15
2. Cassava Property of Deterioration
One of the major constraints in the utilization of cassava is the rapid perishability of the tubers after harvest. Biochemical changes and microbial
infestation spoil the tubers and make them unfit for consumption. This very often poses problems as the transportation over very long distances to the processing
sites leads to the deterioration in the quality of the tubers. According to Brautlecht 1953, two types of deterioration have been
reported in the case of cassava. The primary deterioration manifested as blue- black streaks which become more intensive towards the periphery of the cortex
has been described. Secondary, deterioration is caused by invading pathogens. The vascular streaking phenomena is initially of a blue or blue-black color later
turning brown in the form of vascular streaks which can be clearly seen in longitudinal sections of the roots. The changes in color spread to parenchymal
cells which turn to a bluish color. The biochemical nature of spoilage of tubers have been investigated in detail Table 6.
Rapid reduction in starch and moisture, and increases in sugar content were observed during the course of deterioration of tubers after harvest.
Involvement of enzymes like cellulases, amylases, and pectinases have also been recorded during the course of spoilage of cassava tubers. Both cellular and extra-
cellular enzymes in harmony participated in the deterioration of cassava after harvest.
Table 6 Biochemical change during deterioration of fresh cassava
Period of storage days Constituents
Variety 1
2 3
4 5
6 7
H-1687 38.4
38.4 36.4
35.2 34.8
34.4 31.6
30.0 Dry matter
H-2304 41.6
40.4 38.4
38.4 38.0
38.4 38.0
35.2 H-1687
28.3 27.3
24.0 24.0
24.7 22.7
23.3 23.3
Starch g100g fresh weight
H-2304 29.2
29.2 28.3
24.7 24.7
24.0 24.0
24.0 H-1687
0.70 0.80
0.89 0.80
0.95 1.05
1.10 1.31
Sugar g100g fresh weight
H-2304 0.59
0.59 0.65
0.87 0.95
1.00 1.05
1.05 H-1687
90 90
45 30
38 60
30 30
HCN rngg dry weight
H-2304 60
60 45
30 30
45 30
23
Source: Brautlecht 1953
16
3. Tapioca Starch Properties
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