Claire I. G. L. Sarantópoulos

Propriedades de barreira e solubilidade de filmes de amido de ervilha associado com goma xantana e glicerol

The aim of this work was to evaluate the barrier properties and solubility of biofilms made from wrinkled pea starch with high amylose content in association with xanthan gum and glycerol. Filmogenic solution (FS) with different levels of pea starch (3, 4 and 5%), xanthan gum (0, 0.05 and 0.1%) and glycerol (glycerol-starch 1:5 W/W) were tested. FS was obtained by boiling (5 minutes), autoclaving for 1 hour at 120 oC and the films were prepared by casting. The increased concentration of starch and glycerol in the composition caused increases in thickness of the films and in their solubility in water. The plasticizer also generated higher coefficients of water vapor and oxygen permeabilities to water vapor and to oxygen. The increasing concentration of xanthan gum did not interfere in the properties studied. Biofilms produced with wrinkled pea starch, with or without xanthan gum and glycerol, showed better barrier to oxygen and water vapor and low solubility in water, in comparison with films of yellow pea starch and other starch sources.

Estabilidade de repolho minimamente processado sob diferentes sistemas de embalagem

Stability of fresh-cut cabbage packed in low density polyethylene under active modified atmosphere and in expanded polyestyrene trays wrapped with PVC was evaluated. The fresh-cut product was stored for 16 days in a cold room at 5 ± 1 °C and 95 ± 5% RH and in a refrigerated display case similar to those found in grocery stores. The following variables were analyzed: content of oxygen and carbon dioxide inside the package headspace; browning, luminosity, polyphenoloxidase and peroxidase activities, pH, titratable acidity; soluble solids, fresh mass loss, and ascorbic acid content. The stability of fresh-cut cabbage was higher at the temperature of 5 °C compared to those stored in the refrigerated displays. The active modified atmosphere was not effective in extending the shelf life of fresh-cut cabbage compared to other treatments. LDPE packaging was more adequate for fresh-cut cabbage storage. However, PVC wrapping also presented satisfactory effects.

Qualidade de melão minimamente processado armazenado em atmosfera modificada passiva

ABSTRACT Quality of fresh cut melons stored under passive modifiedatmosphere Fruits of net melon cv. Bonus II were minimally processed ascubes, wrapped in several plastic materials and stored at 3oC for 9days. The following materials were used for packaging: AFG: DuPontpolyolephinic film 15µm; HP: DuPont polyolephinic film 15µm,PD-900: Cryovac polyolephinic film 58µm, PEBD: low densitypolyethylene film 87µm; PP: polypropylene film 52µm; BB-200:Cryovac multilayer film 65 µm; PET: rigid polyethylene terephtalattray. The gas permeability of each film was determined. The gascomposition within the packages was evaluated every day during 8days and the physico-chemical and sensorial characteristics wereevaluated on the 9 th day. The melon respiration rate was determinedbefore and after processing. The packaging systems did not promoteeffective atmosphere modification, except for the PET tray whichpromoted, after the 6 th day, an equilibrium atmosphere of 12% O 2 and 7% CO 2. Physical-chemical characteristics of the processedmelons were maintained in all treatments during storage, whereassensorial characteristics were kept only for the melons in the PETtray. Passive atmosphere modification was not effective for freshcut melons stored at 3oC. Probably due to the low respiration rate atthis temperature associated with the high relationship betweenpermeation area of the packages and melon mass.

