Quality Of Fresh-cut Melon Research Articles

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.

Preservation Techniques to Extent the Shelf Life of Fresh-Cut Melon

Effective preservation strategies were assessed on fresh-cut melon quality during refrigerated storage. In order to screen process variables (package headspace conditions and polymeric materials), the work was divided into subsequent experimental trials. In the first one, a preliminary screening of different packaging films was performed to select the best polymeric material to be used for melon packaging. Among the screened films, an oriented polypropylene with 40 μm thickness (OPP40) showed good performance on both coated and uncoated fruit. In the subsequent experimental step, the inefficiency of modified headspace conditions applied at time of bag closure was demonstrated. In the third trial, the effects of various antimicrobial compounds were analyzed by dipping treatment. In the last step, samples dipped in hexanal, coated with sodium alginate and packaged in OPP40 recorded a shelf life of about 16 days compared to the control samples that reached a shelf life of less than one week. Practical Application The current work studies main strategies to preserve fresh-cut melon for more than 2 weeks. This product is very perishable but proper use of technological options during minimally processing can improve significantly the shelf life. The optimized preservation techniques proposed in the current work can be easily applicable also at industrial level. Therefore, recorded results could find interest in fresh-cut fruit sector and could further promote diffusion of ready-to-eat products also beyond the local market of production.

Heat treatment and active packaging to improve the storage of fresh-cut melons (Cucumis meloL.)

Introduction. Melon (Cucumis melo L.) is highly appreciated by consumers due to its sensory attributes and nutritional content. Producing minimally processed fruit has potential, because consumers look for freshness and convenience. However, fresh-cut processing increases the contact enzymes and their respective substrates because the cell tissue rupture, and this causes browning, softening and decay. This study investigated the effect of a combination of heat treatment with active modified atmosphere packaging on the quality of fresh-cut melons. Materials and methods. Whole ‘Charentais’ melon fruits were dipped in hot water (at 50 °C for 30 min), cooled, minimally processed and packaged in traditional polymeric film (oriented polypropylene, OPP) or biodegradable film (polylactic acid, PLA) with an initial flush of a gas mixture composed of 2−3% O2 and 7−8% CO2 . The quality of the fresh-cut melons was monitored for 11 days after treatment. Results and discussion. Gas changes demonstrated that (i) PLA permeability was higher than OPP permeability, and (ii) the heat treatment could temporarily reduce the respiration rate of fresh-cut melons. Heat treatment as a stress could also increase the beta-carotene content. Conclusion. The combination of heat treatment and active MAP with OPP film significantly improved both the decay development and the visual quality of fresh-cut melons for up to 11 days.

Fresh-cut melon quality during storage: An NMR study of water transverse relaxation time

Molecular mobility is a fundamental parameter which reflects the dynamic properties of food components and contributes to food degradation reactions comprehension. Fresh-cut fruits have become an important food market segment. However, processing of fruits promotes faster its physiological deterioration, biochemical changes and microbial degradation. The purpose of this work was to use NMR methodology as a tool to evaluate fresh-cut fruit quality, during storage at refrigerated conditions. The fresh-cut melon transverse relaxation time (T2) was measured for a period of 7days of storage at 5°C. The relationship between the obtained values, microstructure and quality parameters was investigated. In general, results show the existence of one class of water fluidity in the system, the one present in cells after processing. T2, a measure of this fluidity, is affected by the processing and storage time. Also, it is possible to find a close relationships between T2 and quality parameters of total colour difference (TCD), firmness and aw. As T2 increases TCD also increases, while firmness and aw decrease. These results highlight the usefulness of NMR methodology application in food science.

Biopreservation of fresh-cut melon using the strain Pseudomonas graminis CPA-7

The use of biopreservation is a promising technique to ensure microbial safety of fresh-cut produce. The objective of this work was to test the effectiveness of the strain CPA-7 of Pseudomonas graminis against a cocktail of Salmonella spp. and Listeria monocytogenes on fresh-cut melon, and evaluate its effect on its quality during shelf-life when tested in conditions simulating commercial application.Fresh-cut melon was artificially inoculated with Salmonella spp. and L. monocytogenes and with or without the biopreservative strain at different concentrations and stored at 20, 10 and 5°C. Moreover, the effect of the strain was tested in conditions simulating commercial application. Fresh-cut melon was packaged using passive modified atmosphere (MAP) and AIR conditions and stored at 5 and 10°C. Quality of fresh-cut melon was evaluated in CPA-7 treated and untreated samples. At laboratory scale trials, P. graminis reduced Salmonella and L. monocytogenes growth on fresh-cut melon stored at 5, 10 and 20°C. Effectiveness depended on their concentration and on storage temperature. At low pathogen concentration and 20°C, L. monocytogenes growth was reduced between 2.1 and 5.3logcfu g−1 units after 2 days of storage and Salmonella growth between 2.0 and 7.3logcfu g−1 depending on CPA-7 dose. At 10°C, similar reductions of pathogens were observed after 5 days of storage. In studies simulating commercial conditions, packaging atmosphere and temperature influenced P. graminis effectiveness, with better results in samples packaged under AIR conditions and 10°C. Reduction of pathogen growth was <1-log unit in fresh-cut melon stored in MAP whilst it was >4-log units in AIR. Soluble solids content, titratable acidity, pH and firmness of fresh-cut melon were not significantly different in CPA-7 treated and untreated (control) melon. In general, lightness, chroma and hue values of fresh-cut melon stored in AIR decreased faster in CPA-7 samples than on control ones. At 5°C, CPA-7 treated melon was visually scored lower than untreated melon. P. graminis has demonstrated promising results at 10°C, which is a temperature more compromised for safety. Nevertheless more detailed studies on the modified atmosphere are required because AIR packaging is not recommended due to the rapid loss of quality.

