Using polysaccharide-based edible coatings to enhance quality and antioxidant properties of fresh-cut melon

The effect of alginate, pectin and gellan-based edible coatings on the shelf-life of fresh-cut ‘Piel de Sapo’ melon was investigated. Gas exchange, antioxidant properties, color, firmness, sensory quality and microbial growth of fresh-cut melon were studied during 15 days at 4 °C. Gellan, pectin and alginate coatings increased the water vapor resistance of fresh-cut melon, thus preventing dehydration. They also had an inhibitory effect on ethylene production although O₂ and CO₂ diffusion through coated melon tissue was not avoided. Calcium chloride used as a crosslinking agent helped to maintain fruit firmness. Edible coatings themselves did not improve microbiological stability of fresh-cut ‘Piel de Sapo’ melon packaged under passive modified atmosphere. Pectin or alginate could reduce the wounding stress induced in fresh-cut melon, which triggered an accumulation of total phenolic compounds and other compounds with antioxidant properties. In addition, pectin-based coating seemed to best maintain sensory attributes.     

Alternative Sanitizers to Chlorine for Use on Fresh‐Cut “Galia” (Cucumis melo var. catalupensis) Melon

ABSTRACT: Chlorine is commonly used to reduce microbial load in fresh‐cut vegetables. However, the production of chlorinated organic compounds, such as trihalomethanes, which are potential carcinogens, has created the need to investigate the efficiency of nontraditional sanitizers and alternative techniques. The effects of 4 novel sanitizers were tested in fresh‐cut “Galia” melon: chlorine dioxide (ClO₂) at 3 mg/L, peracetic acid (PAA) at 80 mg/L, hydrogen peroxide (H₂O₂) at 50 mg/L, and nisin at 250 mg/L plus EDTA 100 mg/L (nisin + EDTA). A chlorine treatment (NaOCl at 150 mg/L) was used as a control. Pieces of melon were packed in polypropylene trays under passive modified atmosphere (3 to 4 kPa of O₂ and 10 to 11 kPa of CO₂) and stored up to 10 d at 5 °C. Microbial growth, firmness, respiration rate, gas composition, sensory evaluation, color, total soluble solids (TSS), and tritable acidity (TA) were evaluated at days 0, 7, and 10. The novel sanitizers PAA, H₂O₂, and nisin + EDTA, in the studied concentrations, reduced the microbial growth to a more efficient range than chlorine and ClO₂. In addition, those sanitizers delayed softness, did not affect the respiration rate, SST, or AT. The sensorial parameters were kept above the upper limit of marketability and they did not impart an “off flavor.” These sanitizers maintained quality and shelf life of fresh‐cut Galia melon for 10 d of storage at 5 °C. Nevertheless, other concentrations, in particular for ClO_2, could be tested to study an extended shelf life in melon pieces.     

Combined effects of postharvest heat treatment and chitosan coating on quality of fresh‐cut mangoes (Mangifera indica L.)

The influence of heat treatment combined with coating on sensory quality, physico‐chemicals characteristics (firmness, colour, pH, titratable acidity, total soluble solids and total carotenoids content) and microbiological quality of fresh‐cut mangoes were studied. Whole mangoes (Mangifera indica cv ‘Tommy Atkins’) were subjected to hot water dipping (HWD) at 50 °C for 30 min and cooled for 15 min. Heated and unheated fruits were minimally processed and mango cubes were coated with chitosan solution (0.25% w/v) dissolved in 0.5% (w/v) citric acid, and stored for 9 days at 6 °C under ambient atmosphere. This study showed that both HWD 50 °C for 30 min and chitosan coating, either alone or combined, did not affect the taste and the flavour of mangoes slices. The chitosan coating combined with HWD or not inhibited the microbial growth for 9 days at 6 °C. Indeed chitosan coating was used for his antimicrobial proprieties. HWD 50 °C for 30 min was the beneficial treatment to maintain firmness and colour during 9 days at 6 °C.     

