The effect of postharvest calcium application in hydro-cooling water on tissue calcium content, biochemical changes, and quality attributes of sweet cherry fruit

Recent advances in the preservation of postharvest fruits using edible films and coatings: A comprehensive review

In recent years, there has been considerable growth in the creation of edible films and coatings, which is predicted to have a major impact on fruit quality in the coming years. Consumers want fresh fruits that are pesticide-free, good quality, high nutritional value, and a long shelf life. The use of edible coatings and films on fruits is an environmentally dependable approach to a creative solution to this problem. The application, recent trends, and views of coatings and edible films, as well as their impact on fruit quality, are presented in this article, along with a knowledge of their key roles and benefits. According to numerous studies, natural polymers are highly suited for use as packaging material for fresh fruits and can often be a viable alternative to synthetic chemicals. Plasticisers, surfactants, cross-linkers, antimicrobial agents, functional additives, nanoparticles, and fruit and vegetable residues can be used to alter the properties of edible coatings.

Study of Mineral Composition and Quality of Fruit Using Vascular Restrictions in Branches of Sweet Cherry

Calcium (Ca) and carbohydrate (CHO) supply in sweet cherry have been associated with fruit quality at harvest and during storage. There is little published information integrating CHO and Ca availability and distribution in sweet cherry and their effects on fruit quality. Accordingly, in the 2019-20 season, vascular restrictions were imposed on the phloem (girdling, G, stopping phloem flow) and xylem (transverse incision, S, cutting 50% of xylem cross-section area) of individual vertical branches of the sweet cherry combination 'Lapins'/Colt trained as Kym Green Bush system to modify mineral and CHO composition in fruit and associate such changes with quality at harvest and storage. The girdling to the phloem was used to induce changes in CHO distribution. The transverse incision to the xylem was a tool to modify Ca distribution. Five treatments (TR) were implemented: TR1-CTL = Control (without vascular restriction), TR2-G, at its base, TR3-G + G: at its base, and G further up at the change of year between the second and the third years of growth TR4--S and TR5-S + G. The vegetative (i.e., shoot and leaf growth), reproductive (i.e., fruit set and yield) development and stomatal conductance were monitored. Each branch was divided into the upper (1-and 2-year-old wood) and the lower (3-and 4-year-old wood) segments of the restriction applied. The quality and mineral composition (Ca, Mg, K, and N) of fruit borne on each segment were measured at harvest. The upper segment of TR3-G + G branches were harvested 10 d before the lower segment. The fruit from the upper segment of TR3-G + G was the largest, the sweetest, and had the higher titratable acidity concentration. However, fruits of this segment were the softest, had the lowest Ca concentrations, and had the highest ratios of N:Ca and K:Ca, compared with the other TRs. TR3-G + G branches developed the highest number of lateral current season shoots including shoots below the second girdling in the lower segment of the branch. This vegetative flow of growth would explain the mineral unbalance produced in the fruit from the upper segment of the branch. TR2-G did not register changes in fruit quality and mineral concentration compared with TR1-CTL. Surprisingly, the fruit from the branches with xylem restriction did not show changes in Ca concentration, suggesting that the xylem stream was enough to supply the fruit in branches without lateral shoot development. Fruit firmness was positively related to fruit Ca concentration and negatively related to the ratios of K:Ca and N:Ca.

Impact of Pre-Storage Melatonin Application on the Standard, Sensory, and Bioactive Quality of Early Sweet Cherry

Melatonin (N-acetyl-5-methoxytryptamine) is involved in multiple functions in plants. However, its role in some metabolic pathways and exogenous application's effect on fruits is still unclear. Furthermore, the effects of pre-storage melatonin treatment on sensory traits and consumer acceptance of cherries have yet to be studied. For this reason, the early sweet cherry cultivar 'Samba' harvested at the commercial ripening stage was treated with different melatonin concentrations (0.1, 0.3, and 0.5 mmol L^-1) and stored for 21 days under controlled cold temperature and humidity. The standard quality, respiration rate, postharvest aptitude, sensory quality, phenols, and antioxidant systems (non-enzymatic and enzymatic) were analysed at 14 and 21 days of storage. Postharvest treatment with melatonin 0.5 mmol L^-1 improved firmness and reduced weight loss and non-commercial fruit percentage while increasing respiration rate, lipophilic antioxidant activity, and ascorbate peroxidase enzyme activity. Furthermore, the treated cherries showed better sensory qualities, such as uniformity of colour and skin colour, as well as being sourer and showing better consumer acceptance and liking after 14 days of storage. Therefore, we conclude that the 0.5 mmol L^-1 concentration is effective on the standard, sensory, and bioactive quality of early sweet cherries and can be considered an eco-friendly tool for maintaining the postharvest quality of early cherries.

Foliar Application of CaCO3-Rich Industrial Residues on 'Shiraz' Vines Improves the Composition of Phenolic Compounds in Grapes and Aged Wine

The quality of wine grapes and wine depends on their content of phenolic compounds. Under commercial conditions, the phenolic maturity of grapes is mostly achieved by applying abscisic acid analogues. Some Ca forms represent a cost-effective alternative for these compounds. In this study, 'Shiraz' vines (veraison of 90%) were sprayed with CaCO₃-rich residues from the cement industry (4.26 g of Ca per L). Fruit from treated and untreated vines was harvested 45 days after CaCO₃ spraying and evaluated for quality. The fruit was vinified, and the obtained wines were bottled and stored in darkness for 15 months at 20 °C. Wines were evaluated for quality after storage. The evaluation of grape and wine quality included the content of phenolic compounds and antioxidant capacity. The treatment with CaCO₃ did not affect the ripening rate of grapes. However, the treatment improved the fruit yield as well as the color development, the content of phenolic compounds, and antioxidant capacity of grapes and wine. The treatment favored especially the accumulation of malvidin-3-O-glucoside, pelargonidin-3-O-glucoside, caftaric acid, caffeic acid, trans-cinnamic acid, quercetin, catechin, epicatechin, resveratrol, and the procyanidins B1 and B2. Wine made with treated fruit was of higher quality than that of control fruit.

