ISSN:0894-3214    

DOI:10.1002/pts.2770050602

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0894-3214    

DOI:10.1002/pts.2770050603

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0894-3214    

DOI:10.1002/pts.2770050604

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0894-3214    

DOI:10.1002/pts.2770050605

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractIt is a well‐known fact that the permeability of polymer materials increases as the temperature increases. As the temperature drops to its original level, the permeability in many instances does the same. When packages are processed in an autoclave, the material will be exposed to both high temperature and high relative humidity. This can strongly affect the barrier of some materials, e.g. ethylene vinyl alcohol (EVOH) and polyamide (PA), because the water will act as a plasticizer.A current project is now studying the permeability of different materials after sterilization. The aim of the project is to determine the permeability of different materials during sterilization at autoclave conditions and during storage. Factors that can reduce the negative effect on the barrier are also examine

ISSN:0894-3214    

DOI:10.1002/pts.2770050606

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractMany polymeric materials, e.g. polyvinyl chloride (PVC) and polyethylene (PE), are processed with 20% scrap added to the virgin material. Polypropylene (PP) scrap seems to be very susceptible to the generation of new odorous products during the thermoforming processes. This study is aimed at defining the highest possible reapplication rate of PP scrap. Films made of 20‐60% scrap plus virgin material and of 100% scrap were investigated; six different PP blends were used in this work. First of all the migrational behaviour was assessed in contact with various food simulants at 40 C for 10 days. Migration was followed using our spectrophotometric method and finally determined by measuring the residue left after evaporation of the simulant. The organoleptic properties were also evaluated following the NBN S29‐001 standard. The results show that organoleptic changes were detected at such an intensity as to eliminate plastic for food contact purposes, but as yet no changes in migrational behaviour have been found. The results show clearly that the addition of more than 30% regenerated PP is not acceptable. Investigations are continuing to detect and to determine the hazardous produ

ISSN:0894-3214    

DOI:10.1002/pts.2770050607

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe aim of the study was to determine the effect of packaging materials with different oxygen permeability, residual oxygen concentration in the package and light upon discoloration of the surface of sliced bologna.The packaging material caused significant differences in the discolouration of vacuum‐packed, sliced bologna. The surface colour of sliced bologna packed in films with an oxygen transmission rate lower than 10cm3/m2/24h/atm was not affected by illuminated storage.Packages of sliced bologna with 0% oxygen in the head space showed good colour stability after 28 days of illuminated storage at 4 C. The discolouration of bologna was almost directly proportional to oxygen concentration in the package. Bologna stored in a high oxygen concentration developed more off‐odour; 1% and 2% oxygen in the packages caused higher worst spot colour, discolouration and off‐odour scores after 3 days of st

ISSN:0894-3214    

DOI:10.1002/pts.2770050608

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThis study was conducted on bag‐in‐box packages for wine to show how the transport stress changes the oxygen permeability of the bags and the possible consequences for the wine's shelf‐life. Bags from five leading bag suppliers/film producers were tested.The bags were subjected to two types of transport stress–simulated vibration testing in the laboratory and actual road transport (1000 km) and the same type of corrugated fibreboard box was used throughout. During road transport a red French table wine was used. Emphasis was placed on leakage and O2permeability in the investigation of the bags. The study showed no visible bag leakage. Measurement of the O2permeability revealed that the bag with an Al‐laminated barrier film had the lowest permeability. The ethylene vinyl alcohol (EVOH) bags were more permeable than the Al‐laminated bags, while metallized polyester (Met. PET) had the highest O2permeability.Chemical analysis of the wine included the measurement of free and total SO2, oxygen and colour, carried out 1, 4.5 and 9 months after filling. Sensory analysis was carried out as a series of rank order tests performed 5 and 9 months after filling.The chemical and sensory measurements showed small differences between the various bag types. Regarding wine quality, none of the tested bag types distinguished themselves either in a positive or a negative direction in relation to similar table wine stored in glass bottles. The analysis after 9 months of storage showed that none of the wines were oxidized to an unacceptable quality compared to the quality of the same wine stored in glass bottles (not transported) for the same period.The shelf‐life of wine is often calculated on the basis of the measured values for oxygen permeability. The theoretical shelf‐life of wine is 130‐450 days for new bags of Met. PET and 30‐130 days for worn (transported) bags. The analysis of the wine showed a longer shelf‐life than the theoretical calculations. This is because phenolics, which prevent oxidation, are not accounted for in the formula. The formula is therefore probably best suited for white wines.The selection of barrier material for bag‐in‐box bags (Met. PET, EVOH or Al‐lami‐nates) does not seem to be critical for the shelf‐life of a red table wine with a rather high content of phenolic components if the wine i

ISSN:0894-3214    

DOI:10.1002/pts.2770050609

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0894-3214    

DOI:10.1002/pts.2770050610

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0894-3214    

DOI:10.1002/pts.2770050601

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY