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Developmental and ripening-related effects on cell wall of apricot (Prunus armeniaca) fruit
Abstract
Alcohol-insoluble residues (AIRs) were prepared from apricots at six stages during development/ripening on the tree. To investigate the changes in cell wall polymers, and in particular those affecting pectic polysaccharides, the AIR preparations were sequentially extracted with water, cyclohexane-trans-1,2-diamine-N,N,N′,N′-tetraacetate (CDTA) and Na2CO3. A significant proportion of initially Na2CO3-soluble pectic polysaccharides became water- and CDTA-soluble during the ripening process. In terms of composition, a significant decrease in galactose and uronic acid content was detected in all the extractions, whereas the percentage of arabinose increased in both water and CDTA-soluble polymers but decreased in the Na2CO3-extracted polysaccharides. The ability of pectic polysaccharides to cross-link was diminished during ripening due to an overall increase in the concentration of Na+ or K+ associated with the AIRs. This was accompanied by a decrease in the amounts of Ca2+ and Mg2+. The decrease in pectic galactans and the inhibition of pectin cross-linking detected within the pectic backbone are probably linked to the softening process observed during apricot ripening. © 1998 SCI.
... mg g −1 FW) and lower than obtained cell wall yields (30.5-52.4 mg g −1 ) for Canino apricot variety (Femenia et al., 1998). The compositions of the AIS (Table 1) were characterised by high amounts of uronic acid (179 -300 mg g −1 AIS). ...
... This result was in line with previous studies: Ella Missang et al. (2012) report that for all nine fresh tissues, uronic acids (268-338 mg g −1 AIS) from pectin was the predominant sugar, followed by glucose (197-217 mg g −1 AIS). Lahaye et al. (2014) and Femenia et al. (1998) describe that glucose and uronic acid as the main monosaccharides in apricot AIS. Arabinose, galactose, commonly found in pectin side-chains, and mannose, which is a hemicellulose sugar (mannan), were all present in higher concentrations than reported by previous studies (Ella Missang et al., 2012;Lahaye et al., 2014). ...
... The presence of fucose, in addition to relatively high amounts of xylose, suggested the presence of hemicelluloses composed of xyloglucan polymers as found recently in apricot (Liu et al., 2017) and in other Prunus species, such as plum (Nunes et al., 2008;Renard and Ginies, 2009) or peach (Brummell et al., 2004;Yoshioka et al., 2011). This monosaccharide was in the ranges reported by other authors (Femenia et al., 1998;Ella Missang et al., 2012;Lahaye et al., 2014) but lower than in Kurz et al. (2008). Recently, in other fruit specie, Ren et al. (2020) report that glucose was the most abundant component followed by arabinose and galactose in composition of cell-wall polysaccharides of custard apple (Annona squamosal). ...
The changes of texture and cell wall characteristics of apricot were investigated in ten clones at two maturity stages. Fruit firmness, cell wall composition and enzyme activity of three apricot flesh zones were analysed. The AIS (alcohol-insoluble solids) were characterised by high amounts of uronic acid (179-300 mg g-1 AIS) and relatively high amounts of cellulosic glucose (118-214 mg g-1 AIS). The methylesterification degree varied significantly among the different clones ranging from 58 to 97 in Ab 5 and Mans 15 respectively. Conversely to zones firmness, enzymatic activity was higher in pistil followed by equatorial and peduncle zones. The ripening effect has been observed in firmness evolution according to enzymatic activity. This correlation allowed a classification of clones depending on softening. Among studied clones, Ab 5, Marouch 16, Mans 15 and Cg 2 were less influenced by softening and have the advantage of a technological valorisation for the processing industry.
... Fruits 'Jinhong' apricot (Prunus armeniaca L.) fruits were harvested in an orchard in Zhengzhou, Henan Province, China, and transported to the laboratory within 2 h. Only fruits with medium size at firm ripe (mature with change of peel color, about 1 week before fully ripe) of ripening stage with similar color and stalks were chosen for the experiment [20]. The firmness was 9.74 ± 3.50 N (n = 10). ...
... This is related to reducedcarboxyl-based cross-linking sites, which were destroyed gradually during fruit softening because of action of pectindegrading enzymes, resulting in deceased branches [24]. Our result was consistent with a previous report [20]. ...
... During ripening, pectin modifications cause fruit softening and firmness decreasing due to pectin solubilization and hydrolysis of fruit cell wall. At least two enzymes are involved in this process: polygalacturonase (PG) and pectin methylesterase (PME) [20]. Pectin methylesterase (PME) activity of apricot fruits changes in response to different postharvest treatments [2]. ...
Firmness is one of the most important quality attributes of apricot fruits and is associated with chelatesoluble pectin (CSP). To elucidate the changes in CSP during postharvest, in vitro investigation of pectinase effects on CSP of apricot fruits was applied to simulate the in vivo changes in CSP fraction during postharvest. It was found that effects of pectinase (40 U/mg) treatment were similar to those of storage time on CSP nanostructures from the results of atomic force microscopy. Relative frequency of widths less than 31.25 nm was 3.6 % for control group, while it was 16.2, 52.0 and 65.5 %, respectively, for 1:10,000 (pectinase/CSP), 1:1,000 and 1:100 pectinasetreated groups. Most of the CSP lengths were 0.5–1 μm, while it was 0–1 μm for pectinase-treated groups. Pectinase treatment had some similar effects on CSP fraction as storage time
... Fruits 'Jinhong' apricot (Prunus armeniaca L.) fruits were harvested in an orchard in Zhengzhou, Henan Province, China, and transported to the laboratory within 2 h. Only fruits with medium size at firm ripe (mature with change of peel color, about 1 week before fully ripe) of ripening stage with similar color and stalks were chosen for the experiment [20]. The firmness was 9.74 ± 3.50 N (n = 10). ...
... This is related to reducedcarboxyl-based cross-linking sites, which were destroyed gradually during fruit softening because of action of pectindegrading enzymes, resulting in deceased branches [24]. Our result was consistent with a previous report [20]. ...
... During ripening, pectin modifications cause fruit softening and firmness decreasing due to pectin solubilization and hydrolysis of fruit cell wall. At least two enzymes are involved in this process: polygalacturonase (PG) and pectin methylesterase (PME) [20]. Pectin methylesterase (PME) activity of apricot fruits changes in response to different postharvest treatments [2]. ...
Firmness is one of the most important quality attributes of apricot fruits and is associated with chelate-soluble pectin (CSP). To elucidate the changes in CSP during postharvest, in vitro investigation of pectinase effects on CSP of apricot fruits was applied to simulate the in vivo changes in CSP fraction during postharvest. It was found that effects of pectinase (40 U/mg) treatment were similar to those of storage time on CSP nanostructures from the results of atomic force microscopy. Relative frequency of widths less than 31.25 nm was 3.6 % for control group, while it was 16.2, 52.0 and 65.5 %, respectively, for 1:10,000 (pectinase/CSP), 1:1,000 and 1:100 pectinase-treated groups. Most of the CSP lengths were 0.5–1 μm, while it was 0–1 μm for pectinase-treated groups. Pectinase treatment had some similar effects on CSP fraction as storage time.
... Pectin solubilisation during fruit maturation and ripening has been shown in apricot (Bouranis and Niavis, 1992). The amount of tightly bound pectin was reduced and more pectin became loosely bound during maturation and ripening of fruit on the tree (Bouranis and Niavis, 1992;Femenia et al., 1998). Firmness at harvest correlated strongly with water-soluble pectin content (Missang et al., 2012). ...
... Firmness at harvest correlated strongly with water-soluble pectin content (Missang et al., 2012). Galactose and uronic acid (UA) content decreased during maturation for all cell wall fractions, whereas the proportion of arabinose increased in the water-and CDTA-soluble fractions and decreased in the Na 2 CO 3 -soluble fraction (Femenia et al., 1998), suggesting that decline in cell wall strength and cell-to-cell adhesion associated with apricot fruit ripening were linked to the structural changes in the pectic polysaccharides (Femenia et al., 1999). The cell wall enzyme -galactosidase was related to maturity stage at harvest (Kovacs and Nemeth-Szerdahelyi, 2002), and increased as fruit matured on the tree (Kovacs et al., 2008). ...
... Abbreviations: CDTA, trans-1,2-cyclohexanediaminetetraacetic acid; LR, linear regression; FW, fresh weight; M1, Maturity 1; M2, Maturity 2; M3, Maturity 3; UA, uronic acid; wks, weeks. Femenia et al., 1998). Soluble pectins increased during ripening and storage in plums (Taylor et al., 1995), although they were not affected by maturity at harvest, unlike our results for apricots. ...
... Fruit cell wall polysaccharides extracted sequentially with water, chelator, and alkaline were good resources to study the modifications of pectin polysaccharides of fruits (Femenia, Sánchez, Simal, & Rosselló, 1998;Kirby, Ng, Waldron, & Morris, 2006;Lara, García, & Vendrell, 2004;Yang, An, Feng, Li, & Lai, 2005;Yang, Feng, An, & Li, 2006;Yang, Lai, An, & Li, 2006;Zhang et al., 2008). Chelate-soluble pectin (CSP) is considered ionically-bound pectin. ...
... CSP content increased from 5.65 at harvest to 10.33, 10.84 and 8.89 mg/100 g À1 FM for control, 1% CaCl 2 group, and 3% CaCl 2 group, respectively, on day 42 of storage (Fig. 1B). The result was similar to the report by Femenia, Sánchez, Simal, and Rosselló (1998). CSP content of 1% CaCl 2 treated fruit was higher at late stage (days 24-42). ...
... 3A and 4A, E, I. At the last period of storage, only about 18% of the pectin chains showed branching structures in all the three groups, which was supported by the result of Femenia, Sánchez, Simal, and Rosselló (1998). The reason was that, as the fruit softened, carboxyl-based crosslinking sites were destroyed gradually due to the action of pectin degrading enzymes, which resulted in the deceased branches (Cosgrove, 2005). ...
The effects of calcium and storage time on physicochemical properties and nanostructure of chelate-soluble pectin (CSP) of apricots (Prunus armeniaca L.) at 0 °C were investigated. During the storage, the firmness did not change with the contents but consistent with the morphology changes of CSP, which were characterized by atomic force microscopy (AFM). The branching structures of CSP decreased, meanwhile, the frequencies of chains with small width (<35 nm) and lengths (<500 nm) of CSP chains increased, which showed more in the control group than in the 1% calcium treated group. Compared to the control and 3% calcium treated groups, treatment with 1% calcium delayed the changes of physicochemical properties and degradation of the depolymerization of CSP during the fruit softening. The results provided us with a way to investigate the quality indexes from structural studies of nanoscale.
... Au cours du pressurage, à cause de leur solubilité, elles sont partiellement entrainées dans les jus en quantité variable selon l'état de maturité du fruit. En effet, la teneur en pectines solubles augmente au cours de la maturation, ce qui s'accompagne d'une dépolymérisation (Femenia, Sanchez et al., 1998;Duan, Cheng et al., 2008) Les pectines sont un ensemble de polysaccharides plus ou moins ramifiés caractérisés par un squelette constitué de résidus d'acide -D-galacturonique avec des faibles proportions de -L-rhamnose ( Figure 35). Les oses neutres sont concentrés dans des blocs hautement ramifiés où la chaîne principale est riche en -L-rhamnose (Voragen, Thibault et al., 1995;Ridley, O'Neill et al., 2001). ...
... Une autre hypothèse pouvant expliquer ce phénomène serait l'augmentation de matière sèche, notamment de la teneur en pectine qui freinerait l'extraction. En effet, de Prune nombreuses études sur la maturation des fruits ont montré une augmentation de la teneur en pectines solubles au cours de la maturation (Femenia, Sanchez et al., 1998;Duan, Cheng et al., 2008). ...
