992 resultados para Modified atmosphere


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The marketing of organically labeled prawns is predominately in a cooked or raw frozen form to avoid the development of melanosis (black spot). Certification for organic status prohibits the use of any added chemicals. The application of 60% CO2/40%N2 modified atmosphere to chilled (raw) prawns using two species of prawn was investigated for the ability to control black spot formation. Sensory assessment and microbiological counts were used to determine the end of product shelf life. Modified atmosphere packaged (MAP) prawns exhibited no melanosis for up to 16 days. The high quality life was retained for 12 days; shelf life of 16 days, according to standard microbiological criteria, was achieved, which is more than twice previously reported for non-MAP prawns. Results suggest MAP may be an effective method for the marketing of organically grown prawns as well as those produced by conventional prawn aquaculture without application of the normal chemicals used to prevent black spot. Copyright © 2014 Crown Copyright.

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Fish protein concentrate (FPC) is a healthy, sustainable and high nutritive product which sanitized produced from fishes in which, protein and other nutrients are more concentrated than in fresh fishes. The aim of this research is to study on the sustainability of FPC produced from Kilka (Clupeonella engrauliformis , C. grimmi and C. cultriventris) in two Vaccum Packaging and Modified Atmosphere Packaging at different environmental factors during six months. In our study the analysis of FPC protein showed 91.2%, lipid: 0.5%, ash: 3.6%, moisture: 2.3%, Total Volatile Nitrogen: 10 ml/100gr and peroxide: 5meq/kg. Amino acids and fatty acids were also determined. Bacteria and Fungi were lower than 1000 colony. Samples are kept in different condition of temperature (5, 20 and 35 degree centigrade), humidity (25, 40 and 90 percent) and light and dark environment in six month. Lipid rate in FPC after 6 months in VP and MAP (60% C02, 30 % N2 and 10% O2), packages was decreased but was not significant (P>0.05). It was also detected that increase temperature lead to more decrease in lipid content. Protein rate of FPC was decreased from 91.2% to 73.6% during six months at 35°C in VP Package and from 91.2% to 69.4% in MAP package. These changes were significant (P<0.05). TVN and PV rate in FPC after 6 months in VP and MAP packages was increased but was significant (P<0.05). Amino acids and fatty acids were also determined. But more changes in MAP packages was detected.

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A modified atmosphere may be defined as a packaging or storage of a perishable product in an atmosphere other than that of air. A modified atmosphere (MA) applies to food packaged products changes continuously throughout the storage period. The pearl spot (Etroplus suratensis) is an important brackish water fish belonging to the family Cichlidae. The present work was carried out to see the effect of modified atmosphere packaging on the shelf life fresh pearl spot stored in ice to extent the shelf life. The objectives of the present study are to study the suitability of Thermoformed Trays for modified atmosphere packaging, to standardize the most suitable gas mixture for modified atmosphere packaging pearl spot based on sensory evaluation, to find out the effect of modified atmosphere packaging in comparison to air packaging, to study the biochemical, microbiological, sensory and textural characteristics during storage, to study the safety concern regarding the Clostridium botulinum during modified atmosphere packaging, to find out the most suitable chemical quality indices for modified atmosphere stored pearl spot

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Postharvest quality of Alphonso mangoes (Mangifera indica L) is vital to ensure proper ripening and good quality. 500 g mature green mangoes, were subjected to three pre- packaging hot water dips (20, 30 & 40°C) for 40 min, two packaging films (OPP unperforated and perforated), using three levels of gas concentrations of 25,50 and 75% v/v CO2 treatments (balance N2) and stored at 10°C for 21 days. During the storage period headspace gas composition, weight loss, ascorbic acid, pulp firmness, external fruit colour and overall quality score were measured to determine optimum storage conditions. The most effective postharvest condition was found to be dipping in water maintained at 40°C for 40 min, followed by packaging under 50% CO2 in bags made of unperforated film when compared to mangoes packed under 25 and 75% CO2 which showed deteriorated quality including spoilage and mould. Good keeping quality of at least 21 days was achieved under these conditions, which was much superior to the control samples that showed deterioration after 12 days of storage.

