Maintained Fruit Firmness Research Articles

Reducing Sultani Figs Losses During Markeeting by Thymol and Chitosan Dipping

The aim of this study was to evaluate the effect of chitosan and thymol postharvest dipping on maintaining fruitquality attributes of Sultani figs. Ripe fig fruits gently picked manually and treated with 0.3 or 0.6 mM thymol and 2.5 or5 g/L chitosan in addition to water treatment then stored at 0°C and 85-90 % RH. A Samples of stored fruits were takenevery week to estimate determine fruit quality and storability. The results of the study showed that chitosan treatmentssignificantly reduced fruit weight loss and shriveling percent up to three weeks as compared with the untreated fruit.Thymol and chitosan treatments decreases the percentage of decay incidence and quantitative losses after one, two orthree weeks of cold storage plus two days at room temperature especially at the high concentration. All treatments causeda decrease in the percentage of quantitative losses after two or three weeks of storage as compared to control and 0.3 mMthymol. Chitosan significantly maintained fruit firmness, SSC, total and non-reducing sugars up to 3 weeks. In addition,thymol and chitosan treatments had higher phenolic content than control after 1 or two weeks.

Productivity and quality of organic strawberries pre-harvest treated with silicon

ABSTRACT Mineral nutrients have important role in plant metabolism, acting on specific vital metabolic pathways for the cell. Among the nutrients, we highlight silicon (Si), for promoting growth, improving post-harvest quality and plant productivity, as well as being able to induce resistance to pest and disease. In this sense, this study aimed to evaluate the productivity and post-harvest quality of strawberry fruits cultivars Aromas and Albion cultivated in organic system with four doses of foliar applications of SiO2 in pre-harvest (0, 5, 10, 15 g L-1), and refrigerated storage (8 days under refrigeration and 1 day at room temperature). The valuated traits were: mass loss, fruit mass, productivity, fruit firmness, soluble solids, titratable acidity, total phenolics, total anthocyanins, ascorbic acid and soluble solids titratable acidity ratio. The cultivar Aromas presented higher productivity per area (33.05 t ha-1), and more fruits per plot (479.42); however, higher average fruit mass was obtained in cultivar Albion (24.44 g), presenting better-quality fruits for fresh market. Soluble solids content, SS/TA ratio and ascorbic acid content were not influenced by silicon doses, however, refrigeration during 8 days and 1 day at room temperature provided reduction of fruit firmness, titratable acidity and, ascorbic acid content and increased soluble solids content and SS/TA ratio. Refrigeration attenuated significant reductions in anthocyanin content and, in addition, foliar silicon application promoted higher levels of anthocyanins in the fruits of both strawberry cultivars, increasing with the applied dose. The application of silicon was also efficient in maintaining fruit firmness of both cultivars.

Effects of 1-MCP in combination with Ca application on aroma volatiles production and softening of ‘Fuji’ apple fruit

Abstract 1-Methylcyclopropene (1-MCP) can maintain the physical quality of climacteric fruits, such as apple and pear, but inhibit aroma volatile production and fruit flavor. In this study, the effects of calcium (Ca) in combination with 0.6 and 1.0 μL L−1 1-MCP on flesh firmness and aroma volatiles has been investigated on ‘Fuji’ apples stored at room temperature. Results from electronic nose detection and texture evaluation showed that 1-MCP of reduced concentration (0.6 μLL−1), but not 1.0 μL L−1, presented an interactive effect with Ca application on promoting volatile emission and reducing softening. The amount of branched and straight esters and total aroma volatiles, as well as related enzymes including aromatase-related acyltransferase (AAT), alcohol dehydrogenase (ADH), and pyruvate decarboxylase (PDC), were significantly higher in fruit treated with (1-MCP 0.6 + Ca) than 1-MCP 1.0 after 50 and 100 days storage. There was no significant difference between two treatments of (1-MCP 0.6 + Ca) and 1-MCP 1.0 in maintaining fruit firmness. Fruit treated with (1-MCP 0.6 + Ca) had higher aroma quality than 1-MCP 1.0 according to sensory evaluation, but showed no significant difference in terms of texture quality. In conclusion, 1-MCP of reduced concentration combined with Ca treatment had synergetic effect on the aroma formation and softening inhibition of apple fruit, resulting in advanced sensory quality.

