Concentrates sweet potatoes

The literature on concentrated sweet potato protein is sparse. Amino acid patterns for sweet potato protein isolates have been reported by three groups (16, 45, 46). One report showed that when compared to the FAO standard (47), no amino acids were limiting. The other reports showed total sulfur amino acids and lysine to be limiting (Table III). The patterns indicate a nutritionally well balanced protein. The improvement in nutritional quality, when compared to amino acid patterns from whole sweet potato, is due to the fact that whole sweet potatoes contain substantial amounts of NPN, which consists mainly of nonessential amino acids. This effectively dilutes the EAA and lowers the amino acid score. 

It would appear that commercial quantities of sweet potato protein might be readily available as a by-product of the starch industry. The laboratory concentrates were bland, light-colored powders containing 80-88% protein. 

Feeding studies with the rat as the test animal verified the high nutritional quality indicated by the amino acid pattern (45). Using isolates and concentrates prepared from Jewel and Centennial cultivars, PER values were equal to that of casein (milk protein) (Table IV). Examination of the amino acid patterns of sweet potato protein and casein revealed that both contained... 

Over 2,650 plant species can produce hydrogen cyanide (Seigler 1991 Swain et al. 1992). These include edible plants such as almonds, pits from stone fruits (e.g., apricots, peaches, plums, cherries), sorghum, cassava, soybeans, spinach, lima beans, sweet potatoes, maize, millet, sugarcane, and bamboo shoots (Fiksel et al. 1981). The cyanogenic glycoside content of a foodstuff is usually expressed as the amount of cyanide released by acid hydrolysis glycoside concentrations are rarely reported (WHO 1992). 

Because concentrations of thorium in foods are very low, very few data exist. The thorium-232 content in fresh fruits, vegetables, and tea was determined (in pCi/g), and the values are listed in Table 5-1. Vegetables grown in an area of high natural activity in Brazil had the following concentrations of thorium (pg/g in dry sample) (Linsalata et al. 1987) brown beans, 0.011 potato, 0.0019 zucchini, 0.011 corn, 0.0022 carrot, 0.0074 and sweet potato, 0.0027. These authors did not observe rapid transport of thorium-232 from soil to the edible parts of the plants. 

The solubility of P-carotene in supercritical fluids has been studied extensively [81 to 85], The extraction of P-carotene from a wide varieties of natural sources has also been described like alfalfa-leaf protein concentrates [86], carrots [34,87], sweet potatoes [88], and algae [89],... 

Studies on the adsorption of Congo Red on starch803-812 have shown that potato starch does not adsorb that dye. In contrast to Acridine Orange, this dye enables determination of the amylose content in varieties of starch. The following percentages of amylose have been reported812 wheat, 23 corn, 15 rice, 16 tapioca, 16.5 sweet potato, 2.8 and potato, 1.8. These results are suspect because of the relatively low amylose concentrations reported, particularly for sweet potato and potato. 

The chemical profile of New Kawogo root latex, which is also presented in Figure 3, contained peaks for 1, 2 and 4 but also contained 3, tentatively identified as octadecyl caffeate. This compound appears to be present at much lower concentrations in the variety Tanzania. Compounds 1 and 3 have not previously been found in sweet potato and so are reported here for the first time. When the synthetic compound 2 (100% E-form) was left in solution for 3 days at room temperature a second compound appeared, eluting approximately 30 seconds earlier and with a similar mass spectrum and a UV spectrum consistent with the Z-form of coumaric acid. Thus it is presently proposed that the peak eluting in fi ont of 4 in Figure 3 is the Z-form of 4 since this peak has an identical MS to 4 and a UV spectrum consistent with the Z-form of octadecyl /7-coumarate. 

There was a significantly higher concentration of caffeic and coumaric acid esters in New Kawogo latex as compared to those found in the variety Tanzania (Figure 3). The incorporated compounds increased the mortality of 2" instar larvae significantly (Figure 4). This effect was dose-dependent. This clearly shows that the compounds are active and affect the development of Cylas weevils in sweet potato, and could account for the differences in resistance among varieties. 

Reactor configurations other than dead end or CSTR can offer improvements. In Figure 7.13, the performance of a thin channel flat membrane reactor for the hydrolysis of sweet potato by means of a-amylase is reported in terms of filtration rate and product concentration vs time plots. A comparison to Figure 7.11 shows how great the improvements due only to the change of configuration can be. At an appreciably high flow rate and product concentration level, a steady state is also attained. 

The CGTase action was evaluated on cassava starch, sweet potato starch, com starch, and waxy com starch. Substrates concentrations were at 2.5%. Enz5mie, conditions, and quantity were conducted as described above, except that aliquot samples were withdrawn periodically until 24 h. In an independent experiment, starches were gelatinized by autoclave process. The percentage of starch converted into CDs was calculated by ratio of total grams of CDs formed divided per gram of starch and multiplied per 100. 

Generally, starches contain about 20 to 30% of amylose and 70 to 80% of amylopectin, and these concentrations change with the botanical source of starch. Cassava starch, sweet potato starch, com starch, and waxy com starch showed, respectively, 17.0, 20.7, 25, and less than 1% of amylose (28,29, 30). The ratio amylose/amylopectin is an important factor to consider for CD production. The helicoidal stracture of amylose with loops of six to seven glucose imits can contribute with action of CGTase on a- and 3-CD formation (2). 

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

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