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Fresh-cut fruit products, including carambola (Averrhoa carambola L.), have limited marketability due to cut surface browning attributed to phenolic compound oxidation by enzymes, such as polyphenol oxidase (PPO). The objective of this study was to evaluate postharvest changes in carambola slices in three different packages. Carambola fruit (cv. Fwang Tung) were picked from the Estacao Experimental de Citricultura de Bebedouro orchard at the mature-green stage. The fruit were washed, dipped in NaOCl solution (200 mg L-1 for 5 min), stored overnight at 10 degrees C, then manually sliced into pieces of approximately 1 cm. The slices were rinsed with NaOCl solution at 20 mg L-1, drained for 3 min, and packaged in polyethylene terephthalate (PET) trays (Neoform (R) N94); polystyrene trays covered with PVC 0.017 turn (Vitafilm (R), Goodyear); and vacuum seated polyolefin bags (PLO, Cryovac (R) PD900). The packages were stored at 6.8 degrees C and 90% RH for 12 d, with samples taken every 4 d. PET trays and PVC film did not significantly modify the internal atmosphere and the high water permeability of PVC led to more rapid slice desiccation. PPO activity was lower when the slices were packaged in PLO vacuum sealed bags, which reduced degreening and led to better appearance maintenance for up to 12 d. (R) 2006 Elsevier B.V. All rights reserved.

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Fresh-cut fruit products, including carambola (Averrhoa carambola L.) have limited marketability due to cut surface browning attributed to oxidation of phenolic compounds by enzymes such as polyphenol oxidase (PPO). The objective of this study was to evaluate postharvest changes of carambola slices in three different packagings. Carambola fruit (cv. Fwang Tung) were picked from the orchard of Estação Experimental de Citricultura de Bebedouro at mature-green stage. Fruit were washed, dipped in NaOCl solution (200 mg.L -1 for 5 minutes), and stored overnight at 10°C. Fruit were manually sliced into pieces of approximately 1 cm. Slices were rinsed with NaOCl solution at 20 mg.L-1, drained for 3 minutes, and packaged in polyethylene terephthalate (PET) trays (Neoform N94); polystyrene trays covered with PVC 0.017 mm (Vitafilm - Goodyear); and vacuum sealed polyolefin bags (PLO, Cryovac PD900). The packages were stored at 6.8°C and 90%RH for 12 days and samples taken every 4 days. PET trays and PVC film did not significantly modify internal atmosphere and the high water permeability of PVC led to more rapid slice desiccation. PPO activity was lower when slices were packaged in PLO vacuum sealed bags, which reduced discolouration and led to better appearance maintenance for up to 12 days.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Literature cited: p. 70-77.

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The effects of modified atmosphere (MA) conditions on the quality of minimally processed pineapple slices were determined. Commercial pineapple slice packs sealed with 40 pm thick polyester film were kept at 4.5 degrees C for 14 d. The oxygen transmission rate of the film was 23 ml m(-2) day(-1) atm(-1) (at 25 degrees C, 75% RH). In-built atmospheres and the quality of the products were determined. O-2 concentrations within the packs stabilised at 2%, while CO2 concentrations increased to 70% by day 14. The high CO2 level suggested an inappropriate lidding film permeability for the product, and hence affected its quality. Three batches of pineapple slices were packed in the laboratory using lidding films with oxygen transmission rate of 75, 2790 or 5000 ml m(-2) day(-1) atm(-1) (at 23 degrees C, 0% RH). Headspace atmospheres from laboratory-packed pineapple slices suggested an optimum equilibrium modified atmosphere of ca. 2% O-2 and 15% CO2. Respiration data from the laboratory-prepared packs were pooled together and used to develop a correlation model relating respiration rates to O-2 and CO2 concentrations. The model showed a decrease in respiration rate with decreasing O-2 and increasing CO2 concentrations. Respiration rate stabilised at 2% 02 and 10% CO2. The high concentrations of CO2 observed in the commercial packs did not fit the range in the respiration model. The model could aid in selection of MA conditions for minimally processed pineapple fruit.

