This investigation was concerned with the cooling of 4-gal. batches of food by agitation using a rotating tube as agitator through which flowed refrigerated water. The aim was: (a) to gain information on the total cooling time of various white sauces; and (b) to observe changes in certain quality characteristics affected by this method of cooling such as, relative viscosity, density, whiteness reflectance, and acceptability for service. The variables were the level of flour in the sauces (4, 6, and 12 oz-/gal. milk), the level of fat in the sauces (4, 6, and 12 oz./gal. milk), and the rate of agitation of the cold tube (6, 12, and 18 rpm.)
In general, the rate of cooling increased as the rate of agitation increased. The twenty-four sauces cooled from 140°F. to 60°F. within 5 hours, and half of them within 3 hours. The high-fat sauces cooled more slowly. Changes in relative viscosity were small, and in all but two cases they did not affect the acceptability of the sauces for service.
It appears that efficient cooling can be obtained with the u-tube without obejctionable loss in culinary quality.
An analysis of variance and t test comparisons were carried out.
1This is part of a larger project titled “Heat Transfer in Foods Prepared and Cooled in Quantity.”