ISSN:0894-3214    

DOI:10.1002/pts.2770050102

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThis paper presents the design criterion and evaluation of a new package system designed to ship fresh strawberries and raspberries. the study describes the evaluation of the new package systems for pre‐cooling after field picking. in addition data is presented describing damage to berries in the form of bruising and cutting owing to vibration in shipment. the paper compares this new concept to the traditional polyethylene injection moulded baskets used in the usa for the past 30 year

ISSN:0894-3214    

DOI:10.1002/pts.2770050103

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractPackaging engineers need to be able to accurately determine the forces present in the shipping environment in order to protect packaged goods. The purpose of this study was to determine the vertical vibration levels measured in three separate truck‐trailer suspension systems; conventional leaf‐spring, conventional air‐ride and damaged air‐ride. The main conclusion reached in this study is that the air‐ride suspension when maintained gives lower power density (PD) levels on all road surfaces studied. A damaged air‐ride suspension and leaf‐spring suspension are very similar in response frequencies, although the damaged air‐ride produces higher vibration levels at lo

ISSN:0894-3214    

DOI:10.1002/pts.2770050104

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe measurement of the relative humidity (RH) at high levels to the desired accuracy is still a problem, especially for levels above 90% RH. The reasons for this are:iThe accuracy of the standard apparatus is lower at high RH than at moderate and low RH;iiThe need for accurate measurement of the RH in moisture controlled rooms is greater at high RH than at lower RH, because for moisture sensitive products, such as fibreboard boxes and certain horticultural products, the influence of a minor deviation in RH on the properties of these products is considerably greater at high RH than at moderate and low RH.

ISSN:0894-3214    

DOI:10.1002/pts.2770050105

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe permeability coefficients (P) of linalool, citral ethyl butyrate, d‐limonene and octanal permeating through LDPE and ionomer films were measured alone as individual and as a component of a mixture at a temperature of 23 °C and in saturated water vapour. Values ofPfor ionomer film were approximately two orders of magnitude below those for LDPE for the compounds tested. Both PET and PETG films were found to be much better barriers against the compounds tested than LDPE and ionomer films. In general, the permeability, diffusion and solubility coefficients (P. D, andS) values measured in mixture were substantially less than the values obtained individually. Permeability behaviour of these compounds at low concentrations in the mixture was similar to that of permanent gases. Reduction of solubility coefficients in mixture permeation was greater with the higher solubility coefficients. These results provide a better understanding of the mechanism of vapour diffusion through polyme

ISSN:0894-3214    

DOI:10.1002/pts.2770050106

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe permeabilities of two commercial ceramic‐filled LDPE films were measured and compared with those of a plain LDPE film. The ceramic films have higher oxygen (02), carbon dioxide (CO2) and ethylene (C2H4) permeabilities, higher CO2to O2permeability ratio, and higher C2H4to 02permeability ratio. The temperature dependence of the permeability was found to follow the Arrhenius relationship. The data suggest that these ceramic films are more suitable than plain LOPE film for packaging fresh produce of high respiration rat

ISSN:0894-3214    

DOI:10.1002/pts.2770050107

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe work was based on the need to develop a horizontal form/fill/seal pouch machine to produce retortable meal‐and‐ready‐to‐eat pouches for the military. The pouch‐forming process can be considered as cold‐forming involving non‐uniform biaxial stretching of the film. Tensile properties are well‐established characteristics of films, which can be used to describe their deformation ability.An Instron Universal Testing Machine was used to measure the tensile properties of ten cold‐formable aluminium‐plastics laminate films, with structure of PET/AI/PP or OPP/AI/PP, in which the aluminium foil thickness ranged from 10 to 51 μ. The data showed that elongation of the films was not affected significantly by separation speed. All the films failed at or very close to maximum peaks of the load‐elongation curves. Because of the orientation of the OPP layer, the tensile properties were found to depend on whether the films containing OPP were stretched in the machine direction or in the transverse direction. The aluminium layer was the most critical factor in determining the maximum elongation of the entire laminate film, and the elongation‐at‐break of the films ranged from 25 to 45%. The load‐at‐break values of the films increased linearly with increasing aluminium thickness, and values of the tensile properties versus aluminium thickness curves extrapolated at zero thickness provided a measure of the strength of the plastic layers in the lamination. There was synergism between the laminate layers allowing the aluminium layer to stretch m

ISSN:0894-3214    

DOI:10.1002/pts.2770050108

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractVarious experimental packaging containers were tested for their tendency to absorb fruit juice volatiles in the innermost heat‐sealing layer.Analysis of head‐space gas by GLC and sensory evaluations were carried out in order to evaluate the effect of each type of sealant. Coextrusion sealants (thin low‐density polyethylene, LDPE), a sealant containing the orange essence powdered with cyclo‐dextrin (CD), and polyethylene‐terephthalate (PET) or polyacrylonitrile (PAN), synthetic resisns with high transition temperatures (Tg) were prepared.Coextrusion or CD‐containing sealants as compared with LDPE, reduced the sorption of d‐Limonene from Mandarin orange[Citrum unshiuMarc.] juice by 15–20% but did not show effective results in sensory evaluations. On the other hand PET or PAN sealants showed no sorption at all. Similar results were obtained with 'citrus mix' model essence. However, LDPE also did not show volatile sorption in the case of 'soft fruit mix' model essence.It is difficult to prevent sorption of the volatiles of citrus fruit juices if the sealants are of the coextrusion type or CD‐containing LDPE type. Sorption can be controlled most effectively when the seala

ISSN:0894-3214    

DOI:10.1002/pts.2770050109

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe use of polymer films for food packaging requires a knowledge of their transport properties under varying conditions. The permeability to gases and water vapour of the packaging films at the specific conditions of use, i.e. temperature, relative humidity and pressure gradient, are needed for selecting the optimum packaging system to ensure the required shelf‐life of the packed product. Migration from, and absorption by, plastic films also play an important role in their selection.The 02and CO2permeabilities of three plastic films at four different temperatures were evaluated and shown to follow the Arrhenius relationship in the range tested. The effects of four thicknesses of one film on its permeability are also reported.Three methods to evaluate migration from polymeric films were compared using different weight/volume ratios. The extraction method recommended by the FDA, usingn‐hexane in a stirred flask, was found to be best.The shelf‐life of Matzoth (Jewish Passover bread) packed in polyethylene (stored at 25°C) was found to be longer than the shelf‐life of those packed in the higher barrier PVDC/PE. This was apparently due to the absorption of undesirable oxidation compounds, given off from the Matzoth by the PE, which were not absorbed at detectable levels by the

ISSN:0894-3214    

DOI:10.1002/pts.2770050110

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThis study investigated the error in measuring package drop heights using the drop height recorder developed by Dallas Instruments and the environmental data recorder developed by Instrumented Sensor Technology. The shock measuring capabilities of the two recorders were also studied. Drops were made onto the bottom, edge and corner orientations from heights of 18, 24, 30 and 36 inches. The study concluded that the drop height recorder predicts the drop height most accurately and with the least variation using its'zero‐g'channel. Both recorders show much larger variations in predicted values (up to 30%) when using the recorded acceleration‐time data. The edge and corner orientation drop heights are generally underestimated by both, owing to the inability of the accelerometers to differentiate between partial rotation on impact and vertical tra

ISSN:0894-3214    

DOI:10.1002/pts.2770050111

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY