Preparation from potatoes

Electrolyte leakage. Tissue discs, prepared from potato tubers as described above, were incubated for 16 h at 25°C between wet filter papers. After incubation, the discs were shaken in 20 ml H2O for another 60 min. One ml of this extract was diluted 30-fold with water, and subjected to conductivity measurements using a HI 8788 apparatus (Hanna Instruments). An increase in conductivity indicates a leakage of electrolytes through lesions in the cell wall caused by enzyme action. Control samples were not incubated, they were shaken in water only. 

Another way that P(l,2)-linked xylose can be removed from plant proteins involves the use of P(l,2)-xylosidase. This is a degradative enzyme that is easily prepared from potatoes. If the 3-position of this maimose is not occupied, P(l,2)-xylosidase releases xylose residues that are P(l,2)-linked to the heta-mannose of an A-glycan core. This techiuque can also be applied to plant-derived therapeutic glycoproteins to remove potential immunogenic epitopes (Lerouge et al., 1998). 

Enzymes of the peroxidase-type which use hydrogen peroxide as the oxidizing species, are capable of performing oxidative coupling of phenolic alkaloids (16). The commercially available horseradish peroxidase as well as peroxidase preparations from potatoes and other sources have been used in conjunction with hydrogen peroxide to perform these transformations. The... 

Scientists are making biodegradable plastic from garbage. Lactic add can be prepared from potato peels or whey. The lactic acid can then be polymerized to produce the plastic polylactic add, which can be broken down by microorganisms. 

As an illustration of SLS, in what follows, we give some interesting examples of the application of this technique to study the structure of complex systems. Figure 18.8 shows the experimental results of Galinsky and Burchard [44] on the determination of P 6) for a collection of seven samples of branched macromolecules in a solution of 0.5 N NaOH, prepared from potato starch by controlled acid degradation. Previously, Burchard [45] had derived a form factor for trifunctional polycondensation model without excluded volume effects, namely. 

Most PPO preparations from potato, apple, mushroom, and bean possess both monophenol and diphenol oxidase activities, whereas those from tea leaf, tobacco, mango, banana, pear, peach, and sweet cherry have been reported not to act on monohydroxyphenols [28]. Whether a single enzyme system exhibits both mono- and diphenol oxidase activities is still unclear. It was suggested that both cresolase and catecholase functions are catalyzed by a single site. Verdedoncella apple PPO showed both monophenol and diphenol oxidase activities with a reaction mechanism involving one... 

BONIWELL, J.M., BUTT, V.S., Flavin Nucleotide-Dependent 3-Hydroxylation of 4-Hydroxyphenylpropanoid Carboxylic-Acids by Particulate Preparations from Potato-Tubers, Z Naturforsch. Sect. C, 1986, 41, 56-60. 

Still more recent work by the same authors has suggested an alternative possibility. It has been generally assumed that L-ascorbic acid has no effect on the polyphenolase system other than its effect as a reducing agent for the o-quinone formed by the oxidation of the phenols. It has now been shown that ascorbic acid itself has an inhibitory action on the polyphenolase enzyme. When polyphenolase prepared from potato was treated with ascorbic acid under anaerobic conditions, and the ascorbic acid subsequently removed by dialysis, the activity of the enzyme was very considerably reduced. The enzyme after such treatment could not be reactivated by the addition of cupric salts and appeared to bo irreversibly inactivated. It was also shown that neither dehydroascorbic acid nor the further oxidation products of dehydroascorbic acid were responsible for this result. There is at present no explanation of the mechanism of this inhibitory action of ascorbic acid, but it is quite clear that, if these results are confirmed, other explanations are possible of why these enzymes do not exert their full potential effect in vivo. 

Amylum Mixed amylose and amylopectin Amylose content 15-25 % Amylopectin content 75-80 % n = 100-2000 Prepared from potato and com 0.5-3 % water solution boiled, NaOH, soda... 

Li W, Chen M, Wang C (2011) Spherical hard carbon prepared from potato starch using as anode material for Li-ion batteries. Mater Lett 65 3368-3370... 

Traditionally, carotenoid standards are prepared in each laboratory using the best sources of each individual carotenoid, for example, violaxanthin from spinach, antheraxanthin from potatoes, capsanthin and capsorubin from paprika, a- and P-carotene from carrots, and lycopene from tomatoes. 

Figure 2. Cells liberated from potato tuber tissue by the jErw/n/a isoenzyme PL3. Scanning electron micrograph taken after air-drying of the preparation on the support.

Walter et al. (38) measured the protein efficiency ratio (PER) of flour prepared from sweet potatoes which were cooked in a drying oven. Because the PER is determined on the basis of a diet containing 10% protein, the Jewel and Centennial sweet potatoes used in this study were stored until sufficient starch had metabolized to increase crude protein content to 11.25% (dry basis). When the flour was fed to Sprague-Dawley strain rats, the corrected PER values were 2.22 and 2.00 for Centennial and Jewel cultivars, respectively, compared to 2.50 for casein. Centennial had the highest PER value of the two cultivars because its NPN content was lower. The net effect of increased NPN content is to lower the amount of essential amino acids as a percentage of the total nitrogen and thus decrease the PER value. 

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... 

Figure 3. Dehydrated Flakes Prepared from Fresh Peeled Yam Tubers by the SRRC-Sweet Potato Flaking Process.

Sas-Piotrowska, B., Aniszewski, T. and Gulewicz, K. 1996. An evidence for fungistatic activity of some preparations from alkaloid-rich lupin seedy on potato pathogenic fungi. Bulletin of the Polish Academy of Sciences. Biological Sciences, 44(1-2) 42 7. 

The fact that glycogen phosphorylase can be used to polymerize amylose was first demonstrated by Schaffner and Specht [110] in 1938 using yeast phosphorylase. Shortly after, the same behavior was also observed for other phosphorylases from yeast by Kiessling [111, 112], muscles by Cori et al. [113], pea seeds [114] and potatoes by Hanes [115], and preparations from liver by Ostern and Holmes [116], Cori et al. [117] and Ostern et al. [118]. These results opened up the field of enzymatic polymerizations of amylose using glucose-1-phosphate as monomer, and can be considered the first experiments ever to synthesize biological macromolecules in vitro. 

Examination of moist, isolated potato cell walls using atomic force microscopy (AFM) showed the cellulose microfibrils as an interwoven network (Kirby et al., 1996,2006). Although accurate height measurements of cellulose microfibrils have not been obtained using AFM on potato cell walls, they have on similar parenchyma cell-wall preparations from onion (Allium cepa) and Arabidopsis thaliana (Davies and Harris, 2003). These studies showed that the microfibrils were 4-6 nm in diameter, and reduced to 3.2 nm (A. thaliana) when extracted to remove some of the non-cellulosic polysaccharides. 

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