Application of Whey Protein-Based Emulsion Coating Treatment in Fresh-Cut Apple Preservation

Fresh-cut fruit requires an edible and water-resistant coating to remain fresh. This article investigated the effects of transglutaminase (TGase) and sunflower oil on the water-resistant characteristics, mechanical properties, and microstructure of a whey protein-based film. The whey protein-based emulsion coating’s preservation effect on fresh-cut apples was confirmed. According to the findings, sunflower oil (added at 1.5% w/w) could interact with β-lactoglobulin, α-lactoglobulin dimer, and β-lactoglobulin dimer to form emulsion droplets that are evenly dispersed throughout the protein film. This effect, combined with the covalent cross-linking of TGase, significantly improves the films’ microstructure, mechanical properties, and water resistance. However, too much and unevenly distributed sunflower oil (add 3% w/w) partially prevented the covalent cross-linking of TGase, reducing the elongation at the break of the composite film. In the fresh-cut apple storage experiment, the whey protein-based emulsion coating treatment significantly reduced the weight loss rate and browning index of fresh-cut apples by 26.55% and 46.39%, respectively. This was accomplished by the coating treatment significantly inhibiting the respiration rate increase, PPO and CAT activity enhancement, H2O2 production, and MDA accumulation. This research provides practical, technical, and theoretical guidance for the preservation of fresh-cut fruit.

Methods for quality evaluation of sweet cherry

Sweet cherry (Prunus avium L.) is a highly valued fruit, whose quality can be evaluated using several objective methodologies, such as calibre, colour, texture, soluble solids content (SSC), titratable acidity (TA), as well as maturity indexes. Functional and nutritional compounds are also frequently determined, in response to consumer demand. The aim of the present review is to clarify and establish quality evaluation parameters and methodologies for the whole cherry supply chain, in order to promote easy and faithful communication among all stakeholders. The use of near-infrared spectroscopy (NIRS) as a non-destructive and expeditious method for assessing some quality parameters is discussed. In this review, the results of a wide survey to assess the most common methodologies for cherry quality evaluation, carried out among cherry researchers and producers within the framework of the COST Action FA1104 'Sustainable production of high-quality cherries for the European market', are also reported. The standardisation of quality evaluation parameters is expected to contribute to the preservation and shelf-life extension of sweet cherries, and the valorisation of the whole supply chain. For future studies on sweet cherry, we put forward a proposal regarding both sample size and the tests chosen to evaluate each parameter. © 2022 Society of Chemical Industry.

Moisture Sorption Isotherms of Sweet Cherry (Prunus Avium L.): Comparative Study of Kinetics and Thermodynamic Modeling of Five Varieties

Moisture sorption isotherms of five sweet cherry cultivars (Prunus avium L.) at three temperatures of 30°C, 40°C, and 50°C, and water activity range of 0.057–0.898 were determined using the static gravimetric method. The sorption isotherms of all cultivars decreased with increasing temperature, and they all exhibited type II behavior according to the classification of IUPAC (International Union of Pure and Applied Chemistry). The isosteric heat of sorption, differential entropy, spreading pressure, and water surface area were determined, and the energy associated with the sorption processes was defined. The curves were fitted to GAB, PELEG, and ENDERBY models, and the GAB model gave the best fit for the whole set of data. The enthalpy–entropy compensation proved that the process occurs spontaneously and is fully controlled the enthalpy. The spreading pressure value varied with temperature in all sweet cherry cultivars in both the desorption and adsorption processes. The average surface area varied from 78.05 to 214.02 m²/g for desorption and from 49.0 to 204.4 m²/g for adsorption from 30 to 50°C.

Effects of postharvest coating using chitosan combined with natamycin on physicochemical and microbial properties of sweet cherry during cold storage

Sweet cherry is prone to senesce and decay due to high postharvest respiration rate and fungal infection. The effects of natamycin-chitosan coating on physicochemical and microbial properties of sweet cherries stored at 4 °C were investigated. Scanning electron microscopy results revealed that natamycin was more uniformly distributed on sweet cherry pericarps with the help of chitosan coating. Respiration rate of sweet cherries was suppressed by chitosan coating during the storage and as a result, total soluble solids (13.53 %-13.80 %) and titratable acidity (0.91 %-0.93 %) were remained higher values and weight loss (2.54 %-2.85 %) was decreased in chitosan and natamycin-chitosan groups. Although both natamycin and chitosan were effective in inhibiting yeast and mold, sweet cherries treated with the combination of natamycin and chitosan showed significantly lower yeast and mold count (3.31 log CFU/g) and decay rate (1.67 %) compared with control. Natamycin combined chitosan inhibited the pathogenic fungi of sweet cherries, such as Alternaria, Cladosporium and Penicillium. These results indicated that postharvest natamycin-chitosan coating has great advantages in maintaining fruit quality, inhibiting fungi, and reducing decay rate of sweet cherry.

Comparative physiological and transcriptomic analysis reveal MdWRKY75 associated with sucrose accumulation in postharvest 'Honeycrisp' apples with bitter pit

BACKGROUND

Calcium (Ca) deficiency can cause apple bitter pit, reduce the quality and shelf life. WRKY transcription factors play essential role in plant response to multiple disorders. However, the underlying mechanisms causing bitter pit in apple fruit due to Ca deficiency during storage is extremely limited.

RESULTS

In the present study, the nutritional metabolites and reactive oxygen species (ROS) were compared in Ca-deficient and healthy apple fruit (CK) during storage. Results showed that Ca-deficient apples sustained significantly higher production of ROS, PPO activity, flavonoids, total phenol, total soluble solids (TSS), and sucrose contents, but the contents of Ca, H₂O₂, titratable acids (TA), glucose and fructose were significantly lower than those of CK during storage. Principal component analysis (PCA) showed that TSS, •O₂^-, PPO, malondialdehyde (MDA) and Ca were the main factors, and TSS had a positive correlation with sucrose. Furthermore, transcriptome analysis revealed that WRKYs were co-expressed with sucrose metabolism-related enzymes (SWEETs, SS, SPS). qRT-PCR and correlation analysis indicated that MdWRKY75 was correlated positively with MdSWEET1. Moreover, transient overexpression of MdWRKY75 could significantly increase the sucrose content and promote the expression of MdSWEET1 in apple fruit.

CONCLUSIONS

Calcium deficiency could decrease antioxidant capacity, accelerate nutritional metabolism and up-regulate the expression of WRKYs in apple with bitter pit. Overexpression of MdWRKY75 significantly increased sucrose accumulation and the expression of MdSWEET1. These findings further strengthened knowledge of the basic molecular mechanisms in calcium deficiency apple flesh and contributed to improving the nutritional quality of apple fruit.

