Temperature Effects on Produce Degradation 643
Possible results of slicing produce may include increased ethylene production and
respiration rates, accelerated senescence, and enzymatic browning.
Storage temperature has a significant effect on the keeping quality of fresh-cut
products. Behrsing et al.^75 looked at factors affecting the quality of chopped broccoli
florets, broccoli stem pieces, cauliflower florets, julienne and diced carrots, and
chopped red coral and butter lettuces. They found that respiratory activity of the
chopped vegetables was reduced as storage temperature was lowered from 10^ to 4.5
to 1°C. Depending on the product, shelf life was increased between 48 and 154%
by storage at 4.5°C rather than at 10°C. Further increases in shelf life of 12.5 to
85% were observed by storage at 1°C rather than 4.5°C. However, chopped butter
lettuce held at 1 or 4.5°C showed increased browning over that held at 10°C.
20.6 SUMMARY
Good temperature management is the single most important factor in determining
the ultimate quality of fresh fruits and vegetables. Temperature influences the res-
piration rate of products and, therefore, the speed of product deterioration. It also
affects ripening, ethylene production and utilization, product moisture loss, rate of
decay, and the balance of starch and sugar contents.
Temperature management of produce begins with harvest in the field and should
continue throughout the handling and distribution chain to the consumer’s table. For
most products, rapid cooling after harvest is important to slow undesirable changes
that occur in the produce. A number of methods are in use for this cooling; however,
the two used most commonly are cold air cooling and hydrocooling.
Produce is frequently exposed to temperature extremes. Some, such as low
temperature storage to extend shelf life and heat treatment to eliminate pests, are
intentional. Others, such as high temperatures during harvest, are unintentional.
Some produce suffers chilling injury at low temperatures above their freezing point.
Some are damaged by high temperatures. Freezing damages all produce. Research
efforts continue to discover the optimal temperature and other storage and handling
conditions for individual species of fruits and vegetables.
REFERENCES
- Mitchell, F. G., Cooling horticultural commodities. I. the need for cooling, in Postharvest
Technology of Horticultural Crops, 2nd ed., Kader, A.A., Ed., University of California
Division of Agriculture and Natural Resources Publication 3311, 1991, Chap. 8. - Wills, R.B.H. et al., Temperature, in Postharvest: An Introduction to the Physiology
and Handling of Fruit and Vegetables, AVI Publishing, Westport, CT, 1981, Chap. 4. - Lurie, S., Temperature management, in Fruit Quality and Its Biological Basis, Knee,
M., Ed., CRC Press, Boca Raton, FL, 2002, Chap. 5. - Shewfelt, R.L., Postharvest treatment for extending the shelf life of fruits and vege-
tables, Food Technol., 40(5), 70, 1986. - Woodroof, J.G., Harvesting, handling, and storing vegetables for processing, in Com-
mercial Vegetable Processing, Luh, B.S. and Woodroof, J.G., Eds., AVI Publishing,
Westport, CT, 1975.