The paper presents results of comparative investigations of packaging materials and packages made by thermoforming of polystyrene ribbon, polypropylene compound ribbon and co-extruded multi-layer ribbon containing polypropylene layer, barrier layer and polypropylene layer. The investigations have established that polypropylene compound packaging has much better characteristics, and particularly the one made of co-extruded multi-layer ribbon. In this way a better protection is provided for the packed content. Polypropylene package ensures the conditions of sterilization at temperatures up to 121 °C.
Authors:M. Szalai, J. Szigeti, L. Farkas, L. Varga, A. Réti, and E. Zukál
The shelf-lives of major commercial cooked meat products (i.e., Bologna sausage, Italian-type cooked sausage, and cooked ham) packaged under vacuum or modified atmospheres were tested in this study. Samples were taken from commercial meat processing lines, sliced to 1.2 mm thickness and placed overlapped into polypropylene trays sealed with plastic films. The headspace of modified atmosphere packaged formulations consisted of 30% CO2 and 70% N2 or 60% CO2 and 40% N2. The samples thus produced were stored under refrigerated conditions. The values of microbiological, chemical, physical or sensory properties were plotted against storage time, and Gompertz curves were fitted to all time series that changed from an initial to a final value during any period of storage. The influence of headspace CO2 concentration on the properties of sliced cooked meat products varied considerably and, therefore, it was not possible to specify general rules. However, the presence of CO2 in the packaging atmosphere slowed down the rate of microbial growth, thereby delaying the spoilage of meat products. A CO2 level of 60% had beneficial effects on both the microbiological and sensory properties of sliced sausages and cooked ham. It was concluded that cooked meat products packaged under modified atmospheres had a shelf-life of 20 days.
In this study, cauliflower florets were treated with NaCl (1%) + Na-metabisulphite (1500 ppm) solution and chlorinated (150 ppm, pH: 6.9). They were then rinsed with tap water. In this manner, one group of vegetables was treated with citric acid solution (1.5%) and the other group with Ca-ascorbate (0.5%) + citric acid (1%) solution. After centrifugation, the samples were packed in 20% atmospheric air + 80% N2 and 20% atmospheric air + 70% N2 + 10% CO2 conditions with bi-axially oriented polypropylene (BOPP) film.After 15 days of storage at 4±2 °C ascorbic acid, total phenolics, and total carotenoids contents have decreased; whereas aerobic mesophilic, psychrophilic, total coliform bacteria counts and polyphenol oxidase activity have increased. The losses of ascorbic acid, total phenolics, total carotenoids, and antioxidant activity were determined as 11.54%, 7.56%, 29.08% and 17.36%, respectively. Generally, greater reductions occurred in blank samples which were not treated with any chemicals, but were packed under modified atmosphere conditions. A little weight loss, total dry matter loss, and polyphenol oxidase activity increase was found in samples packaged in carbon dioxide enriched atmosphere and treated with Ca-ascorbate + citric acid. This condition was also found to be more effective in limiting the quality losses and preventing organoleptic degradation. On the contrary, control samples were generally rejected by the panelists at the 95% probability level because of their deleterious odour and colour.
Authors:E. Fogarassy, E. Bekassy-Molnar, Cs. Balla, and Gy. Vatai
In this study, pressed apricot (Prunus armeniaca L.) juice was concentrated using complex membrane technology with different module combinations: UF-RO-OD, UF-RO-MD, UF-NF-OD and UF-NF-MD. In case of the best combination a cross-flow polyethylene ultrafiltration membrane (UF) was applied for clarification, after which preconcentration was done using reverse osmosis (RO) with a polyamide membrane, and the final concentration was completed by osmotic distillation (OD) using a polypropylene module. The UF-RO-OD procedure resulted in a final concentrate with a 65-70 °Brix dry solid content and an excellent quality juice with high polyphenol content and high antioxidant capacity.Nanofiltration (NF) and membrane distillation (MD) were not proper economic solutions.The influence of certain operation parameters was examined experimentally. Temperatures of UF and RO were: 25, 30, and 35 °C, and of OD 25 °C. Recycle flow rates were: UF: 1, 1.5, and 2 m3 h−1; RO: 200, 400, and 600 l h−1; OD: 20, 30 and 40 l h−1. The flow rates in the module were expressed by the Reynolds number, as well. Based on preliminary experiments, the transmembrane pressures of UF and RO filtration were 4 bar and 50 bar, respectively. Each experimental run was performed three times. The following optimal operation parameters provided the lowest total cost: UF: 35 °C, 2 m3 h−1, 4 bar; RO: 35 °C, 600 l h−1, 50 bar; OD: 20, 30 and 40 l h−1; temperature 25 °C.In addition, experiments were performed for apricot juice concentration by evaporation, which technique is widely applied in the industry using vacuum and low temperature.For description the UF filtration, a dynamic model and regression by SPSS 14.0 statistics software were applied.
polypropylene foil. Measurements Measurements were carried out on the 1 st , 4 th , 7 th and 10 th days. Three packages of each group were removed from the fridge to analyze the quality indices of catfish fillets for each storage interval. Surface color
Authors:Mai Sao Dam, Lien Le Phuong Nguyen, Tamás Zsom, Géza Hitka, Ildikó Csilla Zeke, and László Friedrich
during 15 days of cold storage at 5 °C. Another study found that microperforated polypropylene based bags had benefit in extending shelf-life of fresh cut carrot ( Mastromatteo et al., 2012 ). Guimarães et al. (2016) also reported that the passive
, friction is not considered. The material of the plastic buckle is PolyPropylene (PP) in Fig. 2 , which has a Young’s modulus E =1300 MPa. There are three different structural components with different beam properties. The geometric properties of the first