Pectin Methyl Research Articles

Response of bio-extract coatings on decay, carotenoid and enzymes activity ofKinnow (<i>Citrus reticulata</i>)

Kinnow is a well-known mandarin grown in Haryana. Edible coatings are useful for controlling ripening by reducing the oxygen penetration into the fruits, thus, reducing metabolic activity and softening of fruits. Present study was carried out during 2019 and 2020 at Horticulture Farm, CCS Haryana Agricultural University, Hisar, Haryana. Kinnow fruits were treated with different bio-extract coatings, viz. Aloe vera extract, til oil, CMC, lac coating, lemongrass oil and commercial coating. The carotene content of the fruits did not differ significantly irrespective of the coatings. Decay loss and activities of pectin methyl esterase and cellulase were minimum resulting in better retention of the firmness in Aloe vera extract coated fruits. Minimum polygalacturonase activity was noticed in commercial coating treated fruits.

Gelation behavior between Nicandra physalodes (Linn.) Gaertn. pectin and Ca2+ is governed by degree and pattern of methylesterification

Nicandra physalodes (Linn.) Gaertn. Pectin (NPGP) is a new type of natural low methoxy pectin (LMP), however, the relatively poor gelling capacity of NPGP and neutral calcium limits its applicability in the food industry. In this study, we improved the gelling capacity of NPGP, and the impact of the degree and pattern of methyl esterification on NPGP gelation behavior triggered by neutral calcium was investigated. To achieve this goal, NPGP was treated with pectin methyl esterase (PME, 30 °C, pH 4.5) for various time. This modification decreased the degree of methyl esterification (DM) and generated different patterns of methyl ester distribution, quantified as the degree of blockiness (DB). The obtained PME-NPGPs possess the ability to form self-supporting gels in the presence of CaCl2, with the highest gel hardness being 331.98 g. By estimating the DM and quantifying the DB of PME-NPGP, the DB value of PME-NPGP was increased from 17.74% to 31.84% with DM decreasing from 33.09% to 17.37%, indicating a shift toward a more blockwise distribution of nonmethylated GalA in NPGP. Additionally, adsorption isotherms for Ca2+ on de-esterified NPGP were determined, enabling the quantification of its cation binding capacity and interaction energy. Reducing DM and increasing DB of NPGP were found to enhance NPGP's binding capacity to Ca2+. This research provides an important foundation for NPGP food processing, and the obtained PME-NPGP can be promising in the fields of food gel and drug delivery.

Salicylic acid and putrescine treatments reduce yellowing, decay and retain postharvest quality of bitter gourd (Momordica charantia L.) during cold storage

Bitter gourd is a valuable cucurbitaceous vegetable rich in various beneficial phytochemicals such phenols, antioxidants, saponins, charantin etc. In spite of high medicinal value bitter gourd faces significant postharvest losses due to factors such as mass reduction, tissue softening, yellowing, and fungal contamination, especially when stored under ambient conditions. To combat these issues, immature green bitter gourd fruits (16 DAP) were subjected to different concentrations of salicylic acid (SA) at 5, 7.5, and 10 mM) and putrescine (PUT) at 1, 2, and 3 mM, through a 15-minute dipping process. In contrast, untreated fruits were dipped in distilled water and served as the control group. These treated and control fruits were subsequently stored at 10 ºC with a relative humidity range of 85–95 % for 20 days. Results showed that among all treatments, bitter gourd fruits treated with 10 mM SA exhibited the most noteworthy outcomes. They retained higher levels of total phenols (26.28 μg GAE 100 g-1), radical scavenging activity (27.95 %), ascorbic acid content (50.0 mg 100 g-1 FW), and total chlorophyll (0.32 mg g-1 FW) on the 20th day of storage. Additionally, the 10 mM SA treatment demonstrated the highest inhibition of α-amylase and α-glucosidase activity, as well as the lowest decay percentage when compared to the control. On the other hand, 3 mM PUT treatment resulted in greater fruit firmness (27.45 N), lower per cent postharvest loss weight (6.60 %), and reduced pectin methyl esterase (PME) activity (0.0075 µmol min-1 g-1 FW). These findings were further validated through principal component analysis (PCA), which highlighted that bitter gourd fruits could be effectively stored for up to 20 days at 10 ºC with pre-storage treatment involving 10.0 mM SA and 3.0 mM PUT. Overall higher quality and shelf-life of bitter gourd were obtained in bitter gourd treated with 10.0 mM SA. Consequently, it is recommended that the application of SA and PUT represents an environmentally friendly approach to preserve the quality of bitter gourd during storage, benefiting both retailers and consumers alike.