Protective role of epiphytic fluorescent Pseudomonas on natural postharvest decay of tomato at room temperature.

Following harvest, tomato fruits are susceptible to attack by many fungal pathogens, but healthy fruits may also harbor beneficial microflora, which can delayed the spoilage of fruit. In this study, 30 isolates of epiphytic fluorescent Pseudomonas were isolated from healthy fruits of lemon, melon, grapefruit, tomato and orange. Twelve isolates were identified on molecular basis by amplifying 16S rDNA using a genus-specific primer set PA-GS-F 5’-GACGGGTGAGTAATGCCTA-3’ and PA-GS-R F 5’-CACTGGTGTTCCTTCCTATA-3’ on a conserved sequence of the genus Pseudomonas with a product size ~618 bp. Three potential isolates were examined for their ability to delayed the postharvest natural spoilage and maintained the physiochemical properties during storage for fifteen days in season 2013 and 2014. All three isolates showed promising control of postharvest diseases of tomato in comparison with control in both seasons up to fifteen days of storage at room temperature (23±4 oC, Rh 25-70%). The epiphytic bacterial isolates has delayed the fruit weight loss and maintained fruit firmness, total solids, pH and titratable acidity. Isolates also slowed the accumulation of lycopene indicating their potential in controlling the major changes in physiochemical properties. In both season Pseudomonas treated tomatoes showed no or negligible infestation of common postharvest fungi and bacteria as compared to control and positive control (1% K-sorbate).

Effect of chitosan coating on postharvest life and quality of plum during storage at low temperature

Abstract The effect of chitosan coating on the storage life and quality of ‘Santa Rosa’ plum was investigated. The plum fruits were treated with 2% chitosan coating and stored at 1 ± 1 °C under 90 ± 5% RH. During storage, observations on weight loss, fruit firmness, colour, rates of respiration and ethylene evolution, biochemical and quality attributes were recorded at weekly interval. Our experiment yielded that chitosan had a significant effect in maintaining fruit firmness (∼78%), retarding weight loss (∼52%), respiration and ethylene evolution rates and delaying the colour change as compared to non-coated fruits. Furthermore, at the end of 35 days of storage at low temperature, a significant reduction in pectin methylesterase activity (∼44%) and malondialdehyde production (∼21%) was observed. Similarly, anthocyanin content (∼24%) was significantly retarded in chitosan-coated ‘Santa Rosa’ plums. Thus, postharvest application of chitosan as an edible coating can effectively maintain the quality and extend the storage life of plum up to 35 days under low temperature storage condition.

Gamma irradiation-induced disease resistance of pear (Pyrus pyrifolia “Niitaka”) against Penicillium expansum

In this study, the effects of gamma irradiation on the resistance of pear fruit against Penicillium expansum, the causal agent of blue mould disease, were investigated. A low dose of gamma irradiation for 14 days increased the disease resistance and firmness of pear fruits. Remarkably, exposure to 200 Gy of gamma irradiation significantly maintained fruit firmness, markedly reduced disease incidence and enhanced the activity of defence-related enzymes (e.g., β-1,3-glucanase, phenylalanine ammonia lyase, peroxidase and polyphenol oxidase) and expression of pathogenesis-related (PR) genes (e.g., PR-1, PR-3 and PR-4). Therefore, the gamma irradiation-induced resistance against P. expansum involves both metabolic changes and the induction of expression of defence-related genes. In addition, scanning electron microscopic analysis revealed that gamma irradiation significantly inhibits the growth of P. expansum. These results suggest that exposure of mature harvested pear fruits to artificial gamma irradiation confers fungal disease resistance; therefore, gamma irradiation represents an important strategy for controlling postharvest diseases in pear fruit.

