Agriculture Reference
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contents than the others, while Mangochi and Salima provenances contained
significantly more potassium (
P
< 0.001) than the other provenances. The
differences are probably due to variations in soil type and climate. Mangochi
and Salima districts are situated along the lake shore (Lake Malawi) and thus
share similar rainfall patterns and soil properties, while Dedza and Mwanza are
at high altitudes.
16.4.4 Effect of processing on some physicochemical properties of
indigenous fruits
The composition of fresh pulp of
Strychnos cocculoides
and derived jams is
shown in Table 16.8 (Tembo, 2006). The results indicate that the composition
of the fresh pulp depends on several factors, such as tree age and the extent of
ripening (Krige
et al.
, 2006). For example, pre-ripe fruit pulp from middle-aged
fruit trees (10-15 years) had a significantly higher (
P
< 0.001) vitamin C
content (101.1 mg/100 g) than pre-ripe fruit pulp from young (5-9 years) and
old (>15 years) trees. The reducing sugar levels were also significantly higher
(
P
< 0.001) in pre-ripened pulp from old trees. Generally, all pre-ripe fruit pulp
had a significantly higher (
P
< 0.001) vitamin C content and significantly lower
acidity (%) than ripe fruit pulp. Very ripe fruit pulps had lower total soluble
solids, probably because of a dilution effect.
Clearly, significant variation (
P
< 0.001) exists between the composition of
fresh pulp and
Strychnos
jam. For example, ascorbic acid levels decreased
Table 16.8.
Effect of processing on some physicochemical properties of
Strychnos
cocculoides
pulp and jams.
Total
Reducing
soluble
Vitamin C
sugars
solids
Acidity
Moisture
(mg/100 g)
(%)
(%)
pH
(%)
(%)
Pulp
Young green and mature
85.5
2.90
11
18.24
1.39
73.5
Young ripe and mature
15.0
5.96
11
17.29
1.39
76.5
Mature green and mature
105.1
3.39
11
16.07
0.986
74.9
Mature ripe and mature
16.1
5.83
11
16.35
1.72
77.4
Old green and mature
34.7
3.34
11
19.39
1.035
74.7
Old ripe and mature
11.4
5.85
11
17.86
1.789
76.5
LSD
(0.05)
38.6
1.08
11
1.73
0.07
2.75
Jams
Young green and mature
7.05
14.0
11
3.30
0.39
Young ripe and mature
10.45
12.4
11
3.54
0.45
Mature green and mature
6.51
14.4
11
3.43
0.42
Mature ripe and mature
10.21
14.4
11
3.51
0.33
Old green and mature
8.50
13.2
11
3.49
0.34
Old ripe and mature
8.31
12.1
11
3.45
0.37
LSD
(0.05)
0.00
2.04
0.01
0.02
Source: Tembo (2006).
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