Application of 1-MCP does not slow down the ripening process of Mango (Mangifera indica L)

Fruits and vegetables are perishable so that they are easily degraded and thus have a short shelf life. Some studies have been carried out intensively to extend the shelf life of fruit with the application of 1-methylcyclopropene (1-MCP) which is an ethylene inhibitor (indirectly) to slow down the ripening process and extend its shelf life. The benefits of using 1-MCP to delay fruit softening have also been published, however the inhibition of ripening and fruit softening by 1-MCP in mango (Mangifera indica) is very limited. 1-MCP delays fruit softening during storage by indirectly inhibiting ethylene synthesis and slowing the activity of cell wall-damaging enzymes, such as pectin methyl esterase (PME). To study the effect of 1-MCP on mango fruit quality and its shelf life, the experiment was carried out by measuring weight loss, colour, firmness, vitamin C, total soluble solids, titratable acidity, and reducing sugars periodically. For all fruit samples, the pulp was chopped, frozen in liquid nitrogen, and then stored at 8°C until further use. The results showed that application of 1-MCP at room temperature did not slow down neither the senescence process nor the shelf life of mango fruit on weight loss, colour, firmness, vitamin C, total soluble solids, titratable acidity, and reducing sugars parameters.

Hydrogen sulfide retards fruit softening and prevents flesh browning in cold-stored peaches by regulating cell wall-modifying enzymes, phenolic, and proline metabolism

Utilizing transcriptome analysis, higher expression of genes encoding hydrogen sulfide (H2S) synthetase in fruit stored at 0 ℃, where the expression pattern of differentially expressed genes (DEGs) correlated with softening and phenolic synthesis demonstrated more alterations than fruit storage at 5 ℃ and 15 ℃. Further research into how exogenous H2S affected the unappealing swift softening and internal browning (IB) of fruit was investigated. H2S orchestrated the cell wall-modifying enzymes, inhibiting polygalacturonase, cellulase, β-glucosidase, and pectin methyl esterase, and incompletely suppressing α/β-galactosidase and α-mannosidase during later storage. In H2S-treated fruit, total phenolic content was higher and IB symptoms were alleviated. In addition to enhancing phenylpropanoid metabolism, correlation analysis supported the hypothesis that H2S promoted phenolics in fruit by possibly facilitating proline accumulation. Cys192 and Cys217 of PpMYB75, which are involved in the biosynthesis of anthocyanin, were potential targets for persulfidation, and application of H2S reduced anthocyanin content in peach fruit. Together, our results demonstrate that H2S could ameliorate the chilling injury of cold-stored peach fruit and provide a perspective for controlling phenolic synthesis.

Texture classification and in situ cation measurements by SEM-EDX provide detailed quantitative insights into cell wall cation interaction changes during ageing, soaking, and cooking of red kidney beans

