PROCESS & MANUFACTURING TECHNOLOGY
Sucrose esters –
the multifunctional, coldprocessable emulsifier With Sisterna SP70-C, an HLB 15 sucrose stearate in powder form, formulators can design a cold process o/w emulsion. This article from Sisterna zooms in on the possibilities of this production method and explains the crucial additional benefits of sucrose esters. These advantages combined with a cold processing method result in excellent formulations that meet the sustainability and clean beauty needs of consumers.
T
he most common way to make an o/w emulsion is using a hot production method. The pros of this type of production technique is that the heating energy eases the emulsification step. Another argument is that the heat could kill all the microorganisms. Of course, you have your solid ingredients which require heating. But if you can work around using solid ingredients, there are many benefits to making a cold process emulsion. It’s a much easier process as it’s safer to prepare and more economical than heated emulsions. The reduced energy consumption makes a cold manufacturing process more environmentally friendly and it doesn’t present any limitations in terms of the temperature sensitivity of ingredients.
COLD EMULSIFICATION POSSIBILITIES Sisterna SP70-C is an HLB 15 powder-grade emulsifier, which makes it quite unusual for use in a cold process. However, it’s easily colddispersible in the oil phase. A basic formulation with Sisterna SP70-C is presented in Table 1 with comparisons between an oil phase of 20% up to 60% and the effects on the oil droplet size and viscosity. Two common oils are also compared: 1. sunflower oil, which is a more polar vegetable oil 2. isopropyl myristate (IPM), which is a medium polarity ester oil.
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Figure 1: Oil concentration and the effect on the emulsion viscosity
OIL CONCENTRATION AND DROPLET SIZE High shear is enough to produce standard emulsions with Sisterna SP70-C. There are no particles visible and it gives droplet sizes between 1μm and 10μm, small enough to obtain a stable emulsion while having an oil phase of 20% to 60%. With a 60% oil dosage, 3% of Sisterna SP70-C works well. At lower oil levels of 20% to 30%, it’s possible to reduce the dosage to 2%.
OIL CONCENTRATION AND VISCOSITY In order to select the right viscosity of the formulation, it’s important to note that the higher the oil phase (internal phase), the more viscous the product becomes. There is a slight difference between the two oils used, as IPM gives a slightly higher viscosity (see Figure 1). Another key consideration is that it’s not only the oil concentration that can influence the
viscosity, but also the selected hydrocolloid, which can have a big impact. Using a viscosityincreasing hydrocolloid, such as sclerotium gum, gives a good viscosity build-up as well as stability to the emulsion.
THE BENEFITS OF SUCROSE ESTERS Although we’ve already mentioned the reason why cold emulsification is so interesting, there are more objectives why it should be done specifically with sucrose esters. The ability to combine the benefits of Sisterna SP70-C with this manufacturing technique gives the formulator an opportunity to design products in line with the current natural, clean beauty and responsible cosmetics trends. The result is an innovative processing technique that is ideal for creating simple and effective natural formulations. Sisterna SP70-C is a non-ionic and PEGfree/ethylene-oxide-free emulsifier, which is
