Phosphates in sugarcane. / Os fosfatos na cana-de-açúcar.




The objective of the present study was to estimate total, inorganic and organic phosphate amounts in the juice of stalk segments (basal, middle and top) of three sugarcane varieties, as well as assessing the presence of myo-inositol 6-phosphate (phytic acid) in sugarcane stalks. The chemical and technological compositions of sugarcane stalks are linked to the genetic characteristics of each variety. Sugarcane stalks are composed of fiber and absolute juice. The juice contains about 25% of soluble solids, mainly sucrose. Phosphorus is an important element in agriculture, due to its participation in the photosynthetic metabolism of plants. Phosphorus is found in its mineral and organic forms in the sugarcane juice and plays a key role in the clarification and fermentation processes for the production of sugar and alcohol. Studies on phosphorus, or rather, on myo-inositol 6-phosphate (phytic acid), in cereal and leguminous grains have evidenced some anti-nutritious, antioxidant and anticarcinogenic characteristics of the phytic acid when complexed with certain cations. Basal (3/8), middle (3/8) and top (2/8) stalk segments from SP 82-3530, SP 83-5073 and RB 83-5486 sugarcane varieties were analyzed for their phosphate amounts. Only stalk segments from the variety SP 82-3530, separated in nodes and internodes, peeled or not, were analyzed for phytic acid amounts. The juice of sugarcane stalks was extracted on hydraulic press. Total P2O5 varied from 370 to 936 mg per liter of juice. The three types of phosphate showed decreasing amounts from the bottom to the top of the stalk. Organic phosphate constituted approximately 5% of total phosphate. Percentages of organic phosphate in relation to total phosphate amounts increased gradually from the basal to the top stalk segments. As phytic acid was found in insignificant amounts, the assessment of its presence was limited by the methodology used, which showed to be inappropriate.


caldo de cana-de-açúcar fosfato – teor phosphates sugarcane

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