Hard-to-cook (HTC) is a textural defect that delays the softening of common bean seeds during cooking. While this defect is commonly associated with conventionally stored beans, soaking/cooking of beans in CaCl2 solutions or sodium acetate buffer can also prolong the cooking time of beans due to formation of Ca2+ crosslinked pectin retarding bean softening during cooking. In this study, the role of the cell wall-bound Mg2+/Ca2+ content and the degree of pectin methyl esterification (DM) was quantified, as important factors for bean texture-related changes stipulated in the pectin-cation-phytate hypothesis, the most plausible hypothesis of HTC development. Evaluation of texture changes during cooking of conventionally aged beans (35 °C and 83% RH for up to 20 weeks), beans soaked/cooked in CaCl2 solutions (0.01 to 0.1 M) or soaked in 0.1 M sodium acetate buffer (pH 4.4) revealed large bean-to-bean variations. Therefore a texture-based classification approach was used to better capture the relation between texture characteristics and cell wall polymer, in particular pectin, related changes. While cell wall-bound Ca2+ and pectin DM did not change/were not related to the texture variation during cooking of fresh beans, increased cell wall-bound Ca2+ and decreased pectin DM were associated with prolonged conventional storage of beans and their texture changes during subsequent cooking (due to pectin cross linking, retarding its solubilization during cooking). Exogenously added Ca2+ from pre-treating beans in CaCl2 solutions promoted to a great extent the cell wall-bound Ca2+ during soaking but even more so during cooking, complementing the harder texture associated with these beans during cooking (compared to conventionally stored and fresh beans). Similarly, free Ca2+ endogenously generated by phytase-catalysed phytate hydrolysis (beans treated by acetate buffer) promoted crosslinking of pectin by Ca2+ (cell wall-bound Ca2+), delaying softening of beans during cooking.

Effect of hydrodynamic cavitation processing on orange juice physicochemical and nutritional properties

Effect of hydrodynamic cavitation (HC) processing on pH, °brix, separation index, viscosity and color properties, retention of nutritional bioactive compounds (Vitamin-C, total phenolics, and antioxidant), and inactivation of enzyme pectin methyl esterase (PME) in freshly expressed juice from Brazilian oranges was investigated. HC at 4 bar pressures with a treatment time of 0, 10, 20, 30, 40, 50, 60, and 90 min at low temperatures (42 °C) were studied. There was no significant change in the values of pH, and TSS was noted in HC-treated juices. Further decreased flow behavior index while increased values of flow consistency index were recorded for the juice treated with HC showing a significant physical modification of the juice. Degradation and loss in vitamin C and total phenolics were observed when juices were HC-treated for a longer time. Therefore, it was concluded that HC could be used as a non-thermal method for improving the stability and physicochemical properties of Brazilian orange juice.

Application of thermosonication for guava juice processing: Impacts on bioactive, microbial, enzymatic and quality attributes

The present work explores different conditions of thermosonication (TS) processing that would ensure microbiological and enzymatic safety for guava juice while simultaneously maximizing the preservation of its quality attributes. The guava juice was subjected to TS treatment (frequency: 40 kHz; power: 200 W; Temperature: 40, 60, and 80 °C; Time: 2, 6 and 10 min) and was compared with fresh and pasteurized (90 °C/60 s) juice samples. The objectives of the research work were to determine the effect of thermosonication on the quality attributes such as total soluble solids (TSS), pH, titratable acidity, cloud value, color attributes, total phenolic contents, total flavonoid contents, antioxidant activity, ascorbic acid levels, enzymatic, microbiological, and sensory properties. The thermosonicated and pasteurized samples showed no significant (p > 0.05) changes in pH, total soluble solids, and titratable acidity. TS improved the cloud value and color attributes. Furthermore, TS enhanced total phenols (10 to17%), flavonoids (5 to 25%), antioxidant activity (10.45% to 14.55%) and retention of ascorbic acid (61.98–83.32%) relative to control. Thermosonicated sample at 80 °C/10 min gives the maximum inactivation of Pectin methyl esterase (PME), Peroxidase (POD) and Polyphenol oxidase (PPO) enzymes. While both thermosonication and pasteurization drastically decreased the microbial count to undetectable levels, only TS exhibited modest improvement in sensory qualities. The results demonstrated that TS can enhance the overall safety, quality, and commercial viability of guava juice as a practical substitute to pasteurization.

