In particular, the emulsifying agent can be chosen from anionic surface-active agents, such as the sodium or potassium salts of fatty acids, in particular sodium laurate, sodium stearate, sodium palmitate or sodium oleate, the mixed sulfates of sodium or of potassium and of fatty alcohol, in particular sodium lauryl sulfate, the sodium or potassium salts of sulfosuccinic esters, the sodium or pota