Keratin hydrolysates (KHs) are established standard components in hair cosmetics. Understanding the moisturizing effects of KH is advantageous for skin-care cosmetics. The goals of the protocol are: (1) to process chicken feathers into KH by alkaline-enzymatic hydrolysis and purify it by dialysis, and (2) to test if adding KH into an ointment base (OB) increases hydration of the skin and improves skin barrier function by diminishing transepidermal water loss (TEWL). During alkaline-enzymatic hydrolysis feathers are first incubated at a higher temperature in an alkaline environment and then, under mild conditions, hydrolyzed with proteolytic enzyme. The solution of KH is dialyzed, vacuum dried, and milled to a fine powder. Cosmetic formulations comprising from oil in water emulsion (O/W) containing 2, 4, and 6 weight% of KH (based on the weight of the OB) are prepared. Testing the moisturizing properties of KH is carried out on 10 men and 10 women at time intervals of 1, 2, 3, 4, 24, and 48 h. Tested formulations are spread at degreased volar forearm sites. The skin hydration of stratum corneum (SC) is assessed by measuring capacitance of the skin, which is one of the most world-wide used and simple methods. TEWL is based on measuring the quantity of water transported per a defined area and period of time from the skin. Both methods are fully non-invasive. KH makes for an excellent occlusive; depending on the addition of KH into OB, it brings about a 30% reduction in TEWL after application. KH also functions as a humectant, as it binds water from the lower layers of the epidermis to the SC; at the optimum KH addition in the OB, up to 19% rise in hydration in men and 22% rise in women occurs.
BACKGROUND: Although keratin hydrolysates have become established as standard components in hair and nail cosmetics, studies on the moisturizing effects of keratin hydrolysates do not appear among contemporary literature. OBJECTIVES: To test if adding keratin hydrolysate into an ointment base increases hydration of the skin and improves skin barrier function, or diminishes trans-epidermal water loss. METHODS: Formulations were prepared containing 2%, 4%, and 6% keratin hydrolysates (based on weight of the ointment base). The moisturizing properties of keratin hydrolysates were tested by measuring skin hydration, trans-epidermal water loss and skin pH; measurements were carried out at intervals of 1, 2, 3, 4, 24, and 48 h. Testing was conducted on 10 women. RESULTS: As regards hydration, adding 2% keratin hydrolysate to the ointment base is optimal, as an increase of 14%-23% occurs in hydration of the stratum corneum. For trans-epidermal water loss, adding 4% KH to the ointment base is preferential, as this triggers a 26%-46% decrease in trans-epidermal water loss. CONCLUSIONS: Keratin hydrolysate acts as a humectant (it binds water from lower layers of the epidermis to the stratum corneum) as well as an occlusive (it reduces trans-epidermal water loss). The highly favorable properties of keratin hydrolysates are attributed to the wide distribution of keratin hydrolysates molecular weights; low-molecular weight fractions easily penetrate the SC, while high-molecular weight fractions form a protective film on the epidermis. Adding keratin hydrolysates to the ointment base did not cause phase separation even after 6 mo storage.
- MeSH
- dospělí MeSH
- epidermis chemie účinky léků fyziologie MeSH
- fyziologie kůže účinky léků MeSH
- hygroskopické látky farmakologie MeSH
- keratiny farmakologie MeSH
- koncentrace vodíkových iontů MeSH
- kosmetické přípravky farmakologie MeSH
- lidé MeSH
- masti MeSH
- perspiratio insensibilis účinky léků MeSH
- proteinové hydrolyzáty farmakologie MeSH
- voda metabolismus MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Short and long tendons of abattoir cattle are collagen by-products of the meat industry. They offer no utilisation at present, being a raw material source of over 90 % protein characteristic. This contribution deals with the three-stage extraction of gelatine from short cattle tendons. The principle of treatment consists in processing degreased tendons in the first processing stage in an environment resulting in the swelling of the starting material. In the second stage, the material is treated with a proteolytic enzyme to produce such disruption of the collagen substrate that makes gelatine extraction when boiling possible in the third stage of the process. In order to study the influence of the significant parameters during the extraction process on gelatine yield, experiments were planned using a factor experiment of 2(3) types. The variables under study were the duration of the second processing stage (5-25 h), temperature in the first and second processing stages (10-40 °C) and the addition of a proteolytic enzyme (1-5 %) on the quantity of the extracted gelatine. The results were processed statistically, and statistical significance of the studied factors was thus found. Contour graphs were plotted to easily survey the influence of the observed factors on gelatine yield. The process achieves up to 71 % efficiency, runs under atmospheric pressure and mild reaction conditions, and is conducive to preparing quality gelatines.
The subject of our previous paper (part 1) was three-stage extraction of gelatines from short cattle tendons. In this paper, we studied influence of extraction conditions on quality of produced gelatines-protein content, ash content, rigidity of gelatine gels, viscosity, and distribution of molecular weights. Ash content of gelatines ranged in limits 3.5-10.5 %. Rigidity of the gels was influenced by extraction conditions and by elastin content in gelatines; highest-quality gels display rigidity of 213 Bloom. Viscosity of gelatines ranged from 2.47 to 12.11 mPa s. Molecular weights of gelatines display a proportion of fractions from 20 to 36 kDa, a quite high proportion of fractions from approximately 50 to 100 kDa, in some cases even fractions above 200 kDa appear. It was found that transition temperature and melting temperature of gelatines extracted from tendons are in accord with data on gelatines obtained by traditional extraction techniques from skins and bones. With respect to efficiency of the whole extraction process and to quality of extracted gelatine, we may recommend extraction conditions as follows: in the 1st processing stage, shaking degreased starting material with water in ratio 1:10 at 25 °C for 5 h; in the 2nd stage, treating the swelled material with 5 % (w/w) added proteolytic enzyme at 40 °C for 25 h; in 3rd stage, extracting gelatine while boiling for 16 min.
Poultry feathers make up for as much as 8.5% of chicken weight and represent a considerable amount of almost pure keratin waste which is not being adequately utilized at the present time. The present study dealt with the processing of poultry feathers through a two-stage alkaline-enzymatic hydrolysis. In the first stage, feathers were mixed with a 0.1 or 0.3% KOH water solution in a 1 : 50 ratio and were incubated at 70°C for 24 h. After adjusting pH to 9, the effects examined in the second processing stage on the amount of degraded feathers were those of proteolytic enzyme additions (1-5%), time (4-8 h) and temperature (50-70°C). Processing feathers in 0.3% KOH and hydrolysing for 8 h in the second stage at 70°C with a 5% dose of enzyme (relative to dry feathers weight) produced approx. 91% degradation. Keratin hydrolysate is distinct for its high nitrogen content and reasonable inorganic solids level. Two-stage technology of alkaline-enzymatic hydrolysing of poultry feathers in an environment of 0.3% KOH achieves high efficiency under quite mild reaction conditions (temperature not exceeding 70°C with pH in a mildly alkaline region), and is feasible from an economic viewpoint. Keratin hydrolysate can find particular application in packaging technology (films, foils and encapsulates).
- MeSH
- drůbež MeSH
- hydrolýza MeSH
- keratiny chemie MeSH
- koncentrace vodíkových iontů MeSH
- odpadky - odstraňování metody MeSH
- peří chemie MeSH
- proteasy chemie MeSH
- průmyslový odpad analýza statistika a číselné údaje MeSH
- teplota MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- finanční podpora výzkumu jako téma MeSH
- Publikační typ
- abstrakty MeSH
- MeSH
- finanční podpora výzkumu jako téma MeSH
- Publikační typ
- abstrakty MeSH
