Sweet potato properties

If amylases are to be used as tools for the detailed study of the breakdown and structure of their substrates it is obviously important to separate them from other enzymes and from other naturally associated constituents which may influence the results. It is then equally important to study the properties of the purified amylase and to supply it with the chemical environment necessary to protect it from inactivation and to enable it to act efficiently. With beta amylases this ideal has often been approached. Beta amylases from several sources have been prepared by selective inactivation of other enzymes that accompany them in nature23 and highly active products have been obtained by extensive purification.20 24-26 Balls and his associates have recently reported the crystallization of beta amylase from sweet potato.27... 

Because composition and nutritional properties of the major food legumes and oilseeds have been reported in numerous technical journals and books (listed above), the section devoted to composition and chemistry highlights lesser-known but potentially important sources of plant protein that have not received the same attention. Some of these food crops have been cultivated for many years so that they are not "new" sources. Such crops as winged bean, sweet potato, tropical seeds, fruits and leaves, yams and cucurbits are potential sources of protein in areas where they are grown. These are discussed in greater detail in the remaining five chapters. 

Gelatinization of sweet potato, tania, and yam tuber starches. Starch/Starke. 47, 298-306. Varavinit, S., Shobsngob, S., Varanyanond, W., Chinachoti, P., and Naivikul, O. (2003). Effect of amylose content on gelatinization, retrogradation and pasting properties of flours from different cultivars of Thai rice. Starch/Starke 55,410-415. 

Truong, V. D., Walter, W. M., Bett, K. L. (1998). Textural properties and sensory quality of processed sweet potatoes as affected by low temperature blanching. J. FoodScL, 63, 739-743. 

Takeda, Y., Tokunaga, N., Takeda, C., andHizukuri, S. 1986. Physicochemical properties of sweet potato starches. Starch 38 345-350. 

Property Chestnut Kuzu Com Potato Rice Sweet potato Tapioca Water chestnut Wheat... 

Chemical and physical properties of sweet potato starch." Ind. Eng. Chem., 25 565-568. 

Sorptive capacity is one of the most important properties, and it has been investigated by many authors for several varieties of starch.331-333,335,419 Sair and Fetzer,420 and also Rakowski,331-333 compared the water-retention capacities of wheat, arrowroot, and potato starch, and the results were similar. Among the following starch varieties, the sorptive capacity decreases in the order given potato > arrowroot > wheat. The order potato > corn > wheat was reported by El-Khawas et al.42] Nara el a/.407 reported the order potato > tapioca > waxy rice > sweet potato > rice Smolina422 reported the orders potato > maize > rice > wheat at low humidity and potato > rice > maize > wheat at high humidity. These orders do not agree with the order reported in Table XVII on the effect of desiccation on the water retention of starch. Based on these data, the... 

Although fungitoxlclty is the most characteristic biological property, phytoalexins may be antibacterial as well. Additionally, phytoalexins of legumes have been shown to be toxic to insects, while those from the sweet potato are poisonous to vertebrates (5J. 

This enzyme, which yields jff-maltose as the initial product, has been crystallized from barley, wheat, sweet-potato, and soya-bean extracts. The properties of these enzymes are generally similar (for example, sulf-hydryl groups are essential for activity), but are not identical (for example, the pH optimum varies between 4 and 6). The action patterns of the various -amylases appear to be identical. 

Studies performed on the etherification of potato amylose and amylopectin with (diethylamino)ethyl chloride showed that amylose in the starch granule was more reactive than amylopectin.2429 However, the relative reactivity of both starch components could be changed by physical pretreatment of the granules, for instance, by milling, heat-moisture treatment, freeze-thawing, and chemisorption. The physicochemical properties of amino starches depend on the starch variety reacted 2430 Among potato, sweet potato, rice, wheat, and tapioca starch studied, the last reacted most readily. 

Taiwo, K. A. and Baik, O. D. (2007). Effects of pre-treatments on the shrinkage and textural properties of fried sweet potatoes. LWT—Food Science and Technology, 40(4), 661-668. 

The crystal structures of tyrosinase from Streptomyces castaneoghbisporus HUT 6202 and catechol oxidase from the sweet potato Ipomoea batata have been determined. They confirm that the coordination of the type-3 copper site in tyrosinase and catechol oxidase is very similar to that found in hemocyanin. This had been deduced before from the similarity of spectroscopic properties and a comparison of many tyrosinase and hemocyanin primary structures. On the basis of the biological source of the proteins seven different domain organizations could be identified. Plant catechol oxidases of different organisms have a sequence identity of about 40-60%. The sequence identity between catechol oxidases and mulluscan hemocyanins is about 35% over almost the whole length of the sequences. In contrast, the sequence identity between plant catechol oxidases and other type-3 copper proteins from any nonplant source is limited to the two copperbinding regions. 

Uehara, K., Fujimoto, S., Taniguchi, T. and Nakai, K. (1974) Studies on violet-colored acid phosphatase of sweet potato. II. Enzymatic properties and amino acid composition. Journal of Biochemistry 75, 539-649. 

Commercially, the most important compound containing the 1,2,6 thiadiazine system is Bentazone 5, a well-known, highly active, and selective herbicide. It controls broadleaf and sage weeds and is important for weed control in soybeans, sweet potatoes, pepper, oats, and barley <1996JSH519>. The great preponderance of literature from this period has to do with the properties (biological, environmental, synergistic, etc.) of this material. 

A. Bulk Ingredients from Three Cv. of Sweet Potatoes Composition and Properties (Bovell-Benjamin et al, 2004)... 

D. Effects of pH and Concentration Times on Selected Functional Properties of a Sweet Potato Syrup (Yousif-Ibrahim et al, 2003)... 

E. Physical Properties and Sixth Graders Acceptance of an Extruded Ready-to-Eat Sweet Potato Breakfast Cereal (Dansby and BoveU-Benjamin, 2003c)... 

The sweet potato is also an important starch source in China, Vietnam, Korea and Taiwan, and the Philippines (Collado et al, 1999 Marter and Timmins, 1992). Although sweet potato may contribute essential nutrients, it is usually consumed for its sensory properties, as a substitute or supplement to corn, rice, or wheat or as the main ingredient of traditional, but infrequently consumed dishes in many developing countries (Shewry, 2003 Van Den and del Rosario, 1984). 

Sweet potato also contains the coumarins scopoletin (3, / =H), aesculetin (3, i =OH), and umbelliferone (3, J =OMe) compounds, which have anticoagulation properties and are postulated to inhibit HIV replication (Weiss and Finkelmann, 2000). The sweet potato could be considered as an excellent novel source of natural health-promoting compounds, such as anthocyanins, for the functional food market. Ultimately, this could increase utilization and demand for the crop by consumers, and the food industry. 

A. BULK INGREDIENTS EROM THREE CV. OF SWEET POTATOES COMPOSITION AND PROPERTIES (BOVELL-BENJAMIN ET AL., 2004)... 

---