Fresh-cut Melon Research Articles

Storage Temperature Affects the Accumulation of Phenolics in Fresh-Cut Melon by Accelerating the Sucrose Decomposition

To accurately evaluate the role of storage temperature in improving the quality of fresh-cut fruits and vegetables, the effects of two storage temperatures (5 °C and 15 °C) on the phenylpropanoid pathway and sucrose metabolism in fresh-cut melon (cv. Yugu) cubes were determined. A higher temperature (15 °C) expedited sucrose decomposition in the melon cubes at the early stage of storage, resulting in higher levels of glucose and fructose. This effect was corroborated by increased activities of acid invertase (AI), neutral invertase (NI), and sucrose synthase cleavage (SS-c), along with higher expressions of CmAI1/2, CmNI1/2, and CmSS1/2 in the melon cubes at 15 °C. Additionally, the higher activity and gene expression of hexokinase in melon cubes at 15 °C led to an increase in the utilization rate of sugars toward downstream metabolic pathways. Moreover, the melon cube storage at 15 °C elevated the activities and gene expressions of phenylalanine ammonia lyase (PAL), cinnamic acid 4-hydroxylase (C4H), and 4-coumaric acid: CoA ligase (4CL), thereby increasing the synthesis of phenolics. Sucrose showed a significant negative correlation with PAL, C4H, and 4CL, as well as with CmPAL5/7 and CmC4H1/3. However, hexokinase displayed a significant positive correlation with PAL, C4H, and 4CL, as well as with CmPAL1, CmPAL3-9, CmC4Hs, and Cm4CLs. These findings demonstrate that a higher-temperature storage of melon cubes can accelerate the phenylpropanoid pathway and sucrose metabolism by regulating the activity and gene expression of related enzymes, thereby inducing phenolic accumulation. These results also indicate that lower-temperature storage is not conducive to the conversion of sugars into phenolics in fresh-cut melon. Therefore, the temperature can be appropriately and briefly raised in the production and preservation process of fresh-cut melon to obtain higher levels of phenolics.

An Innovative Layer-by-Layer Edible Coating to Regulate Oxidative Stress and Ascorbate–Glutathione Cycle in Fresh-Cut Melon

Fresh-cut fruits, renowned for their convenience and nutritional value, are susceptible to rapid deterioration, compromising their quality and shelf life. In this study, a sustainable and environmentally friendly edible coating was developed based on sodium alginate (SA; 1% w/v), cedar mucilage (CM; 4% w/v), and calcium chloride (2% w/v), applied using a layer-by-layer technique to preserve the quality and prolong the shelf life of fresh-cut melon. Fruits were cut into cubes coated or uncoated by dipping and subsequently packaged in a polyethylene terephthalate container and stored for 15 days at 4 °C. Physicochemical traits and qualitative features such as polyphenol, flavonoid, carotenoid, ascorbic acid content, as well as antioxidant activity, were assessed. Furthermore, the enzymatic antioxidant system and the ascorbate–glutathione cycle were investigated. The coating reduced weight loss and enhanced polyphenol, flavonoid, and ascorbic acid content and antioxidant activity during cold storage. Edible coating (SA + CM) represents a valid tool to extend the postharvest life, improve the storability, and enhance the physicochemical and qualitative traits of fresh-cut melon. Further research is required to optimize coating formulations and application techniques to maximize their effectiveness and commercial viability in the food industry.

Effects of Genotype and Modified Atmosphere Packaging on the Quality of Fresh-Cut Melons.

Marketing melons (Cucumis melo) as convenient fresh-cut products is popular nowadays. However, damage inflicted by fresh-cut processing results in fast quality degradation and food safety risks. The life of fresh-cut produce can be extended by a modified atmosphere (MA), either generated in a package by tissue respiration (a passive MA) or injected by gas flushing (an active MA). This work investigated the effect of passive and active MA formed in packages of different perforation levels on the quality of fresh-cut melons of two genetic groups: C. melo var. cantalupensis, characterized by climacteric fruit behavior, and non-climacteric C. melo inodorus. The best product preservation was achieved in passive MA packages: non-perforated for inodorus melons and micro-perforated for cantalupensis ones. The optimal packages allowed for the preservation of both genotypes for 14 days at 6-8 °C. The major factors limiting the shelf life of fresh-cut melons were microbial spoilage, translucency disorder and hypoxic fermentation associated with cantalupensis melons with enhanced ethyl acetate accumulation. Inodorus melons were found to be preferable for fresh-cut processing since they were less prone to fermented off-flavor development.