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The establishment and control of oxygen levels in packs of oxygen-sensitive food products such as cheese is imperative in order to maintain product quality over a determined shelf life. Oxygen sensors quantify oxygen concentrations within packaging using a reversible optical measurement process, and this non-destructive nature ensures the entire supply chain can be monitored and can assist in pinpointing negative issues pertaining to product packaging. This study was carried out in a commercial cheese packaging plant and involved the insertion of 768 sensors into 384 flow-wrapped cheese packs (two sensors per pack) that were flushed with 100% carbon dioxide prior to sealing. The cheese blocks were randomly assigned to two different storage groups to assess the effects of package quality, packaging process efficiency, and handling and distribution on package containment. Results demonstrated that oxygen levels increased in both experimental groups examined over the 30-day assessment period. The group subjected to a simulated industrial distribution route and handling procedures of commercial retailed cheese exhibited the highest level of oxygen detected on every day examined and experienced the highest rate of package failure. The study concluded that fluctuating storage conditions, product movement associated with distribution activities, and the possible presence of cheese-derived contaminants such as calcium lactate crystals were chief contributors to package failure.

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Export of Fijian papaya (Carica papaya) fruit to destinations such as New Zealand has increased significantly over the last several years. Shipment by sea rather than air is the preferred method, given the capacity for larger volumes and reductions in cost. Long shipping times, however, can compromise fruit quality, although the use of modified atmosphere packaging (MAP) may provide a viable solution for extending fruit storage life. In a collaborative ACIAR project, Australian and Fijian researchers investigated the potential of using MAP to extend storage life of a Fijian papaya ('Fiji Red') fruit based on simulated sea transport conditions. Fruit were packed in one of three MAP environments within cartons, consisting of either a (1) Low Density Polyethylene (LDPE) bag with 10 g of KMnO4, (2) Polyamide Film (PF) bag with macro-perforations or (3) without a bag (control fruit). Fruit were held for 1, 2 or 3 weeks at 10°C before being unpacked, ripened and assessed for quality. On day 6 after outturn, fruit with the highest overall quality were those held in LDPE bags. LDPE fruit generally coloured up faster at outturn than PF or control fruit, had less overall moisture loss and scored high in flavour. Headspace carbon dioxide and oxygen concentrations within the LDPE bags were also near recommended levels for maintaining optimum storage-life quality. The LDPE bag provided the most suitable conditions for long term storage of fresh papaya fruit and is therefore the recommended MAP type for use with sea freight export out of Fiji.

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The effect of modified atmosphere packaging (MAP) on the postharvest quality of fresh-cut watercress (Nasturtium officinale R. Br.) stored at 4 ºC for 7 d was studied. A portion of watercress was immediately analyzed (non-stored control) and the remaining fresh material was stored packaged under atmospheres enriched with N2, Ar, air, or vacuum. The analyzed parameters included colour, total soluble solids, pH, macronutrients, the individual profiles of sugars, organic acids, tocopherols and fatty acids, and total phenolics and flavonoids. Furthermore, four in vitro assays were performed to evaluate the antioxidant activity. After assessing the effect on individual quality parameters, it was possible to conclude that air was the less efficient atmosphere in preserving quality attributes of the non-stored control samples during cold storage. In turn, Ar-enriched MAP was the most suitable choice to preserve the overall postharvest quality. The present study also highlighted the nutritional and antioxidant properties of watercress, as well as the interest of its inclusion in human diets.

