ABDUL HAI AL-HADI

The basic steps in thee manufacturing ice cream are as follows:     blending of the mix ingredients     pasteurization     homogenization     aging the mix     freezing     packaging     hardening Ice cream Manufacturing process by Abdul Hai- BAU

Freezing/Whipping of Ice Cream Following mix processing, the mix is drawn into a flavour tank where any liquid flavours, fruit purees, or colours are added. The mix then enters the dynamic freezing process which both freezes a portion of the water and whips air into the frozen mix. The "barrel" freezer is a scraped-surface, tubular heat exchanger, which is jacketed with a boiling refrigerant such as ammonia or freon. Mix is pumped through this freezer and is drawn off the other end in a matter of 30 seconds, (or 10 to 15 minutes in the case of batch freezers) with about 50% of its water frozen. There are rotating blades inside the barrel that keep the ice scraped off the surface of the freezer and also dashers inside the machine which help to whip the mix and incorporate air. Diagram of a continuous ice cream (barrel) freezer Ice cream contains a considerable quantity of air, up to half of its volume. This gives the product its characteristic lightness. Without air, i

Dairy Technology by Abdul Hai Al-Hadi ▼ Common Defects and their Remedy Defects may appear in ice cream due to following reasons:      Use of low quality ingredients      Improper mixing of ingredients      Faulty method of manufacture      Faulty method of storage and transport  Quality of ice cream is judged for its delicate and pleasing flavour, smooth body and texture and attractive colour. The reasons for the development of defects in ice cream and the preventive actions to be taken to remove the defects are discussed in the following paragraphs. i. Colour and appearance Defects and Preventive Measures: i) Un-natural colour in ice cream develop due to following reasons:      Careless-ness in adding colour      Improper use of colour      Use of foreign materials  ii) Uneven colour results if the colour is not added and mixed properly. iii) Excessive colour is due to addition of too much colour. To avoid any of the above colour defects in ice cream correct