Effect of ripeness on the shelf-life of fresh-cut melon preserved by modified atmosphere packaging

Fresh-cut ‘Piel de Sapo’ melon was processed at different ripeness stages and stored under modified atmosphere packaging for 35 days at 5 °C. Raw material firmness and soluble solids content ranged from 6.5 to 3.9 N and 11.1 to 14.3 °Brix, respectively. The effects of a 2.5 kPa O₂+7 kPa CO₂ packaging atmosphere and a dip of 1% ascorbic acid and 0.5% calcium chloride on physiology, microbiological stability as well as color and firmness were evaluated. An intermediate stage of ripeness at processing was the most suitable to extend the shelf-life of fresh-cut ‘Piel de Sapo’ melon. Green-mature fresh-cut melon reduced CO₂ accumulation and ethanol production. In addition, a treatment with ascorbic acid and calcium chloride in combination with modified atmosphere packaging, contributed to a greater extension of the shelf-life of fresh-cut melon than that reported for fruits stored under non-modified atmosphere, slowing down the growth of microbial populations, maintaining the original color and reducing softness. Thus, the shelf-life of green-mature fresh-cut ‘Piel de Sapo’ melon dipped in an ascorbic acid and calcium chloride solution and packaged under modified atmosphere was about 10 days.     

Effect of temperature and modified atmosphere packaging on overall quality of fresh-cut bell peppers

The effect of vacuum packaging (VP) and modified atmosphere packaging without vacuum (MAP) on shelf-life of fresh-cut green bell pepper stored at 5°C and 10°C were evaluated. In-package atmosphere, overall quality, percentage of leaked juice, texture, ascorbic acid content, ethanol and acetaldehyde, and microbial growth, were evaluated at different intervals of storage. MAP-fresh-cut peppers presented better visual quality, less leaked juice and higher firmness than those stored under VP. Microbiological and quality analysis revealed a limit of shelf-life of 14 and 21 days, when fresh-cut peppers were stored at 10°C and 5°C, respectively. We conclude that MAP could be used to maintain quality attributes of fresh-cut peppers for up 21 days at 5°C.     

Quality attributes of shredded carrot (Daucus carota L. cv. Nantes) as affected by alternative decontamination processes to chlorine

The effects of alternative decontamination processes to chlorine: ozonated-water (1 ppm/5 min), hot water (100 °C/45 s) and ultrasonication (45 kHz/1 min), applied pre- or post-cut in the technological diagram of minimal processing of carrots were tested. Ultrasonication in chlorinated-water and thermo-ultrasonication as combined processes applied just in pre-cut carrot were also tested. The initial microbial load reduction, soluble solids content, pH and sensorial attributes of shredded carrot just after processing were evaluated. Decontamination processes applied on pre-cut carrot provided maintenance of fresh-like sensorial quality, regardless the type of treatment, due to diminished leaching phenomena which is critical for shredded carrot. Chlorination, ozonization and ultrasonication achieved ca. 1 Log₁₀ reduction of initial microbial load. No additional decontamination effect in combined processes was observed. The use of heat in pre-cut carrot proved to be the most efficient process regarding microbial reduction (3 Log₁₀ units) providing, as well, an acceptable fresh-like quality product.Industrial relevanceThe major constraint for marketability of minimally processed shredded carrot is its limited shelf-life due to rapid microbial growth and colour loss (decrease of orange intensity and/or whitening of the shreds). These questions arise from the practical experience of a fresh-cut industry directly involved in the R&D research project which supported this study. Chlorine solutions have been widely used to sanitize fruit and vegetables in the fresh-cut industry. However, reduced microbiological efficiency allied to the eventual formation of carcinogenic chlorinated compounds pointed out the need for alternative methodologies. The present work aimed the evaluation of clean alternative decontamination processes applied both to pre- and post-cut carrot for the production of shredded carrot, operating under conditions of industrial practice at pilot-plant scale.     