Application of sodium alginate-based edible coating with citric acid to improve the safety and quality of fresh-cut melon (Cucumis melo L.) during cold storage.

The safety and quality of fresh-cut melons is reduced by a series of decay processes by enzymatic browning and microbial contamination. This study aimed to assess the impact of a 2% sodium alginate-based edible coating (ALC) combined with different concentrations of citric acid (CA; 0.5%, 1%, 2%, and 3%) on the microbial safety and physical quality of fresh-cut melons during a 7-day storage period at 10°C. The findings revealed that the combination of ALC and 3% CA was successful in preventing the growth of pathogenic bacteria (Escherichia coli O157:H7, Salmonella spp., Listeria monocytogenes, and Staphylococcus aureus) and natural microflora on fresh-cut melons during storage. In addition, treating fresh-cut melons with ALC containing 3% CA improved their quality by reducing browning and softening during storage at 10°C. Based on these findings, it can be concluded that using ALC with 3% CA is an effective method to improve the safety and quality of fresh-cut melons.

Effect of postharvest edible coating materials on sugar and organic acid contentof fresh-cut melons grown with different fertilizer treatments

Effect of postharvest edible coating materials on sugar and organic acid contentof fresh-cut melons grown with different fertilizer treatments

Combined antibacterial effect of 460nm light-emitting diode illumination and chitosan against Escherichia coli O157:H7, Salmonella spp. and Listeria monocytogenes on fresh-cut melon, and the impact of combined treatment on fruit quality.

This study evaluated the combined antibacterial effect of 460nm LED illumination and chitosan on Escherichia coli O157:H7, Salmonella spp. and Listeria monocytogenes on fresh-cut melon surface and its impact on the quality of melon at a total dose of 2.4kJ/cm2 at 4 and 10 °C. Results showed that the antibacterial effect of LED illumination in combination with chitosan (0.5 and 1.0%) was much better than that of LED illumination alone, showing their synergistic effect. Among the pathogens, L. monocytogenes was the most susceptible pathogen to LED illumination. Although the color of melons became paler after LED illumination, there was little to no change in ascorbic acid content, total flavonoid content, or antioxidant capacity of the illuminated fruits compared with non-illuminated fruits. Thus, these results suggest that chitosan-mediated 460nm LED illumination could be applied to inactivate foodborne pathogens on fresh-cut melons during storage at food establishments.

Development of edible coating based on Aloe vera gel to extend the shelf life of fresh-cut melon

Edible coating has been widely used in the food and agriculture industry to maintain the quality of food, specifically fresh-cut fruits, and can extend the shelf life of fruits. In this research, Aloe vera-based edible coating was developed with the addition of carboxymethyl cellulose (CMC) and citric acid (CA) as additives to maintain the quality and extend the shelf life of fresh-cut melons (Cucumis melo L). Edible coating based on Aloe vera was made with 30% (v/v) and 50% (v/v) Aloe vera gel and mixed with 1% (w/v) and 3% (w/v) CMC as additives and 1% (w/v) citric acid. Fresh-cut melons were uncoated and coated with six combinations of Aloe vera and CMC concentrations, then stored for ten days at 30 °C. Weight loss, microbiological contamination, ascorbic acid content, titratable acidity, colorimeter analysis, and sensory analysis were evaluated every two days to assess the quality of fresh-cut melons. The findings indicated that the samples coated with 50% (v/v) Aloe vera gel and 3% (w/v) CMC had superior effectiveness and the highest quality in terms of weight loss, microbiological contamination, ascorbic acid content, titratable acidity, colorimeter analysis, and sensory evaluation.

Cut-Wounding Promotes Phenolic Accumulation in Cucumis melo L. Fruit (cv. Yugu) by Regulating Sucrose Metabolism

