Effect of package light transmittance on the vitamin content of pasteurized whole milk

Pasteurized whole milk (3% fat) was stored under fluorescent light at 8°C in clear 1 litre polyethylene terephthalate (PET) bottles and three variants of pigmented PET bottles with different light transmittance. Changes in the vitamin content were monitored over a period of 10 days. Milk packed in pigmented PET bottles with the lowest light transmittance, which was stored in the dark under the same experimental conditions, served as the ‘control’ sample. Data were obtained for vitamin A (retinol), vitamin B₂ (riboflavin) and vitamin B₁₂ (cobalamin) content. Standard plate counts were determined to ensure an acceptable microbiological status of the pasteurized milk during the sampling period. In clear PET bottles a reduction of 22% of the initial content was observed for vitamin A and 33% for vitamin B₂, while the vitamin B₁₂ content remained almost stable. In all pigmented PET bottles the vitamin retention was significantly higher; the losses were 0–6% for vitamin A and 11–20% for vitamin B₂, depending on the pigmentation level, as compared to 6% for vitamin A and no significant loss for vitamin B₂ in the ‘control’ sample. An impact of the package light transmittance on the vitamin B₁₂ content could not be observed. Copyright © 2006 John Wiley & Sons, Ltd.     

不同包装容器对劲酒品质的影响

目的 研究包装容器对酒体品质的影响因素,为劲酒包装容器的选择提供科学的数据支撑。方法 采用光学透过率测试仪对不同包装容器的透光率进行了测定,并对贮存2年的劲酒的总黄酮含量、总皂苷含量、色率、淫羊藿苷含量、口感进行分析,数据分析的方法为随机区组设计资料的方差分析。结果 无色玻璃瓶、PET瓶透光率高达90%以上,深色瓶、涂漆瓶、陶瓷瓶、不锈钢瓶透光率均极小。总体来说高硼硅玻璃瓶和PET瓶储存的劲酒均有不同程度的颜色变浅,总黄酮、总皂苷含量降低,口感变差,其他容器储存的酒体之间没有明显差异,且它的总体品质要高于高硼硅玻璃瓶和PET瓶储存酒体的总体品质。结论 包装容器的透光性会对劲酒的品质产生影响,避光包装容器可能更适合劲酒的储存,避光容器的材质和形状对劲酒品质基本没有影响;对于透光性容器,容器形状可能影响劲酒品质,相较于圆柱型的包装容器,扁平型的可能更能保护劲酒品质。     

荧光照射下PET阻隔瓶对杀菌乳风味的保护研究

目的 研究分析添加质量分数为8%的阻光色油的PET瓶（简称阻光8%PET瓶）包装对杀菌乳风味物质组成和含量的影响,为杀菌乳保质期的延长提供数据支撑。方法 模拟超市货架光照情况,以纯PET瓶和阻光8%PET瓶包装做对比,分析不同贮存期杀菌乳感官风味指标变化及特征风味物质组成及含量变化。结果 相对纯PET瓶杀菌乳,阻光8%PET瓶杀菌乳,光照3、7 d后两样品关键感官特性指标（奶香气、奶腥味、异味强度）及整体喜好度平均值均表现出显著性差异（P<0.05）,阻光8%PET瓶杀菌乳的奶香气、整体喜好度评价均优于纯PET瓶杀菌乳的,奶腥味、异味强度均低于纯PET瓶杀菌乳的。经特征风味化合物分析,醛类化合物对杀菌乳异常风味贡献最大,酸类、酮类、醇类物质贡献较小。结论 阻光8%PET瓶包装能有效延缓光照31 d贮存期杀菌乳产品醛类物质的种类和含量的迅速增加,能一定程度减少部分酸类、酮类、醇类物质的增加,从而减少异常风味,提高产品的喜好度,可一定程度延长杀菌乳的货架期。     

Migration of Aluminum and Silicon from PET/Clay Nanocomposite Bottles into Acidic Food Simulant

