Carotenoides com atividade pro-vitaminica A em cultivares de mandioca(Manihot esculenta Crantz) do Estado de Sao Paulo / Carotenoids with provitamin A activity in several cassava cultivars (Manihot esculenta Crantz) from Sao Paulo State

Foram analisadas raizes de quatro cultivares de mandioca (Manihot esculenta Crantz) a saber: F 2030 Pao do Ceu, IAC 352-7 Jacana e SRT 1330 Xingu. As analises visaram a identificacao dos principais carotenoides e a determinacao da atividade pro-vitaminica A presente nas mesmas. Pelo cozimento das raizes foi possivel avaliar a perda do teor vitaminico A pelo processamento termico. Os resultados das analises permitiram concluir que os principais carotenoides presentes nas raizes estudadas foram o beta-caroteno e seus isomeros neo-beta-caroteno B, beta-caroteno todo trans e neo-beta-caroteno U. Os teores de vitamina A nas mandiocas estudadas, expressos em Equivalentes de Retinol/100g, variaram de 0,33 a 55,67 para as amostras cruas e de 4,33 a 33,17 nas amostras cozidas, sendo que o cultivar IAC 352-7 Jacana foi analisado somente na forma crua por apresentar teor muito baixo de carotenoides, o que nao permitiu sua quantificacao apos o cozimento. O cozimento promoveu diminuicao da atividade pro-vitaminica A, que variou de 38,14 a 50,00%

Enrichment of nutrient quality of cassava (Manihot esculenta Crantz) with microbial proteins.

The effect of fermentation on the nutrient quality of cassava was investigated. Chemical analysis revealed a general increase in ash, fibre and crude protein content of the fermented cassava mash, while the carbohydrate content showed a substantial decrease. The results of the chemical analysis indicated that fermentation resulted in a slight protein enrichment of the fermentated cassava mash. When active yeast cells were inoculated into the cassava mash before fermentation, the yeast cells grew and generated additional cell mass which was reflected in a higher content of crude protein in the fermented cassava mash. Results obtained also revealed that 3.3% concentration of yeast cell inoculum added to cassava mash before commencement of fermentation was optimum for maximal crude protein formation.

The mutagenicity of cassava (Manihot esculenta Crantz) preparations.

Different cassava products were found to contain mutagenic activities in the Ames test. This paper describes how the flavonol quercetin is released during the cooking of fresh cassava leaves, following a process very similar to culinary habits. The hydrolysis of the glucoside(s) and the release of free quercetin has been followed by the monitoring of mutagenic activities with a simultaneous isolation and purification by thin-layer chromatography. The fluorodensitometric method applied revealed that fresh leaves contained about 1300 mg quercetin per kg wet weight, of which 800 mg were released during a normal cooking process.

Effects of tapioca obtained from cassava (Manihot utilissima) on the disintegration and dissolution rates of paracetamol tablets.

The properties of tapioca obtained from cassava (Manihot utilissima) have been evaluated. Its binding effect in tablets of paracetamol on the disintegration and dissolution rates was compared with tablets prepared with polyvinylpyrrolidone and gelatin. The nature and amount of the binders were found to alter the disintegration and dissolution rates of the tablets by reducing their wettability as measured by the adhesion tension of water. A linear relationship has been found to exist between the adhesion of water on the tablets and their disintegration and dissolution rates.

Immobilization of linamarase and its use in the determination of bound cyanide in cassava using flow injection analysis.

Extracts from the tubers (cortex and parenchyma) and leaves of Manihot esculenta Crantz (cassava) were analyzed for their releasable cyanide content using flow injection analysis incorporating an immobilized linamarase bioreactor. Linamarase was immobilized under very mild conditions to an activated 2-fluoro-N-methylpyridinium Fractogel support. The released cyanide, which was monitored spectrophotometrically at 525 nm using an alkaline picrate reagent, was found to be highest in the cortex and lowest in the parenchyma.

Effect of cyanogenic glycosides and protein content in cassava diets on hamster prenatal development.