Effect of Cold Plasma Treatment on the Softening of Winter Jujubes (Ziziphus jujuba Mill. cv. Dongzao)

Cold plasma (CP) is a green and efficient preservation technology, but its effect on preventing the postharvest softening of fruits and vegetables is still unclear, and the effects of different CP intensities on the postharvest softening of winter jujubes (Ziziphus jujuba Mill. cv. Dongzao) have been little studied. In this study, we investigated the effects of different CP intensities (0 kV, 40 kV, and 80 kV) on the postharvest storage quality of winter jujubes and the activities of key enzymes related to softening during storage. The results showed that compared with the control group, the contents of firmness, total soluble solids (TSS), titratable acidity (TA), and vitamin C (VC) in the CP treatment group were higher and the respiratory intensity and weight loss rate were lower. In addition, CP treatment can also inhibit the degradation of protopectin and cellulose and the accumulation of soluble pectin. Moreover, CP treatment inhibited the activities of polygalacturonase (PG), pectin methyl esterase (PME), 3α-L-arabinoside (α-L-Af), 4β-galactosidase (β-gal), cellulase (Cx), and β-glucosidase (β-Glu). This shows that CP treatment has a positive effect on the preservation of winter jujubes, and the preservation effect of the 80 kV treatment was better than that of the 40 kV treatment. This provides a certain basis for cold plasma treatment in the preservation of winter jujubes.

NPs-Ca promotes Cd accumulation and enhances Cd tolerance of rapeseed shoots by affecting Cd transfer and Cd fixation in pectin

The use of rapeseed (Brassica napus) as a hyperaccumulator plant has shown great promise for the remediation of cadmium (Cd) contaminated soils. Nanosized materials (NPs) have been shown to mitigate heavy metal toxicity in plants, but it is unknown how l-aspartate nano-calcium (NPs-Ca) affects Cd uptake, transport, and tolerance in rapeseed. A soil pot experiment was conducted with two treatments: a control treatment (CK) with 2.16 g CaCl2 and NPs-Ca treatment with 6.00 g NPs-Ca, to evaluate the effects and mechanisms of NPs-Ca on Cd tolerance in rapeseed. Compared to CaCl2, NPs-Ca promoted Cd transportation from roots to shoots by up-regulating the expression of Cd transport genes (ABCC12, HMA8, NRAM6, ZIP6, CAX4, PCR2, and HIP6). Therefore, NPs-Ca increased Cd accumulation in rapeseed shoots by 39.4%. Interestingly, NPs-Ca also enhanced Cd tolerance in the shoots, resulting in lower hydrogen peroxide (H2O2) accumulation and proline content, as well as higher antioxidant enzyme activities (POD, CAT). Moreover, NPs-Ca reduced the activity of pectin-degrading enzymes (polygalacturonase: PG, β-galactosidase: β-GAL), promoted the activity of pectin methyl esterase (PME), and changed transcription levels of related genes (PME, PMEI, PG, PGIP, and β-GAL). NPs-Ca treatment also significantly increased the Cd content in cell walls by 59.8%, that is, more Cd was immobilized in cell walls, and less Cd entered organelles in shoots of NPs-Ca treatment due to increased pectin content and degree of pectin demethylation. Overall, NPs-Ca increased Cd accumulation in rapeseed shoots by promoting Cd transport from roots to shoots. And meantime, NPs-Ca enhanced Cd tolerance of shoots by inhibiting pectin degradation, promoting pectin demethylation and increasing Cd fixation in pectin. These findings suggest that NPs-Ca can improve the potential of rapeseed as a hyperaccumulator for the remediation of Cd-contaminated soil and the protection of the environment. Furthermore, the study provides a theoretical basis for the application of NPs-Ca in the phytoremediation of Cd-contaminated soils with hyperaccumulating plants.

Transcriptome Profiles Reveal the Promoting Effects of Exogenous Melatonin on Fruit Softening of Chinese Plum.