The effect of cutting on the molecular changes underlying sucrose metabolism and the phenylpropanoid pathway in melon fruit (cv. Yugu) during storage at 15 °C was investigated. Furthermore, the key metabolites, enzymes, and genes involved in sucrose and phenylpropanoid metabolism were determined. Results showed that the cutting of melon increased the activities of acid invertase (AI), neutral invertase (NI), and sucrose synthase-cleavage (SS-c) and the expressions of CmAI1/2, CmNI1/2, and CmSS1, while sucrose synthase-synthesis (SS-s) and sucrose phosphate synthase (SPS) activities and the CmSS2/3 and CmSPS1/2/4 gene expressions were suppressed. These led to sucrose decomposition and fructose and glucose accumulation in fresh-cut melon at the early stage of storage. Moreover, cutting increased the activity and gene expression of hexokinase, which accelerated the transformation of hexose in fresh-cut melon. In addition, cutting enhanced the activities of phenylalanine ammonia lyase (PAL), cinnamate-4-hydroxylase (C4H), and 4-coumarate-CoA ligase (4CL) and up-regulated the expressions of CmPAL1-9, CmC4H1-4, and Cm4CL1/2/3, which activated phenylpropanoid metabolism and resulted in phenolic accumulation in fresh-cut melon. These findings demonstrate that cutting of melon can enhance sucrose metabolism and phenylpropanoid pathway by regulating the activities and gene expressions of related enzymes. Therefore, cut-wounding promoted the conversion of sugars to supply the necessary substrates for phenolic accumulation in fresh-cut melon.

Investigation of edible coatings on the physical, chemical and microbiological characteristics of processed melons during storage

The possible use of chitosan coating on fresh-cut melons (Cucumis melo var. Cantalupensis) was investigated in this research topic. Manually sliced melons were treated with solutions of 10 g/kg chitosan and 10 g/kg chitosan with calcium lactate and then stored at 4°C for 8 days. Physical, physicochemical, microbiological and sensory properties of the samples were monitored during the storage period. It was found that chitosan coatings inhibited the growth of microorganisms and affected significantly and positively the storage time of the products. Changes in the sensory qualities of taste were evaluated. A chitosan coating retarded water loss and the drop in sensory quality, increasing the soluble solid content and titratable acidity. The data revealed that applying a chitosan coating preserved effectively the quality and extended the shelf life of fresh-cut melons.

Chitosan enhances antibacterial efficacy of 405 nm light-emitting diode illumination against Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella spp. on fresh-cut melon

This study aimed to evaluate the influence of chitosan on the antibacterial efficacy of 405 nm LED illumination against Escherichia coli O157:H7, Salmonella spp., and Listeria monocytogenes on fresh-cut melons. The antibacterial efficacy of LED illumination (a total dose of 1.3 kJ/cm2) with or without chitosan (0.5 and 1.0 %) against these three pathogens was determined at 4 and 10 °C, respectively. Non-illuminated and chitosan-treated fruits were stored in the dark for 36 h under the same temperature. Color changes, ascorbic acid content, and total flavonoid content of illuminated and non-illuminated fruits were also analyzed. The results showed that the populations of all three pathogens on the non-illuminated and chitosan-treated fruits remained unchanged during storage. Regardless of bacterial species and chitosan concentrations, LED illumination in combination with chitosan greatly reduced the bacterial populations by 1.5 – 3.5 log/cm2, which was greater than LED illumination alone. Among the three pathogens, L. monocytogenes was the most susceptible to chitosan-mediated LED illumination. However, the whiteness index of illuminated fruits significantly increased by 1.3-fold compared to that of non-illuminated fruits, regardless of the presence of chitosan. Unlike color, no significant difference was observed in ascorbic acid and total flavonoid contents between illuminated and non-illuminated fruits. Although the fruit color was changed by LED illumination, these results indicate that adding chitosan could enhance the antibacterial efficacy of 405 nm LED illumination against major foodborne pathogens on fresh-cut melons without changing nutritional quality.

Effect of citral nanoemulsion on the inactivation of Listeria monocytogenes and sensory properties of fresh-cut melon and papaya during storage

This study evaluated the survival of Listeria monocytogenes on fresh-cut melon and papaya treated with citral nanoemulsion (CN) during 7 days of storage at 4, 8, 12, and 16 °C. CN was prepared by catastrophic phase inversion, and fresh-cut melon and papaya were artificially inoculated, resulting in 5 log cfu/g of L. monocytogenes. Then, they were treated with 0.30 (CN-0.3) and 0.15 (CN-0.15) μL/mL of CN. CN presented droplet size below 200 nm, monodisperse distribution, and negative surface charge. CN-0.3 reduced the L. monocytogenes counts more efficiently, with counts below the detection limit (1 log cfu/g) in both fruits after 48 h at 4 °C, and 72 h at 8 °C and 12 °C. At 16 °C, L. monocytogenes counts were below the detection limit for CN-0.3 after 120 h in papaya, but it survived the other treatments for 7 days. Both CN-0.3 and CN-0.15 decreased the indigenous microbiota. Scanning electron microscopy (SEM) showed bubbles in L. monocytogenes membrane and cell disruption in fruits treated with CN-0.3. Finally, CN-0.3 treated melon and papaya showed greater brightness, herbal flavor and aroma, firmness, and juiciness, as well as lower sugar and organic acid profile changes than the control samples during storage. Results indicate citral nanoemulsion's efficiency in controlling L. monocytogenes growth on fresh-cut melon and papaya stored at refrigerated temperatures without negatively influencing the sensory parameters.

