scholarly journals Changes in the Physico-chemical Properties of Peach Fruit Pectin during On-tree Ripening and Storage

1993 ◽  
Vol 118 (3) ◽  
pp. 343-349 ◽  
Author(s):  
M.L. Fishman ◽  
B. Levaj ◽  
D. Gillespie ◽  
R. Scorza
Keyword(s):  
Molecular Weight ◽  
Cell Wall ◽  
Intrinsic Viscosity ◽  
Cell Walls ◽  
Prunus Persica ◽  
Chemical Properties ◽  
Radius Of Gyration ◽  
Weight Percentage ◽  
Pectin Content ◽  
Cell Wall Polymers

Radius of gyration (size), intrinsic viscosity, molecular weight, percentage of galacturonate, and percentage of neutral sugars were measured for chelate-soluble (CSP) and alkaline-soluble (ASP) pectins extracted from the cell walls of melting flesh (MF) and nonmelting flesh (NMF) peach [Prunus persica (L.) Batsch]. Weight percentage of cell walls, pectin content, and firmness were measured also. Peaches were extracted at 20, 21, and 22 weeks after flowering (WAF) and after various lengths of shelf storage at 25 ± 2C for the peaches picked at 21 WAF. Weight percentage of cell walls and firmness decreased markedly between the 21st and 22nd WAF; and between the 3rd and 6th day of storage for MF peaches as compared to NMF peaches. During these same periods, there were marked drops in the pectin content and the uronide content for MF as compared to NMF peaches. Size and intrinsic viscosity dropped markedly for CSP of MF peaches in comparison with NMF peaches during these same periods, whereas the molecular weight of CSP and ASP increased in MF peaches over that measured for NMF peaches. These results suggested that α -D-galacturonase (E.C. 3.2.1.15) was involved in softening only in the latter stages of ripening MF peaches. Further, cell wall polymers containing long thin pectin aggregates were destroyed, whereas cell wall polymers containing short thick pectin aggregates remained.

scholarly journals The Placenta of Physcomitrium patens: Transfer Cell Wall Polymers Compared across the Three Bryophyte Groups

Diversity ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 378
Author(s):  
Jason S. Henry ◽  
Karen S. Renzaglia
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Cell Wall Composition ◽  
Transfer Cells ◽  
Primary Cell ◽  
Transfer Cell ◽  
Primary Cell Wall ◽  
Slight Variation ◽  
Wall Ingrowths ◽  
Cell Wall Polymers

Following similar studies of cell wall constituents in the placenta of Phaeoceros and Marchantia, we conducted immunogold labeling TEM studies of Physcomitrium patens to determine the composition of cell wall polymers in transfer cells on both sides of the placenta. Sixteen monoclonal antibodies were used to localize cell wall epitopes in the basal walls and wall ingrowths in this moss. In general, placental transfer cell walls of P. patens contained fewer pectins and far fewer arabinogalactan proteins AGPs than those of the hornwort and liverwort. P. patens also lacked the differential labeling that is pronounced between generations in the other bryophytes. In contrast, transfer cell walls on either side of the placenta of P. patens were relatively similar in composition, with slight variation in homogalacturonan HG pectins. Compositional similarities between wall ingrowths and primary cell walls in P. patens suggest that wall ingrowths may simply be extensions of the primary cell wall. Considerable variability in occurrence, abundance, and types of polymers among the three bryophytes and between the two generations suggested that similarity in function and morphology of cell walls does not require a common cell wall composition. We propose that the specific developmental and life history traits of these plants may provide even more important clues in understanding the basis for these differences. This study significantly builds on our knowledge of cell wall composition in bryophytes in general and in transfer cells across plants.

scholarly journals HEMICELLULOSE APPARENT MOLECULAR SIZE CHANGES DURING SOFTENING OF PEACH FRUIT

HortScience ◽  
1994 ◽  
Vol 29 (7) ◽  
pp. 737d-737
Author(s):  
Supreetha Hegde ◽  
Niels Maness
Keyword(s):  
Molecular Weight ◽  
Cell Wall ◽  
Apparent Molecular Weight ◽  
Weight Fraction ◽  
Exchange Chromatography ◽  
Size Exclusion ◽  
Neutral Sugar ◽  
Fruit Softening ◽  
Peach Fruit ◽  
Cell Wall Polymers

Peach fruit softening appears to be associated with changes in cell wall polymers, particularly pectins and hemicelluloses. To determine changes of cell wall polymers associated with peach fruit softening, we conducted sequential extractions of pectin and hemicellulose from softening fruit. A more tightly bound hemicellulose fraction contained considerable amounts of pectin associated sugars. This fraction was separated into charged and neutral fractions, using anion exchange chromatography, and then fractionated into two apparent molecular weight classes by size exclusion chromatography. Virtually all of the charged fraction eluted in the higher apparent molecular weight fraction. The neutral sugar fraction segregated into both apparent molecular weight size classes, with a redistribution from the large to the small size class during softening. This redistribution was accompanied by changes in neutral sugar composition. A possible relationship between changes in this fraction and fruit softening will be discussed. Supported by USDA grant 92-34150-7190 and the Oklahoma Agricultural Experiment Station.