Effect of various storage conditions and calcium treatments on physico-chemical properties of peach (Prunus persica) cv. Shan-e-Punjab

Peach (Prunus persica L. Batsch) fruits of cv. Shan-e-Punjab were treated with various concentrations of CaCl2 (2,4 and 6%), packed in poly bags and stored at 3+2 °C and 85–90% RH for 24 days followed by storage at ambient conditions (28 to 30 °C, 65–70% RH) for 6 days. The results showed that fruits treated with CaCl2 (6%) reduced the physiological loss in weight (PLW) and maintained fruit firmness, acidity, TSS content and ascorbic acid activity during storage. The fruits stored under refrigerated conditions showed maximum PLW of 9.13 per cent in untreated fruits while it was minimum 6.22% in fruits treated with 6% CaCl2 on 24thday of storage. The fruits treated with 6% CaCl2 showed maximum firmness (13.28 lb/inch2), acidity (0.71 %) and ascorbic acid (3.58 mg/100 g) content on 24th day under refrigerated conditions. Thus, 6 % CaCl2 was found to be the best as it showed minimum PLW and maximum firmness and ascorbic acid under both ambient and refrigerated conditions.

Textural changes in ‘Hayward’ kiwifruit during and after storage in controlled atmospheres

Storage of kiwifruit in controlled atmospheres (CA) is a common practice to extend the marketing window. An investigation into the softening of CA-stored ‘Hayward’ kiwifruit is described. Fruit softening during and after CA was recorded by standard penetrometer and also for specific tissue zones: outer pericarp, inner pericarp and core. In addition, when making standard penetrometer measurements, the degree of displacement of the fruit surface prior to penetration was recorded. The data have been used to describe the rate of post-CA softening and the relative softening of the outer pericarp, inner pericarp and core tissue zones.Results confirmed the benefit of CA storage in maintaining fruit firmness. Firmness retention in a 5% CO2 CA was better than in a 2% CO2 CA. The effect of 5% CO2 was maintained for a couple of weeks after transfer from CA- to air-storage. The rate of softening on transfer from CA- to air-storage increased to a rate equivalent to that of a fruit of similar firmness stored in air. The softening patterns of the inner and outer pericarp tissues were exponential whilst the core was closer to linear. Whilst the softening of all tissue zones was slowed by CA, the outer pericarp appeared to be slowed to a greater extent than the inner pericarp. A consequence of the differential effect of CA on the two pericarp tissue zones was that after CA storage the inner pericarp had become relatively softer than the outer pericarp when compared with air-stored fruit at the same fruit firmness value. This may account for the observed greater deformation of the fruit before tissue rupture for CA-stored fruit than air-stored fruit at the same firmness when making a penetrometer measurement.

Effect of Application Propolis as Biocoating on the Physical and Chemical Properties of Tomatoes Stored at Room Temperature

Tomatoes is considered as one of important horticulture commodities which highly consume by Indonesia consumer. However, this horticulture product is perishable with high rate which reduce quantity and quality of marketable products. One of the method could be used to prevent this problem by application of edible biocoating. In this study, various concentration of ethanolic propolis extract was applied to tomatoes in order to find the effect of propolis coating in tomato preservation and best concentration for application. Tomatoes were grouped into 5 group, namely control group (no coating application), ethanol group (tomato wash with ethanol), and application group (coated with 5%, 10%, and 15% propolis). Variables observed during study were weight change, fruit firmness, total soluble solute, vitamin C, and lycopene. All tomatoes were kept in room temperature for 14 days and observation conducted every 2 days. Result showed that application of 10% propolis as biocoating reduced rate of weight loss and maintained fruit firmness while other variables relatively unaffected by propolis coating.