1-MCP对切分哈密瓜保鲜效果的研究

以新疆哈密瓜(8601)为材料,在5℃贮藏温度下,研究了1-MCP 对切分哈密瓜生理、品质和食用安全性的影响。结果表明：1.0μl/L 1-MCP 处理可显著抑制贮藏期间果实乙烯释放量,保持果实的感官,硬度、糖度和高VC 的含量,抑制切分哈密瓜透明化,降低了切分哈密瓜的细胞膜脂质过氧化水平,抑制微生物的数目,延长了切分哈密瓜的货架期。     

Use of neutral electrolysed water (EW) for quality maintenance and shelf-life extension of minimally processed lettuce

Experiments were conducted to determine the effectiveness of different treatments based on the use of neutral electrolysed water (EW) on fresh-cut lettuce. EW was diluted to obtain different free chlorine concentrations (120, 60 and 12 ppm) and to compare with standard washing treatment of 120 ppm chlorine solution. Shelf-life quality and safety markers were studied at the beginning and at the end of the 7-day-storage at 4 °C. The use of EW decreased the respiration rate of the samples which might be related with the observed reduction in microbial spoilage. The use of EW also increased the activity of a browning-related enzyme (polyphenoloxydase) although sensory results showed all samples as acceptable at the end of the 7 day-storage. Perhaps longer storage time might increase the risk to browning development in the samples treated with EW. The highest EW concentration (120 ppm free chlorine) was the most effective treatment in reducing sample microbial load; however this treatment also affected the final produce with effects such as loss of turgor, plasmolysis and a reduction in mineral content.Results suggest an intermediate EW concentration with 60 ppm free chlorine could be an alternative to 120 ppm chlorine (from sodium hypochlorite) for sanitizing fresh-cut vegetables, reducing to half the amount of chlorine used and maintaining the antimicrobial effectiveness and without differences affecting the quality. However further studies will be necessary in order to observe the effect of the oxidising capacity of EW on other quality and safety markers as pathogens and nutritional content.Industrial relevanceChlorine solutions have been widely used to sanitise fruit and vegetables in the fresh-cut industry. However, the association of chlorine with the possible formation of carcinogenic chlorinated compounds in water has called into question the use of chlorine in food processing. The efficacy in controlling the microbial load and browning of samples treated with electrolysed water shows it as a promising decontaminant agent for fresh-cut lettuce. Due to the high oxidising potential of the EW quality requirements must be balanced to obtain the optimal treatment conditions keeping satisfying safety levels. The use of EW-60 showed similar safety and quality (browning) results as the use of chlorine or double EW concentration (EW-120). However the treatment EW-120 affected negatively the textural properties. The study suggests the use of EW-60 as an alternative to sodium hypochlorite solution with 120 ppm available chlorine, obtaining similar safety and quality results and reducing the amount of chlorine needed. Further investigations in the effect of EW on lettuce, such as those on pathogens or nutritional markers (e.g. carotenoids and vitamin C) are recommended in order to explore this alternative that might reduce the increasingly concerning use of chlorine to decontaminate this type of product.     

Effect of Osmotic Dehydration and Pectin Edible Coatings on Quality and Shelf Life of Fresh-Cut Melon

The aim of this work was to investigate the influence of osmotic dehydration and pectin edible coating on quality parameters of fresh-cut melon. Fruits were osmodehydrated in 40°Bx sucrose solution containing 0.5% calcium lactate or dipped in 0.5% calcium lactate solutions. Then, samples were coated with 1% pectin. Melon pieces dipped in sanitizing solution (nontreated sample) were used as control. Weight loss, respiration rate, firmness, color parameters (lightness, chroma, and whiteness index), sensory acceptance, microbial growth, and structural changes of fruits were evaluated during storage at 5 °C for 14 days. The shelf life of the control sample was limited to 9 days due to microbial growth and sensory rejection, while treated samples showed a shelf life of 14 days. Higher preservation of firmness in coated samples was attributed to the action of calcium salt on melon structure, causing a strengthening of the cell wall. Calcium lactate also inhibited microbial growth along storage, improving microbiological stability of fresh-cut melon. The use of calcium lactate dips and pectin edible coatings hindered weight loss and maintained fruit color characteristics during the storage time. However, these pretreatments probably masked melon taste, reducing the sensory acceptance scores at the end of shelf life study. The combination of osmotic dehydration and pectin coatings was a good preservation alternative for fresh-cut melon, since it improved fruit sensory acceptance, promoting the reduction of product respiration rate, as well as the maintenance of quality parameters during 14 days.     