Le procédé innovant d’hydrodiffusion par micro-onde a été testé et validé pour la fabrication de jus de fruit sur des raisins, abricots et prunes. Ce procédé présente des avantages au niveau technique : rapidité d’extraction, pas de préparation de l’échantillon, aucun auxiliaire de fabrication. Il permet l’obtention de jus à partir de fruits difficiles à presser, avec une pasteurisation « in line » et des produits se différenciant nettement des jus commerciaux par leur couleur et texture.Le jus est expulsé du fruit sous l’effet de la vapeur produite in situ. A partir du fruit congelé, la déstructuration liée à la croissance des cristaux de glace facilite l’extraction. Les rendements le plus élevés sont obtenus à partir de fruits congelés, et à basse puissance. Une partie de l’eau des fruits est convertie en vapeur, mais peut être récupérée en utilisant un réfrigérant, ce qui permet d’atteindre des rendements proches des rendements de jus obtenus avec un prétraitement enzymatique et pressurage. Globalement, le jus a une composition proche de celle du jus présent dans le fruit ou obtenus par pressurage. La composition du jus expulsé des fruits change au cours de l’extraction. La concentration des composés présents dans la chair et hydrosolubles (sucres, acides, acides phénoliques) baisse nettement en fin d’extraction, tandis que les anthocyanes, présentes dans l’épiderme des raisins ou des prunes, montrent un pic de concentration lors de la phase d’expulsion rapide des jus. La teneur en procyanidines est nettement plus élevée que pour des jus obtenus par pressurage.
... As described previously, during the Prunus fruit ripening process, the middle lamella dissolves, cells collapse, and cell walls break down due to pectin and hemicelluloses depolymerization and solubilization, reducing polymer length, branch amounts, and aggregate sizes [132]. The increase in water-soluble pectin and the decrease in insoluble pectin methyl-esterification and cell wall galactose content lead to the loss of cohesion of pectin gel matrix, cell wall dissolution, and cell separation by the combined action of PG, PME, and β-GAL in the middle lamella. ...
... As a consequence, these changes affect the calcium-mediated cell-cell adhesion and contribute to softening. EXP induces plant cell enlargement by disrupting non-covalent linkages such as hydrogen bonds between cellulose and hemicellulose without any cell wall hydrolytic activity, and it seems to be down-regulated by ethylene in apricot fruits [120,[132][133][134][135]. ...
In plants, fruit ripening is a coordinated developmental process that requires the change in expression of hundreds to thousands of genes to modify many biochemical and physiological signal cascades such as carbohydrate and organic acid metabolism, cell wall restructuring, ethylene production, stress response, and organoleptic compound formation. In Prunus species (including peaches, apricots, plums, and cherries), fruit ripening leads to the breakdown of complex carbohydrates into sugars, fruit firmness reductions (softening by cell wall degradation and cuticle properties alteration), color changes (loss of green color by chlorophylls degradation and increase in non-photosynthetic pigments like anthocyanins and carotenoids), acidity decreases, and aroma increases (the production and release of organic volatile compounds). Actually, the level of information of molecular events at the transcriptional, biochemical, hormonal, and metabolite levels underlying ripening in Prunus fruits has increased considerably. However, we still poorly understand the molecular switch that occurs during the transition from unripe to ripe fruits. The objective of this review was to analyze of the molecular bases of fruit quality in Prunus species through an integrated metabolic, genomic, transcriptomic, and epigenetic approach to better understand the molecular switch involved in the ripening process with important consequences from a breeding point of view.
... The difference could be due to factors affecting fruit quality such as year with specific pedoclimatic conditions or agricultural practices or the used of different analytical methods that introduce some variations in the content of extracted components (Myhara, Al-Alawi, Karkalas, & Taylor, 2000;Gribba et al., 2013;Shafiei, Karimi, & Taherzadeh, 2010;Mustafa, Harper, & Johnston, 1986). Date palm fruits were richer in AIS content than other fruits like apple parenchyma, i.e. 17 mg/g to 25 mg/g FW (Le Bourvellec et al., 2011), pear parenchyma, i.e. 28 mg/g FW (Le Bourvellec et al., 2013) and apricot parenchyma, i.e. 30.5 mg/g FW (Femenia, Sánchez, Simal, & Rosselló, 1998a;1998b), but contained less than fig flesh cell, i.e. 110-160 mg/g FW (Trad, Ginies, Gaaliche, Renard, & Mars, 2014). ...
... In our experiment, AIS contents varied with the year and were statistically lower in 2018 than in 2017 (Table 1). However, storage time had no effect on AIS yield content meaning that cell wall contents were stable over time whatever the temperature (Table 1), in contrast to other fruits where cell walls contents change considerably during storage (Chen et al., 2015;Femenia et al., 1998aFemenia et al., , 1998bMurayama et al., 2002;Kim, Solomos, & Gross, 1999). ...
The aim of this study was to identify optimal storage conditions able to preserving date palm quality and minimising their loss in the supply chain. Hence, the effect of storage at −18, 0, 2 and 4 °C for 3, 6 and 9 months during two harvest seasons (2017 and 2018) on sugars, organic acids, polyphenols and cell wall yields and composition of ‘Deglet Nour’ Tunisian dates, were studied. Mid Infrared Spectroscopy (MIR) as a non-targeted method allowed to highlight a year effect on chemical composition and to discriminate samples stored at 4 and 2 °C regarding to major components (moisture, sugars, organic acids.). Cell wall yields were stable during the time. However, galactose from pectin side chains decreased with time, causing an increase of lignin, cellulosic glucose, fucose and rhamnose. Procyanidins, accounting for 98% of total polyphenols, were not affected by storage. Regarding quality parameters stability, stored fruits at −18 °C could be the solution for a long term storage but due to its high energetic costs, 2 °C must be the optimal temperature with a lower time.
... Au cours du pressurage, à cause de leur solubilité, elles sont partiellement entrainées dans les jus en quantité variable selon l'état de maturité du fruit. En effet, la teneur en pectines solubles augmente au cours de la maturation, ce qui s'accompagne d'une dépolymérisation (Femenia, Sanchez et al., 1998;Duan, Cheng et al., 2008) Les pectines sont un ensemble de polysaccharides plus ou moins ramifiés caractérisés par un squelette constitué de résidus d'acide -D-galacturonique avec des faibles proportions de -L-rhamnose ( Figure 35). Les oses neutres sont concentrés dans des blocs hautement ramifiés où la chaîne principale est riche en -L-rhamnose (Voragen, Thibault et al., 1995;Ridley, O'Neill et al., 2001). ...
... Une autre hypothèse pouvant expliquer ce phénomène serait l'augmentation de matière sèche, notamment de la teneur en pectine qui freinerait l'extraction. En effet, de Prune nombreuses études sur la maturation des fruits ont montré une augmentation de la teneur en pectines solubles au cours de la maturation (Femenia, Sanchez et al., 1998;Duan, Cheng et al., 2008). ...
The hydrodiffusion process was tested and validated for production of juices from grapes, apricots and plums. Its major advantages are speed, no sample preparation, no processing aid. It allows production of juices from hard-to-press fruits with an in line pasteurisation. The juices present original characteristics notable bright colours, texture, and a fresh fruit aroma.The juice is expulsed from the fruit by the pressure due to in situ vapour generation. The destructuration occuring in frozen fruits due to growth of ice crystals facilitate the juice expulsion. The highest yields are obtained from frozen fruits and at low power densities. Part of the water from the fruits is vaporised, and can be collected by use of a cooler, allowing to reach yields comparable to those obtained by pressing after an enzymatic pre-treatment. Juice composition is close to that of juice extracted by pressing, though with slightly lower concentrations of most soluble solids. The composition of juice changes along the extraction. The highly soluble compounds present in the fruit flesh mostly show a clear exhaustion at the end ofextraction. Anthocyans, present exclusively in the peel of the test fruits, present a maximum during the fast juice extraction phase. Procyanidin concentrations is much higher in juices obtained by hydrodiffusion than in conventional juices
... Given that by our definition of CR, fruit was in the ripening stage and growth had ceased, significant differences in these parameters was not expected between the two harvests. 28,29 However, an increase in fruit weight and size from CR to TR was observed in 'Vivagold' and, in both 'Vivagold' and 'Harogem', edible portion increased with ripening. Fruit was also assessed for possible changes in color of peel and flesh with ripening on-or off-tree; observations or relationships unearthed here could have contributed to the search for nondestructive methods of assessment of apricot maturity. ...
... This stood to reason since one of the criteria for pickers in harvesting CR fruit (in our study orchards) was full color development, and thus striking increases in a or b, as occur in the transition from ground color, were not present in this case. 28 A greater diversity in colors of varieties and increase in sample points through fruit development would be necessary to observe and/or establish reliable trends. Chemical Characterization. ...
The phenolic and carotenoid content and quality indices of five Northeast apricot varieties were assessed over two years and the impact of maturity at harvest was evaluated. Four varieties were analyzed at commercial and tree ripe stages and one variety after storage for 4 weeks (0-1 °C, 90-95% relative humidity). Total phenolic content ranged from 44.0 to 345.1 mg/100 g, total antioxidant capacity (oxygen radical absorbance capacity assay) from 2096.9 to 7165.1 μmol/100 g, and total carotenoid content from 1312.1 to 7371.1 μg/100, fresh weight. 'Hargrand' apricot had the highest phenolic and carotenoid content. Catechin, chlorogenic acid, and neochlorogenic acid were the predominant phenolic compounds and β-carotene was the predominant carotenoid compound. Carotenoid content increased with ripening and postharvest storage while changes in phenolic content and antioxidant capacity were variety-dependent. Results show the apricot varieties studied to be good or excellent sources of vitamin A despite moderate carotenoid content attributed to cultivation in a colder climate.
... Non significant differences were found when comparing lignin content in the concentrates. Values obtained were higher than the ones reported by Grigelmo-Miguel et al. (1999) for dietary fibre obtained from peach washed bagasse but it has to be considered that raw materials, ripening stage and type of processing affected products obtained (Femenia, Sánchez, Simal, & Rosselló, 1998a, 1998bGrigelmo-Miguel et al., 1999;Kay McPherson, 1982). ...
... In addition, only slight reduction in the proportion of hairy regions occurred with the air drying process herein applied. Femenia et al. (1998aFemenia et al. ( , 1998b stated that drying causes further degradation of pectic polysaccharides and, to a minor extent, xyloglicans; more recently they also suggested that methylated pectins exhibited a higher resistance to degradation/solubilisation promoted by thermal processing (Femenia et al., 2009). Pectins from peach pulp and peel herein assayed, showed a high methylation degree (more than 90%) for all fractions and an acetylation degree ranging from 19 to 22.6%. ...
... Pectin regulation has been extensively studied in tomato, where expression of polygalacturonase (PG) and pectin methyl esterase (PME) enzymes was individually suppressed by antisense RNA technology, to obtain a desired end result of improved texture. 3,4 Qualitative changes in pectic polysaccharides during ripening have been shown in a number of fruits, eg kiwi fruit, 5 peach, 6 melon, 7 banana, 8 persimmon, 9 bell pepper, 10 apricot, 11 olive, 12 bush butter fruit 13 and some varieties of mango. 14 -16 Nevertheless, detailed investigations showing the entire spectrum of pectic polymers present and their extent of participation in textural softening, along with the corresponding enzyme profiles, are not well documented for fruits. ...
... Textural loss was expressed as the * Correspondence to: RN Tharanathan, Department of Biochemistry and Nutrition, Central Food Technological Research Institute, Mysore 570013, India E-mail: tharanathan@yahoo.co.uk Contract/grant sponsor: DBT Contract/grant sponsor: CSIR (Received 2 December 2002; revised version received 2 January 2003; accepted11 June 2003) Fractionation of alcohol-insoluble residue (AIR) of raw and ripe mango pulp based on differential solubility ( * values in parentheses indicate the percentage of galacturonic acid): CWIR, cold water-insoluble residue; HWIR, hot water-insoluble residue; CEIR, cold EDTA-insoluble residue; HEIR, hot EDTA-insoluble residue; SCIR, Na 2 CO 3 -insoluble residue; C, cellulosic complex. ...