In this study, we investigated the effect of exogenous melatonin (MT) on cell wall metabolism leading to Chinese plum (Prunus salicina Lindl.) fruit softening. Exogenous MT treatment increased the endogenous MT content in plum fruits before fruit ripening. However, in mature plum fruits, exogenous MT treatment decreased the fruit hardness, pulp hardness, fruit elasticity, contents of ion-bound pectin, covalently-bound pectin, hemicellulose, and cellulose, and activities of xyloglucan endotransglycosylase/hydrolase and endo-β-1,4-glucanase, and increased the water-soluble pectin content, and activities of pectin methyl esterase, pectin lyase, polygalacturonase, β-galactopyranosidase, and α-L-arabinofuranosidase. Transcriptome analysis revealed that the differentially expressed genes (DEGs) associated with cell wall metabolism in the exogenous MT-treated plum fruits were mainly enriched in the pentose and glucuronate interconversions, phenylpropanoid biosynthesis, cyanoamino acid metabolism, and galactose metabolism pathways. Analysis of these DEGs revealed that exogenous MT treatment affected the expression of genes regulating the cell wall metabolism. Overall, exogenous MT treatment promotes the fruit softening of Chinese plum.

Mechanisms of persimmon pectin methyl esterase activation by high pressure processing based on chemical experiments and molecular dynamics simulations

High pressure processing (HPP) was found to have a kinase effect on persimmon pectin methyl esterase (PME), while the mechanism remains unclear. In this study, chemical experiments and molecular dynamics (MD) simulations were used to reveal its mechanisms. Persimmon PME was first extracted and purified using ion exchange columns with 81.89% purity. After 500 MPa/5 min, PME activity increased 11.3%, the α-helix and β-folding decreased 10.8% and 6.1% compared to the 0.1 MPa group, respectively. MD results showed that HPP decreased the volume, increased the number of hydrogen bonds between PME and pectin. Under high pressure, Asp-157, Asp-136 and Gln-135 in the enzyme activity center remained stable, while the positions of Arg-225 and Gln-113 changed a lot. The conformation of the substrate binding channel also changed. The secondary structure and volume changes of the HPP-treated PME affected the active center and substrate channels, ultimately altering the activity.

Harmonized biochemical modification of cell walls to get permission for entrance of Azospirillum sp. to rice roots

Biological nitrogen-fixation is important in increasing crop efficiency. Azospirillum is a nitrogen-fixing microorganism that naturally coexists with grasses roots. The present study was undertaken to clarify the role of rice root cell walls in the acceptance of two Azospirillum species, alone or in combination with indole-3-acetic acid (IAA) and gibberellic acid (GA3) treatments. Rice seedlings were grown in Yoshida solution for 21 days and then inoculated with A. brasilense and A. irakens in the presence of 0, 0.57, and 1.14 mM of IAA or 0, 0.29, and 0.58 mM GA3 or a combination of 1.14 mM of IAA and 0.58 mM of GA3. The results showed that the amount of hydrogen peroxide, lipid peroxidation, total nitrogen and activity of ferulic acid peroxidase, NADPH oxidase, nitrate reductase, pectin methyl esterase, cellulase, mannanase, xylanase and pectinase were significantly increased in inoculated samples treated with or without phytohormones. The highest activity of these enzymes was observed in A. brasilense- inoculated rice roots in auxin+gibberellin treatment. In the latter, the activity of phenylalanine ammonia lyase and wall ferulic acid peroxidase enzymes, the content of cell wall polysaccharide, lignin, and total phenolic compounds were the least, compared to controls and also with those samples which were inoculated with A. irakens. The results indicate an active role of the wall and its enzymes in allowing bacteria to enter the roots. Understanding this mechanism can improve the methods of inoculating bacteria into plants and increase crop efficiency, which will result in reduced use of chemical fertilizers and their destructive environmental effects.

Melatonin treatment delays the softening of blueberry fruit by modulating cuticular wax metabolism and reducing cell wall degradation

The effects of postharvest melatonin (MT) treatment on cuticular wax and cell wall metabolism in blueberry fruit (Vaccinium spp.) were evaluated. The results revealed that MT treatment maintained the cuticular wax rod-like structure and delayed wax degradation. The gas chromatography-mass spectrometry analysis results revealed that MT application changed the cuticular wax composition in blueberries, and 25 metabolic components were screened. The metabolic regulation of wax quality in blueberry fruit may therefore be influenced by MT. Additionally, MT slowed down pectin and cellulose degradation by reducing the activities of cell wall degrading enzymes like pectin methyl esterase polygalacturonase, β-galactosidase, and cellulose in the later stages of storage. It also downregulated the transcriptional expression of related genes like VcPE, VcPG, VcBG6, and VcGAL1. Thus, MT prevented softening and senescence by postponing the degradation of the cell wall in postharvest blueberry fruit.