Effects of the Use of Different Temperature and Calcium Chloride Treatments during Storage on the Quality of Fresh-Cut “Xuebai” Cauliflowers

This study revealed the effect of the use of different temperature and calcium chloride (CaCl₂) treatments on the storage quality of fresh-cut “Xuebai” cauliflowers. Fresh-cut “Xuebai” cauliflowers were soaked with 2% CaCl₂ solution at different temperatures. The change in the firmness, color, and ascorbic acid (ASA), total glucosinolates (TGLS), polygalacturonase (PG), and lipoxygenase (LOX) content of fresh-cut “Xuebai” cauliflowers during the cold storage period was assessed. In addition, the sensory quality was also evaluated. The results show that the combined treatments with CaCl₂ at different temperatures could effectively maintain the storage quality of fresh-cut “Xuebai” cauliflowers. Then, a method based on factor analysis with comprehensive quality evaluation was proposed. A factor analysis with a principal component analysis (PCA) was conducted on nine indicators of cauliflowers. Two principal components were extracted with a cumulative contribution rate of 97.513%. The results demonstrated that the treatment with the best fresh-keeping effect of cauliflowers in storage was the combination treatment at 40 °C with 2% CaCl₂ solution, while the optimal storage period was 15 days.

The Effect of Pre- and Postharvest Calcium Gluconate Treatments on Physicochemical Characteristics and Bioactive Compounds of Sweet Cherry during Cold Storage

The effects of pre- and postharvest calcium gluconate (Ca-Glu) treatments on some physicochemical characteristics and bioactive compounds of sweet cherry cv. Sweetheart during cold storage were investigated. For preharvest treatments, the Ca-Glu (1%) solution was applied to the cherry trees two times at 21 and 35 days after full bloom stage. Control trees were sprayed with distilled water at the same days. Sweet cherries, sprayed with and without Ca-Glu, were dipped into cold water (4°C) containing calcium gluconate (1%) for 30 s and only in cold water (4°C) as control, after harvest Following each treatment, cherries were placed in plastic boxes and stored at 1 ± 0.5 °C and 90 ± 5% relative humidity for 3 weeks. The weight losses of cherries increased over time but calcium (Ca) treatments, especially pre-and postharvest combination, limited these increases compared to control groups. The best result for suppressing the respiration rate of cherries was also obtained from combined treatment. Moreover, combined treatment delayed the losses of titratable acidity, fruit firmness, decay rate and sensory quality in sweet cherries during storage comparison with the pre or postharvest application of Ca-Glu alone. The effect of Ca-Clu treatments on stem chlorophyll content and antioxidant activity was not significant. Preharvest and combined treatments retarded the loss of ascorbic acid content of cherries compared to postharvest and control treatments. The total phenolic and anthocyanin content increased regularly throughout storage, regardless of treatment; however, Ca treatments delayed the accumulation of these compounds. As a result, the combined Ca-Glu treatment could be a promising method for maintaining some physicochemical characteristics and bioactive compounds in sweet cherries during cold storage.

Inhibitory Effects of CaCl2 and Pectin Methylesterase on Fruit Softening of Raspberry during Cold Storage

Quality of raspberry fruit experiences a rapid decline after harvest due to its vulnerable texture and high moisture content. Application of calcium chloride (CaCl2) combined with pectin methylesterase (PME) is efficient in delaying fruit softening. In this study, the effects of exogenous CaCl2 alone or in combination with PME on the structure of the cell wall, the molecular properties of pectin, and the amount of free water of raspberry during postharvest storage were investigated. The results showed that CaCl2 combined with PME treatment could maintain fruit firmness and inhibit weight loss. The treatment of CaCl2+PME maintained the cell wall structure via sustaining middle lamella integrity and reducing the activities of cell wall-degrading enzymes, such as polygalacturonase, pectin methylesterase, β-galactosidase, α-L-arabinofuranosidase, and β-xylosidase. In addition, CaCl2+PME treatment could effectively increase the content of chelate-soluble pectin (CSP) and develop a cross-linked structure between Ca2+ and CSP. Moreover, CaCl2+PME treatment was of benefit in maintaining free water content. CaCl2 in combination with PME treatment could be a promising method for inhibiting softening and maintaining the quality of postharvest raspberry during cold storage.

Effect of calcium treatment on the browning of harvested eggplant fruits and its relation to the metabolisms of reactive oxygen species (ROS) and phenolics

Eggplant is a popular vegetable in Asia; however, it has a short storage life and considerable economic losses have resulted from eggplant browning. Calcium has been reported to play a key role in the postharvest storage of plants. Here, we found that exogenous calcium application could delay eggplant fruit browning and maintain higher storage quality. The increased browning index (BI), relative electrolytic leakage (REL), and water loss were suppressed by calcium treatment during storage. Delayed browning with calcium treatment might result from a higher phenolic level and suppressed the activity of polyphenol oxidase (PPO). Less H2O2 and O2 - but more activated reactive oxygen species (ROS) scavenging enzymes accumulated in calcium-treated fruits than in H2O-treated fruits. Moreover, the nonenzymatic antioxidant, ascorbic acid (AsA), was accumulated more in calcium-treated eggplant fruits. Taken together, our data demonstrated that exogenous calcium application delayed eggplant fruit browning by regulating phenol metabolism and enhancing antioxidant systems.

Identification of the Causal Agent of Aqueous Spot Disease of Sweet Cherries (Prunus avium L.) from the Jerte Valley (Cáceres, Spain)

The pre and postharvest disease named ‘aqueous spot’ is an emerging risk for sweet cherries growing in Jerte Valley (Cáceres, Spain). Early stages of the disease appear in the tree, but it is usually detected after harvesting, during the postharvest period. Symptoms include the appearance of skin discolouration and translucency in the shoulder areas. At the most advanced stages, a mycelium of white colour partially or completely covers the fruit. This manuscript provides a detailed description of the microbes involved in this disease, such as bacteria, yeasts, and moulds. Microbes of different cherry cultivars were studied during two consecutive seasons (2019 and 2020). The counts of bacteria and yeast in damaged tissues were higher (7.05 and 6.38 log10 CFU/g for total aerobic mesophilic microbes and yeasts, respectively) than sound tissues (6.08 and 5.19 log10 CFU/g, respectively). The Enterobacterales order dominated the bacteria population. Among yeasts, Yarrowia lipolytica, in 2019, and Metschnikowia pulcherrima and Metschnikowia viticola, in 2020, were consistently isolated from all samples. The presence of moulds was inconsistently detected at the early stage of this disease by plate counts. However, microscopic observations revealed the presence of hyphae in cherry flesh. Different pathogenic moulds were identified, although white mycelium, identified as Botrytis cinerea by molecular methods, was consistently isolated at later stages. Inoculation tests confirmed the involvement of white-mycelium B. cinerea in the development of this new postharvest disease in the Jerte Valley. Its combination with Enterobacterales enhanced the evolution of rotting, whereas the combination with yeasts decreased and delayed the symptoms. This work presents the first report of a consortia of microorganisms implicated in the development of ‘aqueous spot’, an emerging disease in sweet cherry cultivars in the Jerte Valley.

