Manufacturing Procedures

i) Selection of ingredients: Fresh, sweet dairy products should be preferred for making soft serve mix in order to obtain a good quality product. Generally,cane sugar is used but a part of it is replaced with dextrose or corn syrup. The selection of ingredients should be based on the composition given in section above.

ii) Mixing of ingredients: To avoid difficulties in mixing, pre-calculated quantities of dry ingredients, i.e. milk power, sugar and stabilizer should be mixed in a lot.Similarly, the liquid ingredients, viz., milk and cream, etc. should be mixed separately in a container. The dry mixture shall be incorporated within the liquid ingredients mixture gradually with constant stirring and heating to the homogenization temperature of 65.5 C.

iii) Homogenization: In order to avoid fat separation, clumping of fat and fat churning in soft ice cream, the mix should be homogenized in two stages. First at a pressure of 2500 psi. and then at a pressure 500 psi.

iv) Pasteurization: To safeguard health consumers by means of destroying all the pathogenic and disease producing organisms present in the mix, it must always be pasteurized. Pasteurization is normally done at 80 C for 25 seconds by High Temperature Short Time (HTST) method or at 69 C for 30 min. by Batch method.

v) Ageing of mix: The mix is to be aged at temperatures 2-5 C for at least 4 to 6 hours before freezing.

vi) Freezing: A soft ice cream freezer, apart from freezing a portion of water of ice cream mix, also incorporates the air in the mix to obtain a swell in volume or ‘overrun’. A soft ice cream freezer is very similar to the batch freezer of ice cream. It is usually a self contained machine in which the low pressure refrigeration system is either directly attached, or is adjacent to the freezer.

The design of the dasher is such that it gives a good degree of aeration to the mix as it freezes and can operate for a long period of time without undue breaking down of the ice cream mix. Excessive speed of the dasher causes too much air to be incorporate, and adversely affects the body of ice cream if the dasher ran for extended periods of time. The refrigeration system is so designed that the freezer cylinder is kept at the proper temperature for a soft serve ice cream for an indefinite period of time. Most of these freezer use Freon as a refrigerant. In this case, they often use a thermo valve control rather than the flooded system. Care and maintenance of this type of freezer consists mainly of keeping the scraper blades properly sharpened,and ensuring that the refrigeration system is properly adjusted.

The automatic cycling of ice cream can cause major problems including fat separation, occurrence of sandiness due to lactose crystallization and coarse texture.

Soft server frozen products are usually drawn from the freezer at -6.5 to -7.5 C.The overrun of soft serve varies between 40-60% depending on the total solids content. It is possible to achieve high overrun and desired body and texture characteristics on a product with a high solids content.

Overrun and serving temperatures for different types of ice

cream