Poly(ethylene terephthalate) (PET)/clay nanocomposite samples were prepared by melt blending PET and Cloisite 20A nanoparticles. A stretch blow‐moulding machine was used to produce bottles from neat PET and PET nanocomposite. Tests were performed on the migration of aluminum and silicon from PET nanocomposite bottles into acidic food simulant. The samples were stored at room temperature (about 25°C) and 45°C for time durations ranging from 7 to 90 days. A specific surface of sheets (prepared from PET/clay nanocomposite) immersed in acidic food simulant, and two‐sided migration of Al and Si was investigated. According to X‐ray diffraction analysis, the nanoclays show intercalated structure in the PET matrix. Transmission electron microscopy and atomic force microscopy micrographs displayed both intercalation and exfoliation morphology for PET/clay nanocomposites. Inductively coupled plasma was used to quantify amounts of Al and Si that had migrated into the acidic food simulant. It was observed that the migration process is dependent on storage time and temperature, and the molar ratio of aluminum and silicon in the acidic aqueous solution (Al/Si)_aq to the ratio in the solid phase of prepared nanocomposites (Al/Si)_solid was about 23% higher in the samples stored at 45°C. Copyright © 2013 John Wiley & Sons, Ltd.     

Quality Changes of Extra Virgin Olive Oil Packaged in Coloured Polyethylene Terephthalate Bottles Stored Under Different Lighting Conditions

In this paper, the influence of light storage and the exposure on quality parameters of a monovarietal extra virgin olive oil packaged in polyethylene terephthalate (PET) bottles were investigated. Coloured PET bottles (clear, green, orange, white and blue) were stored under different artificial lighting conditions in order to simulate the market environment (one fluorescent cool white lamp) and to perform an accelerated test (four fluorescent cool white lamps); storage in the dark was considered as a control. Total peroxide value, polyphenols, chlorophyll and carotenoids contents were, among the ones tested, the quality indexes most affected by lighting and were useful to investigate the bottle colour influence. Concerning the global quality of olive oil, under one fluorescent lamp, the best performances were obtained using blue and white PET bottles; whereas under accelerated conditions, the differences in the protection efficacy offered by the differently coloured bottles were reduced. Copyright © 2013 John Wiley & Sons, Ltd.     

Preparation and optimization of a low cost,high breakage resistance ceramic proppant special for the coal-bed methane

A kind of low cost, high breakage resistance ceramic proppant special for exploitation of the coal-bed methane is successfully produced. The producing conditions are optimized through orthogonal experimental design method. The breakage resistance results of the orthogonal analyses show the best condition of this kind of ceramic proppant is A₄B₃C₃D₂, which means sintering temperature of 1350 °C, manganese mineral powder content of 5 wt.%, weight ratio of 75/25 (second grade bauxite to mujie clay), and holding time of 3 h. The ceramic proppants under this very condition of A₄B₃C₃D₂ are then prepared and their phase structure and microstructure are characterized subsequently. X-ray diffraction pattern exhibits that mullite and corundum are the main crystallographic phases. Scanning electron microscopy illustrates the A₄B₃C₃D₂ sample is with non-porous morphology and small amount of corundum grains and liquid phase, which play the role of improving strength. It reveals the orthogonal experimental design is a feasible optimization method and the ceramic proppant made under the condition of A₄B₃C₃D₂ is a promising material for exploiting the coal-bed methane resources.     

Growth and characterization of indium tin oxide thin films deposited on PET substrates

Transparent and conductive indium tin oxide (ITO) thin films were deposited onto polyethylene terephthalate (PET) by d.c. magnetron sputtering as the front and back electrical contact for applications in flexible displays and optoelectronic devices. In addition, ITO powder was used for sputter target in order to reduce the cost and time of the film formation processes. As the sputtering power and pressure increased, the electrical conductivity of ITO films decreased. The films were increasingly dark gray colored as the sputtering power increased, resulting in the loss of transmittance of the films. When the pressure during deposition was higher, however, the optical transmittance improved at visible region of light. ITO films deposited onto PET have shown similar optical transmittance and electrical resistivity, in comparison with films onto glass substrate. High quality films with resistivity as low as 2.5 × 10^− 3 Ω cm and transmittance over 80% have been obtained on to PET substrate by suitably controlling the deposition parameters.     

