These are effective in ice cream either because they form gels with water or because they can combine with water as part of hydration. Either way, they function because of their high water holding capacity, preventing the formation of large crystals particularly under adverse or fluctuating storage conditions. Because of this they produce a smoother, more stable texture and body and assist in maintaining the shape on melting. They have no apparent effect on the freezing point of mix. In excess, they are likely to give much too much body and resistance to melting and a poor sensation on the palate.

Many substances are available and some suppliers offer combinations of products for improved effect. Points to bear in mind when choosing a stabiliser include cost, ease of dispersion and resistance to heat. Some substances tend to lose stabilising power when excess heat, such as that met in high temperature methods of pasteurisation, is applied. Common stabilisers include gelatine (used at the rate of about 0.5% of the total mix), sodium alginate (0.25%), carageenan or Irish Moss (0.15%) cellulose ethers such as sodium carboxymethyl cellulose (0.15%) agar (0.5%) and pectin (0.15%). Generally, stabilisers can be added by mixing them with about five times their weight of sugar or by suspending the material in cold water before adding to the hot mix.

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