Vineyard calcium sprays reduce the damage of postharvest grape berries by stimulating enzymatic antioxidant activity and pathogen defense genes, despite inhibiting phenolic synthesis

Calcium supplements have been increasingly used for decay prevention, sanitation and nutritional enrichment of fruits, as more environmentally friendly alternatives to fungicides. However, little is known on the effects of these supplements on grape berry biochemical and molecular properties during storage. In this study, we addressed the hypothesis that the application of calcium chloride (CaCl₂) in grapevines throughout the fruiting season reduces damage (and decay) of postharvest grape berries, through several biochemical and transcriptional modifications in sugar transport, secondary metabolism, antioxidant activity, cell wall organization and pathogen defense. Results showed that calcium (Ca) treatments in cv. "Vinhão" vines increased fruit Ca content and significantly decreased fruit damage by 60%, 10-d after storage at 4 °C. Grape berries from Ca-treated vines displayed lower levels of total phenolics and anthocyanins, compared to control fruits, corroborating the downregulation of PAL1 and STS which resulted in decreased non-enzymatic antioxidant capacity estimated by FRAP assay. In contrast, a strong upregulation of CAT1, ASPX1, ASPX3, GLPX1, CSD3 and CSD6 encoding antioxidant enzymes was observed. Accordingly, catalase enzyme activity was stimulated, significantly reducing hydrogen peroxide (H₂O₂) levels by 36%. The overexpression of the cell wall and pathogen defense genes PME, PGIP, PIN and PR1 likely contributed to the reduction in fruit rot. This work suggested that preharvest Ca treatment is an efficient agronomical strategy that prolongs the shelf life of grape berries through modifications at molecular and biochemical levels, bringing further insight on the benefits and drawbacks of preharvest Ca applications on postharvest fruit quality attributes.

Effect of Edible Carboxymethyl Chitosan-Gelatin Based Coating on the Quality and Nutritional Properties of Different Sweet Cherry Cultivars during Postharvest Storage

Sweet cherry has many cultivars with different storability and nutritional properties. To reveal the reasons for the differences in storability among cultivars and improve the quality of sweet cherries, the surface microstructure of four representative sweet cherry cultivars (Red Light, Ranier, Red Agate, Friendship) epidermis and peduncle at harvest were examined and the effects of carboxymethyl chitosan-gelatin (CMCS-GL) based edible coating incorporating CaCl2 and ascorbic acid (AA) (AA-CaCl2-CMCS-GL) on the quality and nutritional characteristics of sweet cherry were evaluated. Results showed there were significant differences in the wax distribution of the epidermis and the number of stomata on the peduncle surface between four cultivars of sweet cherries at harvest, which was closely related to fruit decay ratio during storage. AA-CaCl2-CMCS-GL coating delayed the onset of decay and the fruit decay ratio in coated groups (3.0%–15.3%) was significantly lower than in control groups (17.7%–63.0%) after 33 d storage. The coating also helped to maintain the quality and nutritional characteristics of four sweet cherry cultivars, including reducing weight loss, maintaining better skin color, peduncle freshness, higher fruit firmness, titratable acidity, AA, total phenolics content, total anthocyanins concentration, and antioxidant capacity. These results suggested that AA-CaCl2-CMCS-GL coating could be considered as a new preservation method for improving postharvest quality and nutritional properties of different sweet cherry cultivars.

Regulatory influences of methyl jasmonate and calcium chloride on chilling injury of banana fruit during cold storage and ripening

Fruit quality is preserved through cold storage, but climacteric fruits are prone to chilling injury (CI) which limits their shelf life and marketability. Two postharvest treatments, 1 mM methyl jasmonate (MeJA) and 4% (wt/vol) calcium chloride (Ca2+), were separately used to investigate their influences on chilling injury (CI) incidence and fruit quality in unpacked banana cultivar "Grand Nain" during cold storage and subsequent ripening. Banana fruits were dipped for 2 min in aqueous emulsions containing 1% Tween-80-used here as a surfactant with untreated fruits being used as control. Fruits were stored at 10 ± 2 or optimal 14 ± 2°C temperature and relative humidity 85%-90% for a 20-day cold storage period and then removed from cold storage at 5, 10, 15, and 20 days followed by ripening at 22 ± 2°C. Treatments with MeJA or Ca2+ significantly reduced CI in banana fruit during cold storage and subsequent ripening temperature. Untreated controls exhibited increased CI, weight loss, and decreased hue angle, as well as firmness. In contrast, the aforementioned changes were considerably delayed after treatments with MeJA or Ca2+. Application of MeJA or Ca2+ also increased total phenolic compound contents and maintenance of total antioxidant activity throughout cold storage and during ripening periods as compared to that of the control. These findings indicate that coating bananas with 1 mM MeJA or 4% (wt/vol) Ca2+ can improve the postharvest quality and shelf life of fruits, and it can ameliorate chilling injury during cold storage and at ripening temperature.

Exogenous Calcium Delays Grape Berry Maturation in the White cv. Loureiro While Increasing Fruit Firmness and Flavonol Content

Vineyard calcium (Ca) sprays have been increasingly used by grape growers to improve fruit firmness and thus maintain quality, particularly in periods of heavy rains and hail. The observation that Ca visibly modified berry size, texture, and color in the most prominent white cultivar of the DOC region 'Vinhos Verdes', cultivar (cv.) Loureiro, led us to hypothesize that Ca induced metabolic rearrangements that resulted in a substantial delay in fruit maturation. Targeted metabolomics by ultra-performance liquid chromatography coupled to mass spectrometry and directed transcriptomics were thus combined to characterize the metabolic and transcriptional profiles of cv. Loureiro berries that, together with firmness, °Brix, and fruit weight measurements, allowed to obtain an integrated picture of the biochemical and structural effects of Ca in this cultivar. Results showed that exogenous Ca decreased amino acid levels in ripe berries while upregulating PAL1 expression, and stimulated the accumulation of caftaric, coutaric, and fertaric acids. An increase in the levels of specific stilbenoids, namely E-piceid and E-ω-viniferin, was observed, which correlated with the upregulation of STS expression. Trace amounts of anthocyanins were detected in berries of this white cultivar, but Ca treatment further inhibited their accumulation. The increased berry flavonol content upon Ca treatment confirmed that Ca delays the maturation process, which was further supported by an increase in fruit firmness and decrease in weight and °Brix at harvest. This newly reported effect may be specific to white cultivars, a topic that deserves further investigation.

