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Table 1.
Comparison of freezing times for small fruits and vegetables
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Method
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Approximate freezing times
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| Package freezing (10-oz. containers): |
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air blast |
3 to 5 hr. |
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Plate |
1/2 to 2 hr. |
| Bulk freezing -- air blast: |
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Belt |
20 to 30 min. |
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Fluidized belt or tray |
5 to 10 min. |
| Cryogenic freezing |
1/2 to I min. |
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Figure 2.
Comparative costs supplied by an equipment manufacturer.
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For a general comparison, freezing times for various methods are roughly as shown in table I for small fruits and vegetables. Experience at any one plant may be significantly different, depending upon the circumstances involved.
Figure 2 shows freezing costs for breaded turkey pieces as supplied by a company that makes both air-blast and liquid-nitrogen (LN) freezers. Pertinent assumptions in the estimate are as follows
- Product -- cut-up breaded 4 oz. portions.
- Output -- 2,500 pound an hour; 5,000,000 pounds a year.
- Losses assumed -- 2 percent in air-blast freezing; I percent in LN freezing.
- Liquid nitrogen cost -2 1/2 cents a pound; 1.12 pounds required per pound of produc
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