Postharvest management of anthracnose in avocado (Persea americana Mill.) fruit with plant-extracted oils

Abstract We tested the inhibitory properties of five different plant extracts to extend avocado fruit shelf life against anthracnose (Colletotrichum gloeosporioides Penz.). Essential oils were extracted from mint, savory, thyme, cinnamon and lavender and then analysed by gas chromatography-mass spectrometry. Carvacrol (71.2%) and thymol (73.3%) were the main components in savory and thyme. The main chemical compounds in mint oil were menthone (33.8%) and menthol (36.1%). cis-cinnamaldehyde (59.1%) was the main constituent of cinnamon oil, whereas linalyl acetate (43.1%) and linalool (26.3%) were the key compounds in lavender oil. The polymerase chain reaction (PCR) method using the internal transcribed spacer (ITS) primer confirmed the identity of the C. gloeosporiodes isolate. In-situ antifungal activity was assayed by artificially inoculating avocado fruit with C. gloeosporioides then applying essential oils to the fruit at concentrations of 0, 0.05, 0.1 or 0.2 percent. After four weeks of storage, savory and thyme oils applied at 2000 ppm exhibited the strongest antifungal activity, reducing expansion of necrotic lesions around the inoculation sites on the fruit by 58–64%. Savory and thyme oils also considerably decreased (54–67%) lesion expansion. The results of a fruit firmness assay showed that savory and thyme oils applied at 500–2000 μl L−1 resulted in fruit that were 2.5-3.3 times firmer than the non-treated controls, whereas other oils applied at 500 μl L−1 did not help maintain fruit firmness. Disease severity and fruit firmness variables were quadratically related to savory oil concentration. This study confirms the potential for using savory and thyme essential oils as biological fungicides for increasing the storage time of avocado fruit.

The combination of ethoxyquin, 1-methylcyclopropene and ethylene treatments controls superficial scald of ‘d’Anjou’ pears with recovery of ripening capacity after long-term controlled atmosphere storage

Superficial scald is the most devastating storage disorder of ‘d’Anjou’ pears (Pyrus communis L.) and the current commercial controlling method of ethoxyquin (Etq) + controlled atmosphere (CA) storage is not adequate for the fruit produced in hot seasons. In the hot years of 2014 and 2015, ‘d’Anjou’ pears were harvested at commercial maturity and treated with Etq at 2700mgL−1, 1-methylcyclopropene (1-MCP) at 0.3μLL−1 along or in combination with ethylene at 0.3, 0.6, or 1.5μLL−1 (M+E: 1:0, 1:1, 1:2, and 1:5, respectively), and the combination of Etq plus M+E (1:1), and then stored in CA (1.5kPa O2, <0.5kPa CO2) at −1.1°C for 8 months. The non-treated control fruit developed 82% and 100% scald after 4 and 6 months storage, respectively. Etq-treated fruit developed unacceptable level of scald (>10%) after 6 months. M+E (1:0) treatment inhibited ethylene production, prevented scald through decreasing the syntheses of α-farnesene and conjugated trienols, maintained fruit firmness and green color, and reduced decay; however, inhibited ripening capacity following 8 months storage. Compared with M+E (1:0), M+E (1:1 or 1:2) treatments allowed fruit recovering ripening capacity but decreased efficacy on controlling scald; Etq plus M+E (1:1) could control scald <5% for 8 months. M+E (1:5) largely offset the 1-MCP efficacy. In summary, the combination of Etq plus M+E (1:1–2) controls scald, extends storage quality, reduces decay, and allows recovering of ripening capacity of ‘d’Anjou’ pears after long-term CA storage.