有机复合摩擦材料的成分优化及其对摩擦性能的影响

采用正交试验设计方法对有机复合摩擦材料的成分进行优化,利用MMS-2A摩擦磨损试验机对材料的摩擦系数进行测试,用比磨损率表征复合材料的磨损性能,并通过极差法对试验结果进行了分析。用Leica体式显微镜和3D激光共聚焦显微镜观察了材料摩擦磨损后的表面形貌,探索了不同成分下合成材料的摩擦磨损机理。结果表明:改性酚醛树脂对材料的平均摩擦系数和比磨损率的影响最大。摩擦系数较优的组合为A1B1C2D2,比磨损率较优的组合为A3D1C1B3。树脂含量较少时,摩擦表面的摩擦膜较少,犁沟较深,呈严重的磨粒磨损特征;随树脂含量增加,摩擦表面形成完整且连续的摩擦膜,犁沟较浅,材料的主要磨损形式为粘着磨损和磨粒磨损。     

Degradation Kinetics of Thiamine Hydrochloride in Directly Compressed Tablets I: Effect of Ageing Under Varying Temperature and Relative Humidity Conditions

Abstract

The degrzadation kinetics of thiamine hydrochloride in tablets directly compressed with either single or binary vehicles was studied. The presult shows that, tabletted vitamin stored at varying temperature conditions degraded by first order mechanism. The magnitude of the rate constant K, was dependent on the type and concentration of the vehicle used. The decomposition of vitamin B₁ at varying temperatures was amenable to Arrhenius treatment. The degradation pattern of the vitamin in Avicel or binary blend of Avicel with another vehicle, stored at varying relative humidity conditions deviated from a first order mechanism. There was indication that equilibrium phenomenon is involved in the degradation of the vitamin contained in these vehicles. A log-linear relationship was seen to exist between K, and moisture content of the tablet.     

Melting, crystallization and optical behaviors of poly (ethylene terephthalate)-silica/polystyrene nanocomposite films

Poly (ethylene terephthalate) (PET)-silica (SiO₂)/polystyrene (PS) nanocomposite films were prepared by melting PET with the core-shell SiO₂/PS nanoparticles. Differential scanning calorimetry (DSC) results showed that the crystallization temperature of PET-SiO₂/PS nanocomposite films with 2 wt.% PS-encapsulated SiO₂ nanoparticles reached 205.1 °C, 11.6 °C higher than that of PET. For crystallized PET-SiO₂/PS nanocomposite films, double melting peaks appeared in DSC curves similar to PET. Scanning electron microscopy revealed a netlike fibre morphology for the amorphous PET-SiO₂/PS nanocomposite films with 2 wt.% PS-encapsulated SiO₂ nanoparticles. The light transmittance of these amorphous PET-SiO₂/PS nanocomposite films reached 87.9%, compared to 84.2% for PET. With the increase of annealing temperature from 110 to 150 °C, the transmittance of PET-SiO₂/PS nanocomposite films decreased slowly from 69.9 to 46.9%, while their haziness increased slightly from 45.8 to 48.2%. All these phenomena are suggested to result from the strongly heterogeneous nucleation of PS-encapsulated SiO₂ nanoparticles in PET.     

Quality of orange juice in barrier packaging material

The vitamin C content and the colour of orange juice made from concentrate were measured during 9 months of storage at 20°C either under artificial light or in darkness. The packaging materials used were glass, standard monolayer polyethylene terephthalate (PET) and multilayer PET (PET/nylon and oxygen scavenger/PET) containers. In this experiment, all bottles were sealed with aluminium foil in order to avoid any cap effect. The results showed that in plastic packaging materials, the loss of vitamin C was related to the oxygen permeability, and that glass provided the best preservation of ascorbic acid. No statistical difference (p < 0.05) was revealed between the vitamin C content in the juice stored under artificial light or in darkness, whatever the packaging used. The modification of colour was studied with the L, a* and b* values during storage at 20°C under artificial light. L and b* decreased, revealing a reduction of lightness and yellow colour of the juice, whereas a* increased, due to the formation of brown pigments. This change in colour was partly related to the oxygen permeability of the packaging used. The losses of aroma compounds by permeation through the bottle (PET) and the cap (high‐density polyethylene, HDPE) have also been investigated. The results showed that permeation mainly took place through the cap. The use of a multilayer cap [HDPE with internal barrier layer of low‐density polyethylene (LDPE)/EvOH/LDPE] considerably limited the permeation of the aroma compounds studied, whatever the PET bottle used. Copyright © 2007 John Wiley & Sons, Ltd.     