The content of pectin decreased from 2.0 to 0.7% fresh weight (FW) and there was a concomitant increase in free galacturonic acid from 36 to 168 mg% FW during ripening of mango. Ion exchange chromatography on DEAE/cellulose resolved the pectic fraction into seven distinct peaks, with all of them showing a drastic decrease in pectin content and molecular weight as fruit ripening progressed, which indicated significant depolymerisation in vivo. Fraction I appeared to be an arabinogalactan-type polymer, while fractions II and III were heterogalacturonans containing more than 60% galacturonic acid. Hydrolases implicated in pectin depolymerisation were polygalacturonase (PG), pectin methyl esterase (PME), galactanase, arabinanase and β-galactosidase. They all showed a climacteric peak in activity during ripening, except for PME which showed a continuous decrease in activity after an initial increase. These results are discussed in the light of fruit softening during ripening. Copyright © 2003 Society of Chemical Industry
... Au cours du pressurage, à cause de leur solubilité, elles sont partiellement entrainées dans les jus en quantité variable selon l'état de maturité du fruit. En effet, la teneur en pectines solubles augmente au cours de la maturation, ce qui s'accompagne d'une dépolymérisation (Femenia, Sanchez et al., 1998;Duan, Cheng et al., 2008) Les pectines sont un ensemble de polysaccharides plus ou moins ramifiés caractérisés par un squelette constitué de résidus d'acide -D-galacturonique avec des faibles proportions de -L-rhamnose ( Figure 35). Les oses neutres sont concentrés dans des blocs hautement ramifiés où la chaîne principale est riche en -L-rhamnose (Voragen, Thibault et al., 1995; tel-00557288, version 1 -18 Jan 2011 Ridley, O'Neill et al., 2001). ...
... Une autre hypothèse pouvant expliquer ce phénomène serait l'augmentation de matière sèche, notamment de la teneur en pectine qui freinerait l'extraction. En effet, de nombreuses études sur la maturation des fruits ont montré une augmentation de la teneur en pectines solubles au cours de la maturation (Femenia, Sanchez et al., 1998;Duan, Cheng et al., 2008). ...
Le procédé innovant d'hydrodiffusion par micro-onde a été testé et validé pour la fabrication de jus de fruit sur des raisins, abricots et prunes. Ce procédé présente des avantages au niveau technique : rapidité d'extraction, pas de préparation de l'échantillon, aucun auxiliaire de fabrication. Il permet l'obtention de jus à partir de fruits difficiles à presser, avec une pasteurisation « in line » et des produits se différenciant nettement des jus commerciaux par leur couleur et texture.Le jus est expulsé du fruit sous l'effet de la vapeur produite in situ. A partir du fruit congelé, la déstructuration liée à la croissance des cristaux de glace facilite l'extraction. Les rendements le plus élevés sont obtenus à partir de fruits congelés, et à basse puissance. Une partie de l'eau des fruits est convertie en vapeur, mais peut être récupérée en utilisant un réfrigérant, ce qui permet d'atteindre des rendements proches des rendements de jus obtenus avec un prétraitement enzymatique et pressurage. Globalement, le jus a une composition proche de celle du jus présent dans le fruit ou obtenus par pressurage. La composition du jus expulsé des fruits change au cours de l'extraction. La concentration des composés présents dans la chair et hydrosolubles (sucres, acides, acides phénoliques) baisse nettement en fin d'extraction, tandis que les anthocyanes, présentes dans l'épiderme des raisins ou des prunes, montrent un pic de concentration lors de la phase d'expulsion rapide des jus. La teneur en procyanidines est nettement plus élevée que pour des jus obtenus par pressurage
... Strawberry fruit softened continuously during the final step of growth and ripening of the three cultivars analyzed, and this process strongly correlated with the decrease in the amount of AIR, representing most of cell wall materials. Similar results were observed in Dover cultivar of strawberry [13] and other fruit such as cherry [2], apricot [9] and mango [22]. However, no clear correlation has been established between fruit firmness and AIR content of different strawberry cultivars. ...
... We have not detected differences among cultivars and ripening stages in the content of EDTA-soluble pectins and no correlation with firmness evolution could be established. Other fruits such as apricot [9], cherry [2] and avocado [33] also have low quantities of chelator soluble pectins, which probably indicates a small contribution of ionic bonds in the pectin network. ...
Fleshy fruit soften during ripening mainly as a consequence of solubilization and depolymerization of cell wall components. We have performed a comparative study of the polysaccharide content of fruit cell walls during final steps of development and ripening of three strawberry (Fragaria x ananassa Duch.) cultivars with different softening rates. The three chosen varieties showed very different firmness; Camarosa was the firmest, Toyonaka the softest, and Pajaro intermediate between them. Cell walls were extracted, quantified and fractioned by sequential extraction to obtain particular subclasses of cell wall polymers. Cell wall content diminished during the process in the three cultivars. Differences among cultivar cell wall contents were detected only in immature stages. The amount of water soluble polymers (WSP) increased in all cultivars from small green (SG) to white (W) stage, although from the W to 100% red (100%R) stage the WSP remained constant in Camarosa and Pajaro and decreased in Toyonaka. On the contrary, the hydrochloric acid-soluble pectins (HSP) decreased during ripening of all the cultivars analyzed. Camarosa had the largest amount of HSP, but there were no differences between Pajaro and Toyonaka. The amount of hemicellulosic polysaccharides and cellulose also decreased in the three cultivars. Camarosa had the highest amounts of both polysaccharides while Toyonaka had the lowest at immature stages, but there were no differences among cultivars at 100%R stage. WSP showed depolymerization only in Toyonaka cultivar, while HSP showed depolymerization in Pajaro and Toyonaka cultivars. A slight depolymerization was observed in hemicelluloses extracted from any of three cultivars.
... Galacturonic acid is the most important constituent of pectins, polysaccharides concurring in building the plant cell walls. Fruit ripening is characterized by pectins depolymerisation and generally leads to flesh softening and decreased fruit firmness (Femenia et al., 1998;Brummel, 2006;Goulao and Oliveira, 2008;Kovács et al., 2008). However, no evident relation was found between galacturonate and firmness, probably due to harvesting done at full physiological ripening stage. ...
Consumers continuously report a lack of taste in many apricot cultivars currently available on the market, highlighting the necessity of renewing the apricot varietal landscape grown worldwide. Sugars and acids content largely affect sweetness and aroma perception, being an important driving factor of consumers’ preferences and purchase. In this work, a large apricot germplasm collection of 164 accessions was evaluated for several fruit organoleptic attributes: maturity date, fresh fruit weight, flesh firmness, soluble solids content, titratable acidity and organic acid content separated for fruit flesh and skin and dry matter. A major focus was reserved to ten organic acids (cis-aconitate, citrate, fumarate, galacturonate, malate, oxalate, quinate, shikimate, succinate and tartrate) composition in both flesh and skin tissues, quantified by HPLC technique coupled to UHPLCHRMS. Malate, citrate and succinate were the most abundant, accounting for 98.5% and 97.2% of the total organic acids in fruit flesh and skin, respectively. The tested accessions showed consistent fruit acidity contents and almost similar organic acids profiles between flesh and skin, albeit some exceptions of acidity higher in flesh than in skin -and viceversa- occurred. This work highlights an extremely large diversity in apricot germplasm, representing a valuable genetic resource to be long term preserved and exploited in new fruit-quality oriented breeding programs. Also, a better understanding of phenotypic diversity will help the characterization of apricot accessions and a more effective management of germplasm for selecting phenotypes with improved taste.
... However, little information is available in the literature on texture deterioration of apricots under HHAIB pretreatment. Many investigations report that, the cell wall modification and the changes in the polymer within cell wall are the main causes of tissue softening (Luh & Dastur, 1966;Femenia, Sánchez, Simal, & Rosselló, 1998;Bordoloi, Kaur, & Singh, 2012). Pectin is the primary polysaccharide constituent of primary cell walls and middle lamellae, and it plays an important role in determining the strength, adhesion and porosity of the cell wall (Bordoloi et al., 2012). ...
Effects of high-humidity hot air impingement blanching (HHAIB) on peroxidase (POD) and polyphenol oxidase (PPO) activities, ultrastructure, water distribution, drying time, and key quality attributes of apricots were investigated under air temperature of 110 °C and relative humidity of 35%–40% for various exposure times ranging from 30 to 150 s. HHAIB inactivated POD and PPO fully within 120 s, induced alteration of cellular structure and resulted in redistribution of water among the cell compartments. Compared to the untreated sample, HHAIB reduced the drying time by 19.36%–36.40%. Optimal pretreatment (120 s) resulted in dried apricots with higher total phenolics (TP) and total carotenoids (TC) along with enhanced antioxidant capacity, as well as better color. The TP, TC and antioxidant capacity were observed to be significantly correlated to POD and PPO activities, water distribution and drying time. Over-blanching (150 s) prolonged drying time, induced higher degradation of TP, TC, antioxidant capacity and color compared to dried products pre-blanched for 120 s. Hence, proper HHAIB pretreatment enhances drying process and improves the quality attributes of dried apricots.
... However, little information is available in the literature on texture deterioration of apricots under HHAIB pretreatment. Many investigations report that, the cell wall modification and the changes in the polymer within cell wall are the main causes of tissue softening (Luh & Dastur, 1966;Femenia, Sánchez, Simal, & Rosselló, 1998;Bordoloi, Kaur, & Singh, 2012). Pectin is the primary polysaccharide constituent of primary cell walls and middle lamellae, and it plays an important role in determining the strength, adhesion and porosity of the cell wall (Bordoloi et al., 2012). ...
... An extensive IR study on various polysaccharides has been published by Wilson et al. (42). The information extracted from the FTIR spectrum can give insight on cell wall composition such as pectic polysaccharides and hemicelluloses, and can distinguish the structural and compositional changes (43). ...
Development of modern infrared spectroscopy and imaging technique has wide range of applications in health and plant sciences. Initially, it was extensively used for the study of proteins, nucleotides, lipids and carbohydrates. With time, it extended to the disease assessment to discriminate healthy and diseased samples on the basis of chemical changes. Now, with the application of advanced focal plane array detector able to scan large area of samples in a short time helps to investigate the specific changes that could be correlated with different environmental stresses. An IR microscope connected with a synchrotron light source further enhances the lateral spatial resolution at diffraction limit because of the compact beam size. For example, synchrotron-based IR spectroscopy imaging in combination with multivariate statistical analysis has been proven a powerful non-destructive analytical tool to probe changes in the plant cell wall composition/structure in response to biological processes and environmental stresses. New development of nano-FTIR combines with scattering type scanning near-field optical microscopy breaks the diffraction limitation, which opens the new area of applications. This review focused on a new area of diagnostic research as well as development of IR spectroscopy and imaging for biological specimen including compositional changes in plant cell wall.
... The observed thinning of cell walls may negatively affect the texture of the olive fruit, and thus reduce its commercial quality. In fact, cell wall thinning that naturally takes place during fruit maturation and ripening is associated with a loss of firmness in many fruit species like apples or apricots or even olives (Percy et al., 1997;Femenia et al., 1998;Jiménez et al., 2001;Mafra et al., 2006). The cell wall could be degraded by cell biochemical changes produced during the aforementioned oxidation process. ...
... These proportions are in accordance with results from other studies [Wills et al. 1983;Drogoudi et al. 2007;Schmitzer et al. 2011]. However, Femenia et al. [1998] reported that glucose was dominant sugar in apricot; however, a different extraction and analytical method was used [Hegedűs et al. 2010]. In addition, other sugars such as sorbitol [Schmitzer et al. 2011], xylose, mannose, maltose [Bassi and Selli 1990] and raffinose [Ledbetter et al. 2006] were also found in apricot fruit in varying contents. ...
The experiment was established at private apricot orchard near Cacak (Western Serbia) during 2010 and 2011. In the present study we wanted to determine the physicochemical attributes, phenolics content and antioxidant capacity of three new Serbian cultivars ('Aleksandar', 'Biljana', 'Vera') grafted on Myrobalan seedlings. Results indicated that physico-chemical attributes significantly varied among cultivars. Similarly, total phenolics and flavonoids content and antioxidant capacity significantly depend on the cultivars. Generally, new Serbian cultivars had better properties evaluated than control ('Hungarian Best'), except stone weight, fruit firmness, moisture and total phenolics content. The highest values of total phenolics and flavonoids content were found in 'Aleksandar', whereas the highest antioxidant capacity was recorded in 'Vera'. Finally, new Serbian cultivars could be recommended for planting in similar conditions and apricot growing programs.