Improvement of Shelf Life and Sensory Quality of Pummelos by Fruit Waxing and Wrapping

The aims of this study were to evaluate the physical and chemical change of pummelo fruit during storage with waxing and wrapping, and to determine the effect of waxing and wrapping and their its interaction in affecting shelf life of pummelo fruits. This research was arranged in a randomized complete block design with two factors and three replications. The first factor was waxing consisted of without waxing, 10% beeswax, 5% beeswax, and chitosan. The second factor was wrapping consisted of without wrapping and wrapping using either transparent yellow or white plastic wrap. Pummelo fruits experience weight loss, reduced total soluble solid (TSS), decrease in firmness and total acidity during 48 days of storage in room temperature. Waxing using beeswax or wrapping using plastic wraps significantly suppressed weight loss and maintained fruit firmness compared to those without waxing and wrapping. However, waxing and wrapping did not significantly affect the quality of pummelo fruits. Based on the fruit’s weight loss, firmness, and panelist preferences, 5% or 10% bees wax can be used as waxing. Both transparent yellow and white plastic wraps can be used to maintain fruit weight, firmness, and appearances during storage.

Defense Responses of Salicylic Acid in Mango Fruit Against Postharvest Anthracnose, Caused by Colletotrichum gloeosporioides and its Possible Mechanism

AbstractThe effects and mechanisms of salicylic acid (SA) on defense response to Colletotrichum gloeosporioides from mango fruits were investigated by in vitro and in vivo test. In vitro experiment results showed that SA significantly reduced mycelial growth of C. gloeosporioides in a concentration‐dependent manner. SA effectively controlled anthracnose decay on inoculated mango fruit, as well as natural infection. Disease incidence and lesion diameter in SA‐treated fruit were significantly lower than those of the control fruit. SA treatment increased the activities of chitinase, β‐1,3‐glucanase, phenylalanine ammonia‐lyase and polyphenoloxidase, and the content of total phenolic compounds and lignin in mango fruit. Moreover, SA treatment effectively maintained fruit firmness by suppressing conversion of insoluble protopectin into water soluble pectin. And correlation analysis showed there is a higher negative correlation between fruit firmness and disease incidence. These findings suggest that the effect of SA on postharvest diseases was attributed to its direct antimicrobial activity and the elicitation of resistant responses, as well maintaining the firmness in mango fruit. Therefore, SA treatment is a promising measure for controlling postharvest anthracnose rot in mango.Practical ApplicationsInduction of fruit resistance against pathogenic infection with biological or chemical elicitors has been thought to be a promising approach for controlling of postharvest diseases and reducing the use of synthetic fungicides. Anthracnose, caused by Colletotrichum gloeosporioides is the predominant postharvest disease in mango production that causes severe postharvest losses and fruit quality deterioration. SA is a natural plant substance involved in plant defense responses to biotic stresses. The present results from in vitro and in vivo experiment suggested that SA treatment could effectively inhibit mycelial growth of C. gloeosporioides, enhance resistance of mango fruit against the pathogen and reduce anthracnose rot, as well maintain fruit firmness. Hence, SA can be applied in mango storage and preservation.

Evaluation of polyfilm for shelf-life extension of mango (Mangifera indica) cv. Dashehari

Present study reports the impact of polyfilm having ethylene absorbing property for study on ripening behavior of mango (Mangifera indica L.) cv. Dashehari. The fruits stored in open condition decomposed after 10 days of storage but the fruits stored in polyfilm remained fresh even after 14 days of storage with low physiological weight loss (15%) and acceptable for marketing on the basis of their higher firmness (0.8 kg/cm2) and TSS (18.69oBrix). There was a marginal difference in carotenoids, phenol content and antioxidant values in both the conditions. The level of polygalacturonase activity retarded from 0.146 to 0.095 U/ml in polybag, while it increased from 0.146 to 0.268 U/ml in fruits stored under open condition. Thus polybag is effective in prolonging the shelf-life of mango fruits by way of its ability to maintain fruit firmness and delaying the ripening process.