Cassava is a staple food for 450-500 million people in 26 tropical countries. Groups of pregnant hamsters were fed diets consisting of cassava meal:laboratory chow (80:20) during Days 3-14 of gestation. One low cyanide (sweet) cassava meal and one high cyanide (bitter) cassava meal were studied. One additional group was fed a diet which resembled cassava in nutritional value, but which lacked the cyanogenic glycosides. Thiocyanate concentrations increased significantly in the urine and blood of dams fed cassava diets. Increased tissue thiocyanate concentrations were observed in fetuses recovered from cassava-fed dams. Cassava-fed dams gained significantly less weight than did control animals and their offspring showed evidence of fetotoxicity. Reduced fetal body weight and reduced ossification of sacrocaudal vertebrae, metatarsals, and sternebrae were associated with cassava diets. High cyanide cassava diets were also associated with a significant increase in the numbers of runts compared to litters from dams fed either low protein or laboratory stock diets.

Spectrophotometric determination of cyanoglucosides in cassava.

A new method is reported for determination of cyanoglucosides in cassava. The method is simple, rapid, and sensitive. Ten g cassava tuber is homogenized with warm (65-70 degrees C) 80% ethanol (1 + 6, w/v) to extract cyanoglucosides (CNG). The ethanol is evaporated, and an aliquot of the extract (0.1-0.2 mL) is incubated with added linamarase in pH 6.0 phosphate buffer for 15 min at 30 degrees C. The reaction is stopped by adding 0.2 N sodium hydroxide, the solution is neutralized, and cyanide is estimated by adding chloramine T and barbituric acid-pyridine reagent and measuring the absorbance at 570 nm. Complete CNG extraction and rapid inactivation of endogenous linamarase is possible with 80% ethanol. There is no interference from extractives in the linamarase reaction or in the estimation of cyanide. Recovery of added linamarin (as cyanide) is 98% by this assay. The minimum detection limit of cyanide in the assay is 0.1 micrograms/mL.

Mantakassa: an epidemic of spastic paraparesis associated with chronic cyanide intoxication in a cassava staple area of Mozambique. 2. Nutritional factors and hydrocyanic acid content of cassava products. Ministry of Health, Mozambique.

An outbreak of spastic paraparesis which mostly affected women and children occurred in a northern province of Mozambique in 1981. The epidemic was related to chronic cyanide intoxication associated with a diet consisting almost exclusively of cassava. A prolonged drought in the area had exhausted all food resources except cassava, especially the bitter varieties. A nutritional, toxicological and botanical investigation was carried out in two of the five districts affected. The main findings were that cyanide levels were unusually high in the cassava plant as a consequence of the drought with daily intakes estimated at 15-31.5 mg HCN. Detoxification of the bitter varieties by sun-drying was inadequate because of the general food shortage, and metabolic detoxification was probably reduced owing to the absence of sulfur-containing amino acids in the diet. The raw and dried uncooked cassava was eaten mostly by women and children. The nutritional status of the population, however, was not very poor and symptoms of advanced under-nutrition were rarely seen.

Detoxification of cassava leaves by simple traditional methods.

Cassava leaves, which usually contain large quantities of cyanogenic glycosides, were processed into a Zairian traditional vegetable sauce "Mpondu" by simple methods which included blanching (10 min), mashing and then boiling for 20-80 min. These methods enhanced the detoxification of the leaves, with blanching alone resulting in the loss of 57% of the free (non-glycosidic) cyanide content and of 60% of the bound (glycosidic) cyanide. It is presumed that losses of cyanide during these processes would be accounted for in volatile HCN, its derivatives and in the boiling water.

Cassava as a food.

This review has attempted to examine information pertaining to the role of cassava (Manihot esculenta) as a major food source for a large part of the world population, particularly the countries of South America, Africa, and Asia, where it is primarily a major source of energy for 300 to 500 million people. Its cultivation, usually on small farms with little technology, is estimated to cover on an annual basis about 11 million hectares providing about 105 million tons, more than half of which is consumed by humans. The importance of cassava as an energy source can be seen by its growing demand in the European economic community countries where it forms up to 60% of the balanced diets for swine. Cassava is one of the crops that converts the greatest amount of solar energy into soluble carbohydrates per unit of area, thus 1 kg of moisture-free cassava meal may yield up to about 3750 kcal which would mean that a yearly production of 15 tons of cassava meal per hectare would yield some 56 million kcal. The major limitations of cassava as food appear to be its poor protein content and quality and the rapid post harvest deterioration of its roots which usually prevents their storage in the fresh state for more than a few days. However, in addition to its use for culinary purposes, cassava finds application in industrial products such as an adhesive for laundry purposes, for manufacturing paper, alcohol, butanol, dextrin, adhesive tape, textile sizing, and glue.