Aloe vera gel coating incorporated with citric acid preserves the chemical and the microbiological qualities of fresh-cut melon

Fresh-cut fruit is categorized as minimally processed food that is susceptible to quality deterioration. In this study, Aloe vera gel coating was incorporated with 0.1% citric acid and 1 or 2% of glycerol (Gly). The effect of coating on the physicochemical properties and microbial quality of fresh-cut honeydew was studied. Fresh-cut honeydew samples were coated with different gel formulations (80% AV 1% Gly, 80% AV 2% Gly, 100% AV 1% Gly, 100% AV 2% Gly) and stored at 4°C in polyethylene bag. Physicochemical properties (weight loss, pH) and microbial quality of the honeydew samples were evaluated on storage days two, four and six of storage. The sample treated with 100% AV 2% Gly had the lowest weight loss and aerobic plate count. Further investigation was done on the titratable acidity, ascorbic acid, total polyphenol content, total yeast and mould count between coated sample (100% AV 2% Gly) and the uncoated sample. The coated sample (100% AV 2% Gly) was found to have significantly higher titratable acidity, ascorbic acid content and total polyphenol content compared to the uncoated sample (p<0.05). The coating of 100% AV 2% Gly significantly reduced total yeast and mould count on day six. Aloe vera-citric acid gel coating serves as a potential alternative to maintaining the quality of the melon.

A Film of Chitosan Blended with Ginseng Residue Polysaccharides as an Antioxidant Packaging for Prolonging the Shelf Life of Fresh-Cut Melon

Ginseng residue polysaccharides (GRP) at three levels were excellently blended into chitosan to form antioxidant composite films, which exhibited higher density, opacity and moisture, as well as lower water vapor permeability, tensile strength and elongation ratio than those of neat chitosan film. Thermogravimetry evidenced no difference in stability, and SEM and AFM revealed smooth and dense surfaces with no cracks and micropores, whereas structural analyses disclosed slight changes in films’ structures after adding GRP. A chitosan film containing 0.5% GRP (Chitosan + GRP) was then employed for a fruit preservation study. Fresh-cut melon covered with Chitosan + GRP displayed delayed deteriorating compared with other groups. A possible antioxidant mechanism in fruit preservation was then suggested, and PCA and correlation analyses supported these findings. The results demonstrated that our antioxidant chitosan films incorporated with GRP are quite promising for enabling the food industry to produce eco-friendly and sustainable packaging.

Comparison of storage method and packaging material on physicochemical properties of fresh-cut melons (Cucumis melo L.) during distribution

ISHS V Asia Symposium on Quality Management in Postharvest Systems Comparison of storage method and packaging material on physicochemical properties of fresh-cut melons (Cucumis melo L.) during distribution

Comparative metabolomics profiling reveals the molecular information of whole and fresh-cut melon fruit (cv. Xizhoumi-17) during storage

This study aimed to elucidate the effect of cutting on the quality of melon fruit (cv. Xizhoumi-17) during storage as well as assess changes at metabolite level by an LC-MS-based comparative metabolomics profiling and multivariate analysis. A total of 93 differential metabolites were observed in whole and fresh-cut melon during storage. Among them, 10 differential metabolites were found exclusively in stored whole melon, and 17 nonrepetitive differential metabolites were found during storage of fresh-cut melon compared to stored whole melon. 4′-Methyl-(-)-epigallocatechin 3′-glucuronide (MEG) and pyranocyanin A of flavonoids accumulated in melon fruit during storage; in fresh-cut melon, increased flavonoid biosynthesis induced by the higher expression of CmPAL1-9, CmC4H1-4, and Cm4CH1/2/3 might explain accumulation of MEG and pyranocyanin A. Moreover, cell membrane composition in melon changed throughout storage, as indicated by the increased contents of phosphatidic acids (PAs), phospholipid inositols (PIs), phosphatidylglycerols (PGs), and monogalactosyldiacylglycerols (MGDGs) as well as the decreased contents of Lyso PG, Lyso PIs, Lyso PCs, Lyso PEs, and Lyso PAs. Cutting of melon promoted change in cell membrane composition, resulting from the increased expression of CmPLC1/2/3, CmPLD1/2/3, CmAGPAT, and CmGPAT1/2 in fresh-cut melon compared to whole melon. In addition, increased content of salicylic acid beta-D-glucoside (SAG) was observed in fresh-cut melon during storage compared to the whole melon, indicating that SAG helps the fresh-cut melon in resisting the cut-wounding stress. Therefore, metabolomics might provide a molecular basis for assessing the qualitative deterioration of whole and fresh-cut melon during storage.