Effect of temperature fluctuation on colour change and softening of postharvest sweet cherry

The inevitable temperature fluctuation during cold chain transport accelerates the colour change and softening of postharvest sweet cherry, leading to further deterioration of quality and decline of the marketable value of cherries. The influences of temperature fluctuation on the contents of total anthocyanin, phenolic, malondialdehyde, and sodium carbonate-soluble pectin (SSP), as well as the activities of polyphenoloxidase (PPO) and peroxidase (POD) in sweet cherry, were assessed. In addition, the effects of temperature fluctuation on the activities of polygalacturonase (PG), pectin methyl esterase (PME), and beta-galactosidase (β-Gal) activities, and the paPG, paPME, and paPME genes expression were studied. The evolution of SSP nano-morphology was measured by atomic force microscopy. The results showed that the temperature fluctuation promoted anthocyanin synthesis, phenolic metabolism, and malondialdehyde accumulation, which immediately affected the brightness (6.2% lower than that of the cherry stored at 5 °C) of sweet cherry. Temperature fluctuation also led to a significant increase in POD and PPO activities during subsequent isothermal storage, accelerating the colour change (24.8% more than that of the cherry stored at 5 °C), which almost reached the level observed during constant 10 °C storage. In addition, temperature fluctuation not only affected the firmness (13.7% lower than that of the cherry stored at a constant temperature of 5 °C) of fruit immediately, but also, during subsequent isothermal storage, accelerated the deterioration of firmness (19.6% lower than that of the cherry stored at a constant temperature of 5 °C). This could be explained by temperature fluctuation inducing the upregulation of paPG1-3, paPME3, and paPME4 expression, which led to a 3.5 and 1.5-fold increase in PG and PME activity, respectively. This led to degradation of the aggregated SSP to its nanostructural basic units. Furthermore, temperature fluctuation resulted in upregulated expression of paβ-Gal1 and paβ-Gal3 and enhanced β-Gal activity during subsequent isothermal storage. The results provide theoretical guidance for the transportation, storage, and preservation of postharvest sweet cherry.

The inevitable temperature fluctuation induced anthocyanin synthesis, phenolic metabolism, and alkali-soluble pectin degradation, which lead to sweet cherry enzymatic browning and softening.

PaMADS7, a MADS-box transcription factor, regulates sweet cherry fruit ripening and softening

E-class MADS-box transcription factors, SEPALLATA (SEP) genes have an important role in floral organ initiation and development and fruit ripening. In this study, four sweet cherry SEP-like genes (PaMADS2, PaMADS4, PaMADS5, and PaMADS7) were cloned and functionally characterized. Gene expression analysis showed that the differential expression levels of PaMADS4 and PaMADS7 coincided with fruit ripening, and expression of PaMADS2 and PaMADS5 did not. Expression of PaMADS7 was affected by ABA and IAA. Subcellular localization assay demonstrated that four sweet cherry SEP-like proteins were all localized inside the nucleus. Silencing PaMADS7 using TRV-mediated virus-induced gene silencing inhibited fruit ripening and influenced major ripening-related physiological processes, such as ABA content, soluble sugar contents, fruit firmness, and anthocyanin content, as well as expression of ripening-related genes. In addition, silencing of PaMADS7 induced phenotype defects that suppressed fruit ripening, which were rescued by exogenous ABA. Furthermore, yeast one-hybrid assay (Y1H) and transient expression analyses revealed that PaMADS7 directly binds to the promoter of PaPG1, which is involved in sweet cherry fruit softening, and positively activated PaPG1expression. These results showed that PaMADS7 is an indispensable positive regulator of sweet cherry fruit ripening and softening.

Effect of preharvest application of calcium chloride, putrescine, and salicylic acid on antioxidant system and biochemical changes of two Indian jujube genotypes

The effects of the preharvest application of calcium chloride (1 and 2%), salicylic acid (1 and 2 mM), and putrescine (1 and 2 mM) on the quality attributes and biochemical changes of two ber (Ziziphus mauritiana Lamk.) genotypes ("Sibi" and "Khormaee") were investigated at harvest and after 30 days of storage (5 ± 1°C and 85 ± 5% RH). The results showed that softening and weight loss in the treated fruit were significantly lower in comparison with the control. The antioxidant capacity of the fruit was higher in treated fruit than the control. Moreover, all the treatments significantly reduced the polyphenol oxidase (PPO) activity, increased the catalase (CAT) and peroxidase (POD) activities, and prevented the quick color change of ber fruit. The best overall visual quality (OVQ) was observed in the fruit treated with calcium chloride (1.5%) and putrescine (2 mM). Compared to the two genotypes, "Khormaee" showed a better appearance, relative to the "Sibi" genotypes. PRACTICAL APPLICATIONS: Ber (Ziziphus mauritiana Lamk.) fruit is a popular fruit which is cultivated widely in the tropical and subtropical countries of the world, due to its high nutritional value. It is rich in bioactive compounds and minerals. However, Indian jujube as a climacteric fruit is highly perishable and have a limited shelf life due to softening, browning, and shrinking. So that, the researchers still need more challenge to keep the quality of this fruit for consumers. In this study, the results showed that the preharvest application of calcium chloride (1.5%), putrescine (2 mM), and salicylic acid (2 mM) effectively kept the total quality of the Indian jujube fruit during storage by improving the firmness of the fruit, retarding the color change and browning, increasing the antioxidant enzymes such as; CAT and POD, and preserving the higher ascorbic acid. Therefore, these treatments can be useful to maintain the quality of Indian jujube during storage.