... Maximum losses were observed in control that were rapid from 4 th to 8 th day followed by 0.5 and 1mM salicylic acid, whereas, higher firmness values were maintained by 1.5 and 2mM concentrations respectively at the 12 th day. Firmness losses are evident during ripening and storage because of degradation in cellular structures resulting from respiration and metabolic activities [22]. At the climacteric peak, increased ethylene accumulation in tissues also aid in accelerating the ripening process of fruits [23]. ...
Fresh fruit consumption is increasing day by day for their numerous nutritional and health benefits. Apricot is among the most nutritious fruits and perishable commodity of high market value. Keeping in view its significance, this study was designed to assess the effect of various concentrations of salicylic acid on fresh apricot market traits as fruit firmness, weight loss, total soluble solids, acidity, total sugars, microbial and organoleptic quality at ambient conditions. Four concentrations of salicylic acid (0.5,1,1.5 and 2mM) were applied on fresh apricot by dipping and evaluated at 2 day intervals for physico-chemical, microbial and sensorial quality. A decreasing trend in fruit firmness and increased weight losses were witnessed during storage. However, higher concentrations of salicylic acid favor firmness and lowered weight loss. Total soluble solids increased steadily among the samples treated with higher level of salicylic acid. Titratable acidity decreased initially in all treatments with a rapid decline in control followed by lower concentrations of salicylic acid, whereas total sugars increased throughout storage. Lower microbial load and higher sensorial scores were achieved at higher concentrations of salicylic acid. This study revealed that 2mM concentration of salicylic acid was effective in retaining keeping quality of apricot significantly up to 12 days at ambient storage.
... However, little is known regarding the physical and chemical changes that take place during fruit development from bloom to harvest of apricot fruit. Cell wall composition of apricots during development periods were studied ( Femenia et al., 1998). Microstructural changes during four stages of apricot ripening were studied ( Kovács et al., 2008). ...
Five apricot (Prunus armeniaca L.) cultivars were examined throughout fruit development period to monitor the changes in quality characteristics including hardness, °Brix, color, titratable acidity and pH. Changes in the amount of sugars (fructose, glucose and sucrose) and organic acids (citric, malic and quinic) were also determined by HPLC. The predominant sugar of cultivars found to be glucose at the initial ripening stages; however, sucrose or glucose became predominant at the end of fruit maturation. Sugar/ acid rate was found to be the highest in Hasanbey (HB) cultivar during unripe period, while Kabaasi (KA) showed the highest value at full ripeness. Low soluble solid containig varieties of Zerdali (ZD) and HB reached fruit maturity earlier than the other cultivars. Soǧanci (SO) measured as the hardest fruit at maturity while ZD was the softest cultivar. Chroma as a measure of color, was found to be well corelated with maturity level rather than L value. In the course of ripening, total acid content decreased along with the increasing amount of total sugar for all cultivars.
... As a function of ripeness in apricots, the mass of fructose, xylose, mannose and galactose increased, while that of arabinose decreased and that of rhamnose fluctuated. The non-cellulose cell wall neutral carbohydrate content and the amount of uronic acid increased as a function of ripeness, however rhamnose did not change and the arabinose increased (FEMENIA et al., 1998b). ...
Colour, texture, pectin autolysis, membrane permeability and microstructure (SEM, TEM), β-galactosidase and polygalacturonase were studied in apricots (cv. Magyar kajszi) harvested in mature green, straw yellow, bright orange and deep orange stages. The L* increased from mature green to straw yellow then decreased from straw yellow to deep orange state. The a* values increased with ripening. The bright and deep orange apricots were significantly softer than the mature green and straw yellow ones and the membrane permeability increased with ripening. The presence of β-galactosidase enzyme was proved by immunoblotting analysis using monoclonal anti-β-galactosidase clone GAL-13 (Sigma) in all ripening stages. The enzyme activity was very low in mature green stage and increased significantly (P>95%) with increasing ripeness and during storage. The PG activity was very low in the mature green apricot. A significant (P>95%) increase was observed in the straw yellow apricot and in the riper fruits. The mature green apricot showed a regular, the straw yellow and bright orange samples showed a moderately regular tissue structure, while the tissue of the deep orange apricot collapsed (SEM). The cell wall and the middle lamella of the green apricot (TEM) were intact. Generally, there were intact cytoplasm membranes with some damaged parts. In the straw yellow apricot, the cell wall started to loosen, the middle lamella lost pectic polysaccharides. The structure of the cytoplasm was not recognisable, the tonoplast and the cytoplasm membrane were injured. The cell wall of the bright orange apricot was similar to that of the straw yellow ones. The middle lamella dissolved and hairy, fibrillar structure of cell wall was found in the deep orange samples.
... The polysaccharides of olive pulp are mainly composed of pectic polysaccharides rich in arabinose, glucuronoxylans and cellulose, and xyloglucans, mannans and glycoproteins occur as minor components. 1,2 Modifications of cell wall components with ripening are particularly well documented for tomato, 3 -6 and several other fruits such as pear, 7 kiwi, 8 apricot, 9 apple 10 and avocado 11 have also been described. The knowledge of the effect of ripening on cell walls of olives is still limited. ...
Olive fruits, harvested in two consecutive seasons at green, cherry and black stages, were used to study compositional changes in the cell walls during ripening. Ripening-related changes in both harvests were characterised mainly by an increase in the solubilisation of pectic and hemicellulosic polysaccharides, an increase in the relative amount of arabinose in pectic polysaccharides and a decrease in the degree of methylesterification of pectic polysaccharides. Further to degrading processes, the data obtained suggest the synthesis of new polysaccharides. The analysis of olive cell wall phenolics showed mainly the presence of p-coumaric acid, which increased in one harvest, whereas in the other the values did not differ. The samples of the second harvest, although presenting green, cherry and black colours, had less distinct ripening characteristics than those of the previous harvest. Different activity levels of polyphenol oxidase, polygalacturonase and pectin methylesterase might have contributed to the differences observed between the two harvests. The results showed the distinct extension of ripening-related changes in the cell walls of the two harvests, indicating that the olive colour, although characteristic of the stage of ripening, cannot be strictly used for its evaluation and definition. Copyright © 2006 Society of Chemical Industry
... The decline in cell wall strength and cell-to-cell adhesion resulting in tissue softening in fresh fruits is also associated with fruit ripening, where structural changes in all cell wall polysaccharides occur (Brummell, Dal Cin, Lurie, Crisosto, & Labavitch, 2004;Femenia, Sanchez, Simal, & Rossello, 1998;Mafra et al., 2006b;Wakabayashi, 2000). Pectin methylesterase (PME) catalyses the hydrolysis of methylester groups from galacturonosyl residues of pectic polysaccharides. ...
“Ameixa d’Elvas” is a candied plum (Prunus domestica L.) produced by a traditional process, using fruits of a specific ‘greengage’ variety, “Rainha Cláudia Verde”. The candying process consists of boiling the intact plums in water for 15 min and then putting them in sugar syrup, which is successively concentrated until 75 °Brix. Although a loss of intercellular adhesion of parenchyma cells after boiling is observed, candied plums are able to recover their cell-to-cell adhesion, giving a final tissue with a consistency similar to that observed for the fresh fruit. In order to explain this observation, cell wall polysaccharides of plums harvested in two orchards, Vila Viçosa (VV) and Cano (CA), from the same geographic region and at the same stage of ripening, were analysed fresh, boiled and candied. Plum cell walls are composed mainly of pectic polysaccharides and cellulose that, during the boiling step, are degraded and solubilised. Highly esterified pectic polysaccharides undergo gelation inside the fruits in the presence of sucrose, leading to the recovery of the fruit’s consistency. During the candying process diffusion of these methylesterified pectic polysaccharides to the sucrose syrup increase the syrup viscosity. The activity of pectin methylesterase, polygalacturonase, and cellulase of fresh fruits explains the observed higher extension of degradation of cell wall polysaccharides of the CA plum tissues after boiling. This higher degradation seems to prevent the complete recovery of the parenchyma cell structure, which was observed for the less degraded polysaccharides of VV plums.
... These differences could be attributed to the different methodology used to obtain the DF fraction. The presence of cellulose could be deduced since most of the glucose could only be released after Saeman hydrolysis (Femenia, Sánchez, Simal, & Rosselló , 1998b). Cellulose was the second most abundant cell wall polymer-type, representing 32% of carrot DF. ...
Four formulations of a dry fermented sausage, known as sobrassada, containing different percentages of carrot dietary fibre (DF) [3% (S3), 6% (S6), 9% (S9) and 12% (S12) (w/w)] were analyzed for various physico-chemical and microbiological parameters and sensory attributes. The ripening process was monitored throughout storage. The pH of DF-supplemented sobrassadas was critically affected during ripening by the amount of DF incorporated, the values for sobrassada samples containing over 3% of DF suggested that the fermentation process in these samples was not successful. In addition, textural parameters, such as hardness and compression work, were significantly affected by the addition of over 3% of DF. The lipolytic process, one of the major biochemical events, was only affected when relatively large percentages of DF concentrate were incorporated. Thus, S3 and S6 samples exhibited similar free fatty acid profiles to the control throughout ripening.
... The dominant sugar in all cultivars and hybrids was sucrose, followed second by glucose and third by sorbitol and fructoseinositol ( Table 5). This is in accordance with results from other studies (16,34,35); nevertheless, Femenia et al. (36) found glucose as the dominant sugar in apricot. Other sugars such as xylose, mannose, maltose (34), and raffinose (4) were also found present in apricot fruit in varying concentrations. ...
Fruit physical and chemical characters of 29 apricot cultivars of Greek and American origin and their hybrids were evaluated using correlation and principal component analysis. A remarkable variation was observed in the total phenol content (0.3-7.4 mg gallic acid equivalent g(-1) FW) and total antioxidant capacity (0.026-1.858 mg ascorbic acid equivalent g(-1) FW), with the American origin cultivars Robada and NJA(2) and the new cultivar Nike exhibiting the greatest values. The cultivar Tomcot and hybrid 467/99 had the highest content of total carotene (37.8 microg beta-carotene equivalent g(-1) FW), which was up to four times greater as compared with the rest of studied genotypes. The dominant sugar in fruit tissue was sucrose, followed second by glucose and third by sorbitol and fructose-inositol. The new cultivars Nike, Niobe, and Neraida contained relatively higher contents of sucrose and total sugars, while Ninfa and P. Tirynthos contained relatively higher contents of K, Ca, and Mg. Correlation analysis suggested that late-harvesting cultivars/hybrids had greater fruit developmental times (r = 0.817) and contained higher sugar (r = 0.704) and less Mg contents (r= -0.742) in fruit tissue. The total antioxidant capacity was better correlated with the total phenol content (r = 0.954) as compared with the total carotenoid content (r = 0.482). Weak correlations were found between the fruit skin color and the antioxidant contents in flesh tissue. Multivariate analysis allowed the grouping of variables, with more important variables being the harvest date, fruit developmental time, skin Chroma, sorbitol, and total sugar, K and Mg contents. Plotting the genotypes in a dendrogram revealed cases of homonymy between parents and hybrids, although independent segregation of the measured traits after hybridization was also found.