Salicylic acid treatment reduces the rot of postharvest citrus fruit by inducing the accumulation of H2O2, primary metabolites and lipophilic polymethoxylated flavones

To comprehensively analyze the effects of salicylic acid (SA) on the storability of Satsuma mandarin (Citrus unshiu), fruits were treated with 2mM SA. The disease incidence of control/SA-treated fruit at 50d and 120d after treatment was 23.3%/10% and 67.3%/23.3%, respectively, suggesting that SA treatment can significantly reduce the rot rate of postharvest citrus fruit. Fruit quality assays revealed that the treatment can maintain fruit firmness without affecting the inner quality. Furthermore, the contents of H2O2 and some defense-related metabolites, such as ornithine and threonine, in citrus pericarp, were significantly increased by SA treatment. Moreover, it was lipophilic polymethoxylated flavones, rather than flavanone glycosides, that accumulated in SA-treated fruits and these can directly inhibit pathogen development. These results suggest that the effects of SA on postharvest citrus fruit may be attributed to the accumulation of H2O2 and defense-related metabolites.

Benzothiadiazole-Mediated Induced Resistance to Colletotrichum musae and Delayed Ripening of Harvested Banana Fruit.

Benzothiadiazole (BTH) works as a plant activator. The effects of different BTH treatments and fungicides SPORGON on fruit ripening and disease incidence were investigated. The results showed that BTH treatment significantly delayed fruit ripening, maintained fruit firmness, color, and good fruit quality, and dramatically reduced the incidence of disease. BTH effectively inhibited the invasion and development of pathogenic bacteria and controlled the occurrence of disease. BTH treatment enhanced the activities of defense-related enzymes, including chitinase, phenylalanine ammonia-lyase, peroxidase, and polyphenol oxidase, increased the content of hydrogen peroxide and total antioxidant capacity, and reduced malondialdehyde content. Cellular structure analysis after inoculation confirmed that BTH treatment effectively maintained the cell structural integrity. SPORGON did not provide benefits for delaying fruit ripening or for the resistance system, while it can control the disease only during the earlier stage and not at later stages.

Effects of an ethylene absorbent and 1-methylcyclopropene on tomato quality and antioxidant contents during storage

We compared the effects of an ethylene absorbent and the ethylene inhibitor 1-methylcyclopropene (1-MCP) on tomato (Solanum lycopersicum Mill. cv. Dotaerang) during storage. Tomato fruits at the ‘breaker’ stage were harvested and treated with an ethylene absorbent, 1 μL·L-1 1-MCP or 2 μL·L-1 1-MCP and stored at 20°C for 15 days. We then measured weight loss, peel color, firmness, soluble solids content (SSC), titratable acidity, pH, ethylene production and total phenolic and flavonoid contents in the fruits. Color development occurred more rapidly in the control than in fruits treated with the ethylene absorbent or 1-MCP (1 μL·L-1 and 2 μL·L-1 ) on day 6 and 9. The Hunter a value (redness) of 1-MCP (2 μL·L-1 )-treated fruit on day 6 was 2.24 ± 3.8, while that of the control was 13.39 ± 2.23, indicating that color development was delayed by 1-MCP treatment (2 μL·L-1 was more effective than 1 μL·L-1 ). Ethylene absorbent treatment was not more effective at maintaining fruit firmness than 1-MCP (2 μL·L-1 ) treatment. There was no statistically significant difference in fruit firmness between the ethylene absorbent treatment group and the control. Total phenolic and total flavonoid contents increased in all treatment groups during storage. These contents did not significantly differ among groups on day 15. These results suggest that 1-MCP treatment is highly effective in delaying tomato ripening during storage and that 2 μL·L-1 1-MCP treatment is more effective than 1 μL·L-1 treatment. However, the ethylene inhibitor did not influence the levels of antioxidant compounds compared with the control.

