Biscuit dough fats, shortenings

Fats may be purchased either warm as an oil in bulk or plasticised as a semisolid at ambient temperature in boxes.

Boxed fats normally appear very white. In the process of chilling and plasticising small quantities of nitrogen may be introduced to enhance this white appearance. Inclusion of a gas may slightly help the plasticity but has no known advantage in the biscuit dough.

Most dough fats are chosen to have physical characteristic similar to butter. This means that they have a relatively long melting range, are semisolid at ambient temperature and are almost completely melted at blood heat. Fats such as palm oil and beef fat can be used as straight fats for biscuit doughs but it is normal to use blends which may involve many different fats of both animal, fish and vegetable origin. Selective hardening and other technical procedures can give blends with the desired physical characteristics. The amount of solid fat present at a particular temperature is known as the Solid Fat Index (SFI).

To meet marketing needs it is of course possible to purchase fats which are all vegetable or do not include fats from pigs, beef or fish. The fats and oils industry is now very sophisticated so bakery fats are available to suit all physical and chemical requirements. Provided that the fat is in suitable physical condition at the time of dough mixing it is unlikely that any tailor-made fat will significantly affect the structure of baked biscuits.

Please click here to view a diagram of the typical melting curve of a biscuit dough fat blend.