La problématique de cette thèse repose sur la caractérisation de la qualité des abricots et leur aptitude à la transformation industrielle. Trois axes principaux ont guidé cette étude. Le premier consistait au départ à une caractérisation morphométrique globale des pieds clones des abricots marocains transplantés vers une station expérimentale de l’INRA Marrakech puis suivie par l’analyse de la diversité génétique. 92 accessions, issus de différentes régions géographiques, ont été génotypés en utilisant 21 marqueurs microsatellites. En effet, la collection analysée a été caractérisée par un polymorphisme élevé et une diversité génétique réduite. Au total, 120 allèles ont été identifiés avec une moyenne de 5,71 allèles par locus.Toutes les preuves statistiques (analyse hiérarchique, ACP et analyse de structure) montrent que la structure génétique de l’abricot marocain peut être subdivisée en deux populations :une majeure population constituée de la plupart des accessions de groupes génétiques(population authentique liée notamment à la variété Delpatriarca) et une seconde population moins diversifiée et liée à toutes les variétés de références, y compris la variété Canino. La variabilité observée entre les 92 génotypes pourrait être un atout pour améliorer la culture de l’abricot et permettre un développement durable dans l’espace et dans le temps du fruit par la sélection de nouveaux génotypes d’abricots. Finalement, la variabilité génétique observée a été utilisée dans le choix et la sélection de nouveaux clones d’abricots pour une analyse phénotypique. Le deuxième axe s’est intéressé à l’étude des marqueurs biochimiques qui permettent de comprendre et d’évaluer la qualité des abricots sélectionnés, à savoir : le changement des acides organiques et des sucres solubles en relation avec la qualité sensorielle, le développement des pigments et le changement de la couleur, l’’évolution des composés phénoliques en relation avec l’activité antioxydante et la perte de la texture en relation avec la biochimie de la paroi cellulaire. En effet, de bonnes propriétés physicochimiques et biochimiques ont été rapportées pour les dix clones choisis (Valeurs maximales rapportées pour certains composés bioactifs : Vitamine C = 0,15 g/kg ; β-carotène= 149,251 μg/kg ; provitamine A = 0,028 mg/kg), ainsi que des caractères qualitatifs associés à la saison de maturation et au génotype, cela représente certainement une source génétique précieuse pour prolonger la saison des abricots et alimenter les étalages et l’industrie.Le troisième axe était sur l’implication de la texture du fruit dans la transformation industrielle de l’abricot. Nous avons analysé l’aptitude variétale des abricots à la transformation industrielle, par l’analyse de leurs propriétés texturales, avant et après la transformation. Et pour mieux comprendre la variabilité de la texture de l'abricot, nous avons étudié l'impact du traitement thermique en fonction du stade de récolte des fruits sur une large gamme de cultivars français. Au final, cinq variétés d’abricots ont été choisies les plus appropriés pour le processus industriel.
‘Kabaaşı’ kayısı çeşidinin meyve gelişim sürecindeki fiziksel, kimyasal ve renk değişimlerinin belirlenmesi*
Mehmet ÖZELÇİ1, Rafet ASLANTAŞ2, Duygu ÖZELÇİ1, Erdoğan ÇÖÇEN1
1Kayısı Araştırma Enstitüsü Müdürlüğü, Malatya
2Eskişehir Osmangazi Üniversitesi, Eskişehir
*Birinci yazarın yüksek lisans çalışmasından alınmıştır.
Alınış tarihi: 12 Mayıs 2020, Kabul tarihi: 27 Nisan 2021
Sorumlu yazar: Mehmet ÖZELÇİ, e-posta: muh_mehmet_44@hotmail.com
Öz
Amaç: Ekonomik meyvecilik için kültürel uygulamaların ve hasadın doğru zamanda yapılması gerekir. Bu maksatla meyvelerin büyüme, gelişme ve olgunlaşma dönemlerindeki fiziksel ve kimyasal değişimlerin bilinmesi önem arz eder. Bu çalışmada Türkiye’nin kayısı üretim ve ihracatında önemli paya sahip Kabaaşı çeşidinde meyve gelişim dönemindeki fiziksel, kimyasal ve renk değişimlerinin belirlenmesi amaçlanmıştır.
Materyal ve Yöntem: Çalışmanın materyalini Kabaaşı kayısı çeşidi oluşturmuş olup çalışma alanı Malatya Meyvecilik Araştırma Enstitüsünde yer almaktadır. Çalışmada fenolojik gözlemler yapılmış, meyve gelişim süreci boyunca periyodik aralıklarla meyvede fiziksel, kimyasal ve renk ölçümleri gerçekleştirilmiştir. Toplam şeker içeriği spektrofotometrik yöntemle, SÇKM miktarı dijital el refraktometresi, pH değeri titrasyon metodu ile belirlenmiştir
Araştırma Bulguları: Kabaaşı çeşidinde toplam çiçeklenme süresinin 16 gün ve tam çiçeklenmeden hasada kadar geçen sürenin ise 112 gün olduğu belirlenmiştir. Fiziksel ölçümlerde; çağla döneminden hasada kadar geçen sürenin ilk bir aylık periyodunda hasattaki meyve boyunun yaklaşık %75’ine, meyve genişliği ve kalınlığının ise %50’sine ulaşıldığı belirlenmiştir. Meyve ağırlığındaki artışın yaklaşık %50’si hasada yakın son bir aylık periyotta gerçekleşmiştir. Meyve olgunluğu arttıkça SÇKM, pH ve toplam şeker içeriğinin arttığı, buna karşılık TEA değerinin düştüğü görülmüştür. Meyve kabuk ve zemin rengi ölçümlerinde, çağla döneminden olgunluk dönemine doğru L değerindeki artış düşük düzeyde kalırken, a ve b değerlerindeki artışın yüksek olduğu belirlenmiştir.
Sonuç: Meyvelerde fiziksel gelişimin büyük bölümü çağla döneminin ilk bir aylık periyodunda gerçekleşirken, tatlanma ve renklenme gibi kalite parametreleri hasada yakın dönemde yükselmiştir. Bu nedenle meyve hasadı, yeterli renk oluşumu için tam çiçeklenmeden en az 96 gün sonra yapılması önerilmektedir. Fitokimyasal özellikler bakımından ise minimum 103 gün sonra derim yapılması tavsiye edilmektedir.
Anahtar kelimeler: Prunus armeniaca L., Meyve kalitesi, Kayısı, Kabaaşı, Pomoloji
Determination of physical, chemical and color changes of ‘Kabaaşı’ apricot cultivar during fruit development
Abstract
Objective: For economic fruit growing, it is important to carry out cultural practices and harvest at the right time. For this purpose, To know the physical and chemical changes in the growth, development and ripening periods of the fruit species and varieties are important. This study was carried out to determine physical, chemical and color changes of Kabaaşı apricot cultivar, which has a
20 Özelçi, M., Aslantaş, R., Özelçi, D., Çöçen, E.
significant share in Turkey's apricot production and export, in fruit development period.
Material and Method: The material of the study was the Kabaaşı apricot variety. In the study, phenological observations were taken, and physical, chemical and color measurements were carried out at periodic intervals throughout the fruit development process.
Results: In the study, it was found that the period between flowering and harvesting was 112 days in Kabaaşı apricot cultivars and total flowering time is 16 days. In physical measurements; In the first month of this period, approximately 75% of the fruit length, 50% of the fruit width and thickness were reached and 50% of the increase in the fruit weight reached in the last month. It was observed that the increase in fruit maturity, TSS, pH and total sugar content increased, while TA value decreased. In fruit color measurements; it was observed that a and b color values increased, while a partial increase in L color value was observed as fruits approached harvest period.
Conclusion: Most of the physical development of the fruits take place in the first one month period of the unripe fruit period, but quality parameters such as sweetening and coloring are increasing near harvest. Therefore, fruit harvest should be done at least 96 days after full bloom for adequate color formation. In terms of phytochemical properties, it is recommended to be applied after a minimum of 103 days.
Keywords: Prunus armeniaca L., Fruit quality, Apricot, Kabaası, Pomology
ntroduction: Raspberry has been considered a good source of some micro and macro nutrients namly (anthocyanins, polyphenol, ascorbic acid, fiber, proteins and minerals). Due to high metabolic activity and susceptibility to fungal decay and especially gray mold, it is one of the most perishable fruits and has a short shelf life. The use of modified atmospheric packaging increases the shelf life of the fruits like raspberries and therefore the commercial value of the fruit is increased.
Materials and Methods: In this study the RSM design is used to assess the effects of three variables; CO2/O2 (three levels; zero, one and two v/v), time (0, 5 and 10 days) and perchlorine concentration (0, 250, 500ppm) on raspberry weight loss, acidity, texture and microbial load. Rasberry fruits were packed in the two layer plastic packaging made of polyamide with thickness of 50 microns and stored at 4RC Results: The results showed that the time, perchlorine concentration and CO2/O2 ratio had significant effects on the qualitative properties of raspberry fruit and its shelf life. Increases in perchlorine concentration and CO2/O2 ratio had positive effects on keeping quality of the fruit.
Conclusion: The application of modified atmospheric packaging can improve the qualitative characteristic of raspberry fruit
In order to study overripening impact on cell wall–procyanidin interactions, perry pear cell walls and procyanidins were isolated and characterized at ripe and overripe stage. Their associations were quantified using Langmuir isotherms and isothermal titration calorimetry.Perry pears were rich in procyanidins with high degree of polymerization and their constitutive units were mainly (-)-epicatechin. Cell walls isolated from the whole flesh and parenchyma cells were characterized by extremely methylated pectin and highly branched rhamnogalacturonans whereas cell walls from stone cells and skin were more lignified and rich in hemicelluloses.Overripening did not modify procyanidin structure and molar mass distribution, but the distribution of the procyanidin-containg aggregates in the vacuoles was modified, from dispersed in ripe pears to close to the tonoplast in overripe pears. Between the ripe and overripe stage, pear cell walls lost pectic side chains, arabinans and galactan, mostly from cell walls isolated from parenchyma cells and the whole flesh.The affinity between procyanidins and cell walls decreased as follows: parenchyma cells > flesh > stone cells > skin as reported by Langmuir isotherms. The amount of bound procyanidins increased at the overripe stage notably for the cell walls from stone cells and whole flesh. Isothermal titration calorimetry indicated that overripening induced the modification of cell wall binding mechanism especially for parenchyma cells where interactions were driven by hydrophobic interactions.The increase of procyanidin binding capacity at the overripe stage was confirmed by juice pressing where overripe pear juices were poorer in procyanidins than ripe pear juices whereas fruit procyanidin contents did not change with overripening.
Wild apricot (Prunus armeniaca L.) is an important fruit tree species found in temperate regions of Himachal Pradesh and Uttarakhand states of India at an altitude up to 2500–3000 msl. From time immemorial P. armeniaca L. has been used in folk medicine as a remedy for various diseases. Apricot seed oil has been used as biodiesel and oil cake as organic manure. The plant is rich in sugars, mono and polysaccharides, polyphenols, fatty acids, sterol derivatives, carotenoids, cynogenic glucosides and volatile compounds. Polyphenols are abundant micronutrients in the human diet, and evidence for their role in the prevention of degenerative diseases such as cancer and cardiovascular diseases is emerging. Cyanogenic glycosides responsible for a bitter taste of apricot seeds and these seeds cause some degree of intoxication primarily on nervous system and thyroid. P. armeniaca L. has also been investigated for various biological activities such as antimicrobial, antioxidant, hepatoprotective, antinociceptive, antiinflammatory, antimutagenic, inhibitory activity against several enzymes. Among them the antimicrobial and antioxidant potential has been of much exploration and were proved to be highly efficacious under in vitro conditions. In the present review, the antioxidant properties of P. armeniaca L. and its potential use as natural dietary supplement has been discussed. We have also thrown light on the phytochemistry and biological activity reports published on the species worldwide.
This review summarizes accumulated data about the structural organization of pectic macromolecules, including the latest developments in structural investigations of the molecular determinants of pectins, the existing models of pectic macromolecules, and several examples of pectins structure. Biological functions of pectic polysaccharides in a plant cell are described. The role of pectic polysaccharides as physiologically active components of the dietary fiber in nutrition is discussed and the data is given on their transformations in the digestive process. The effect of the structure of pectic polysaccharides on their gel forming ability is surveyed. The key issues are reviewed, which account for the importance of the further investigation of the structure and functional properties of pectins.
The variability of histological and cell wall chemical characteristics of apricot were assessed in nine apricot varieties: Harogem, Goldrich, Hargrand, Iranien, Moniqui, Orangered® Bhart, Stark Early Orange, Ravicille and Rouge du Roussillon. For chemical analyses, Iranien and Moniqui were harvested twice at two weeks interval and Goldrich parenchyma was subdivided into inner and outer tissue.
Image texture analysis of parenchyma tissue sections allowed distinguishing varieties on the basis of cell and vascular bundle size distributions and tissue organization. Whole parenchyma cell wall sugar composition failed to distinguish varieties. Goldrich outer tissue was richer in arabinose and mannose compared to inner parenchyma. Methyl and acetyl esterification of polysaccharides were better discriminants. The distribution of methyl and acetyl esters on pectin varied among varieties. The tissue regions studied in Goldrich and the different harvests studied in Moniqui and Iranien affected pectin esterification. Hemicellulose fine structure profiles discriminated varieties on the basis of xyloglucan and galactoglucomannan structures proportion.