Accelerated Tests in Relation to Shelf-Life of Multivitamin Liquid Preparations

Abstract

Chemical kinetics for the decomposition of vitamin A, vitamin B₁, sodium pantothenate, folic acid and vitamin B₁₂ were studied at higher temperatures in the case of two multi-vitamin preparations. Vitamin A, vitamin B₁ and sodium pantothenate were found to decompose in accordance with the first order reaction at higher temperatures, whereas folic acid and vitamin B₁₂ did not follow first order kinetics. It was concluded that, in the cases of multivitamin preparations, accelerated study at higher temperatures was feasible only in the case of vitamin A, vitamin B₁ and sodium pantothenate.     

Up-conversion luminescent characteristics of Yb3+/Tb3+/Ho3+ tri-doped phosphate glasses for solid-state lighting

Yb³⁺/Tb³⁺/Ho³⁺ tri-doped phosphate glasses with a chemical composition (in mol %) of 20Na₂O–42ZnO–28P₂O₅–10B₂O₃ were combined by the conventional melt quenching technique. The physical properties, glass network structure, transmittance spectrum, up-conversion (UC) emission spectra, energy transfer mechanism, and chromaticity change of the prepared glasses were systematically studied. The UC emission spectra results show that the strongest UC luminescence is observed for 2.0Yb³⁺/1.0Tb³⁺/0.15Ho³⁺ (mol %) composition. When Yb³⁺ ions as sensitizer, the energy transfer of Ho³⁺?→?Tb³⁺ ions happens. The physical properties indicate that the Yb³⁺, Tb³⁺, and Ho³⁺ ions are beneficial for a compact glass structure. It can be observed that the glasses have a strong light transmittance in the visible range, and its light transmittance is about 90%. Furthermore, Yb³⁺/Tb³⁺/Ho³⁺ tri-doped phosphate glass materials have better thermostability and chroma stability, these findings have significant implications for the use of advanced solid-state lighting.

     

A mathematical model for the migration of naphthalene from the atmosphere into milk drink packaged in polyethylene bottles

A model was established to relate the amount of naphthalene migrating from the surrounding air into milk contained in LDPE bottles after exposure to an environment having a considerable amount of naphthalene. Although the real situation is very complicated, the model was established by treating the case as involving migration into milk from a time-dependent source of naphthalene, the equation for which is based on the increase with time in the naphthalene concentration in the LDPE bottles in the same environment. A model was then suggested to relate the amount of naphthalene migrating into milk with time as well as the naphthalene concentration in the surrounding air. Finally, the validity of the established model was checked for milk drinks exposed during storage to a naphthalene-based moth repellent stored in a confined space.     

Effect of recycled content and rPET quality on the properties of PET bottles,part I: Optical and mechanical properties

The effect of recycled content and type of recycled poly (ethylene terephthalate) (rPET) on the haziness; colour parameters L*, a*, and b*; total colour change; ultraviolet-visual spectrum (UV-VIS) absorption; and environmental stress cracking (ESC) of PET bottles was studied. Three series of PET bottles were made at a small scale production facility with same type of virgin PET and three different types of rPET with recycled contents of 25%, 50%, 75%, and 100%. Also, the particle contamination of the produced PET bottles was studied by dissolving bottle fragments and counting the insoluble particles. A linear relationship was found between the haziness of PET bottles and the particle contamination, with a coefficient of determination of 0.96. Linear relationships were also found between the colour parameters L* and b* and the particle contamination of the PET bottles, but the slope differed for each type of rPET. The origin of rPET (mono-collection or cocollection) seems to be the crucial factor determining particle contamination and colour of the produced bottles. No correlation was found between the recycled content and the incidence of ESC. However, PET bottles in which high intrinsic viscosity (IV) values were measured showed lower chances of ESC than PET bottles with low IV values     

Debye-Waller parameters of lead sulphide powders

The Debye-Waller parameters, the effective valueB _eff, the dynamic componentB _d and the static componentB _s, of lead sulphide powders with different particle sizes were determined for the bulk and for each constituent atom, lead and sulphur. The effective values for each atom,B _eff (Pb) andB _eff (S), were linearly related to that for the bulk,B _eff (PbS). The effective value and the dynamic component for the bulk,B _eff (PbS) andB _d(PbS), were almost equal to those for lead,B _eff(Pb) andB _d (Pb), suggesting a small contribution of sulphur atoms to Debye-Waller parameters for the bulk. The mean square displacement of the bulk, u ²_Pbs, was expressed by the atomic mass averaged mean square displacements ;u ²;_Pb and u ²_s in PbS crystal. The Debye temperature _D calculated fromB _d (PbS) increased with the decrease inB _s(PbS), and was extrapolated to the _D-value of the single crystal atB _s(PbS) = 0. A similar relation between _D andB _s were found for lead atom, where _D (Pb) was a little bit smaller than _D (PbS).     