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Leuconostoc spp. are lactic acid bacteria (LAB) implicated in food spoilage, especially on refrigerated, modified atmosphere packaged (MAP) meats. The overall aim of this thesis was to learn more about Leuconostoc spp. as food spoilage organisms with a focus on commercial products where LAB spoilage is considered a problem and the main factor limiting shelf-life. Therefore, we aimed to identify Leuconostoc spp. involved in food spoilage, as well as to characterise the spoilage reactions they caused and their contamination sources during poultry meat processing. In addition, we examined the distribution of strains of Leuconostoc gasicomitatum in different food commodities. Finally, we analysed the genome content of L. gasicomitatum LMG 18811 with a special focus on metabolic pathways related to food spoilage. The findings show that Leuconostoc gelidum and L.gasicomitatum were responsible for the discoloration and off-odours developed in beef steaks. Together with Leuconostoc mesenteroides, these Leuconostoc spp., also cause spoilage of vegetable sausages. In contrast, we showed that Leuconostoc spp. are not important for the shelf-life or quality of non-marinated broiler products although, in marinated broiler fillet products, Leuconostoc spp., L.gasicomitatum in particular, are considered spoilage organisms. Furthermore, the findings of the contamination survey we carried out in a poultry processing plant indicated that spoilage Leuconostoc spp. are derived from the processing environment rather than from the broilers, and that air movement distributes psychrotrophic spoilage LAB, including leuconostocs, and has an important role in meat contamination during poultry processing. Pulsed-field gel electrophoresis (PFGE) based genotyping of L. gasicomitatum strains demonstrated that certain genotypes are common in various meat products. In contrast, genotypes associated with meat were not recovered in vegetable-based sources. This suggests that these two food categories either become contaminated with, or favour the growth of different genotypes. Furthermore, the results indicated that the meat processing environment contributes to L. gasicomitatum contamination as certain genotypes were repeatedly identified from products of the same processing plant. Finally, the sequenced and annotated genome of L.gasicomitatum LMG 18811 allowed us to identify the metabolic pathways and reactions resulting in food spoilage.

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Polyphenolic compounds occurring naturally in knotwood of plants are known to have antimicrobial effects. The knots (i.e. the branch bases inside tree stems) and outer branches in pine trees contain a remarkably high concentration of phenolic stilbenes, while lignans are the major phenolic constituents of spruce knots. Large amount of these phenolic compounds can be extracted from wood knots at pulp and paper mills where their presence is undesirable. In Finland, marinating of broiler meat is done not only to increase or add value to the meat, but also to enhance the safety and shelf-life. These products are usually packed under a modified atmosphere for further protection against spoilage microorganisms. However, studies have revealed that addition of marinades to poultry products do not have an inhibitory effect on either some psychrotrophic anaerobic bacteria, such as Brochothrix thermosphacta or lactic acid bacteria associated with spoilage. Also, the activity of pathogenic Campylobacter jejuni is not affected by marinating. The objective of this study was to investigate the inhibitory and lethal activities of extracts from spruce (Picea spp.) and pine (Pinus spp.) knotwood and outer branches that are dissolved in ethanol against the spoilage microorganisms in modified atmosphere packaged marinated broiler products. Modified atmosphere packaged broiler products were separately inoculated with ‘normal’ marinades, marinades with 70% ethanol, marinades with a mixture of spruce and pine extracts dissolved in 70% ethanol or mixture of spruce and pine extracts in powder form. The bacterial colony forming units per gram obtained from each of the samples were analysed on de Man Rogosa and Sharpe agar at days 1, 6, 12 and 15. The results showed that there were significant differences in bacterial colony forming units per gram (P <0.05) between packages with ‘normal’ marinades and packages with extracts added to their marinades on the 12th and 15th day. It can be concluded that the addition of extracts from spruce and pine knotwood to marinades significantly retarded growth of spoilage microorganisms during the 15 day test period. However further research is warranted to characterise and establish the safety and suitability of the compound(s) in spruce and pine knotwood extracts that are responsible for inhibitory or lethal activity against the microbes that may be present in marinated poultry meat.