Quality and Nutritional Status of Fresh-Cut Tomato as Affected by Spraying of Delactosed Whey Permeate Compared to Industrial Washing Treatment

The aim of this study was to examine the applicability of delactosed whey permeate (DWP) treatment on preserving the quality and antioxidant attributes of fresh-cut tomato. Tomatoes were treated with 3% DWP by dipping, spraying and a combination of both, stored at 4?°C for 10?days and compared with the industrial standard, chlorine. The combination of dipping and spraying of DWP showed the best results for all the markers tested. The combined treatment of dipping and spraying of DWP significantly lowered total counts (??1.0 log cfu/g), yeast and moulds (??1.2 log cfu/g), inhibited the loss of firmness (25%) and reduced POD activity (15%) of the tomato slices after 10?days compared to the chlorine treatment. Moreover, DWP-treated tomatoes maintained significantly (p?<?0.05) higher levels of vitamin C, total phenols and antioxidant activity (DPPH) than the chlorine-treated samples during storage. Sensory scores confirmed that DWP-treated tomatoes retained better aroma and texture. Also, the appearance and overall acceptability were higher than chlorine-treated tomatoes. Thus DWP treatment has potential to extend the shelf life of fresh-cut tomatoes.     

Electrolyzed Water as a Disinfectant for Fresh-cut Vegetables

The effect of electrolyzed water on total microbial count was evaluated on several fresh-cut vegetables. When fresh-cut carrots, bell peppers, spinach, Japanese radish, and potatoes were treated with electrolyzed water (pH 6.8, 20 ppm available chlorine) by dipping, rinsing, or dipping/blowing, microbes on all cuts were reduced by 0.6 to 2.6 logs CFU/g. Rinsing or dipping/blowing were more effective than dipping. Electrolyzed water containing 50 ppm available chlorine had a stronger bactericidal effect than that containing 15 or 30 ppm chlorine for fresh-cut carrots, spinach, or cucumber. Electrolyzed water did not affect tissue pH, surface color, or general appearance of fresh-cut vegetables.     

Evaluation of the use of decontamination agents during fresh-cut leek processing and quantification of their effect on its total quality by means of a multidisciplinary approach

In this study the impact of different decontamination agents (water, peroxyacetic acid, sodium hypochlorite, neutral electrolyzed oxidizing water and gaseous chlorine dioxide) on the microbial and sensory quality as well as the nutrient content of minimally processed leek was investigated. Washing with 250 mg/L peroxyacetic acid and contact with 1.59 mg/L chlorine dioxide gas reduced the native microflora with 1.52 and 1.48 log cfu/g respectively whereas the other treatments did not induce a reduction that was significantly higher than the one achieved after washing with water. None of the treatments had a significant effect on the sensory quality of the raw fresh-cut leek, whereas a treatment with 200 mg/L sodium hypochlorite or with 250 mg/L peroxyacetic acid changed the sensory quality of cooked leek significantly when compared with water washing. Apart from the effect of leaching of nutrients into the wash water, the supplementary effect on nutrient content caused by adding a decontamination agent was limited with the exception of some isolated cases such as the significant losses of vitamin C (23%), tocopherols (11–18%) and violaxanthin (66%) after a treatment with respectively chlorine dioxide, 250 mg/L peroxyacetic acid and electrolyzed oxidizing water.Industrial relevanceVegetables like leek are highly contaminated with micro-organisms due to their contact with soil, water and other debris as a result of preharvest as well as postharvest conditions. Moreover, the sales of fresh-cut vegetables such as fresh-cut leek showed a tremendous increase over the last decade. Usually these products have a limited shelf-life due to microbial, sensorial and chemical alterations. The fresh-cut produce industry is continuously looking for treatments able to replace the traditionally used sodium hypochlorite which is associated with the formation of harmful disinfection by-products. In this study more innovative treatments like neutral electrolyzed oxidizing water, peroxyacetic acid and gaseous chlorine dioxide were studied for their effect on the microbial, sensory and nutritional quality of fresh-cut leek.     

