Have you ever wondered how is an ice-cream made and why some ice-creams are better than others? Did you ever wonder about the functionalities of the ingredients in an ice-cream?
Well, to start from the basis, let’s say that the ice-cream belongs to the family of “aerated” foods that have the peculiarity of being made of both solids and air as in form of air pockets. It, in fact, consists of 50% of air bubbles while the rest is made of fat globules, ice crystals and sugar.
The process of ice-cream formation includes heat treatment of milk which is called pasteurization. After the heath treatment, homogenization and cooling steps of the premix is done. Once the cooling has been done, aeration and freezing of the mix is carried out under shear conditions.
It is during aeration and freezing that many physical phenomena occur between fat and proteins. Such phenomena include the positioning of fat to the interface which is the region between solids and air. The fact that the fat preferably positions at the interface makes it possible for the foam structure to be stabilized. Lastly, water is removed from the mix in the form of ice crystals.
What is fat’s functionality in an ice-cream?
Fat portion is of key importance in terms of desirable properties in the finished product. Some of the beneficial effects of fat in in ice-cream is on the textural point of view. It has its effect on dryness and shape retention as well as slowness of meltdown and smooth texture not only during eating but also after hardening.
Sugar is used not only to impart sweetness but also as a mean of reducing the rate of ice crystal growth and has effects in increasing the production of smaller ice crystals (lower than 50 µm) that will positively impact the finished product’s texture in terms of smoothness. It has indeed been observed that increasing the sugar content, the crystal size also decreases.
The shape of the ice crystal can have its effect on smoothness of an ice-cream. A smooth ice cream requires a majority of ice crystals smaller than 50µm in size. When the ice crystal is larger than 40-55µm, a coarse and sandy texture is perceived and this normally is associated with unpleasant textures.
So, now that you know more about ice-cream, I am pretty sure you will make much more attention to its texture while tasting one. Tasting comfort food can be more exiting than expected!
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Goff H.D. (2002). Formation and stabilization of structure in ice-cream and related products. Current opinion in Colloid & Interface science. (7), 5-6, 432 – 437.