Advantages of Storing
If cassava roots can be stored for more than 2
or 3 days, then two advantages will become apparent:
- Losses and marketing risks will be fewer, thus reducing costs and making cassava more
acceptable to the market.
- Managing possibilities for the processor and consumer are greater.
Criteria for Storing
Selection
Harvested roots are classified according to
the magnitude of their physical damage, which determines whether their destination is the
fresh root market or processing.
Categories for selecting cassava
roots
|
Category
|
Root type
|
Physical damage
|
Proportion (%)
|
A
|
Commercial
|
Little or none
|
80 to 90
|
B
|
Commercial
|
Severe
|
5 to 10
|
C
|
Non-commercial
|
With or none
|
5 to 10
|
Transport
 Fresh cassava roots are transported in bulk, crates, or sacks by different
means: on the farmer’s shoulder, animals, or vehicles. However, the rapidity
with which roots deteriorate and their great bulk means few are transported over large
distances and, if so, at great expense.
Testing
for cassava root quality
Qualities for conservation
The morphological characteristics of the roots
are taken into account, together with their form and peduncle development. These
characteristics are related to a variety’s capacity for conservation.
Root
health
During selection, roots affected by external
or internal rots should be discarded, including those with root smallpox disease, caused
by microbes transmitted through the subterranean burrower bug, which is not visible
externally.
Culinary quality
“Culinary quality” refers to the roots’ cooking time, which is closely
related to their chemical composition (especially the functional
and theological properties of starches). Understanding quality parameters involves
knowing the final destiny of the roots and what is acceptable to the consumer.
Quality
standards for conservation in terms of the cassava plant’s physico-chemical and
organoleptic characteristics
|
Organoleptic characteristics:
|
Flavorr
|
No residual bitterness in taste after cooking
|
Texture
|
100% firm
|
Color
|
Ideally white
|
Odor
|
No objectionable odors
|
Physico-chemical characteristics:
|
Percentage of cassava with root smallpox
|
Maximum of 5%
|
Percentage of dry matter
|
>35%
|
Water absorption
|
15% to 20%
|
Percentage of HCN, in raw roots
|
15 to 20 ppm, maximum
|
Percentage of HCN, after cooking
|
10 to 15 ppm, max.
|
Cooking time
|
20 min, max.
|
Microbiological characteristics
(in cfu/g):
|
Counts of aerobic mesophiles
|
<100,000
|
Total coliforms
|
<500
|
Escherichia coli
|
<10
|
Fungi and yeasts
|
<3,000
|
Psychrophiles
|
<1,000
|
Storage Techniques
Storage techniques are classified as follows:
- Traditional:
roots are left in the soil, adhered to the stems, buried in pits or ditches, or covered
with a layer of straw or mud.
- Improved
traditional: roots are left in field silos or in crates with moist sawdust.
- Prepared:
roots are chemically treated, then conserved in polyethylene bags, paraffin, or
refrigerators.
Choosing a storage technique
When choosing a storage
technique, the following characteristics should be fulfilled:
- Easy to apply and adapted to marketing channels.
- Care has been taken to prevent roots being abused, which otherwise would accelerate
physiological and microbiological deterioration.
- The quality and texture of cassava has not been altered.
- The roots can be used as quickly as possible after harvest.
- The roots have not been exposed to solar rays.
|
Rapid deterioration of roots after
harvesting is a major constraint for those who cultivate, process, market, and eat cassava
roots. The roots’ high perishability increases costs and risks, and causes
considerable losses to wholesale merchants, retailers, processors, and end consumers.
Marketing margins are high to compensate for the appreciable volume of roots that are
lost. Accordingly, techniques for storage and processing must be adopted to either
prolong the root’s useful life or generate other products.
More Information
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