Effect of decontamination on the microbial load,the sensory quality and the nutrient retention of ready-to-eat white cabbage

The effect of different decontamination treatments such as washing with sodium hypochlorite (20 and 200 mg/L), peroxyacetic acid (80 and 250 mg/L), neutral electrolysed oxidising water (4.9 and 31.7 mg/L free chlorine) and contact with 1.55 mg/L chlorine dioxide gas on the microbial and sensory quality, and the nutrient content of fresh-cut white cabbage was studied. Only rinsing with 200 mg/L sodium hypochlorite, peroxyacetic acid or contact with gaseous chlorine dioxide resulted in significantly higher reductions of the total plate count (1.5–2.5 log cfu/g) than the ones achieved by washing with tap water (0.5 log cfu/g). However, those treatments giving the best results from a microbial point of view induced significant changes in the sensory quality. Regarding the effects on nutrient content, the mechanical effects caused by water washing already reduced the vitamin C content by 16–29%. Contrary to washing with neutral electrolysed oxidising water and contact with chlorine dioxide gas, a supplementary decrease of the vitamin C content ranging between 9 and 28% was observed, when peroxyacetic acid or 200 mg/L sodium hypochlorite were used. After the use of peroxyacetic acid or gaseous chlorine dioxide, the phenol content also showed a decreasing trend, although not statistically significant. Apart from the effect of washing with water, the lipophilic nutrients were well retained after a decontamination step except for the α-tocopherol content, when peroxyacetic acid was used (−43 to 56%), and for the all-trans-β-carotene content (−8%) of cabbage in contact with gaseous chlorine dioxide. Because of its potential to reduce the initial microbial load without negative effects on the sensory quality, in combination with its limited effects on nutrient content, a treatment with 80 mg/L peroxyacetic acid is preferable to decontaminate fresh-cut white cabbage.     

Combined action of pure oxygen pretreatment and chitosan coating incorporated with rosemary extracts on the quality of fresh-cut pears

The combined effects of pure oxygen pretreatment (PO) and chitosan coating (C) containing 0.03% rosemary extracts (R) on the quality of fresh-cut pears were investigated. Whole pears were exposed to air and pure oxygen at 2 °C for 10 days. The pretreated pears were cored, sliced and stored at 20 °C for 3 days. The physicochemical and sensorial attributes were monitored. The results demonstrated that air + C + R (ACR), PO + C (POC) and PO + C + R (POCR) combinations improved preservation of the fresh-cut pear compared to the control. When compared to ACR, both POC and POCR inhibited polyphenol oxidase activity, softening and weight-loss, and retained higher firmness and soluble solids content. Membrane permeability, L value, and pH also presented smaller changes. Furthermore, POCR increased these beneficial effects and favourably reduced browning, maintained higher polyphenols and vitamin C content and sensory attributes in contrast to POC. The present data suggests that POCR have the potential to improve the quality of fresh-cut pears and extend the shelf-life.     

ATP bioluminescence assay for estimation of microbial populations of fresh-cut melon