Melatonin treatment inhibits mango fruit (Cv. ‘Guiqi’) softening by maintaining cell wall and reactive oxygen metabolisms during cold storage

Mango fruit (Mangifera indica L, cv. ‘Guiqi’) was treated with melatonin (1 mM) to explore the changing mechanisms in fruit softening and to examine the effects of melatonin on the interaction between the cell wall and reactive oxygen metabolisms subjected to cold storage. The results depicted that compared to control, melatonin treatment (1) improved storage life by maintaining the higher ascorbic acid (AsA) and reduced glutathione (GSH) contents, as well as maintained higher insoluble pectin, hemicellulose, and cellulose contents, and lower soluble pectin content of ‘Guiqi’ mango fruit. (2) Delayed fruit softening by maintaining higher firmness and suppressing the activities of polygalacturonase (PG), pectin methyl esterase (PME), cellulase (Cx), and β-glucosidase (β-glu); and cell wall degrading genes (MiPG14, MiPME, MiCel, and Miβ-glu). (3) Enhanced storage quality by inhibiting decay incidence, respiration rate, and weight loss rate; increased activity of glutathione reductase (GR) and inhibits reactive oxygen species (ROS) metabolites at cold storage. These results indicate that exogenous melatonin could delay mango fruit softening by maintaining cell wall metabolism, inhibiting ROS metabolites (O2.- and H2O2) accumulation via enhancement of non-enzymatic (AsA and GSH contents) and enzymatic (GR activity) antioxidants, and thus maintaining quality and improved storage life.

Dynamic changes occur in the cell wall composition and related enzyme activities during flower development in Rosa damascena.

The flowering period of oil-bearing rose is short and many physiological processes occur during flower development. Changes in the cell wall composition and associated enzyme activities are important as they allow cells to divide, differentiate and grow. In the present study, changes in seven cell wall components and six cell wall-related enzyme activities at five flower development stages were investigated and the relationships between these parameters and flowering were examined. Ash content did not change between stages I to II but decreased at later stages. Neutral detergent fiber (NDF), acid detergent fiber (ADF) and hemicellulose contents increased after stage I but did not change significantly at the other developmental periods. Total pectin content increased throughout flower development. An "increase-decrease" trend was observed in total cellulose content and a "decrease-increase" pattern in uronic acid content. The activities of both glycosidases (β-galactosidase, β-glucosidase and endoglucanase) and pectinases (pectin lyase, pectin methyl esterase and polygalacturonase) increased until stage IV and decreased significantly at stage V of flower development. Correlation analysis revealed 14 positive and one negative correlation with the studied parameters. Cell wall enzymes showed positive correlations with each other. Principal component analysis (PCA) showed that ADF, NDF and cellulose content were significantly altered at stage II of flower development, and significant changes occurred in all cell wall enzyme activities between stages III and V. Overall, blooming is correlated closely with increased pectin and decreased cellulose contents, and changes in cell wall glucosidase and pectin hydrolysis enzyme activities. These results show that cell wall modifying enzymes are part of the flower development process in oil-bearing rose. Therefore, remodeling of cell wall components in petals is a process of flower development.

Pectin modifications promote haustoria development in the parasitic plant Phtheirospermum japonicum.

Parasitic plants are globally prevalent pathogens with important ecological functions but also potentially devastating agricultural consequences. Common to all parasites is the formation of the haustorium which requires parasite organ development and tissue invasion into the host. Both processes involve cell wall modifications. Here, we investigated a role for pectins during haustorium development in the facultative parasitic plant Phtheirospermum japonicum. Using transcriptomics data from infected Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa), we identified genes for multiple P. japonicum pectin methylesterases (PMEs) and their inhibitors (PMEIs) whose expression was upregulated by haustoria formation. Changes in PME and PMEI expression were associated with tissue-specific modifications in pectin methylesterification. While de-methylesterified pectins were present in outer haustorial cells, highly methylesterified pectins were present in inner vascular tissues, including the xylem bridge that connects parasite to host. Specifically blocking xylem bridge formation in the haustoria inhibited several PME and PMEI genes from activating. Similarly, inhibiting PME activity using chemicals or by overexpressing PMEI genes delayed haustoria development. Our results suggest a dynamic and tissue-specific regulation of pectin contributes to haustoria initiation and to the establishment of xylem connections between parasite and host.

