the present disclosure.

7 37100

Detailed Description

The present disclosure provides a process for the preparation of melanoidin-coated inorganic UV filter particles that is inexpensive and elegant in its simplicity, efficiency and costs. It provides stabile melanoidin-coated titanium- and/or zinc particles of homogeneous particle size with suitable UV-absorbing properties.

A. a mixture of the titanium oxide particles and melanoidin in water is ultrasonic treated, followed by spray drying the mixture to form melanoidin-coated titanium- and/or zinc oxide particles;

B. the titanium- and/or zinc oxide particles are activated by acid treatment, followed by slow introduction of the melanoidin to the activated titanium particles to form a melanoidin/titanium- and/or zinc oxide complex, and separation and drying of the resulting melanoidin-coated particles, or

C. the titanium- and/or zinc oxide particles are subjected to high mechanical shear and heating, followed by introduction of the melanoidin through a nozzle and separation and drying of the resulting melanoidin-coated titanium oxide particles.

In the present method melanoidin and titanium- and/or zinc oxide particles are used as starting material in contrast to melanoidin and/or titanium oxide being created in situ.

This provides the advantage of better controlling the

8 37100 melanoidin coating and freedom-of choice of using melanoidins of any source, including melanoidins extracted from food waste products. All methods A, B, and C were found to provide stably coated particles.

Preferably, the inorganic UV filter particles comprise titanium oxide as their main oxide since it is considered to provide the best UV protection. With the term “main” is meant here that at least 50 wt.% of the inorganic UV filter particles are titanium oxide particles.

Any titanium oxide particle that are commercially available may be suitably be used for the present process as long as they have proper homogeneous particle sizes. Examples of suppliers are DuPont, The Chemours Company, Venator

Materials Plc., and Grupa Azoty S.A.

Also zinc oxide particles are commercially available and any particle may be suitably be used for the present process as long as they have proper homogeneous particle sizes.

When using a combination of titanium oxide and zinc oxide particles, it is generally desired that the starting particles have the same particle size.

The particle size of the starting material may vary from 5 to 25 micrometers, preferably between 5 and 10 micrometers.

Melanoidins are a class of brown, hydrophilic nitrogen- containing polymers which are formed during the thermal processing of foods - such as coffee, cocoa, bread, malt, barley, Brewers Spent Grain (BSG), soy, meat, and honey.

During thermal processing of such foods, amino acids and reducing sugars, such as aldose and d-xylose, react to form

9 37100 what are termed initial Maillard reaction products. Under continued heating, melanoidins are formed by cyclizations, dehydrations, retro-aldolizations, rearrangements, isomerizations and condensations of those initial Maillard reaction products. The complexity of the Maillard reaction pathways results in a range of final reaction products, with inter alia the time of heating, type of heating, temperature, initial chemical composition of the system, moisture content, water activity and pH value being determinative of the final composition.

The melanoidins suitable for use in the present description preferably are the ones that have been extracted from food waste material such as spent coffee and cocoa- and beer- production side products. Since spent coffee has the highest amounts of melanoidin this is the preferred melanoidin source.

In order to control the coating thickness, the process and as a result the resulting particle size, generally a fractionized melanoidin is used. Preferably melandoidin having a molecular weight (Mw) above 50 KDa is used. More preferably melanoidin having a molecular weight (Mg) of between 50 to 200 KDa, and most preferably between 80 and 150 kDA is used. The melanoidin may be used in powder form, suspension, wetted or in solubilized form.

Method A

In method A, a mixture of the titanium and/or zinc oxide particles and melanoidin in water is ultrasonic treated.

Said ultrasonic treatment may be performed at increased temperatures of between 20-100°C. This ultrasonic treatment

10 37100 serves to intimately mix and homogenize the starting materials.

Upon complete homogenization the mixture is spray dried to form melanoidin-coated titanium- and/or zinc oxide particles. The resulting melanoidin-coated titanium- and/or zinc oxide particles were found to be stably coated and of homogeneous size.

Method B

In method B, the titanium- and/or zinc oxide particles are activated by acid treatment. For the activation of the oxide particles’ surface any carboxylic acid having 1-4 carbon atoms may be used. However, preferably acetic acid is used for its low cost price and lower risk of side reactions. When wishing to reduce the risk of degrading the titanium- and/or zinc oxide particles higher carboxylic acids or lower concentrations may be used. The amount of the carboxylic acid used may be varied from 5 to 50 wt& of the total weight of the titanium- and/or zinc oxide present. In order to speed up the activation process the temperature of the mixture may be increased. Generally a temperature of from 20 to 100 °C is used.

After activation the melanoidin is slowly introduced to the activated titanium particles to form a melanoidin/titanium oxide complex. The formation of a melanoidin/ titanium oxide complex is indicated by the increase of the pH.