scholarly journals Chilling Injury in Peaches: A Cytochemical and Ultrastructural Cell Wall Study

1992 ◽  
Vol 117 (1) ◽  
pp. 114-118 ◽  
Author(s):  
J.G. Luza ◽  
R. van Gorsel ◽  
V.S. Polito ◽  
A.A. Kader
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Prunus Persica ◽  
Periodic Acid ◽  
Chilling Injury ◽  
Middle Lamella ◽  
Wall Structure ◽  
Positive Staining ◽  
Intercellular Matrix ◽  
Parenchyma Cells

Fruits of mid- (`O'Henry'), late (`Airtime'), and extra-late-season (`Autumn Gem') peach [Prunus persica (L.) Batsch] cultivars were examined for changes in cell wall structure and cytochemistry that accompany the onset of mealiness and leatheriness of the mesocarp due to chilling injury. The peaches were stored at 10C for up to 18 days or at SC for up to 29 days. Plastic-embedded sections were stained by the Schiff's-periodic acid reaction, Calcofluor white MR2, and Coriphosphine to demonstrate total insoluble carbohydrates, ß-1,4 glucans, and pectins, respectively. Mealiness was characterized by separation of mesocarp parenchyma cells leading to increased intercellular spaces and accumulation of pectic substances in the intercellular matrix. Little structural change was apparent in the cellulosic component of the cell walls of these fruits. In leathery peaches, the mesocarp parenchyma cells collapsed, intercellular space continued to increase, and pectin-positive staining in the intercellular matrix increased greatly. In addition, the component of the cell walls that stained positively for ß-1,4 glucans became thickened relative to freshly harvested or mealy fruit. At the ultrastructural level, dissolution of the middle lamella, cell separation, irregular thickening of the primary wall, and plasmolysis of the mesocarp parenchyma cells were seen as internal breakdown progressed.

Biosynthèse des pectines et différenciation des fibres cellulosiques au cours de la croissance du lin

1989 ◽  
Vol 67 (1) ◽  
pp. 135-139 ◽  
Author(s):  
O. Morvan ◽  
A. Jauneau ◽  
C. Morvan ◽  
H. Voreux ◽  
M. Demarty
Keyword(s):  
Cell Wall ◽  
Cation Exchange ◽  
Cell Walls ◽  
Cation Exchange Capacity ◽  
Stem Elongation ◽  
Exchange Capacity ◽  
Pectin Content ◽  
Cellulose Deposition ◽  
Cellulosic Fibres ◽  
Elongation Phase

During the first stage of flax growth, stem elongation reaches 2.4 cm per day and the percentage of cell wall remains quite constant (4–15%). Cellulosic fibres develop principally during capsule formation and seed maturation. During the latter stage, the proportion of walls increases from 15 to 60% and the elongation is diminished to 0.5 cm per day. The lowering of the cation exchange capacity and of the pectin content of the cell walls during growth results principally from increased cellulose deposition in the fibre cells. The changes in the cation exchange capacity and in the percentage of cell wall show that when cellulose biosynthesis predominates, there is a continuous synthesis of pectins (10–15%) during the development of the plant. Methylated pectins are synthesized during the elongation phase. During maturation, the relative amounts of highly and less methylated pectins remain the same and thus it is not possible to determine what type of pectin is preferentially synthesized.

scholarly journals Investigations of the cell-wall substances of plants, with special reference to the chemical changes taking place during lignification

1928 ◽  
Vol 103 (725) ◽  
pp. 365-376 ◽  
Keyword(s):  
Molecular Weight ◽  
Cell Wall ◽  
Special Reference ◽  
High Molecular Weight ◽  
Cell Walls ◽  
Chemical Entity ◽  
Chemical Changes ◽  
Group Iii ◽  
Woody Tissues

As the result of various investigations, to which, reference will be given in the text of this communication, it is possible to divide the substances which accompany cellulose in the cell-walls of plants among this following groups:— (i) The lignins. (ii) The hemicelluloses. (iii) The pectins. It cannot yet be claimed that any one of the products which can be assigned to these groups has been isolated in the form of a definite chemical entity (with the exception, perhaps, of some products in group iii). There are, however, certain characteristics common to each group, to which brief reference must be made. The lignins appear to be products of high molecular weight, which can be extracted by various somewhat drastic methods from woody tissues. The products obtained by different methods vary in their properties, but they appear to give definite colour reactions with a number of reagents.

