Agriculture Reference
In-Depth Information
Habitat and Distribution —
Sorghum is of African origin and is cultivated throughout the
tropical parts of the continent. It is primarily a plant of hot, semiarid tropical environments but is
quite adaptable to very harsh ecological systems. It is particularly adapted to drought due to a num-
ber of morphological and physiological characteristics, including an extensive root system, waxy
bloom on leaves that reduces water loss, and the ability to stop growth in periods of drought and
resume it when the stress is relieved. A rainfall of 500-800 mm evenly distributed over the cropping
season is normally adequate for cultivars maturing in 3-4 months. Sorghum tolerates waterlogging
and can also be grown in areas of high rainfall. It tolerates a wide range of temperatures and is
also grown widely in temperate regions and at altitudes up to 2300 m in the tropics. The optimum
temperature is 25-31°C, but temperatures as low as 21°C will not dramatically affect growth and
yield. Sterility can occur when night temperatures fall below 12-15°C during the flowering period.
Ethnomedicinal Uses —
Sorghum grain is a traditional staple food in most of tropical Africa.
It is a global grain used for the preparation of alcoholic beverages, malted drinks, and for bakery
and food purposes for which maize or wheat is used. In traditional medicine, it has various applica-
tions but usually in combination with other plants. The seed extracts are drunk to treat hepatitis,
and decoctions of twigs with lemon are used against jaundice; leaves and panicles are included in
plant mixtures for decoctions against anemia. One of the most remarkable uses of sorghum is in
the preparation of an effective hemoglobin-regenerating tonic with the stalk, especially the red
variety. For this purpose, the ground plant material is macerated with a water-alcohol mixture
with “potash” for 2 days, boiled for a few hours in an open pot, and left overnight before use. The
tonic is administered for 2 weeks with an observable effect on general health. The red pigment is
used for the treatment of various microbial and fungal infections. In Nigeria, the red sorghum dyes
were traditionally used by the Bunu, Aworo, Igbira, and Okpella people for a fabric called
abata
,
used as a funeral hanging, decorated with patterns made by thick threads added to the weft of the
fabric. The fabrics in which the dominant colors were derived from sorghum were known as
ifala
.
Sorghum is also used to provide the violet colors decorating the masks worn during certain dances
by Yoruba people in southern Benin and in southwestern Nigeria. In Côte d'Ivoire, sorghum and
other tannin-rich dyes are used in combination with mud to create the patterns of the painted cloths
produced in the Korhogo region. The dye was formerly exported to Morocco, where it was used in
the leather industry.
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Constituents —
According to the U.S. Department of Agriculture, the composition of sorghum
grain per 100 g edible portion is water 9.2 g, energy 1418 kJ (339 kcal), protein 11.3 g, fat 3.3 g,
carbohydrate 74.6 g, Ca 28 mg, P 287 mg, Fe 4.4 mg, thiamin 0.24 mg, riboflavin 0.14 mg, niacin
2.9 mg, and ascorbic acid 0 mg. The essential amino acid composition per 100 g edible portion is
tryptophan 124 mg, lysine 229 mg, methionine 169 mg, phenylalanine 546 mg, threonine 346 mg,
valine 561 mg, leucine 1491 mg, and isoleucine 433 mg. The principal fatty acids per 100 g edible
portion are as follows: linoleic acid 1305 mg, oleic acid 964 mg, and palmitic acid 407 mg. Sorghum
grain is first limiting in lysine, then in methionine and threonine. Much of the protein in sorghum
is prolamine (39-73%), which is poorly digestible, making the maximum available protein in sor-
ghum grain less than 10%. Apigenin, quercimeritrin, kaempferol glucosides, apigenidin glucosides,
apigeninidin, luteolinidin, and 7-O-methyl-luteolin-glucoside have been isolated from red sorghum
grain. The yields of some of the pigments are anthocyanidin apigeninidin (17%) and the flavonoids
luteolin (9%) and apigenin (4%). The color of the sorghums appears to be dependent on their flavo-
noid-anthocyanin content; the red/purple variety had the highest levels of 3-deoxyanthocyanidins
(8-187 µg/g), and the lemon-yellow sorghum had the highest levels of flavones (268-362 µg/g).
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Changes of the phytochemical profiles, antioxidant, α-glucosidase, and α-amylase inhibitory
activities of sorghum grain during the processes of sorghum tea production have been observed.
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Significant (
p
< 0.05) changes of TPC, TFC, and PAC contents were found in sorghum grains dur-
ing soaking, steaming, and roasting processing. Significant (
p
< 0.05) increases of ferulic (free)
and p-coumaric acid (bound) were present in sorghum on steam processing. Roasting processing