The results point to variations in chemical and histological characteristics that can be of importance in studies on the understanding the genetics of apricots texture variations.
Sight is the most important sense of a human allowing him to perceive the surrounding world. Size, shape, structure and colour of examined objects are easily recognised by human eye and brain and simultaneously verify whether they correspond to the standard. Interpretation of images registered solely by the sight is somehow limited by the observer’s perception. Increased number of objects and their mobility resulted in difficulties of proper interpretation of human observations. Moreover, the eyes become tired quite fast, thus their ability to differentiate selected features of the object decreases.
Consumer acceptance of dried apricots depends on them having an intense orange color, a gummy texture, and a characteristic flavor. In addition, the growing demand for healthy and nutritive foods has increased the interest in this product, as apricot fruits can be considered a good source of phytochemicals, such as polyphenols, carotenoids, and vitamins. Microwave energy may be an interesting drying method, an alternative to conventional sun or hot air drying, with which to obtain dried apricots with good sensorial, nutritive, and functional properties in a shorter time. This paper aims to evaluate the effect of sulfur pretreatment and the drying process (hot air and/or microwaves) on the color, mechanical properties, and ascorbic acid, vitamins A and E, and total carotenoid content of apricot. The obtained results mean that the use of microwave energy, either in combination or not with mild–hot air, may be recommended to obtain dried apricots, without needing to apply sulfur pretreatment.
The effects of air-drying temperature on the cell wall components of three sets of fresh kiwifruits at different degrees of ripening, unripe, half-ripe and ripe samples, have been evaluated. The modifications affecting the physico-chemical properties of cell wall polysaccharides were largely dependent, not only on the air-drying temperature used (from 30°C to 90°C), but also on the initial stage of ripening of the processed kiwifruits. Thus, whereas in comparison with the fresh fruits, dehydrated unripe and half-ripe kiwifruits maintained their overall cell wall composition better, processed ripe kiwifruits seemed to be more sensitive to cell wall degradation/solubilisation. In fact, important losses of cell wall material (CWM), mainly pectins and, also, hemicelluloses, were detected in the riper kiwifruits when these samples were dehydrated at high temperature (up to 30% CWM losses when drying was carried out at 90°C). Heating also promoted considerable modifications of the degree of methyl-esterification (DME) of pectins. In general, an increase in the DME corresponded to an increase in the degree of ripening of the processed samples, suggesting that methylated pectins exhibited a higher resistance to the degradation/solubilisation caused by heating. All these changes in composition were clearly reflected in the solubility and functional properties (FP) of processed CWMs. Hydration properties, swelling and water retention, and, in particular, the capacity to absorb lipids, were modified after processing. In general, CWMs from processed half-ripe kiwifruits exhibited the highest FP values. Overall, the study clearly reflects the importance of taking into consideration the stage of ripening of fruits in order to determine the final quality of CWMs, and therefore, the properties of the dietary fibre (DF) which could be obtained from processed kiwifruit samples.
The rapid texture loss of apricot fruit during storage and transformation is a limiting factor for its commercialisation and use. Apricot flesh exhibits different tissue zones which differ in texture. To better understand texture in apricot fruit, we have studied (i) the intra-fruit heterogeneity of texture measured by puncture test (tissue firmness) (ii) the effect of thinning on whole fruit firmness (global firmness), measured by compression, and on tissue firmness and (iii) the evolution of texture upon steam cooking, on apricots of contrasted texture. Nine tissue zones were defined in fresh apricot fruits in order to study differences in texture from the peduncle to the pistil zones and from the external to the internal tissue. In the nine apricot varieties used, tissue firmness decreased gradually from the external to the internal tissue. However, from the peduncle to the pistil zone, the variation of texture seemed to be variety-dependent. Overall the textures measured for the nine tissue zones were highly correlated, indicative of the major differentiation between soft and firm fruits. However distinct heterogeneity patterns could be observed on axes 2 and 3 of a principal component analysis carried out on the textures of the nine zones. The effect of thinning on fruit firmness appeared variety-dependent. Tissue firmness of the raw apricots assessed by penetrometry explained about two-thirds of the variability of firmness of cooked apricots, versus only 40% for the compression test. High correlations between texture after cooking and prior to cooking were found for four (external equatorial, external pistil, median equatorial and median pistil) out of the nine tissue zones. (C) 2010 Elsevier Ltd. All rights reserved.
The intra-fruit texture heterogeneity in fresh apricot fruit, the cell wall of the different tissue zones and those of cooked fruit were analysed in order to investigate the implication of cell wall in apricot texture. Firmness decreased gradually from the external to the internal tissue while from the peduncle to the pistil zone, the highest value in firmness was recorded in the peduncle zone, followed by the pistil zone and finally the equatorial zone. Texture was strongly correlated with water-soluble pectin (WSP), firmness being inversely proportional to WSP contents of the different tissue zones. CDTA-soluble pectin (CSP) underwent noticeable variation between tissues but no clear relationship was observed with firmness. Hemicelluloses extracted together with WSP also appeared to be implicated in tissue texture; highly positive correlation coefficients were observed between firmness and hemicellulosic sugars. After cooking, CSP was the only class of pectin which underwent substantial degradation, indicating that CSP was the pectin fraction most implicated in heat-induced softening in apricot fruit. (C) 2011 Elsevier Ltd. All rights reserved.
INTRODUCTION PRODUCTION AND POSTHARVEST PHYSIOLOGY PROCESSED PRODUCTS CHEMICAL COMPOSITION, NUTRIENT PROFILE, AND DIETARY BENEFITS
Apricots (Prunus armeniaca L., cultivars Magyar and Bergeron) were harvested 3 d apart (1st, 2nd and 3rd harvest). Fruits were stored at 4 to 6 °C, 90 % relative humidity, for 3 to 25 d. (β-Galactosidase activity, pectin degradation, and softening were studied as a function of harvest and storage time. (β-Galactosidase activity increased as a function of harvest; it increased continuously during storage in the case of cv. Bergeron. With Magyar enzyme activity reached a maximum value during storage in the case of 2nd and 3rd harvest fruits, then it declined. Total pectin and that solubilized neutral carbohydrate contents decreased as a function of storage. Solubilized pectin quantity did not depend either on harvest or on storage.
The availability and the potential of wine by-products, grape pomaces and stems, obtained from ten different grape (Vitis vinifera L.) varieties (six red and four white) as raw materials for the production of dietary fibre (DF) concentrates were evaluated. The overall chemical composition, carbohydrate analysis and functional properties of DF from fresh grapes, grape pomaces and stems from those grape varieties were analysed. Both winemaking by-products presented considerable quantities of DF, ranging from 60% to 90% of total dry matter. The cell wall polysaccharides (CWP) composition of grape pomaces and fresh grapes was rather similar, pectic substances being the main component of the cell walls (40–54% total CWP). In contrast, cellulose was the predominant cell wall polymer for the stems (40–49% total CWP). In addition, the pectin content of grape pomaces exhibited significant differences between red and white grape varieties. The degree of methyl-esterification of uronic acids from wine by-products ranged from 21 to 39%; thus, pectic polysaccharides from the different samples could be classified as low methyl-esterified pectins. Klason lignin accounted for around 20–25% of DF in both grape pomaces and stems. With regard to the potential incorporation of DF concentrates into the food chain, functional properties were also determined. Swelling, water and fat retention capacity results showed great variability depending on the grape variety analysed.
Broccoli florets and stems tissues were rehydrated at different temperatures, namely 25°C, 40°C, 55°C, 65°C and 80°C. Water sorption capacity (WSC) values exhibited by broccoli tissues largely depended on the temperature used. Broccoli tissues showed maximum WSC values when rehydration was performed at relatively low temperatures. A significant correlation was found between WSC and the total arabinose content of broccoli tissues. Further, sequential extraction of pectic polymers revealed that samples with lower WSC exhibited a larger solubilisation of neutral pectic side-chains, the florets sample being rehydrated at 40°C which better maintained the original pectin structure. Overall, the results suggest that arabinose-rich pectin neutral side-chains might play an important role on the water sorption process of dehydrated broccoli tissues.
Cell wall polysaccharides were investigated for their suitability as markers for quality and authenticity control of fruit products. For this purpose, the alcohol-insoluble residue (AIR) from several cultivars of apricots and peaches of different harvest seasons, provenances, and stages of ripeness was extracted and subsequently fractionated into acid- and EDTA/alkali-soluble pectins, hemicellulose, and cellulose. Each fraction was analysed for its neutral sugar composition by gas chromatography. In addition, analyses were also carried out on several cultivars of pumpkins because of their potential for use in fraudulent admixtures. Within the respective fruit species, characteristic neutral sugar profiles of the AIR and its fractions were observed, which were found to be independent of the cultivar, harvest season, and provenance. The fruit specific saccharide composition may be used for the differentiation of fruit products devoid of carbohydrate-based hydrocolloids. Furthermore, the isolated hemicellulose may also allow the detection of admixtures of non-specified fruit in complex fruit products, such as jams, spreads, and fruit preparations.
Apples (Malus domestica Borkh.) of two table and two cider cultivars were collected during fruit growth and maturation from the end of cell proliferation. Concentrations of flavonoids (flavan-3-ols, dihydrochalcones and flavonols) in the fruit flesh decreased sharply between circa 35 and circa 100 days after flowering. For hydroxycinnamic acids, the decrease appeared slower. In a second experiments apples of the cider cultivars Kermerrien and Avrolles were sampled every 2 weeks from 40 days after flowering to overripeness for a detailed characterisation of polyphenol accumulation kinetics in the fruit flesh. Most polyphenol synthesis had occurred at 40 days after full bloom, though it persisted at a low (Kermerrien) to very low (Avrolles) level during all the fruit growth. All qualitative characteristics of the polyphenols were remarkably stable. The degree of polymerisation of the procyanidins increased slightly in Avrolles and decreased in Kermerrien. This was accompanied by a relative increase in procyanidin B2, while size-exclusion chromatography of Kermerrien polyphenol extracts showed the disappearance of a highly polymerised fraction.
Olive fruits at three stages of ripening (green, cherry, and black) have been studied. After cell wall isolation, the compositions of the cell wall and that of the phosphate-soluble polysaccharides were determined. In cell walls, decreases in arabinose, xylose, glucose, and uronic acid levels were observed, together with a slight increase in mannose on ripening. At the beginning of ripening, fragments of pectic polymers were the major constituents of the phosphate-soluble fraction, with the hemicellulosic ones increasing toward the end of the process. The molecular weight of the fragments solubilized was approximately 6 kDa. After cell wall fractionation, the pectic polysaccharides soluble in imidazole and sodium carbonate were also studied. In both fractions, between the green and cherry stages of ripening, a significant loss of homogalacturonans took place. Between the cherry and black stages of ripening, rhamnogalacturonan side chains were also released in addition to homogalacturonans. In any of the pectic fractions, changes in apparent molecular weight were quantified.
Extraction of oil from almond fruits using supercritical carbon dioxide (SC-CO(2)) was carried out at 50 degrees C and 330 bar on three sets of almonds: raw almond seeds, raw almond kernels, and toasted almond seeds. Three different oil extraction percentages were applied on each set ranging from approximately 15 to 16%, from approximately 27 to 33%, and from approximately 49 to 64%. Although no major changes were detected in the fatty acid composition between fresh and partially defatted samples, carbohydrate analysis of partially defatted materials revealed important changes in cell wall polysaccharides from almond tissues. Thus, at low extraction percentages (up to approximately 33%), pectic polysaccharides and hemicellulosic xyloglucans were the main type of polymers affected, suggesting the modification of the cell wall matrix, although without breakage of the walls. Then, as supercritical fluid extraction (SCFE) continues and higher extraction rates are achieved (up to approximately 64%), a major disruption of the cell wall occurred as indicated by the losses of all major types of cell wall polysaccharides, including cellulose. These results suggest that, under the conditions used for oil extraction using SC-CO(2), fatty acid chains are able to exit the cells through nonbroken walls; the modification of the pectin-hemicellulose network might have increased the porosity of the wall. However, as high pressure is being applied, there is a progressive breakage of the cell walls allowing the free transfer of the fatty acid chains from inside the cells. These findings might contribute to providing the basis for the optimization of SCFE procedures based on plant food sources.
