TITLE:
Physicochemical Characterization of Nine Cassava (Manihot esculenta Crantz) Cultivars from Chad
AUTHORS:
Djirabaye Nadjiam, Nicolas Cyrille Ayessou, Aliou Guissé
KEYWORDS:
Physicochemical Constituents, Leaves, Tubers, Cultivar, Cassava, Chad
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.11 No.7,
July
29,
2020
ABSTRACT: In Chad, despite the multiple culinary uses of cassava leaves and tubers,
their nutritional values are untapped. In this study, the physicochemical
compositions and structure of nine cultivars were assessed. The proteins were
obtained by Kjeldahl’s method. Total sugars were determined according to the
Luff-Schoorl method. For starch content, the polarimetric method of Earle and
Milner was used. Mineral elements were carried out using an atomic absorption
spectrophotometry. The cyanide was evaluated by the method of Williams and
Edwards. Significant variability has been demonstrated in the leaves and dry
tubers except for water content and dry matter. Analysis of the variances of
the components of the tubers reveals that the water contents of the cultivars
vary from 5.01% to 5.86%. The ash contents vary from 4.23% (cultivar DVA2) to
8.32% (cultivar DVL2). For total sugars, the values are between 53.63% (cultivar
DVL2) and 57.99% (cultivars DVL12 and KA0303). The fiber contents are lower and
vary from 1.74% (cultivar DVL12) to 1.92% (cultivars SB1366, DVA2, TL0101 and
PG1314). The starch content varies from 28.93% (cultivar DVL12) to 31.05%
(cultivar SB1366). The variations in mineral constituents of the tubers in
mg/100g are Ca (145.21 - 250.08), Mg (83.89 - 165.22), P (147.34 - 360.78), K
(1534.50 - 3064.09), Zn (0.75 - 0.82) and Mn (0.78 - 0.89). Iron concentrations
are from 7.72 mg/100g (cultivar BA0909) to 60.62 mg/100g (cultivar DVA2). Analysis of the
variances of the leaf constituents reveals
high contents of Calcium for SB1366 (2108.41 mg/100g), of iron (Fe 54.26
mg/100g) and potassium (K 1866.86 mg/100g) for DVL12, of phosphorus for TL0101 (471.87 mg/100g), of phosphorus (470.36
mg/100g) and protein (30.74%) for
PG1314, for magnesium for DVA2 (383.41 mg/100g) and Copper for KA0303 (0.0147 mg/100g). The concentrations of
hydrocyanic acids are high in both leaves than fresh tubers (85 - 150
ppm). Lowest values are observed in tubers (10 - 15 ppm) for cultivar DVA2.
Principal component analysis of the physicochemical characteristics of the
leaves revealed four groups: the first very rich in calcium, magnesium and
average potassium contents. Groups 2 and 3 are poor in calcium and magnesium
but Group 2 has the highest potassium content while Group 3 has an
intermediate content. Group 4 is very rich in calcium but low in magnesium
and potassium. According to tubers, three
groups have been identified which are characterized by low, intermediate and high contents in phosphorus. Cultivars
SB1366, DVA2, DVL2, TL0101 and PG1314 show
promising nutritional values and chemical constituents even if some have high
levels of hydrocyanic acids. They could be recommended for the national selection
program and for various applications.