Influence of Two Different Coating Application Methods on the Maintenance of the Nutritional Quality of Fresh-Cut Melon during Storage

This study aimed at evaluating the effects of two coating application methods, spraying and dipping, on the quality of fresh-cut melons. An alginate-based coating containing both ascorbic and citric acid was applied at two concentrations (5% and 10%) with both methods on fresh-cut melon. The nutritional quality of the products was investigated during 11 days of storage at 10 °C. The suitability and adaptability of the applied coatings on the fruit were evaluated based on rheological and microstructural properties. Moisture, carotenoids, total polyphenols and ascorbic acid content were analyzed on melon samples during storage. Results showed that the coating solution applied by the dipping method and at the highest concentration (10%), allowed to better maintain some quality characteristics of fresh-cut melon, thanks also to the better coating homogeneity and higher thickness observed through microstructural analysis.

Reaction mechanisms for volatiles responsible of off-odors of fresh cut melons

Reaction mechanisms for volatiles responsible of off-odors of fresh cut melons

Physicochemical and antimicrobial properties of cassava starch films with ferulic or cinnamic acid

Plasticised cassava starch films with 1–2% ferulic or cinnamic acid were obtained by melt blending and compression moulding. Partial losses (about 40%) of the more thermo-sensitive ferulic acid occurred during processing. Incorporation of phenolic acids did not provoke remarkable changes in the oxygen and water vapour permeability of starch films, but these became less water soluble (13–25% reduction), more extensible and less resistant to break, especially with the highest concentration of ferulic acid. Films with 2% of either acid effectively inhibited the growth of E. coli and L. innocua in tests carried out in culture medium; being cinnamic acid more effective than ferulic and L. innocua more sensitive than E. coli; a Log CFU reduction, with respect to the control, higher than 6 was obtained for L. innocua with 2% of cinnamic acid in the films. The growth of both strains was also inhibited in chicken breast (log CFU reduction>2) with 2% of either acid. In fresh-cut melon, the L. innocua growth was significantly inhibited by films with 2% cinnamic acid, but lower growth inhibition of E. coli in fresh-cut melon was observed.

Calculating quantities of ice gel for cooling of fresh-cut melon in temporary storage box during distribution

Temperature reduction can be done by adding a cooling media, one of which is ice gel. The use of ice gel as a cooling medium should take notice of the load heat during distribution because the load of heat that is removed by ice gel is limited. The calculation of the required heat load that needed to be removed to determine the amount of ice gel required during distribution. The calculations include the heat load of the storage box, the heat load of the fruit, and the heat load of the fruit respiration. The temporary storage box is made of thermotec heat shield material and has 3 shelves. This study uses fresh-cut melon as a sample of stored fruit. The result of calculating the ice gel needed in the distribution and storage for the top shelf and middle shelf respectively as many as 3 ice gel and the bottom shelf is 2 of ice gel 0.496 grams to storage 22 fresh-cut melon-sized 60 grams.

Covalent linkage of bioactive volatiles to a polysaccharide support as a potential approach for preparing active edible coatings and delivery systems for food products

In this study, a potential of covalent linkage approach for developing active edible coatings was examined. Vanillin and trans-cinnamaldehyde were bound to chitosan by Schiff base reaction and reductive amination. The modified polysaccharides were comprehensively characterized and applied as active coatings on fresh-cut melon. The covalent linkage allowed overcoming solubility problems with the lipophilic vanillin and cinnamaldehyde and neutralizing their volatility, producing well-adhered coatings that enhanced fruit quality and storability without sensorial impairment. The attached hydrophobic moieties also provided new polysaccharides with self-assembling ability. Their aggregates were loaded with antimicrobial citral and added to mandarin juice, resulting in up to 6 log CFU/mL microbial count reduction. Thus, the covalent linkage concept offers several advantages, especially when hydrophobic or volatile active agents are used. Further developed, it may become a safe and effective tool for the formation of advanced active edible coatings and delivery vehicles for direct applications on food products.