Manipulation of ripening progress of different plum cultivars during shelf life by post-storage treatments with ethylene and 1-methylcyclopropene

In order to manipulate ripening progress and increase marketing acceptance, plum (Prunus salicina Lindl.) cultivars ‘Gaixian’, ‘Yuhuang’ and ‘Aozhou 14’ were treated with 500μLL−1 ethylene or 2.0μLL−1 1-methylcyclopropene (1-MCP) for 24h at 25°C after removal from the cold storage at 0°C for 8, 4 and 4 weeks, respectively. Different patterns of physiological progresses including color changes, softening and ethylene production were observed in these plum cultivars during cold storage. Upon removal, regardless of physiological patterns, a sharp increase of ethylene production was found in either plum cultivar during shelf life and the increase was stimulated by post-storage ethylene treatment but dramatically inhibited by post-storage 1-MCP treatment. Skin color changes of ‘Gaixian’ and ‘Yuhuang’ plums during shelf life were greatly enhanced by ethylene but significantly retarded by 1-MCP. Flesh reddening occurred easily in ‘Aozhou 14’ during cold storage and became more serious after removal, which was hastened by ethylene but significantly alleviated by 1-MCP. Firmness decline of plums during shelf life was not significantly influenced by ethylene but effectively delayed by 1-MCP. Post-storage ethylene treatment could ‘recover’ the inherent epidemic color of ‘Gaixian’ and ‘Yuhuang’ during shelf life, while post-storage 1-MCP treatment could maintain fruit firmness and alleviate flesh reddening of ‘Aozhou 14’. Thus the manipulation of ripening progress of plums with post-storage ethylene or 1-MCP treatment would be practical for increasing fruit marketing acceptance, though it depends on cultivars.

Effects of waxing, microperforated polyethylene bag, 1-methylcyclopropene and nitric oxide on firmness and shrivel and weight loss of ‘Manila’ mango fruit during ripening

The mango export market demands varieties with high fruit quality and firmness. The ‘Manila’ mango has high sensory quality, but does not yet reach export markets largely due to high weight loss, shrivel and rapid firmness loss during ripening. Application of 1-methylcyclopropene (1-MCP) alone or combined with a microperforated bag (MP bag) or nitric oxide (NO) alone or combined with waxing were studied for efficacy to delay fruit softening, shrivel and weight loss. The waxing alone or combined with NO maintained fruit firmness up to 18d at 13°C and reduced weight loss and shrivel, whereas the MP bag with 1-MCP reduced weight loss and shrivel but firmness was maintained only for 10d at 13°C. Treatments applied did not have an effect on color, TSS and TA changes during ripening. Pectinesterase (PE) and polygalacturonase (PG) activities in exocarp tissue were not related to firmness loss. However, in waxed fruit, PE and PG activities in the mesocarp only partially explained the softening process. The weight loss of ‘Manila’ mango is directly related to the shriveled appearance of the fruit, as well as contributing to firmness loss.

Effects of Ultrasound on Spoilage Microorganisms, Quality, and Antioxidant Capacity of Postharvest Cherry Tomatoes.

Mature-green cherry tomato fruits (Lycopersicon esculentum cv. Jinyu) were exposed to different power densities of ultrasound (66.64, 106.19, and 145.74 W/L) at 25 °C to study ultrasound non-thermal effects on the storage properties. Among the three levels of ultrasound irradiation, 106.19 W/L ultrasound was effective in reducing the spoilage microorganisms, delaying postharvest ripening through inhibiting ethylene production and respiration rates, and consequently maintaining fruit firmness, flavor, enzyme activities, antioxidants (total phenolics, total flavonoids), and the total antioxidant capacity of cherry tomatoes. The 66.64 W/L ultrasound had similar effects but to a lesser extent. Meanwhile, although 145.74 W/L ultrasound resulted in higher content of ascorbic acid (AA), it showed many negative effects on the storage quality of fruits. These results demonstrated that ultrasound of appropriate power density had great potentials in inhibiting decay, maintaining flavor and nutritional quality of cherry tomatoes. Recently, ultrasound has been considered as a multifunctional pretreatment method for the preservation of postharvest fruits and vegetables. Although the preservation effects were slight because of the screening of the thermal effects, its non-thermal effects presented potentials in improving storage quality of cherry tomato. Further studies are needed to explore the combinations between ultrasound with heating as well as other postharvest preservation technologies to enhance the effects of ultrasound. These explorations would facilitate the large-scale application of ultrasound in the preservation of fresh fruits and vegetables.