The instantly frozen piece closely resembles the structure of a fresh bean, having little cellular damage. At the other extreme is a bean frozen slowly. Cell breakdown is extensive and large cavities develop between the cells. When cooked, beans such as this have a poor texture, in contrast to the instantly frozen beans which are more like the fresh.

If I can conclude anything at this point about costs, it might be this: the differences in costs among the usual methods of freezing (air-blast bulk or package and plate) are likely to be minor. Decision on which method to use will probably be determined by other factors more important in the overall economic picture. If, however, we consider a radically different freezing method, such as use of cryogenic materials, cost differences become large and important. Other factors that may overrule freezing cost considerations must indeed be important, or unavoidable, or both.

Between these extremes is the bean frozen in a matter of minutes, 5 or 6 at the most. The physical condition is greatly improved over the slowly frozen one. When cooked, this bean is hardly distinguishable from the bean frozen instantly.

A similar story for asparagus is shown in figure 5 (unpublished data from Milford S. Brown). The small bundles are the vascular tissues, or plumbing system, that carry fluids through the plant. Again, the quickly frozen one has a much better structure than the one frozen slowly, and its appearance is similar to that of the instantly frozen piece.

(left to right) instantly, quickly, and slowly.