Effects of calcium treatment on malate metabolism and γ-aminobutyric acid (GABA) pathway in postharvest apple fruit

Calcium treatment effects on malate metabolism and the GABA pathway in 'Cripps Pink' apple fruit during storage were investigated. Postharvest apple fruit treated with 1% and 4% calcium chloride solutions were stored at 25 ± 1 °C. The 4% calcium treatment suppressed declines in titratable acidity and malate content and increased succinate and oxalate concentrations. Calcium treatment also reduced the respiration rate and decreased ethylene production peak during storage. Moreover, 4% calcium treatment significantly enhanced cyNAD-MDH and PEPC activities and upregulated MdMDH1, MdMDH2, MdPEPC1 and MdPEPC2 expression while inhibiting cyNADP-ME and PEPCK activities and downregulating MdME1, MdME4 and MdPEPCK2 expression. Surprisingly, calcium treatment changed the content of some free amino acids (GABA, proline, alanine, aspartic acid and glutamate), two of which (glutamate and GABA) are primary metabolites of the GABA pathway. Furthermore, calcium application enhanced GABA pathway activity by increasing MdGAD1, MdGAD2, MdGABA-T1/2 and MdSSADH transcript levels.

Calcium maintained higher quality and enhanced resistance against chilling stress by regulating enzymes in reactive oxygen and biofilm metabolism of Chinese winter jujube fruit

The postharvest senescence of Chinese winter jujube fruit can be effectively delayed by refrigerated storage. However, chilling injury often occurs in jujube fruit during cold storage. In this study, Chinese winter jujubes were sprayed with CaCl₂ (4%) 3 times at intervals of 2 hr on the day of refrigeration. The results presented that maximum difference of 2.7 N firmness, 3.42% TAC, and 0.8 OD₂₈₀ /g polyphenol content were detected in calcium-treated fruit during cold storage, but the levels of O 2 - , MDA, hydrogen peroxide, browning rate, electrolyte leakage, and weight loss rate were significantly inhibited (p < .05). The maximum difference of enzymes activity of CAT, POD, SOD was 2.1, 10.8, and 40.6 mol h^-1 kg^-1 respectively, but 21.1 mol h^-1 kg^-1 PPO was restrained in the treated group. In conclusion, the results provided a reliable method for inhibiting cold injury and explained the internal molecular mechanism of the fruit regulated by calcium. PRACTICAL APPLICATIONS: Refrigerated storage is an important method for extending the storage time of Chinese winter jujube fruit. However, cold damage may occur when the jujubes are stored at low temperature for long-term. It is, therefore, of great significance to find a new method and reveal the molecular mechanism. We believe that our study makes a significant contribution to the literature because it provides an effective method of maintaining higher quality and mechanistic insights into the resistance against the chilling stress of jujubes.

Melatonin triggers metabolic and gene expression changes leading to improved quality traits of two sweet cherry cultivars during cold storage

Sweet cherry is a valuable non-climacteric fruit with elevated phytonutrients, whose fruit quality attributes are prone to rapid deterioration after harvest, especially peel damage and water loss of stem. Here the metabolic and transcriptional response of exogenous melatonin was assessed in two commercial cultivars of sweet cherry (Santina and Royal Rainier) during cold storage. Gene expression profiling revealed that cuticle composition and water movement may underlie the effect of melatonin in delaying weight loss. An effect of melatonin on total soluble solids and lower respiration rate was observed in both cultivars. Melatonin induces overexpression of genes related to anthocyanin biosynthesis, which correlates with increased anthocyanin levels and changes in skin color (Chroma). Our results indicate that along with modulating antioxidant metabolism, melatonin improves fruit quality traits by triggering a range of metabolic and gene expression changes, which ultimately contribute to extend sweet cherry postharvest storability.

Cooperative effects of slight acidic electrolyzed water combined with calcium sources on tissue calcium content, quality attributes, and bioactive compounds of 'Jiancui' jujube

BACKGROUND

Slight acidic electrolyzed water (SAEW) has been widely used in cleaning systems of fruit and vegetables. It strongly reduces microbial contamination. However, no information is available on whether SAEW offers the potential for fresh jujube cleaning. The purposes of this study were, first, to compare the effectiveness of SAEW with commercial sanitizers (i.e. sodium hypochlorite (NaClO) or calcium hypochlorite (Ca(ClO)₂ )) on 'Jiancui' jujube; second, to determine the response of fruit decay, tissue calcium (Ca) content, and quality attributes to dip application of calcium nitrate (Ca(NO₃ )₂ ) by concentration; and third, to investigate the effects of SAEW combined with Ca(NO₃ )₂ or calcium acetate (Ca(OAc)₂ )) on fruit Ca uptake, quality attributes, and bioactive compounds.

RESULTS

Fruits washed with NaClO, Ca(ClO)₂ , or an SAEW solution showed no difference in reduction of decay incidence. In contrast to NaClO treatment, SAEW or Ca(ClO)₂ significantly retarded losses in fruit firmness (FF), green color (hue angle), and skin lightness (L*), and maintained intact pericarp tissue structure during storage at 1 °C. Application of Ca(NO₃ )₂ at 5-10 g L^-1 effectively promoted Ca²⁺ uptake and minimized declines in FF and L* value but had no effect on decay development. Adding 10 g L^-1 Ca(NO₃ )₂ or Ca(OAc)₂ to SAEW provided an additional benefit in increasing decay resistance, increasing Ca²⁺ into fruit and increasing levels of bioactive compounds in jujube fruit.

CONCLUSION

SAEW in combination with Ca(NO₃ )₂ or Ca(OAc)₂ has commercial potential for fresh jujube disinfection and improving storage quality as a result of the cleaning processes. © 2019 Society of Chemical Industry.

