Agriculture Reference
In-Depth Information
Climacteric fruits are those whose ripening is accompanied
by a distinct increase in respiratory rate (climacteric rise)
which is generally associated with elevated ethylene pro-
duction just before the increase in respiration. After the
climacteric rise, ethylene production declines significantly.
Ethylene is necessary for the co-ordination and completion
of ripening.
Non-climacteric fruits are those that do not exhibit
increases in ethylene and respiration, but rather undergo a
gradual decline in respiration during ripening.
It is a general rule that climacteric fruit can be picked
mature but unripe, and can then be ripened off the plant,
whereas non-climacteric fruit will not ripen once picked.
However, even in non-climacteric fruit the quality can
change after harvest in such a way as to make the fruit more
palatable. For example, pineapples will soften after harvest.
Non-climacteric fruit such as pineapples and oranges can be
artificially de-greened by the application of ethylene.
In the case of some fruit, the classification as climacteric
or non-climacteric is not straightforward, and is still a
matter of debate. For example muskmelon was originally
thought to be climacteric, but is now considered by some
scientists as non-climacteric (Obando
et al
. 2007). Several
scientific papers have been published on guava; some
scientists conclude that it is non-climacteric, and others that
it is climacteric, while a few scientists suggest that varieties
may differ in their classification (Brown & Wills 1983;
Reyes & Paull 1995).
Table 1.1 lists a range of climacteric and nonclimacteric
fruit. Examples of both classifications of fruit are consid-
ered in the following chapters within this topic.
Table 1.1
Classification of Fruit into Climacteric
and Non-climacteric.
Climacteric fruit
Nonclimacteric fruit
Apple Blackberry
Apricot Cherry
Avocado Grape
Banana Grapefruit
Cherimoya Lemon
Kiwifruit Lime
Mango Longan
Nectarine Loquat
Papaya Lychee
Passion fruit Mandarin
Peach Muskmelon
Pear Orange
Pepper (chilli) Pepper (bell)
Persimmon Pineapple
Plum Pomegranate
Quince Prickly pear
Sapodilla Rambutan
Sapote Strawberry
Tomato Tamarillo
Watermelon
Source: Information collated from UC Davis (2011).
given in the following chapters of this topic. This trade is an
important source of income for many, and is becoming
increasingly important as a source of revenue for many
tropical developing countries. This trade is possible only
through the development of technologies for extending the
storage life of perishable plant products. Some of the most
important technologies are summarised below.
NUTRITIONAL QUALITY OF PERISHABLE
PLANT PRODUCE
Perishable plant products are extremely important for
human nutrition. Root and tuber crops act as staples in many
parts of the world. Overall, perishable produce is vital as a
source of essential fatty acids, amino acids, vitamins and
minerals. The contribution to human nutrition of individual
commodities is addressed within the individual chapters, as
well as being thoroughly reviewed in Terry (2011).
Development of the cold chain
Temperature control is probably the single most important
factor in the extension of storage life of perishable prod-
ucts. Generally a decrease in temperature slows metabo-
lism and development. However, for all commodities there
is a temperature below which tissue damage occurs. This
varies by commodity, from −1°C for certain temperate
commodities, such as pears, to 15°C for tropical products,
such as bananas and sweet potato.
It is now appreciated that very significant quality improve-
ments can be achieved by considering cooling immediately
after harvest, and maintaining appropriate temperature
through the whole handling chain. In developed countries
this can extend even into the consumer's home, as the use
of domestic refrigerators becomes more widespread. The
POST-HARVEST TECHNOLOGY AND
THE EXPANSION OF INTERNATIONAL
TRADE IN HIGH-VALUE PERISHABLES
International trade in high-value perishables has grown
enormously in the past few decades. In the developed world,
consumers now expect to be able to eat perishable produce
from all parts of the world, and in most cases throughout the
year. Examples of the magnitude of international trade are