Effects of Heat Treatment and Dehydration on Pineapple (Ananas comosus L. Merr) Cell Walls

2007 ◽  
Vol 3 (2) ◽  
Author(s):  
Antoni Femenia ◽  
Susana Simal ◽  
Carme Garau Taberner ◽  
Carmen Rosselló
Keyword(s):  
Cell Wall ◽  
Functional Properties ◽  
Cell Walls ◽  
Chemical Properties ◽  
Ananas Comosus ◽  
Water Retention Capacity ◽  
Pectic Polysaccharides ◽  
Retention Capacity ◽  
Air Drying ◽  
Physico Chemical

The effects of thermal processing on the physico-chemical properties of cell walls from pineapple flesh tissues have been investigated. Commercially canned pineapple exhibited a similar cell wall composition to the fresh pineapple sample, although a marked increase in cell wall solubility, from 21 to 34%, was detected. Dehydration promoted important changes in cell wall components and related functional properties, in particular when relatively high air-drying temperatures were applied. Thus, samples dried at 60ºC and, in particular at 80ºC, exhibited a larger solubilisation/degradation of pectic polysaccharides, probably due to either ?-elimination processes or enzyme-catalyzed degradation. On a fresh weight basis, about 14% and up to 39% of cell wall pectins were not recovered for the dried pineapple at 60ºC and 80ºC, respectively. Pectins from the latter samples also exhibited a notable decrease in the degree of esterification. These physico-chemical changes were probably reflected on the decrease of functional properties such as swelling (Sw), water retention capacity (WRC) and fat adsorption capacity (FAC). Nevertheless, fresh, canned and dehydrated pineapple at 40ºC exhibited higher WRC and FAC values, about 30 g water/g AIR and 15 g oil/g AIR, respectively. A gradual decrease of Sw, WRC and FAC values was observed for the functional properties of pineapple samples dried at 60 and 80ºC. Moreover, high air-drying temperatures also promoted a significant decrease in cell wall solubility. Therefore, the influence that these effects might have on the nutritional properties of cell walls or dietary fibre of thermally processed fruits such as canned and/or dehydrated pineapple needs to be considered.

LIGHT-SCATTERING STUDIES ON ALUMINUM DISTEARATE

1958 ◽  
Vol 36 (11) ◽  
pp. 1584-1595 ◽  
Author(s):  
A. E. Leger ◽  
J. C. Hyde ◽  
H. Sheffer
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Intrinsic Viscosity ◽  
Benzene Solution ◽  
Unit Length ◽  
Random Coil ◽  
Linear Molecule ◽  
Radius Of Gyration ◽  
Average Unit ◽  
Scattering Study

A light-scattering study of aluminum distearate in dilute benzene solution suggests that it is a linear molecule of random coil shape. This is further substantiated by intrinsic viscosity – molecular weight data, the constancy of the ratio of the molecular weight to the square of the radius of gyration (Rg), the value of Φ in Flory's intrinsic viscosity – molecular weight relationship, and the close agreement between the theoretical and experimental results found for the unit length of the polymer chain. This average unit length has been calculated to be 4.46 Å.

scholarly journals Molecular Weight and Degree of Methoxylation in Cell Wall Polyuronide during Softening in Pear and Apple Fruit

1992 ◽  
Vol 117 (4) ◽  
pp. 600-606 ◽  
Author(s):  
H. Yoshioka ◽  
K. Aoba ◽  
Y. Kashimura
Keyword(s):  
Molecular Weight ◽  
Cell Wall ◽  
Cell Walls ◽  
Soluble Fraction ◽  
Apple Fruit ◽  
Water Soluble ◽  
Pear Fruit ◽  
Water Soluble Fraction ◽  
High Degree ◽  
Soluble Fractions

The concentrations of water-soluble polyuronides in apples [Malus domestica Borkh.) and pears (Pyrus communis L.) increased, but those of EDTA- and HCl-soluble polyuronides decreased during softening. Total polyuronide content decreased slightly during softening in both fruits. Depolymerization of polyuronides was observed only in the water-soluble fraction in pear fruit during softening, concomitant with an increase in polygalacturonase (PG) activity. No detectable depolymerization was observed in any of the polyuronide fractions during softening of apple fruit nor was any PG activity detected. The polyuronide fractions extracted from pear and apple cell walls contained various amounts of methoxyl groups. Polyuronides with a high degree of methoxylation were preferentially lost from EDTA- and HCl-soluble polyuronides during softening of both fruit. The water-soluble polyuronide had a lower degree of methoxylation than those lost in the EDTA- and HCl-soluble fractions. These results suggest de-esterification of polyuronides with a high degree of methoxylation rather than the depolymerization of polyuronides in the solubilization of polyuronides during ripening of apples and pears.

Sign in / Sign up

Export Citation Format

Share Document