Fruits constitute a commercially important and nutritionally indispensable food commodity. Being a part of a balanced diet, fruits play a vital role in human nutrition by supplying the necessary growth regulating factors essential for maintaining normal health. Fruits are widely distributed in nature. One of the limiting factors that influence their economic value is the relatively short ripening period and reduced post-harvest life. Fruit ripening is a highly coordinated, genetically programmed, and an irreversible phenomenon involving a series of physiological, biochemical, and organoleptic changes, that finally leads to the development of a soft edible ripe fruit with desirable quality attributes. Excessive textural softening during ripening leads to adverse effects/spoilage upon storage. Carbohydrates play a major role in the ripening process, by way of depolymerization leading to decreased molecular size with concomitant increase in the levels of ripening inducing specific enzymes, whose target differ from fruit to fruit. The major classes of cell wall polysaccharides that undergo modifications during ripening are starch, pectins, cellulose, and hemicelluloses. Pectins are the common and major components of primary cell wall and middle lamella, contributing to the texture and quality of fruits. Their degradation during ripening seems to be responsible for tissue softening of a number of fruits. Structurally pectins are a diverse group of heteropolysaccharides containing partially methylated D-galacturonic acid residues with side chain appendages of several neutral polysaccharides. The degree of polymerization/esterification and the proportion of neutral sugar residues/side chains are the principal factors contributing to their (micro-) heterogeneity. Pectin degrading enzymes such as polygalacturonase, pectin methyl esterase, lyase, and rhamnogalacturonase are the most implicated in fruit-tissue softening. Recent advances in molecular biology have provided a better understanding of the biochemistry of fruit ripening as well as providing a hand for genetic manipulation of the entire ripening process. It is desirable that significant breakthroughs in such related areas will come forth in the near future, leading to considerable societal benefits.
Pretreatments by immersion in 10 and 100 mM CaCl2 prevent the loss in firmness of sweet frozen cherries. This effect can even be detected in fruits preserved for 6 months in a frozen state. The increase in firmness, through the treatments, is mostly apparent after freezing and is attributed to the formation of calcium bridges in the pectic material, caused by a decrease in the degree of, esterification of pectins and an increase in the pectic fraction soluble in EDTA and the Ca2+ cation content in the cell wall. These changes in the pectic materials are of an enzymatic origin, since we observed an increase in the pectinesterase activity of the fruits after treatments with increasing calcium concentrations.
A monoclonal antibody (2 F 4) recognizing a conformational epitope of polygalacturonic acid was used for immunogold localization of pectins in walls of suspension-cultured carrot (D. carota L.) cells at the electron microscopic level. In microcolonies of young or mature cells, polygalacturonic acid was essentially located on the middle lamella material expanded at three-way junctions between cells or lining intercellular spaces but was not found in primary walls. Middle lamellae far from junction zones and intercellular spaces were not recognized. Largely esterified pectic polymers, only detected by the 2 F 4 antibodies after on-grid de-esterification treatment by pectin methyl esterases, were present within all primary cell walls. Golgi bodies and associated vesicles were also labeled by the 2 F 4 antibodies only after de-esterification treatment, which indicates that pectic polymers are synthesized and secreted in a highly esterified form. A decrease of pectin esterification, which results probably from an in situ enzymatic de-esterification of the pectic polymers of the primary walls, was observed in senescent cells. These results are discussed in relation to biochemical analyses showing changes of the methyl ester content of pectins during the cell-wall growth.
Pectin methylesterase (PME, EC 3.1.1.11) is an ubiquitous enzyme in the plant kingdom; however, its role in plant growth and development is not yet understood. Using transgenic tomato (Lycopersicon esculentum Mill.) fruits that show more than 10-fold reduction in PME activity because of expression of an antisense PME gene, we have investigated the role of PME in tomato fruit ripening. Our results show that reduced PME activity causes an almost complete loss of tissue integrity during fruit senescence but shows little effect on fruit firmness during ripening. Low PME activity in the transgenic fruit pericarp modified both accumulation and partitioning of cations between soluble and bound forms and selectively impaired accumulation of Mg2+ over other major cations. Decreased PME activity was associated with a 30 to 70% decrease in bound Ca2+ and Mg2+ in transgenic pericarp. Levels of soluble Ca2+ increase 10 to 60%, whereas levels of soluble Mg2+ and Na+ are reduced by 20 to 60% in transgenic pericarp. Changes in cation levels associated with lowered PME activity do not affect the rate of respiration or membrane integrity of fruit during ripening. Overall, these results suggest that PME plays a role in determining tissue integrity during fruit senescence, perhaps by regulating cation binding to the cell wall.
Dietary fibre (DF) was defined by Trowell et al. in 1976 as all the polysaccharides and lignin in the diet that are not digested by the endogenous secretions of the human digestive tract. This definition embraces the polysaccharides and lignin of plant cell walls (CW) and also the small amount of polysaccharide food additives that makes up less than 2% of fibre in our diet. These may be present as plant gums, algal polysaccharides, pectins, modified celluloses and modified starches. Plant CW are the major source of DF and thus for analytical purposes DF refers mainly to the non-starch polysaccharides (NSP) and lignin in the diet (Southgate 1976). The food additives are, however, commercially available and have similar structural features to CW polysaccharides: for these reasons they have been used as model compounds to study the action of DF.
Unripe Spanish pears (Pyrus communis, c.v. Blanquille) were allowed to ripen at 18°C for 1 week. Cell walls were prepared as alcohol-insoluble residues (AIRS) which were free of starch. On a fresh weight basis, ripening was accompanied by a decrease in cell wall arabinose and uronic acid, a proportion of which were metabolised, and an increase in xylose and glucose. To investigate the origin of the changes in cell wall polymers, the AIRS of unripe and ripe fruit were extracted sequentially with water, cyclohexanetrans-1,2-diamine-N, N, N', N'-tetraacetate (CDTA), Na2CO3 at 1°C and 20°C, 0.5, 1 and 4M KOH to leave a cellulose-rich residue. The extracts and residues were analysed for their carbohydrate composition and, where appropriate, degree of pectin-methyl esterification. The water, CDTA and Na2C03 extracted polymers were rich in pectic polysaccharides. These exhibited heterogeneity in the ratios of neutral and acidic components and contained small quantities of xylose. The KOH-extracted polymers were rich in hemicelluloses, particularly xylans, but also contained sugars common to pectic polysaccharides. The cellulose-rich residues were rich in cellulosic glucose and xylose which probably originated from the highlylignified sclereids. Ripening resulted in an increase in water- and CDTA-soluble pectic polysaccharides which exhibited a lower degree of pectin-methyl esterification. These results and the changes in carbohydrate composition are discussed in the light of corresponding decreases in the yields of pectic polysaccharides of the Na2CO3 extracts and cellulose-rich residues during ripening.
Cell-wall material from parenchymatous tissues of apple was sequentially extracted with 50mm NaOH at 1°, m KOH at 1° and 20°, and 4m KOH at 20°, to leave a residue of α-cellulose. From the 4m KOH-soluble fraction, a crude xyloglucan was isolated by anion-exchange chromatography, and further resolved into seven xyloglucans by borate anion-exchange chromatography. The relative amounts of the xyloglucans, in order of elution, were 2.7:1.3:29.7:1.0:3.2:1.2:10.3. The structural features of five of the xyloglucans were determined by methylation analysis. These results show that apple xyloglucans exhibit heterogeneity.
Cells in plant tissue are surrounded by cell walls which are comparatively rigid and give mechanical support to the tissue. The walls of pome fruits, strawberry and tomato contain a high proportion of galacturonic acid, galactose and arabinose residues which are typical of pectic polysaccharides. The bonding between the polymers in the middle lamella, the region of the wall between adjacent cells, is thought to be ionic in nature involving Ca2+ and carboxyl groups of the pectic polysaccharides. Structural changes occur in the middle lamella and primary cell wall during ripening which lead to cell separation and softening of the tissue.Softening is characterised by an increase in the concentration of soluble pectic polysaccharide. In apple, the molecular weight of this fraction remains unchanged and endo-polygalacturonase (endo-PG), a random cleavage enzyme, is absent. Exopolygalacturonase (exo-PG), a terminal cleavage enzyme, is present and approximately 10% of the galacturonic acid residues of the cell wall are lost during ripening. In other fruits, such as pear and peach, both exo- and endo-PG activities develop and the molecular weight of the soluble pectic polysaccharide decreases. It is concluded that the softening observed in ripening fruits derives from the synthesis and transport to the cell wall of wall degrading glycosidases.
Two pectic fractions were extracted along the growth gradient of the mung bean hypocotyl. The first one (PF1) contained pectins soluble in boiling water and characterized by low uronic acids/cations ratio, high esterification degree and high neutral sugars/acidic sugars ratio. The second one (PF2) contained pectins insoluble in boiling water characterized by high uronic acids/cations ratio, low esterification degree, very low neutral sugar content and a high selectivity for calcium. Water soluble pectins were present in all the wall area whereas the other ones were detected mainly in the middle lamella. The PF1/PF2 ratio was high in fast growing tissues but low in mature, slowly growing tissues. The development of the cell wall exchange properties along the growth gradient was related to the changes observed in the PF1/PF2 balance.
Cell-wall polysaccharides were solubilised from cell-wall materials (CWMs) isolated from kiwifruit at 2 ripening stages, after treatment for 1 and 7 days with ethylene. The fractions soluble in cyclohexane-trans-1,2-diaminetetra-acetate (CDTA), Na2CO3, guanidinium thiocyanate (GTC), and KOH were purified by ion-exchange and gel-permeation chromatography, and subjected to methylation analysis. The pectic polymers in the 7-day fractions had increased proportions of 4-linked galactosyl, 2- and 2,4-linked rhamnosyl, and terminal arabinosyl, xylosyl, and galactosyl residues, and decreased proportions of 4-linked galacturonosyl residues. In the major Na2CO3-soluble pectic fraction, there was an increase in the proportion of branched polymers of high molecular weight during ripening. Therefore, a large proportion of the polyuronides may have been solubilised without significant structural modification, indicating that the action of endo-polygalacturonase was not involved. There was a decrease in Mw of the xyloglucan fraction during ripening, but no detectable changes in the primary structure or in the 4-O-methylglucuronoxylan and galactoglucomannan fractions.
Nectarines (Prunus persica, cv Fiesta Red) were harvested and either ripened for five days at 20° or stored for eight weeks at 0° in air or in a controlled atmosphere (CA) of 10% CO2 and 15% O2 before ripening. Air-stored fruit developed the flesh disorder of mealiness, while CA-stored fruit did not. During storage, the degree of esterification of the cell wall decreased in air- but not CA-stored fruits. Air-stored fruits retained more pectin in the sodium carbonate fraction after ripening and the polymers in the trans-1,2-diaminocyclohexane-N,N,N′, N′-tetraacetic acid (CDTA) and water-soluble fractions were of smaller M, than unstored or CA-stored fruits. Air storage also led to loss of arabinose from the sodium carbonate and guanidine thiocyanate fractions, and a lower arabinose content was also found in the CDTA fraction when air-stored fruits were ripened. The size distribution of componentsof the pectic fractions from air-stored fruits differed from fruits after harvest or CA-storage. In comparison with air-stored fruit, the CA-stored fruit showed changes in cell wall components which were very similar to those in fruit ripened immediately after harvest.
Several cell wall components in ripening pepino fruit have been quantitatively and qualitatively characterised, with the aim of identifying their contributions to the loss of tissue firmness. Pepinos were graded into nine groups based on progressive, characteristic skin colour changes, previously shown to correspond with decreasing fruit firmness. While fruit softening began when the pepinos were still green but with newly acquired purple stripes, the first significant quantitative signs of cell wall modification (total pectin and hemicellulose content declining and CDTA-soluble pectin content increasing, on a fresh weight basis) were detectable later in ripening, when the fruit began to acquire yellow skin pigmentation. Gel fractionation studies demonstrated that there were increased levels of low-molecular-weight pectin and xyloglucan during pepino ripening. The change in molecular weight distribution of CDTA-soluble pectin occurred as fruit started to acquire yellow pigmentation, while xyloglucan polymers were modified at an earlier stage that coincided with the initial loss of firmness. © 1997 SCI.
