Mokrejš Pavel, Huťťa Matouš, Pavlačková Jana, Egner Pavlína
Department of Polymer Engineering, Faculty of Technology, Tomas Bata University in Zlín;
Department of Polymer Engineering, Faculty of Technology, Tomas Bata University in Zlín.
J Vis Exp. 2017 Nov 27(129):56254. doi: 10.3791/56254.
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.
角蛋白水解物（KHs）是毛发化妆品中既定的标准成分。了解KH的保湿效果对护肤化妆品有益。该实验方案的目标是：（1）通过碱酶水解将鸡毛加工成KH，并通过透析进行纯化；（2）测试将KH添加到软膏基质（OB）中是否能增加皮肤的水合作用，并通过减少经表皮水分流失（TEWL）来改善皮肤屏障功能。在碱酶水解过程中，羽毛首先在碱性环境中于较高温度下孵育，然后在温和条件下用蛋白水解酶进行水解。KH溶液经过透析、真空干燥并研磨成细粉。制备了包含2%、4%和6%重量百分比KH（基于OB的重量）的水包油乳液（O/W）化妆品配方。在10名男性和10名女性身上，每隔1、2、3、4、24和48小时测试KH的保湿性能。将测试配方涂抹在脱脂的掌侧前臂部位。通过测量皮肤电容来评估角质层（SC）的皮肤水合作用，这是全球使用最广泛且简单的方法之一。TEWL基于测量在规定面积和时间段内从皮肤传输的水量。这两种方法都是完全非侵入性的。KH是一种出色的封闭剂；根据向OB中添加KH的情况，涂抹后可使TEWL降低30%。KH还具有保湿剂的功能，因为它能将表皮下层的水结合到SC；在OB中添加最佳量的KH时，男性的水合作用最多可提高19%，女性可提高22%。