Estimation of microbial numbers in foods by conventional microbiological techniques takes days, so there is a need for faster methods that can give results in minutes. Research was undertaken to investigate the use of bioluminescent ATP determination and a firefly luciferase assay to estimate the initial population of aerobic mesophilic bacteria on fresh-cut melons immediately after preparation and during storage at 5 or 15 degrees C for up to 12 days. Populations of aerobic mesophilic bacteria on fresh-cut cantaloupe prepared immediately from unsanitized whole melons averaged 3.42 log CFU/g, corresponding to an ATP value of 5.40 log fg/g. Populations for fresh-cut honeydew prepared from unsanitized whole melon averaged 1.97 log CFU/g, corresponding an ATP value of 3.94 log fg/g. Fresh-cut pieces prepared from cantaloupe or honeydew melons sanitized with either chlorine (200 ppm free chlorine) or hydrogen peroxide (2.5%) had similar ATP values: 3.1 log fg/g (corresponding to bacterial counts 1.7 log CFU/g) for cantaloupes and 2.6 log fg/g (corresponding to bacterial counts of 0.48 CFU/g) for fresh-cut honeydew. Positive linear correlations for ATP concentrations and microbial populations were found for fresh-cut cantaloupe (R2 = 0.99) and honeydew R2 = 0.95) during storage at 5 degrees C for up to 12 days. ATP values in fresh-cut melons inoculated with either aerobic mesophilic bacteria or yeast and mold were significantly higher (P < 0.05) than control values and parallel total plate counts on plate count agar. Results of this study indicate that the bioluminescent ATP assay can be used to monitor total microbial populations on fresh-cut melon after preparation and during storage for quality control purposes to establish specific sell-by or consume-by dates.     

Quality of Iceberg (Lactuca sativa L.) and Romaine (L. sativa L. var. longifolial) lettuce treated by combinations of sanitizer,surfactant, and ultrasound

The effects of sonication, sanitizers and sodium dodecyl sulfate (SDS) on the quality of fresh-cut Iceberg and Romaine lettuce were examined. Lettuce samples were treated for 1 min with and without ultrasound with one of the following solutions: tap water, chlorine, Tsunami, and a combination of Tsunami with 1 g/L SDS. Washed samples were packed under modified atmosphere conditions and stored at 4 °C for up to 14 days. Changes in headspace gases, texture, color, tissue damage, visual quality, and natural flora were determined. The O₂ concentrations and CO₂ accumulation in Romaine lettuce were not significantly different among the treatments. In Iceberg lettuce, a lower O₂ and high CO₂ content in the headspace of samples treated with Tsunami and Tsunami + SDS were recorded. After 14-day storage, the tissue damage expressed by electrolyte leakage, total color difference, firmness, and total aerobic plate counts were not significantly different among treatments in two types of lettuce samples. Treatment of Iceberg lettuce with sonication in combination with Tsunami or Tsunami + SDS did not degrade quality compared to samples treated with chlorine alone, whereas for Romaine lettuce, chlorine-treated samples had a significantly higher overall quality score than that from the other treatments.     

Physicochemical changes in fresh-cut wax apple (Syzygium samarangenese [Blume] Merrill & L.M. Perry) during storage

Physicochemical changes, such as peel and flesh colours, total anthocyanin content, browning index, firmness, total soluble solid (TSS), titratable acidity (TA), sugar acid ratio (TSS/TA), antioxidant capacity, total phenolic content and ascorbic acid content, in fresh-cut Taaptimjan wax apple fruit stored at 4 ± 2 °C and 12 ± 2 °C for 7 days were investigated. The skin of fresh-cut fruit stored at 4 ± 2 °C showed higher a^∗ value, chroma and total anthocyanin content and lower hue angle than those stored at 12 ± 2 °C. Lightness (L^∗ value) and whiteness index of the fresh-cut fruit flesh stored at 12 ± 2 °C showed significantly lower than those stored at 4 ± 2 °C which related to an significant increase in browning index. Firmness, total soluble solid, titratable acidity and sugar acid ratio did not significant changes during storage. Antioxidant capacity and total phenolic content increased throughout storage. Ascorbic acid content of the fresh-cut fruit stored at 4 ± 2 °C remained constant throughout storage whilst ascorbic content at 12 ± 2 °C decreased and was lower than that at 4 ± 2 °C. At 4 ± 2 °C antioxidant capacity and ascorbic acid content were higher than that stored at 12 ± 2 °C whilst there was no significant difference in total phenolic content. In conclusion, the reduction of whiteness index and the increase in browning index of fresh-cut wax apple flesh were the key factors affecting its quality and storage at 4 ± 2 °C could reduce the change in the flesh colour and maintained the peel colour and nutritional values of fresh-cut wax apple fruit during storage.     

