Composição química da casca de ramí em diversas fases do seu desenvolvimento

Medina, J. C.; Jensen, G. O.; Neri, J. P.

doi:10.1590/S0006-87051942001100001

Resumo

A study was made of the chemical composition of samples of the ribbons taken from the rami stalks at successive stages of growth with the object of determining the percentage oí lignin, cellulose, pectin, pentosans and of some substances not belonging to the cell wall. After an initial decrease, the percentage of ash increased as the plant grew and matured. The maximum (17,5%) was reached when the plant was 105 days old. The percentage of cellulose increased regularly and reached a maximum (38,2%) when the plant was 75 days old. Subsequently there was a decrease as the plant grew older. After an initial increase, the percentage of lignin decreased somewhat and again increased as the plant matured. The maximum (14,5%), however, was observed when the plant was 45 days old. The percentage of pectin (galacturonic acid) was maximum (22,9%) in the first stage, afterwards showed a nearly regular decrease as the plant developed, but in the last two stages (105 and 120 days) there was a small increase. The percentage of pentosans (calculated of the furfurol phloroglucide yielded by pentosans only, with the Tollens'Tables), as well as the percentage of reducing sugars increased regulaily as the plant grew older. The maximum was 5,2 and 3,8 percent respectively. The percentage of hot-water extractive after a decrease in the earlier stages of the plant growth increased and reached a maximum (24,2%) in the penultimate stage of its development. The percentage of ethanol-benzene extractive from a maximum (8,3%) decreased regularly as the plant developed, but in the last stages of its development it increased somewhat. The percentage of crude protein (N x 6,25) irom a maximum (15,2%) in the first stage showed a regular decrease, but in the last two stages of the plant development there was an increase.

SUMMARY

A study was made of the chemical composition of samples of the ribbons taken from the rami stalks at successive stages of growth with the object of determining the percentage oí lignin, cellulose, pectin, pentosans and of some substances not belonging to the cell wall.

After an initial decrease, the percentage of ash increased as the plant grew and matured. The maximum (17,5%) was reached when the plant was 105 days old.

The percentage of cellulose increased regularly and reached a maximum (38,2%) when the plant was 75 days old. Subsequently there was a decrease as the plant grew older.

After an initial increase, the percentage of lignin decreased somewhat and again increased as the plant matured. The maximum (14,5%), however, was observed when the plant was 45 days old.

The percentage of pectin (galacturonic acid) was maximum (22,9%) in the first stage, afterwards showed a nearly regular decrease as the plant developed, but in the last two stages (105 and 120 days) there was a small increase.

The percentage of pentosans (calculated of the furfurol phloroglucide yielded by pentosans only, with the Tollens'Tables), as well as the percentage of reducing sugars increased regulaily as the plant grew older. The maximum was 5,2 and 3,8 percent respectively.

The percentage of hot-water extractive after a decrease in the earlier stages of the plant growth increased and reached a maximum (24,2%) in the penultimate stage of its development.

The percentage of ethanol-benzene extractive from a maximum (8,3%) decreased regularly as the plant developed, but in the last stages of its development it increased somewhat.

The percentage of crude protein (N x 6,25) irom a maximum (15,2%) in the first stage showed a regular decrease, but in the last two stages of the plant development there was an increase.

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