Chemical composition tubers

Chemical composition of winged bean tubers grown in different countries... 

Kolbe, H., Stephan-Beckmann, S. (1997). Development, growth and chemical composition of the potato crop (Solarium tuberosum L.). II. Tuber and whole plants. Potato Res., 40, 135-153. 

Sharma, M. K., Isleib, D. R., Dexter, S. T. (1959). The influence of specific gravity and chemical composition on the hardness of potato tubers after cooking. Am. Potato J., 36, 105-112. 

Recurrent hepatitis was reported in a 5-year-old girl who had taken 3 tablets daily of shou wu pian, a product made from fo-ti tuber, for 4 months. Elevated serum levels of bilirubin and liver enzymes were observed, and viral markers were used to rule out a number of diseases. Symptoms disappeared and liver function tests were normal 1 month after cessation of the product. The girl experienced hepatitis again after being administered 2 tablets daily of the same product for 1 month (Panis et al. 2005). The product identity was confirmed by nuclear magnetic resonance analysis and showed 2,3,5,4 -tetrahydroxystilbene-2-O-P-D-glucopyranoside, a stilbene glycoside, to be the main constituent. The anthraquinone emodin was present in trace amounts (Panis et al. 2005). Such a chemical composition indicates that raw or incompletely processed fo-ti was used. 

The chemical composition of potato depends on many factors including genetic features, age and maturity, as well as enviromnental conditions, i.e., climatic and soil conditions, weather and growing conditions, such as fertilization, pesticides, diseases, etc. Table 31.1 shows the chemical composition of potato tuber. The potatoes are a considerably richer source of nutrient than energy. Starch is the basic component of potato dry matter, contributing the major amount of energy obtained by potato consumption. Potato contains... 

The chemical composition of potatoes is very variable and is greatly influenced by variety, environment, and farming practices. Starch constitutes 65-80% of the dry weight of the tuber. 

Cassava Manihot esculenta), also known as manioc, is a tropical shrubby perennial plant that produces tubers at the base of the stem. The chemical composition of these tubers varies with maturity, cultivar and growing conditions. About 80 per cent of the carbohydrate is starch, and cassava tubers are used for the production of tapioca starch for human consumption, although the tubers are also given to cattle, pigs and poidtry.The ME value of cassava is similar to that of potatoes, but it has higher dry matter and lower crude protein contents (see Table 21.1). 

Dean B B, Kolattukudy P E, Davis R W 1977 Chemical composition and ultrastructure of suberin from hollow heart tissue of potato tubers Solarium tuberosum). Plant Physiol 59 1008-1010... 

When the objects to be differentiated are very different in chemical composition, a small number ofwavelengths are sufficient. For instance, HSl was evaluated for discriminating potato tubers from clods in the field and under varying humidity conditions [106]. The objective was to select optimal wavelengths to implement... 

Starch is a semi-crystalline biopolymer used for a number of applications. It is a branched homopolymer of glucose, with a-(1 4] linear links and ce-(l 6] branched links (Sweedman et al., 2013]. It serves as a carbohydrate reserve in roots, tubers, seeds, fruits, plants, and cereals (Zavareze and Dias, 2011]. Depending on the original source of starch, the starch granule has been found to vary in size, shape, structure, and chemical composition. Amylose and amylopectin macromolecules are the prime constituents of starch. Figure 1.12 shows the schematic and chemical composition of amylose and amylopectin (Sweedman et al., 2013]. 

JaPc, D., Siroka, R, Fejes, J., Ceresn akov a, Z. (1999). Effect of three strains of Pleurotus tuber-regium (Fr.) Sing, on chemical composition and rumen fermentation of wheat straw., J. Gen. Appl. Microbiol. 6,277-282. 

Hoover, R. (2001). Composition, molecular structure, and physico-chemical properties of tuber and root starches a review. Carbohydr. Polym., 45, 255-261. 

Carbohydrates such as starch and cellulose find application in agriculture practices either as raw materials, in the form of fillers and components in composite films and sheets, or after suitable chemical modification. Starch is the major form of carbohydrate storage in green plants. It is the main component of most seeds, tubers, and roots and it is produced commercially... 

The composition and content of the different tocopherol components in plant tissue vary considerably, ranging from extremely low levels found in potato tubers to high levels found in oil seeds. a-Tocopherol is the predominant form in photosynthetic tissues and is mainly localized in plastids. The particular enrichment in the chloroplast membranes is probably related to the ability of tocopherols to quench or to scavenge reactive oxygen species and lipid peroxy radicals by physical or chemical means. In this way, the photosynthetic apparatus can be protected from oxygen toxicity and lipid peroxidation. In nonphotosynthetic tissues, 7-tocopherol frequently predominates and can be involved in the prevention of autoxidation of polyunsaturated fatty acids. 

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