1. MIXING AND PASTEURIZING: To obtain a well blended and homogenous mix, effective mixing units are essential. The ideal layout for the mixing process depends on the various factors; primarily, of course, on the desired ice cream types but also on the raw material and the scale of production.
The pasteurization unit is usually combined with the mixing unit whereas in small scale production the same vessel is used both as a mixing tank and as a pasteurizes.
Pasteurization serves two purposes, viz. to critically reduce micro-organisms and to obtain the best possible hydration of all the ingredients.
2. HOMOGENIZATION: Homogenization is the next step after the mixing of the raw materials and pasteurization. The purpose of homogenization is to produce a fine, uniform fat emulsion.
3. AGING: After homogenization, the mix should be rapidly cooled to 46oC and kept at this temperature for some time. During aging some physical changes take place that are important for the behavior of the ice cream mix and of the finished ice cream product viz:
- Crystallization of the fat.
- Full hydration of the milk proteins.
- Total hydration of the stabilizer.
These physical changes will influence the properties of the mix and the finished ice cream as follows:
1) Improved whippability of the mix during freezing.
2) Controlled churning out of the fat during freezing.
3) A more warm eating product
4) Improved Body.
5) Improved heat shock resistance.
AGING TIME: Test have shown that aging for 3-5 hours is the minimum For obtaining an optimum result.
AGING TEMP: 46oC after Homogenization.
VISCOSITY: After aging it is common practice to perform certain control measurements on the mix. The minimum required is a viscosity measurement which may be carried out either with a rotation viscometer or as a very quick method with a pipette.
The viscosity measurement will indicate whether any mistakes have been made in the weighing of the raw materials or if other faults have occurred in the processing of the ice cream mix.
Any errors can thus be easily and cheaply corrected at this stage.
Dry blended emulsifiers and stabilizers must be dry mixed with the sugar prior to addition to the mix in order to avoid lump formation, the factor which is of utmost important in the Manufacturing process. |