Impact of UV-C light on safety and quality of fresh-cut melon

Abstract The effectiveness of UV-C light exposure on safety and quality of fresh-cut fruit was investigated with reference to melon cubes. UV-C light was applied during cutting operations and before packaging. Melon cubes were then analysed for microbial counts, colour, firmness, juice leakage, sensory properties and preference during storage at 6 °C for up to 14 days. Fruit exposure to UV-C light leaded to 2 log reductions for both total viable count and Enterobacteriaceae , whose counts remained 2 log units lower than that of the untreated sample during storage. No significant effect of UV-C light treatment on product colour and firmness was detected during storage. By contrast, the exposure to UV-C light decreased melon leakage, probably due to the formation of a thin dried film on the product surface. UV-C treated samples were also associated to a better flavour which made them significantly preferred to the untreated ones. UV-C light treatment was demonstrated to be a high potential novel technology for surface decontamination of ready-to-eat food surface. Industrial Relevance UV-C light treatment represents a high potential novel technology allowing to achieve surface decontamination of ready-to-eat fruit products while improving their sensory properties.

Use of hydrogen peroxide in combination with nisin, sodium lactate and citric acid for reducing transfer of bacterial pathogens from whole melon surfaces to fresh-cut pieces

Hydrogen peroxide (2.5%) alone or hydrogen peroxide (1%) in combination with nisin (25 μg/ml), sodium lactate (1%), and citric acid (0.5%) (HPLNC) were investigated as potential sanitizers for reducing Escherichia coli O157:H7 or Listeria monocytogenes populations on whole cantaloupe and honeydew melons. Whole cantaloupes inoculated with E. coli O157:H7 and L. monocytogenes at 5.27 and 4.07 log 10 CFU/cm 2, respectively, and whole honeydew melons inoculated with E. coli O157:H7 and L. monocytogenes at 3.45 and 3.05 log 10 CFU/cm 2, respectively, were stored at 5 °C for 7 days. Antimicrobial washing treatments were applied to inoculated whole melons on days 0 or 7 of storage and surviving bacterial populations and the numbers transferred to fresh-cut pieces were determined. At days 0 and 7 treatment with HPLNC significantly ( p < 0.05) reduced the numbers of both pathogens, by 3 to 4 log CFU/cm 2 on both types of whole melon. Treatment with HPLNC was significantly ( p < 0.05) more effective than treatment with 2.5% hydrogen peroxide. While fresh-cut pieces prepared from stored whole melons were negative for the pathogens by both direct plating and by enrichment, fresh-cut pieces from cantaloupe melons treated with 2.5% hydrogen peroxide were positive for both pathogens and pieces from honeydew melons were positive for E. coli 0157:H7. The native microflora on fresh-cut melons were also substantially reduced by HPLNC treatment of whole melons. The results suggest that HPLNC could be used to decontaminate whole melon surfaces and so improve the microbial safety and quality of fresh-cut melons.

Qualidade de melão minimamente processado armazenado em atmosfera modificada passiva

Frutos de melão do tipo, rendilhado cv. Bônus II, foram minimamente processados na forma de cubos e acondicionados em embalagens de diversos materiais sendo, em seguida, armazenados a 3ºC. Nas embalagens foram utilizados os materiais: AFG: filme poliolefínico da DuPont 15µm, HP: filme poliolefínico da DuPont 15µm, PD-900: filme poliolefínico da Cryovac 58µm, PEBD: filme de polietileno de baixa densidade 87µm, PP: filme de polipropileno 52µm, BB-200: filme multicamada da Cryovac 65µm, PET: embalagem rígida de polietereftalato de etileno. Foram determinadas as taxas de permeabilidade ao O2 e ao CO2 de cada uma das embalagens. As composições gasosas do espaço livre das embalagens foram determinadas diariamente durante 8 dias e no 9º dia as características físico-químicas e sensoriais foram avaliadas. A taxa respiratória foi determinada nos melões inteiros e nos melões minimamente processados. Os filmes utilizados não promoveram modificação efetiva da atmosfera, mas a embalagem rígida de PET proporcionou, a partir do 6º dia, uma atmosfera de equilíbrio com 12% O2 e 7% CO2. As características físico-químicas dos melões foram mantidas em todos os tratamentos, enquanto as características sensoriais foram mantidas apenas nos melões acondicionados na embalagem rígida de PET. A modificação passiva da atmosfera, para melão minimamente processado armazenado a 3ºC, não foi verificada na extensão desejada com as embalagens estudadas, provavelmente devido à baixa taxa respiratória observada nesta temperatura, associada à alta relação entre área de permeação da embalagem e massa de melão.