Humectants
Humectants are substances that prevent foods from drying out during storage. Gycerol or glycerine is the most common humectant. Some artificial sweeteners such as erythritol, xylitol and sorbitol syrup are also used as humectants and you can find out more about these on the sweetener pages.
Glycerol (E422)
Glycerol (E422) is made by the hydrolysis of fats and can be obtained from both vegetable and animal fats, and consumers will not know the original fat source. Glycerol is a clear almost colourless liquid at room temperature and it is used primarily as a humectant to keep foods moist without risking mould or bacterial growth. It is also used to reduce staling, improve texture by plasticising the food. Glycerol is used in slushies to prevent them from freezing solid and to maintain the slushy texture, especially in low-sugar or sugar-free versions. It acts as an anti-freeze, lowering the freezing point of the liquid and allowing it to remain in a slushy state. Glycerol is permitted in the EU in additives Group I: quantum satis.
Although glycerol is naturally present in food and is formed in the human digestive system, and has a long history of use, the amounts used in slush iced drinks are now known to be dangerous to the health of young children. Warnings about ingestion of glycerol containing slush iced drinks by children can be found at https://www.food.gov.uk/safety-hygiene/glycerol
“Products containing glycerol should not be consumed by children under seven years of age and children under 10 should have a maximum of one 350ml drink per day.”
Polydextrose (E1200)
Polydextrose (E1200) is produced by a vacuum melt process involving polycondensation of glucose in the presence of sorbitol and an acid. This produces a weakly acidic water-soluble polymer which is used as bulking agent as well as a humectant to retard the loss of moisture in baked goods which helps protect against staling. Polydextrose is not sweet and can be used for both sweet and savoury products. It is only partially digested in the large intestine so has a calorie value of 1kcal/g compared to 3.75kcal/g for sugars. As its digestion does not involve insulin it can be used in products marketed for diabetics. It is not fermented by mouth bacteria so will not cause caries. In the EU it is permitted in foods quantum satis.