Microfluidization of juice extracted from partially granulated citrus fruits: Effect on physical attributes, functional quality and enzymatic activity

Citrus juice sac granulation reduces the yield of extractable juice and impairs its nutritional and functional quality. Therefore, present study was carried out to improve the physico-functional quality of juice extracted from partially granulated ‘Dancy’ tangerine. Juice was passed through microfluidizer under varying pressure (41, 62, 83, 103, 124 MPa) for different number of passes (1, 2, 3). The microfluidized juice was evaluated for different quality attributes, viz. cloud value, fractal dimension, lacunarity, colour attributes and pectin methyl esterase (PME) activity. Naringin and hesperidin were quantified through HPLC. Control juice exhibited the highest fractal dimension (18.89), indicating irregular cell structure, while 103MPa/3 passes (1.04) displayed the lowest indicating uniformity in juice. Microfluidized juice showed improved opalescence stability, greater hue, low PME activity and augmented hesperidin and naringin contents. Juice treated at 103 MPa for a single pass exhibited the best organoleptic quality. The high pressure applied during microfluidization can drastically improve the quality of otherwise low quality juice extracted from granulated citrus fruits. Application of appropriate processing pressure and number of passes through the microfluidizer yields citrus juice possessing enhanced bioactive constituents, reduced enzymatic activity with good organoleptic acceptability.

The Structure-Forming Potential of Selected Polysaccharides and Protein Hydrocolloids in Shaping the Properties of Composite Films Using Pumpkin Purée

The work aimed to investigate the rheological properties and the gelling process of selected film-forming solutions obtained based on hydrocolloids, such as sodium alginate, highly methylated pectin, and soy protein isolate with the addition of pumpkin purée. It was found that both concentration of hydrocolloid and the addition of pumpkin purée affected the rheological parameters. The non-linear nature of the flow curves was demonstrated, which allowed the curves to be described using the Ostwald de Waele model. The addition of pumpkin purée and the concentration of the structure-forming substance affected the apparent viscosity of the composite film-forming solutions. Considering the applied parameters, only the gelation temperature of composite gelatin film-forming solutions with the addition of pumpkin purée was possible to determine. Additionally, degassing of the solutions with the addition of pumpkin purée resulted in the reduction of the aeration degree and smoothening of the edible films’ surface.

Genome-wide identification and functional characterization of pectin methylesterase inhibitors associated with male sterility in wheat

Pectin methylesterase inhibitors (PMEIs) can specifically bind to pectin methylesterases (PMEs) and regulate their enzymatic activities to control the status of pectin methyl esterification, which plays crucial roles in stabilizing the cell wall properties during plant growth and development. Although the evolution and biological functions of the PMEI gene family in various plants have been well characterized, the role of PMEI genes in wheat was poorly understood. In this study, a total of 237 PMEI genes (TaPMEIs) were identified in wheat (Triticum aestivum L.), which were dispersed irregularly over 22 chromosomes and tissue-specific in their expression. They were divided into nine groups based on similar motif number and composition. Using quantitative real-time PCR analysis, we discovered that TaPMEI23 as the most abundant-expressed PMEI in anther and significantly upregulated expression in fertile anthers. Moreover, subcellular localization analysis indicated that TaPMEI23 was localized on the plasma membrane or cell wall. Effective silencing of the TaPMEI23 significantly influences the anther dehiscence, pollen activity, seed setting rate, and male fertility, suggesting that PMEIs are necessary for pollen development and male sterility. Our work provides novel insights into the functions of PMEIs in wheat.