An integrated metabolomic and gene expression analysis identifies heat and calcium metabolic networks underlying postharvest sweet cherry fruit senescence

Ηeat and calcium treatments reprogram sweet cherry fruit metabolism during postharvest senescence as evidenced by changes in respiration, amino acid metabolism, sugars, and secondary metabolites shift. Heat and calcium treatments are used to improve postharvest fruit longevity; however, the exact mechanism remains poorly understood. To characterize the impact of these treatments on sweet cherries metabolism, 'Lapins' fruits were treated with heat or CaCl₂ solutions and their combination and subsequently were exposed at room temperature, for up to 4 days, defined as senescence period. Single and combined heat and calcium treatments partially delayed fruit senescence, as evidenced by changes in fruit colour darkening, skin penetration force, and respiration activity. Calcium content was noticeably increased by heat in Ca-treated fruit. Several primary metabolites, including amino acids, organic acids, and alcohols, were decreased in response to both treatments, while many soluble sugars and secondary metabolites were increased within 1 day post-treatment. Changes of several metabolites in heat-treated fruits, especially esculetin, peonidin 3-O-glucoside and peonidin 3-O-galactoside, ribose, pyroglutamate, and isorhamnetin-3-O-rutinoside, were detected. The metabolome of fruit exposed to calcium also displayed substantial modulations, particularly in the levels of galactose, glycerate, aspartate, tryptophan, phospharate rutin, and peonidin 3-O-glucoside. The expression of several genes involved in TCA cycle (MDH1, IDH1, OGDH, SUCLA2, and SDH1-1), pectin degradation (ADPG1) as well as secondary (SK1, 4CL1, HCT, and BAN), amino acids (ALDH18A1, ALDH4A1, GS, GAD, GOT2, OPLAH, HSDH, and SDS), and sugar (PDHA1 and DLAT) metabolism were affected by both treatments. Pathway-specific analysis further revealed the regulation of fruit metabolic programming by heat and calcium. This work provides a comprehensive understanding of metabolic regulation in response to heat and calcium during fruit senescence.

Shelf-life and quality attributes in fresh-cut pear cv. Shahmive treated with different kinds of antioxidants

Synthetic antioxidants can reduce postharvest losses, but consumers are concerned about chemical residues in the product. There is a growing interest in using natural compounds for the preservation of foods. In this study, the efficiency of juices or extracts obtained from three fruit species with high antioxidant activity as browning inhibitors was measured and then compared with that obtained from pomegranate by-product (PBP). The aim was to offer the most significant contributions concerning fresh-cut fruit preservation, using 'Shahmive' pear as the fruit model. Slices of pear were dipped in pomegranate juice (PJ) or extract (PE), kiwifruit juice (KJ) or extract (KE), grape juice (GJ) or extract (GE), PBP and chitosan before being stored at 4 °C. The total phenolic content of solutions ranged from 11 to 127.5 mg gallic acid/100 mL. Extracts of pomegranate peel and grape had the uppermost and the lowermost antioxidant activity (%DPPH), respectively. In comparison with other treatments including the control one, the minimum peroxidase (POD) activity, the maximum ascorbic acid content and the retention of firmness were seen in the fruit which was treated with kiwifruit extract. PJ + GJ treatment decreased POD and polyphenol oxidase activity and improved L* and a* values in the slices. The use of fruit juice or extracts had no adverse effect on the sensory quality of slices, with the exception of samples subjected to PJ or GJ + KJ treatments. Improving antioxidant capacity of fresh cut pear treated with KE and PJ + GJ would have a big advantage of preventing enzymatic browning.

Development of a Microbial Decontamination System Combining Washing with Highly Activated Calcium Oxide Solution and Antimicrobial Coating for Improvement of Mandarin Storability

A new microbial decontamination system combining washing with a natural antimicrobial solution and coating with a carnauba wax (CW)-based antimicrobial coating was developed and its effects on mandarin storability were investigated. Mandarins were washed with an antimicrobial solution and/or coated with grapefruit seed extract-CW (GSE/CW). Values for the disease incidence of Penicillium digitatum in untreated mandarins; mandarins coated with GSE/CW without washing; and mandarins coated with GSE/CW after washing with a fumaric acid (FA) solution of slightly acidic electrolyzed water, a highly activated calcium oxide (CaO) aqueous solution, or CaO solution followed by FA solution were 96.0, 70.0, 78.8, 50.0, and 72.2%, respectively. GSE/CW coating after CaO washing was most effective in inhibiting P. digitatum growth during storage at 25 °C. Compared to untreated samples, GSE/CW coating alone or after CaO washing retained CO₂ generation, firmness, and total polyphenol content of mandarins at 25 °C. Such treatments also effectively maintained mandarin pH, ascorbic acid concentration, and antioxidant capacity at both 4 and 25 °C. Moreover, GSE/CW coating after CaO washing more effectively inhibited P. digitatum growth at 25 °C and maintained ascorbic acid concentration and antioxidant capacity at 4 and 25 °C than GSE/CW coating alone. The microbial decontamination system integrating CaO washing and GSE/CW coating demonstrates potential for improving mandarin storability by inhibiting P. digitatum growth and improving the preservation of quality properties and sensory characteristics. PRACTICAL APPLICATION: This is the first study to develop a microbial decontamination system involving both washing with a natural antimicrobial solution and carnauba wax coating containing grapefruit seed extract to improve the storability of fruits. This system demonstrated a primary effect of inhibiting fungi that cause mandarin surface decay at 25 °C via the highly activated calcium oxide wash and secondary effects of delaying quality degradation and inhibiting fungal growth by the action of the antimicrobial coating. These effects led to improvements in mandarin storability, along with enhanced visual appeal while not affecting taste, flavor, or texture.

Forced Air Precooling Enhanced Storage Quality by Activating the Antioxidant System of Mango Fruits

Effects of forced air precooling on storage quality and physiological metabolism of mangoes were evaluated in this study. Mango fruits were forced air precooled for 30 min at 0°C and then stored at 13°C. Control fruits were stored at 13°C directly. Results showed that forced air precooling treatment maintained fruit firmness, inhibited fruit peel coloration, retarded hydrolysis of polysaccharide to soluble sugar, and decreased fruit decay during storage. Biochemical studies revealed that precooling treatment could eliminate reactive oxygen species (ROS) effects by enhancing related antioxidant enzyme activities, such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), glutathione reductase (GR), and polyphenoloxidase (PPO). They all contributed to the delay of mango fruit ripening and senescence in storage. These results indicate that forced air precooling treatment could maintain mango fruit quality by enhancing antioxidant activity and delaying fruit ripening.

Metabolomic and physico-chemical approach unravel dynamic regulation of calcium in sweet cherry fruit physiology

Calcium (Ca²) nutrition has a significant role in fruit physiology; however, the underlying mechanism is still unclear. In this study, fruit quality in response to CaCl₂, applied via foliar sprays (Ca²) or/and hydro-cooling water (Ca_HC), was characterized in 'Lapins' cherries at harvest, just after cold storage (20 days at 0 °C) as well as after cold storage followed by 2 days at 20 °C, herein defined as shelf-life period. Data indicated that pre- and post-harvest Ca²⁺ applications increased total Ca²⁺ and cell wall bound Ca²⁺, respectively. Treatment with Ca reduced cracking whereas Ca + Ca_HC condition depressed stem browning. Both skin penetration and stem removal were affected by Ca²⁺ feeding. Also, several color- and antioxidant-related parameters were induced by Ca²⁺ treatments. Metabolomic analysis revealed significant alterations in primary metabolites among the Ca²⁺ treatments, including sugars (eg., glucose, fructose), soluble alcohols (eg., arabitol, sorbitol), organic acids (eg.,malate, quinate) and amino acids (eg., glycine, beta-alanine). This work helps to improve our knowledge on the fruit's response to Ca²⁺ nutrition.

