University of California

Ask the Produce Docs (General)

Why can apples be stored for a year, and tomatoes can not?

Category
  • Modified Atmospheres
  • Temperature Management
Question

How would you explain the fact that certain fruits, apples being the best example, can be kept for a year or more under controlled atmosphere storage, while tomatoes can not?  Are other fruits kept in controlled atmosphere storage in the way that apples are? (A.W.A.)

Answer

The storage potential of apple cultivars is the longest among all fresh fruits because they are usually harvested mature, but not ripe (preclimacteric stage) ; most cultivars have relatively low respiration rates; some cultivars, such as Fuji and Granny Smith, have relatively low ethylene production rates; they have a high starch content that is converted to sugars during storage, and decline in firmness (crispness) slowly if kept at 0C (32 F) and especially when kept in low-oxygen atmospheres (1-2% oxygen) and/or treated with the anti-ethylene action chemical, 1-methylcyclopropene. Controlled atmosphere storage is commonly used for apples ( up to one year, depending on cultivar) and to a lesser extent ( up to 6 months) for European pears, Asian pears, kiwifruits, and pomegranates.

Mature-green tomatoes can be kept in controlled atmosphere storage ( 3-5% oxygen, balance nitrogen) at 12 C (54 F) for up to 8 weeks, then ripened in air at 20-25C (68-77 F), but their eating quality will be inferior to tomatoes harvested at the partially- or fully-ripe stage or those picked mature-green and ripened soon after harvest.

Tomatoes are chilling-sensitive (should not be kept below 12C = 54 F), do not have a starch reserve, and their rates of respiration and softening are higher than those of apples. That is why their storage potential is much lower than that of apples. --Adel Kader

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