Apple tissue

When the apple tissues were treated with enzyme preparation for liquefaction (Fig. 3), the cell-wall materials were solubilised with different yields, 95, 86, 66 and 59 % for zones B, C, D and A, respectively. The sequence was the same with the maceration treatment (use of polygalacturonase [PG] only) but the yields were lower. 

Figure 3. Solubilisation of cell.Y ll material (as AtS) when apple tissues were treated with liquefying (SP249) or maceraflng (UM10) preparations...

Janisiewicz, W.J., Conway, W.S., Brown, M.W., Sapers, G.M., Fratamico, P. and Buchanan, R.L. (1999a) Fate of Escherichia coli 0157 H7 on fresh-cut apple tissue and its potential for transmission by fruit flies . Applied and Environmental Microbiology, 65, 1-5. 

Albors, A., Salvatori, D., Andres, A., Chiralt, A., and Fito, P. 1998. Influence of the osmotic solution concentration on the structural and compositional profiles in dehydrated apple tissue. In Drying 98 (C.B. Akritis, D. Marinos-Kouris, and G.D. Saravacos, eds), Vol. A, pp. 877-885. Ziti Editions, Thessaloniki, Greece. 

Barat, J.M., Albors, A., Chiralt, A., and Fito, P. 1999. Equilibration of apple tissue in osmotic dehydration. Microstructural changes. Drying Technol. 17, 1375-1386. 

In normal apple tissue the intercellular spaces are ordinarily filled with air. However, in watercore-affected tissue, the air is replaced by water (or more... 

Mealiness in apples results from a breakdown in adhesion between cells so that chewing the apple tissue results in cell separation rather than cell rupture. Eating a mealy apple is therefore associated with the unpleasant sensory perception of a lack of juiciness, loss of crispness and hardness. A number of studies have succeeded in correlating the degree of mealiness with destructive reference tests such as the Magness-Taylor firmness and confined compression juiciness, but clearly there is a need for non-destructive, on-line detection of mealiness in apples. 

The Ti q) behave as wavevector-dependent relaxation times and the form of the wavevector dependence can provide a useful check on the consistency of models. Table 5 shows a comparison of the experimental coefficients for fresh apple tissue with those calculated with the numerical cell model. The agreement is quite reasonable and supports the general theoretical framework. It would be interesting to apply this approach to mealy apple and to other types of fruit and vegetable. 

Figure E3.1.2 (A) Hand-cut section from fresh apple tissue stained with phloroglucinol/HCl. Cell walls of the xylem tracheary elements (spirals) are stained red indicating they are lignified. (B) Increased magnification of A. (C) Hand-cut section from fresh pear tissue stained with phloroglucinol/HCl solution. Walls of the sclereid cells (stone cells center) are stained red indicating they are lignified. This black and white facsimile of the figure is intended only as a placeholder for full-color version of figure go to http //www.currentprotocols.com/colorfigures...

Figure 1. Over-all relation between softening of irradiated apple tissues as measured by crushing load and degradar tion of tissue pectins and cellulose as measured by changes in viscosity (13)...

Lieberman, M., Kunishi, A., Mapson, L.W., Wardale, D.A. (1966). Stimulation of ethylene production in apple tissue slices by methionine. Plant Physiol. 41, 376-382. 

In recent studies protoplasts prepared from apple tissue did not produce ethylene. The loss of ethylene-producing ability by tissue slices incubated in cell wall-digesting enzymes during preparation of protoplasts is shown in Fig. 9. Methionine, the precursor of ethylene, delayed the loss of ethylene production somewhat during preparation of the protoplasts. 

Figure 4. Influence of JAA, GA, cytokinin (IFA), and ABA, alone and in combinations, on ethylene production of pre-climateric, climacteric, and post-climateric apple tissue slices...

Electrolytes affect dispersed polysaccharides through water inactivation, specific ion binding, and polyanion neutralization. Each effect is valence-dependent, but is less on neutral polysaccharides than on ionic polysaccharides. Di- and polyvalent cations gel or precipitate a constant amount of polysacchride at much lower concentrations than do monovalent cations. The precipitation reaction is used to advantage in isolating pectin with alkaline Al3+, because this cation and polymeric forms of Al(OH)3 readily precipitate and entrain pectinic acid from apple tissue homogenates. Other di- and polyvalent cation effects are crosslinking (Prud homme et al., 1989) and an increased rate of (3 elimination over monovalent cations (Sajjaanan-... 

The determination of sugars in fruits and other materials involves extraction of the sample with 80% ethanol, transfer of sugars into an aqueous phase with the aid of a chloroform—methanol—water system (64 32 24) and drying. The analysis is carried out on SE-54 or SE-52 stationary phase after silylation [424,425]. The concentrations of monosaccharides can similarly be determined in the course of a fermentation process [426] and, after hydrolysis, also in polysaccharides from cellular walls and apple tissues [427,428]. SE-30 served as a stationary phase for these analyses. 

Mattoo, A.K., and Lieberman, M., 1977, Localization of the ethylene-synthesizing system in apple tissue. Plant Physiol. 60 794-799. 

Ishii and Yokotsuka recently used pectin lyases from Aspergillus sojae 170, 171, 172) and Aspergillus japonicus (173) for the enzymatic clarification of fruit juices. This is discussed later in this review. Bush and Codner 174) compared the pectin lyases produced by Penicillium digi-tatum and Penicillium italicum and found them remarkably similar. Both were endo acting, had optimal activities at pH 5.5, and had the same K. The pectin lyase from F. italicum, however, was less stable than that of F. digitatum. Spalding and Abdul-Baki 175) reported the production of a pectin lyase by Penicillium expansum growing on apple tissue or a pectin-polypectate mixture. 

Research why apple tissues turn brown in the presence of air. 

Usually, donor and acceptor functions are located at different ring carbon atoms, but there are also examples in which both functions are linked to the same atom. The most prominent compound of this type is 1-aminocyclopropanecarboxylic acid (ACC, 6), a naturally occurring amino acid which is the precursor of the fruit-ripening hormone ethene. In fruit tissues, such as apple tissue, this amino acid is oxidized to ethene, carbon dioxide and hydrogen cyanide by the enzyme ACC oxidase, also known as ethene-forming enzyme (EFE). This reaction has been studied in detail. ... 

Another defect, which is more difficult to detect than bruises, is bitter pit this appears as a subsurface necrosis of apple tissues, as spots of 2-5 mm diameter. Bitter pit appears as white spots in NIR images, as do old bruises showing dehydration (see Figure 8.7). 

Most recently these ideas have been combined with a numerical cell model to relate S(q, A, r) to cell structure in plant parenchyma tissue.143 Using PGSE data for apple tissue a value for the plasmalemma membrane permeability was estimated. The application of this numerical cell model to mammalian tissue might enable quantitative interpretation of diffusion weighted contrast in clinical MRI. Table 6 lists a number of other applications of the PGSE method to food-related materials, although few of these studies have attempted to explore systematically the whole of the three-dimensional q—A—r space. 

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