The growing use of agricultural and forest by-products as ruminant feed, and of the detergent system to determine their feeding value, makes it of interest to compare direct and sequential detergent analyses in order to examine the differences between them and the extent of accuracy.
The chemical composition of cereal straws (oat, barley, rye, wheat, maize) and legume straws (fenugreek, pea-grass, lupin, pea and bean), grapevines, fenugreek bagasse and poplar bark was determined by applying both methods. Lignin (measured as permanganate lignin) and cellulose (measured as sulphuric acid cellulose) showed the greatest differences (2·0 and 3·2%, respectively). Tannins (1·5% of DM) and cell-wall protein (2·0% of DM) could account for the discrepancy between both routines of analysis and for that between both lignin procedures.
Cell-wall material from the parenchyma of mature potato tubers was fractionated by successive extractions with cyclohexane-trans-1,2-diaminetetra-acetate (CDTA) at 20°, 0.05m Na2CO3 at 1° and 20°, 0.5m and m KOH at 1°, m and 4m KOH at 20°, and 4m KOH + borate at 20° to leave the α-cellulose residue, which contained a significant amount of pectic material. The isolated polymers were fractionated by anion-exchange chromatography. The CDTA-soluble pectic polysaccharides were less branched than those solubilised by Na2CO3. The Na2CO3 (20°) extract contained appreciably more neutral side-chains. The residual cell wall contained cellulose and a highly branched pectic polysaccharide with a significant content of (1→4)-linked galactose residues. There were two main types of xyloglucan that had different degrees of branching. The less branched, solubilised by stronger alkali, were more strongly associated with the cellulose microfibrils. The cell wall contained 1.7% of protein and the content of hydroxyproline was low. Several of the fractions contained protein (0.2–18.0%), but only the fraction solubilised by 4m KOH + borate contained a high level of hydroxyproline. The neutral component of this fraction was also rich in hydroxyproline and contained (1→2)- and (1→3)-linked arabinose.
Portions of stems from the base of asparagus spears (Asparagus officinalis L. cv. Connovor Collossus) were dissected to give the following tissues: (1) pith, which was free of vascular bundles, (2) two surrounding layers, parenchyma and fibre I and II (PFI and PFII), containing parenchyma and vascular bundles, (3) sclerenchyma sheath, (4) epidermis and sub-epidermal layers and (5) asparagus vascular fibre (AVF). The alcohol-insoluble residues (AIRs) from these tissues were shown to be free of starch. They were analysed for moisture and protein, and the component sugars were released by two hydrolytic procedures, which helped to distinguish the sugars from non-cellulosic polysaccharides and cellulose. The AIRs from pith and epidermal tissues were relatively low in xylose, but were rich in cellulosic glucose, and sugars associated with pectic polysaccharides such as galacturonic acid, galactose and arabinose. Their major component polysaccharides (in decreasing amounts) were inferred to be pectic polysaccharides, cellulose, and hemicelluloses. AIR from sclerenchyma was rich in glucose and xylose, suggesting the presence of much cellulose and (acidic) xylans. The AIRs of PFI, PFII and AVF contained significant amounts of xylose in addition tn other sugars, and the major polysaccharides inferred to be present were pectic polysaccharides, cellulose and hemicelluloses, a significant proportion of which may be acidic xylans. Methylation analysis of the AIRs confirmed the above inferences. The bulk of the glucosyl residues were (1–4)-linked, and there were small but significant amounts of (1–4, 6)-linked glucosyl residues (the linkage characteristic of xyloglucans) in all the preparations. The presence of (1–4)-linked galactosyl, (1–5)-linked arabinosyl, terminal galactosyl, terminal arabinosyl, (1–2)- and (1–2, 4)-linked rhamnosyl residues in all the AIRs except that from sclerenchyma, confirmed the presence of significant levels of pectic polysaccharides in all the parenchyma tissues. All the preparations containing vascular tissues contained significant amounts of (1–4)-linked xylosyl residues, probably derived from acidic xylans. Even in the AIR of pith, a significant amount of (1–4)-linked xylosyl residues were detected. This may be due to the ability of these cells and the parenchyma cells associated with the vascular bundles, to undergo lignification in mature asparagus plants.
Non-cellulosic neutral sugar composition of cell walls from seventeen fruit types were analysed during ripening. Galactose was the major non-cellulosic neutral sugar in cell walls of cucurbit and solanaceous fruit, xylose was the predominant non-cellulosic neutral component of berries, and arabinose was the major non-cellulosic component of pome fruits. The major non-cellulosic neutral sugar residue in cell walls of stone fruits varied. In nectarine and peach, plum, and apricot, the major sugar was arabinose, galactose, and xylose, respectively. In 15 of the 17 types of fruit, a net loss of non-cellulosic neutral sugar residues occurred during ripening. No net loss occurred in plums and cucumbers. A net loss of cell wall galactose and/or arabinose occurred in 14 of the types of fruit. Xylose was the major neutral sugar residue lost from walls of apricot during ripening. In general, berry cell walls were comparatively low in galactose and arabinose content.
Cell wall material was isolated from the pericarp of unripe and ripe tomatoes, free from intracellular compounds and active wall degrading enzymes. The wall preparations were sequentially extracted with cyclohexane-trans-1,2-diaminetetra-acetate (CDTA) at 20°, 0.05 M Na2CO3 at 1°, 0.05 M Na2CO3 at 20°, and 0.5, 1 and 4 M KOH at 20° to leave the α-cellulose residue, which contained a significant amount of pectic material. The polysaccharides isolated from the extracts were fractionated by anion-exchange chromatography and selected fractions were subjected to methylation analysis. The CDTA-soluble pectic polysaccharides had slightly-branched rhamnogalacturonan back-bones compared with the sodium carbonate-soluble pectic polysaccharides. The side chains of the pectic polysaccharides were mainly composed of β-(1→4)-Iinked galactopyranosyl and α-(1→5)-Iinked arabinofuranosyl residues, and the evidence for this was obtained by both methylation analysis and 13C NMR spectroscopy. The major hemicellulosic polysaccharide was a xyloglucomannan and there was evidence for the occurrence of a small amount of a xylan-pectic complex. The ripe fruit contained much less pectic galactans compared with the unripe fruit, and there was a significant decrease in the content of galactan side-chains of the ripe fruit. The hemicelluloses of the unripe and ripe fruit, however, showed negligible difference in composition.
Cell wall material (CWM) was prepared from sections of fresh and aerobically-stored asparagus (Asparagus officinalis, L. cv. Connovor Collossus) stems. Polymers were solubilized from the CWM by successive extraction with cyclohexane-trans-1,2-diamine-N N N' N'-tetraacetate (CDTA), Na2CO3 and KOH to leave the alpha-cellulose residue which contained a significant amount of cross-linked pectic polysaccharides. The polymers were fractionated by anion-exchange chromatography and selected fractions were subjected to methylation analysis. The storage-related decrease in (1-4)-linked Galp was detected in all the fractions rich in pectic polysaccharides, particularly in the CDTA, Na2CO3, 0.5 M KOH fractions and alpha-cellulose residue. A smaller decrease in Araf was also observed. This was mainly due to a decrease in (1-5)-linked Araf in the Na2CO3-1-soluble polymers, and terminal Araf in the alpha-cellulose residue. There was evidence for the occurrence of significant amounts of complexes containing pectic polysaccharides and xylans having a relatively low degree of polymerization in the dilute alkali-soluble polymers, and some of these contained phenolic compounds; the storage-induced increase in (1-4)-linked Xylp was confined to these polymers. Interestingly, no free acidic xylans could be detected in the 1 M and 4 M KOH-soluble polymers; instead, the bulk of the hemicellulosic polysaccharides appeared to be mixtures of xyloglucans and xylans in which the ratio of xyloglucan to xylan increased with increasing strength of alkali used for extraction of the polymers. The non-degradative extraction and fractionation procedures revealed heterogeneity in pectic polysaccharides, pectic polysaccharide-xylan complexes and xyloglucans in close association with xylans. The possible relationship between pectic polysaccharide-xylan-phenolic complexes and the onset of lignification in maturing tissues is discussed.
A new method for determination of uronic acids with meta-hydroxydiphenyl is introduced. It is simpler, quicker, more sensitive, and more specific than other methods, and it needs lesser amounts of fluid. It is recommended for determination of acid mucopolysaccharides in biological materials.
Pectic substances are a major component of cell walls in vegetable plants and have an important influence on plant food texture. Cauliflower (Brassica oleracea L. var. botrytis) stem sections at different regions of the mature plant stem have been monitored for tissue-related changes in the native pectic polysaccharides. Chemical analysis detected appreciable differences in the degree of methyl-esterification (ME) of pectic polysaccharides. About 65% of galacturonic acid (GalpA) residues were methyl-esterified in floret tissues. Relative ME showed a basipetal decrease, from 94% in the upper stem to 51% in the lower-stem vascular tissues. The decrease was not related to a basipetal increase in glucuronic acid (GlcpA) residues. The monoclonal antibodies, JIM 5 and JIM 7, produced distinct labelling patterns for the relatively low-methylesterified and high-methyl-esterified pectin epitopes, respectively. Labelling was related to cell type and tissue location in the stem. Floret cell walls contained epitopes for both JIM 5 and JIM 7 throughout the wall. Stem vascular tissues labelled more strongly with JIM 5. Whereas pith parenchyma in the upper stem labelled more strongly with JIM 7, in the lower-stem pith parenchyma, JIM 5 labelling predominated. Localization of pectic polysaccharide epitopes in cell walls provides an insight into how structural modifications might relate to the textural and nutritional properties of cell walls.
Cell walls of tomato (Lycopersicon esculentum Mill.) fruit, prepared so as to minimize residual hydrolytic activity and autolysis, exhibit increasing solubilization of pectins as ripening proceeds, and this process is not evident in fruit from transgenic plants with the antisense gene for polygalacturonase (PG). A comparison of activities of a number of possible cell wall hydrolases indicated that antisense fruit differ from control fruit specifically in their low PG activity. The composition of cell wall fractions of mature green fruit from transgenic and control (wild-type) plants were indistinguishable except for trans-1,2-diaminocyclohexane-N,N,N[prime],N[prime]-tetraacetic acid (CDTA)-soluble pectins of transgenic fruit, which had elevated levels of arabinose and galactose. Neutral polysaccharides and polyuronides increased in the water-soluble fraction of wild-type fruit during ripening, and this was matched by a decline in Na2CO3-soluble pectins, equal in magnitude and timing. This, together with compositional analysis showing increasing galactose, arabinose, and rhamnose in the water-soluble fraction, mirrored by a decline of these same residues in the Na2CO3-soluble pectins, suggests that the polyuronides and neutral polysaccharides solubilized by PG come from the Na2CO3-soluble fraction of the tomato cell wall. In addition to the loss of galactose from the cell wall as a result of PG activity, both antisense and control fruit exhibit an independent decline in galactose in both the CDTA-soluble and Na2CO3-soluble fractions, which may play a role in fruit softening.
Fractionation of pectic polysaccharides from the juice of ripening ;Bartlett' pears (Pyrus communis) gave two general types of polyuronides. The major type was a homogalacturonan (HGA) whose molecular weight decreased upon ripening. The other type comprised heteropolymers composed of various amounts of arabinose, rhamnose, and galactose. Treatment of the major arabinose-containing heteropolymeric fraction of high molecular weight (400,000) with a pear exo-polygalacturonase to degrade contaminating HGA gave a polyuronide which was inert to tomato endopolygalacturonase. Glycosyl-linkage analysis of this arabinosyl-polyuronide gave results expected from a rhamnogalacturonan I-like polysaccharide with large, highly branched araban side chains (RG-I). A linkage between HGA and RG-I was not found. RG-I, in ripening pears, appeared to be degraded with the initial loss of much of its arabinose.