Development of rapid hygrothermal pasteurization using saturated water vapor

We developed a novel rapid hygrothermal pasteurization (RHP) method using saturated water vapor with a dew point of 100 °C. In the present study, the effects of RHP on microbiological quality and quality attributes such as color changes, firmness and ascorbic acid content on many fresh-cut fruits and vegetables (cabbage, cucumber, carrot, cherry tomato, bell pepper, strawberry, pineapple and melon) were investigated. The RHP was performed within a second by free-falling samples through a cylindrical processing chamber filled with steam. The RHP resulted in a 0.7–2.0 log order reduction in the numbers of naturally inoculated mesophilic bacteria. Furthermore, the RHP induced no significant changes in color and firmness of samples, except on the leafy vegetable, cabbage. Ascorbic acid was also retained approximately 80% and above. These results indicate that the RHP is a clean and effective method for decontaminating mesophilic bacteria on fresh fruits and vegetables with minimal changes in quality.Industrial relevanceIn fresh-cut industry, an effective and risk-free decontamination technology is required for use in place of a conventional method, washing by chlorine that can produce carcinogenic chlorinated by-products. In this study, the rapid hygrothermal pasteurization (RHP) method using saturated water vapor was invented and their ability for applying minimal processing was evaluated. The results showed that RHP, without using chemicals, can reduce microorganism load and preserve quality attributes in many kinds of fresh-cut fruits and vegetables. Therefore, RHP could be used as a novel method, which can be generally applicable to fresh-cut fruits and vegetables in the food industry.     

Combination of hot-water surface pasteurization of whole fruit and low-dose gamma irradiation of fresh-cut cantaloupe

Improvements in methods for disinfecting fresh-cut cantaloupe could reduce spoilage losses and reduce the risk of foodborne illness from human pathogen contamination. The objective of this study was to investigate the feasibility of using hot-water treatment in combination with low-dose irradiation to reduce native microbial populations while maintaining the quality of fresh-cut cantaloupe. Whole cantaloupes were washed in tap water at 20 or 76 degrees C for 3 min. Fresh-cut cantaloupe cubes, prepared from the washed fruit, were then packaged in clamshell containers, and half the samples were exposed to 0.5 kGy of gamma radiation. Native microflora populations and sensory qualities were evaluated during the subsequent 7 days of storage at 4 degrees C. The hot-water surface pasteurization reduced the microflora population by 3.3 log on the surface of whole fruits, resulting in a lower microbial load on the fresh-cut cubes compared with cubes cut from fruit treated with cold water. Irradiation of cubes prepared from untreated fruit to an absorbed dose of 0.5 kGy achieved a low microbial load similar to that of cubes prepared from hot-water-treated fruit. The combination of the two treatments was able to further reduce the microflora population. During storage, the headspace atmosphere of the packages was not significantly influenced by any of the treatments. Color, titratable acidity, pH, ascorbic acid, firmness, and drip loss were not consistently affected by treatment with irradiation, hot water, or the combination of the two. Cubes prepared from hot-water-treated whole fruit had slightly lower soluble solids content. The combination of hot-water pasteurization of whole cantaloupe and low-dose irradiation of packaged fresh-cut melon can reduce the population of native microflora while maintaining the quality of this product.     

Metabolic Behavior and Quality Changes of Whole and Fresh Processed Melon

ABSTRACT: Whole fruit and fresh-cut pieces from 4 types of melon were stored for up to 10 d at 0 and 5 °C. After the wound stress period, no differences in the respiration rates were found between intact and the fresh-cut melon. Softness, weight loss, translucency, wound stress, and respiration rate were lower and sensorial quality higher during storage at 0 °C than at 5 °C. Cut cylinders showed a low degree of softness, high translucency, and a poor processing efficiency. Slices showed a higher softness but lower translucency. Trapezoidal sections showed a behavior intermediate between cylinders and slices. For the fresh-cut melon, the best results were obtained with Amarillo trapezoidal sections and a storage temperature of 0 °C.