Behavior of Flavonols and Carotenoids of Minimally Processed Kale Leaves during Storage in Passive Modified Atmosphere Packaging

Minimally processed kale leaves were packed in passive modified atmosphere and stored at 3 conditions: 1 °C in the dark and 11 °C with or without light exposure. The products were evaluated during storage in terms of headspace gas composition, sensory attributes, flavonol, and carotenoid contents. The sensory quality decreased slightly during 17 d at 1 °C in the dark. At 11 °C, the vegetable shelf life was predicted to be 6 d in the dark and 3 d with light. Quercetin and kaempferol were stable during storage for 15 d at 1 °C in the absence of light. At 11 °C in the dark, quercetin was stable during 10 d, increasing slightly on the 8th day. Kaempferol decreased up to the 5th day but increased on the 8th day, decreasing again on the 10th day. After 5 d at 11 °C under light, the flavonol levels were significantly higher than those of the initial values. Neoxanthin and violaxanthin did not change significantly after 15 d at 1 °C in the dark. Lutein and β-carotene, however, decreased 7.1% and 11.3%, respectively. At 11 °C in the dark, neoxanthin, violaxanthin, lutein, and β-carotene decreased 16.1%, 13.2%, 24.1%, and 23.7% after 10 d, respectively. At 11 °C under light, neoxanthin and lutein had a slight increase while violaxanthin and β-carotene decreased 23.1% and 16.5% after 5 d. Practical Application:  Passive modified atmosphere packaging together with refrigeration can extend the shelf life of minimally processed kale, retaining the health-promoting compounds, flavonols and carotenoids. Quercetin, kaempferol, neoxanthin, and violaxanthin are stable and lutein and β-carotene slightly reduced.

Vida útil de fatias de manga armazenadas em embalagem com atmosfera modificada passiva

Fresh and osmodehydrated mango slices were packaged in expanded polystyrene trays covered with low density polyethylene films (PEBD) and stored at 5 °C aiming at verifying the effect of osmotic dehydration process and modified atmosphere packaging on the fruit shelf life. Fresh mango slices packaged under atmospheric conditions were used as control. The slices were evaluated periodically with respect to physicochemichal and microbiological characteristics, internal atmosphere composition of the packages, weight reduction, and sensory acceptance. The osmotic dehydration process and the modified atmosphere packaging had a positive influence on the preservation of the sensory characteristics and microbiological quality of the mango slices. Fresh mango slices stored under atmospheric conditions (FR AR) and modified atmosphere packaging (FR MAP) had a shelf life of only 8 and 14 days, respectively, which was mainly limited by its sensory acceptance and microbial spoilage. On the other hand, the mango osmodehydrated slices packaged under modified atmosphere (OD MAP) presented shelf life of 18 days showing good sensory acceptance throughout the storage period.

Embalagens termoformadas e termoprocessáveis para produtos cárneos processados

Refrigerated processed meats are high added-value products traditionally vacuum-packed in plastic packages to minimize contact of the product with oxygen and, consequently, prolong their shelf life. This study aimed at elaborating a comprehensive and detailed overview of the packaging materials used on the Brazilian market to manufacture thermoformed packages for sausages, hot dogs and sliced processed meat, in addition to cook in-type packages for hams and restructured ham products. Basically, the materials most used are coextruded films or a combination of coextruded and laminated (top film) structures. Polyamides, EVOH and PET-PVDC are used to provide an oxygen barrier. The oxygen transmission rate (O 2 TR) of bottom films for thermoformed packages varied between 5 and 30 cm 3 (STP)/m 2 /day, with lower values for the films used in the package of sliced processed meat. The O 2 TR of top films were of the order of 10 cm 3 (STP)/m 2 /day, determined at 23 °C under wet conditions. Perforation resistance was about 25N (top films) and 35N (bottom films - sausages/ hot dogs). The bottom films for sliced processed meat varied considerably in terms of puncture resistance due to the wide range of thickness available. A series of packages currently in use on the Brazilian market were evaluated for seal integrity and thickness distribution of the thermoformed film. No sealing problems were detected. The reduction of total film thickness at the corner of flexible trays (critical area) for sausages and hot dogs, whose depth is larger than for sliced processed meat packages, varied between 42 and 65%. The reduced thickness at the corners significantly affects the gas barrier properties of the package and justifies the use of EVOH which does not cause the shelf life to decrease.