Potential antioxidant retention and quality maintenance in raspberries and strawberries treated with calcium chloride and stored under refrigeration

Abstract Raspberry and strawberry fruits were stored at 0 °C and relative humidity (RH) of 95% for eight days. The fruits were treated with calcium chloride and their quality parameters and weight loss monitored and compared with those of untreated ones. A higher weight loss was observed for the untreated raspberries (16%) than for the fruits treated with 2% calcium chloride (5.3%). Similarly, untreated strawberry fruits lost more weight (8.5%) than those treated with 2% calcium chloride – only 4.1%. The application of calcium chloride did not significantly influence the total acid content of the fruits. After 8 days storage the total soluble solids (TSS) had decreased to 10.22 ± 0.06, 9.60 ± 0.05 and 9.65 ± 0.12 in the raspberry fruits treated with 0%, 1% and 2% calcium chloride, respectively, and to 7.00 ± 0.17, 6.57 ± 0.08 and 6.35 ± 0.04 in the strawberry fruits treated with 0%, 1% and 2% calcium chloride, respectively. After storage, the ascorbic acid contents were significantly (p ≤ 0.05) higher in samples of raspberry and strawberry fruits subjected to 2% calcium chloride dips. The CaCl2 treatments had a significant effect on retaining the ascorbic acid contents in these fruits. The treatment of raspberry and strawberry fruits with calcium chloride had a positive effect (p< 0.05) on the retention of the total phenolic contents (TPC) during the storage period. 66% and 74% of the antioxidant potentials were retained in the untreated samples of raspberries and strawberries, as against 78% and 89% in the 2% calcium chloride treated samples of these fruits.

Factors Affecting Quality and Health Promoting Compounds during Growth and Postharvest Life of Sweet Cherry (Prunus avium L.)

Sweet cherries are attractive fruits due to their taste, color, nutritional value, and beneficial health effects. Sweet cherry is a highly perishable fruit and all quality attributes and the level of health promoting compounds are affected by growth conditions, picking, packing, transport, and storage. During production, the correct combination of scion × rootstock will produce fruits with higher firmness, weight, sugars, vitamins, and phenolic compounds that boost the fruit antioxidant activity. Orchard management, such as applying drip irrigation and summer pruning, will increase fruit sugar levels and total phenolic content, while application of growth regulators can result in improved storability, increased red coloring, increased fruit size, and reduced cracking. Salicylic acid, oxalic acid, acetylsalicylic acid, and methyl salicylate are promising growth regulators as they also increase total phenolics, anthocyanins, and induce higher activity of antioxidant enzymes. These growth regulators are now also applied as fruit coatings that improve shelf-life with higher antioxidant enzyme activities and total phenolics. Optimizing storage and transport conditions, such as hydro cooling with added CaCl₂, chain temperature and relative humidity control, are crucial for slowing down decay of quality attributes and increasing the antioxidant capacity. Application of controlled atmosphere during storage is successful in delaying quality attributes, but lowers ascorbic acid levels. The combination of low temperature storage in combination with modified atmosphere packaging (MAP) is successful in reducing the incidence of fruit decay, while preserving taste attributes and stem color with a higher antioxidant capacity. A new trend in MAP is the use of biodegradable films such as micro-perforated polylactic acid film that combine significant retention of quality attributes, high consumer acceptability, and a reduced environmental footprint. Another trend is to replace MAP with fruit edible coatings. Edible coatings, such as various lipid composite coatings, have advantages in retaining quality attributes and increasing the antioxidant activity (chitosan) and are regarded as approved food additives, although studies regarding consumer acceptance are needed. The recent publication of the sweet cherry genome will likely increase the identification of more candidate genes involved in growing and maintaining health related compounds and quality attributes.

THE STUDY OF METHODS OF PRELIMINARY COOLING OF FRUITS

The studies were aimed at scientific grounding of expedience of combination of preliminary cooling of apples, pears and plums and their processing by antioxidant compositions before the long storage and also at establishing of the optimal regimes and methods of this technological operation. The objects of studies were apple, pear and plums fruits of the different pomological species. As a result of studies was offered the combined method that provides preliminary cooling of apple fruits firstly by hydro-cooling in solutions of antioxidant compositions during 1 hour to the temperature in fruit center 8,5 °С, then additional cooling in AOC solutions during 1,5 hours to the temperature in fruit center 9 °С, additional cooling in chamber of intensive cooling during 50 minutes to the temperature in fruit center 1°С. For plum: hydro-cooling in AOC solutions during 40 minutes to the temperature in fruit center 9 °С, additional cooling in chamber of intensive cooling during 30 minutes to the temperature in fruit center 1°С. The use of such method of preliminary cooling provides the fast decrease of intensity of breath and thermal flux of fruits and essentially decreases the lost of their mass. It favors the prolongation of term of storage of fruit raw material with maximal preservation of quality and biological value. The received data and their scientific grounding give a possibility to recommend producers to use the offered method of preliminary cooling in production conditions

Calcium and ascorbic acid affect cellular structure and water mobility in apple tissue during osmotic dehydration in sucrose solutions

The effects of the addition of calcium lactate and ascorbic acid to sucrose osmotic solutions on cell viability and microstructure of apple tissue were studied. In addition, water distribution and mobility modification of the different cellular compartments were observed. Fluorescence microscopy, light microscopy and time domain nuclear magnetic resonance (TD-NMR) were respectively used to evaluate cell viability and microstructural changes during osmotic dehydration. Tissues treated in a sucrose-calcium lactate-ascorbic acid solution did not show viability. Calcium lactate had some effects on cell walls and membranes. Sucrose solution visibly preserved the protoplast viability and slightly influenced the water distribution within the apple tissue, as highlighted by TD-NMR, which showed higher proton intensity in the vacuoles and lower intensity in cytoplasm-free spaces compared to other treatments. The presence of ascorbic acid enhanced calcium impregnation, which was associated with permeability changes of the cellular wall and membranes.