Generally speaking the starting pH of the activated titanium- and/or zinc oxide slurry is about 2. After completion of the complex formation the pH has increased to above 7.

After completion of the complexation the resulting melanoidin-coated particles may be separated and dried.

11 37100

This may be done by conventional means such as filtering and drying via oven drying, freeze drying, spray drying or any other conventional ways. The resulting melanoidin- coated titanium- and/or zinc oxide were found to be stably coated and of homogeneous size.

Method C

In method C the titanium oxide particles are subjected to mechanical high shear and heating. This is may be done by exerting high shear to the mixture, preferably by exerting an ultrasonic treatment. Also other homogenization methods known in the art such as {ball} milling, extrusion, and kneading can be used. Optionally the high shear treatment is conducted at a temperature of between 15-100 °C.

After the mechanical high shear, the melanoidin is introduced through a nozzle. The use of a nozzle ensures proper contact between the titanium oxide particles and the melanoidin. (Spraying) Nozzles are known in the art and need no further elucidation here. For handling purposes the melanoidin may be pre-wetted prior to introduction via the nozzle. The resulting melanoidin-coated titanium oxide particles were found to be stably coated and of homogeneous size.

The present description also pertains to melanoidin-coated titanium- and/or zinc oxide particles obtainable by the processes according to the invention because the resulting melanoidin-coated titanium- and/or zinc oxide particles provided with the above-described methods have superior properties over the titanium oxide particles of the prior art. They have homogenous thickness of the coatings, provide UV protection over both the UVA and the UVB range, and pose no threat with respect to photocatalytic activity.

12 37100

The description is further directed to a sunscreen protection agent comprising the melanoidin-coated titanium oxide particles according to the description and compositions comprising said sunscreen protection agent.

The compositions comprising said sunscreen protection agent does not leave a white layer on the skin. The compositions may be cosmetic compositions with UV protection or sunscreen compositions. These compositions may be in the form of a liquid, a gel, an emulsion, a paste, solid or compact powder. In addition to the sunscreen protection agent according to the present disclosure other conventional ingredients may be present in the compositions depending on its purpose, such as fillers, colorants and/or pigments, perfumes, oils and fats, solvents, surfactants, wetting agents, penetrants, and antimicrobial agents.

The following examples are illustrative, but not limiting, of the methods / compositions of the present disclosure

EXAMPLE 1

Melanoidin-coated titanium oxide particles were prepared using method A. Scanning electron microscopy showed the resulting particles to have homogeneous size with certain agglomerated particles also present. The D50 particle size was measured to be 6-10 micrometers.

Figure 1 depicts the absorption spectrum of the melanoidin- coated particles obtained in example 1. This spectrum shows the melanoidin-coated titanium oxide particles provide protection throughout the whole UV range from 215 nm to 400nm.

Claims

13 37100 Conclusions NL CONCLUSIONS

1. A method for the preparation of melancidin-coated inorganic UV filter particles, using melanoidin and titanium and/or zinc oxide particles as starting materials and comprising either:

A. a mixture of the titanium and/or zinc oxide particles and melanoidin in water is ultrasonically treated, followed by spray drying of the mixture to form melanoidin-coated titanium oxide particles;

B. the titanium and/or zinc oxide particles are activated by acid treatment, followed by slow introduction of the melanoidin into the activated titanium particles to form a melanoidin/titanium oxide complex, and separation and drying of the resulting melanoidin-coated particles, or

C. The titanium and/or zinc oxide particles are subjected to high mechanical shear and heating, followed by introduction of the melanoidin through a nozzle and separation and drying of the resulting melanoidin-coated titanium and/or zinc oxide particles.

2. A method according to claim 1, wherein the inorganic UV filter particles contain titanium oxide as the main oxide.

3. A process according to claim 1 or 2, wherein the acid used for the acid treatment in process B is carboxylic acid having 1-4 carbon atoms, preferably acetic acid.

4. A method according to any one of claims 1 to 3, wherein the mechanical high shear of method C is carried out by performing an ultrasonic treatment at a temperature between 15-100°C.

14 37100 Conclusions NL

5. A method according to any preceding claim, wherein the melanoidin used is obtained from food waste products, preferably from spent coffee and by-products from cocoa and beer production.

6. The method of claim 5, wherein a fractionated melanoidin is used having a molecular weight (MW) of at least 50 KDa.

7. Melanoidin-coated titanium oxide particles obtainable by the methods of claims 1-6.

8. Melanoidin-coated titanium and/or zinc oxide particles comprising melanoidin extracted from waste food products.

9. A sunscreen comprising the melanoidin coated titanium and/or zinc oxide particles according to claim 7 or 8.

10. A composition providing sun protection comprising the sunscreen protection agent of claim 9.