Evaluation of a UV absorber added to PET bottles for edible oil packaging

The photo‐oxidation of lipids has significant effects on the quality of edible oils. The oxidation of oils and fats can begin due to the action of external energy sources such as light. Studies showed that the rate of photo‐oxidation of the oil depends on the light transmission of the packaging, the product characteristics and the O₂ barrier of the packaging. The UV absorber 2‐(2′‐hydroxy‐3′‐tert‐butyl‐5′‐methylphenyl)‐5‐chlorobenzotriazole (Tinuvin 326^?) has been used in PET bottles for oil, making possible the reduction of the photo‐oxidation rates. This additive was approved recently by the European Union and included in the Positive List of Directive 2001/62/EC, with a limit of specific migration. This additive is also approved by the Mercosur legislation; nevertheless its restriction of use is being reviewed in Brazil. This study had the objectives of evaluating the efficiency of the additive through the determination of the light barrier properties of PET bottles with various levels of Tinuvin 326^? and of verifying its suitability for use in direct contact with foods. Copyright © 2003 John Wiley & Sons, Ltd.     

“Dark” Excited States of Diphenylacetylene Studied by Nonresonant Two-Photon Excitation Optical-Probing Photoacoustic Spectroscopy

Optical probing photoacoustic spectroscopy (OPPAS), a photothermal calorimetric technique, was applied to investigate one-photon forbidden ??dark?? electronically excited singlet states of diphenylacetylene (DPA), belonging to the D _2h point group. When 502?nm light from a pulsed OPO laser was focused into a DPA hexane solution, an acoustic wave was detected as a transient angular deflection of the probe beam (He?CNe laser). The laser power dependence of the OPPAS signal was estimated to be 1.9 ± 0.2, suggesting two-photon absorption for acoustic generation. With the OPPAS technique, we successfully obtained a nonresonant two-photon absorption spectrum of DPA in solution for the first time. The two-photon allowed 1¹ B _3g and 2¹ A _g states were found to be above the one-photon allowed 1¹ B _1u state. These results show that OPPAS is a highly sensitive technique applicable to two-photon absorption spectral measurements of nonfluorescent species.     

Long‐time Performance of Bottles Made of PET Blended with Various Concentrations of Oxygen Scavenger Additive Stored at Different Temperatures

Blending of poly(ethylene terephthalate) (PET) with oxygen scavenger additives is a way to reduce ingress of oxygen into PET bottles made of these blends. The objective is to reduce oxidation of packaged beverages and oils. However, few studies were performed about the long‐time influence of temperature on PET bottles with oxygen scavenger additives. Such knowledge is relevant for the development of accelerated tests. In this study, the influence of temperature on oxygen permeation of PET bottles with the oxygen scavenger additives MXD6 or Oxyclear® was examined. PET bottles made of blends of PET with 2, 5 and 8 wt.?% MXD6, respectively, or with 2 wt.?% Oxyclear® were filled with deoxygenated water. The bottles were stored at 5, 23, 38 and 55 °C up to 5 years. Oxygen partial pressure of the water in the bottles was measured regularly. As expected, oxygen partial pressure increased earlier at higher temperature because of faster exhaustion of the oxygen scavenger. Oxygen partial pressure of water in PET bottles with 8 wt.?% MXD6 was below 10 mbar even after 5 years storage time at 5 and 23 °C. Oxygen absorption capacity of activated MXD6 was at least 76 mg/g. This study shows that PET bottles with oxygen scavengers are able to reduce the oxygen ingress for several years, even at elevated temperatures. Copyright © 2017 John Wiley & Sons, Ltd.     

Bag-in-box packaging for wine: Analysis of transport stress in barrier films

This 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 O₂ permeability in the investigation of the bags. The study showed no visible bag leakage. Measurement of the O₂ permeability 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 O₂ permeability. 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 is stored for less than 9 months.