Effects of weight reduction of packaging material on the mechanical performance of PET bottles for cooking oil

This study compares and evaluates the mechanical performance of two types of PET bottle of different nominal weights but identical design and filled with 900 ml vegetable cooking oil. The air in the headspace of all the bottles was replaced with liquid or gaseous nitrogen upon conclusion of the filling operation and immediately before capping. Two different closures, with an internal or external tamper-evident feature, were used on the 20 g bottles. The 27 g bottle was closed exclusively with the closure fitted with an external seal. The 20 g PET bottles prior to capping were either flushed with gaseous nitrogen or pressurized with liquid nitrogen. The air contained in the headspace of the 27 g bottle was removed by injection of gaseous nitrogen only. Corrugated fibreboard cases containing 20 bottles each were submitted to a vibration test and all the components of the packaging system were subsequently evaluated with respect to important mechanical properties, such as stacking strength, drop impact strength and package integrity. The results show that the closure with external seal provided considerably better protection against leakage. Also tests conducted with stacks of five corrugated cases each and arranged onto two pallets placed one upon the other demonstrated that reducing total bottle weight by 26% is viable in terms of mechanical performance. On the other hand, the use of pressurized liquid nitrogen was found to be unnecessary. Copyright

Development of an analyser to determine the oxygen and carbon dioxide levels in the head-space of packages

This paper describes the development of an analyser intended to measure the concentrations of CO 2 and O 2 present as part of the gas mixture in the head-space of food packages. The efficiency of the measuring device was evaluated by analysing the atmosphere of packages containing the following food products: grated Parmesan cheese, milk powder and fresh pasta. A comparison between the results of the analysis performed with the newly developed analyser and those obtained by gas chromatography showed good correlation between the two methods. The O 2 and CO 2 analyser presented satisfactory accuracy (absolute error smaller than 2.5%, v/v) and precision (relative standard deviation varying from 0.2% to 8.5%). In addition, final results of the levels of both gas types present in the atmosphere submitted to analysis are obtained after about 2 min. The proposed analyser constitutes an alternative solution for the analysis of gases present in the head-space of packages, especially when gas samples of very small volumes-about 200 μl-are to be used.

Properties of barrier shrink bags made with EVOH and polyamide for fresh beef meat preservation

The objective of this work was to compare the barrier and mechanical properties and shrinkability of coextruded films chlorine-free, with high barrier chlorine multilayer films traditionally used to preserve fresh beef. Four 9-layer barrier-shrink films containing PET, ethylene ionomers, polyamide PA66/6 modified with amorphous PA, 32 or 44 mol% EVOH and PE were produced in a commercial scale triple bubble co-extrusion line. Seal strength, puncture resistance, oxygen and water vapor permeability and film shrink were measured for the four films and compared to the EVA/PVDC/PE film properties. The results obtained under controlled laboratory conditions show that films made with one layer of EVOH 32 mol% of ethylene encapsulated between two layers of PA66/6 modified with amorphous PA have gas barrier properties and puncture resistance better than a typical EVA/PVDC/PE, seal strength and shrinkability comparable to this film and therefore have potential to preserve fresh beef.

Spraying Cellulose Nanofibrils for Improvement of Tensile and Barrier Properties of Writing & Printing (W&P) Paper

An experimental spray coater was used to coat writing and printing (W&P) paper substrate with cellulose nanofibrils (CNFs) suspensions. The effects of spraying variables (i.e. concentration of suspension, spray pressure, distance and time of spray) on the coated sheets were analyzed in terms of the tensile strength, water vapor transmission rate (WVTR), and oxygen transmission rate (OTR). Basis weight and the thickness of coated layers in the different treatments were measured. In addition, image analysis of the microstructure examined the coating adhesion. The WVTR of the papers decreased, while tensile strength increased with one layer of CNF coating. The OTR was not changed with the CNF coating. The tensile strength and microstructure images of the coated papers indicate good adhesion between the CNF coating and the paper substrate when using the spray coater.