Effect of package light transmittance on the vitamin content of milk,part 3: Fortified UHT low‐fat milk

This work is the third and last part of a milk study evaluating the effect of package light transmittance on the vitamin content of milk, in this case on fortified UHT low‐fat milk. The milk was stored under light with an intensity of 700 lux in polyethylene terephthalate (PET) bottles with varying light transmittance to monitor the changes in the vitamin A, B₂ and D₃ contents over a storage period of 12 weeks at 23°C. 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. In clear PET bottles, a reduction of 93% of the initial content was observed for vitamin A and 66% for vitamin D₃, while the vitamin B₂ content was completely degraded. In all pigmented PET bottles, the vitamin retention was only slightly higher; the losses ranged between 70 and 90% for vitamin A, between 63 and 95% for vitamin B₂, and between 35 and 65% for vitamin D₃ depending on the pigmentation level. In the dark‐stored ‘control’ sample, a 16% loss could be observed for vitamin A, while the level of vitamins B₂ and D₃ remained almost stable. Copyright © 2008 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.     

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.     

Nanoparticle Transport in Epithelial Cells: Pathway Switching Through Bioconjugation

The understanding and control of nanoparticle transport into and through cellular compartments is central to biomedical applications of nanotechnology. Here, it is shown that the transport pathway of 50 nm polystyrene nanoparticles decorated with vitamin B₁₂ in epithelial cells is different compared to both soluble B₁₂ ligand and unmodified nanoparticles, and this is not attributable to B₁₂ recognition alone. Importantly, the study indicates that vitamin B₁₂‐conjugated nanoparticles circumnavigate the lysosomal compartment, the destination of soluble vitamin B₁₂ ligand. Whereas cellular trafficking of soluble B₁₂ is confirmed to occur via the clathrin‐mediated pathway, transport of B₁₂‐conjugated nanoparticles appears to predominantly take place by a route that is perturbed by caveolae‐specific inhibitors. This data suggests that, following its conjugation to nanoparticles, in addition to dramatically increasing the cellular uptake of nanoparticles, the normal cell trafficking of B₁₂ is switched to an alternative pathway, omitting the lysosomal stage: a result with important implications for oral delivery of nanoparticulate diagnostics and therapeutics.     

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.     

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.     

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.     

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.     

Effect of recycled content and rPET quality on the properties of PET bottles,part II: Migration

Polyethylene terephthalate (PET) bottles were produced from three types of recycled PET (rPET) with four levels of recycled content. The migration of substances from these bottles to water was studied. Several migrated substances were detected. The migrated amounts of acetaldehyde and ethylene glycol complied with the limits given in the food contact material (FCM) legislation. Migration of 2-methyl-1,3-dioxolane was below the limit of 10 μg·L⁻¹, which is conventionally applied for non-intentionally added substances (NIAS) not classified as ‘carcinogenic’, ‘mutagenic’ or ‘toxic to reproduction’ (CMR). Limonene, acetone, butanone and furan were also detected as migrants, of which limonene is a natural fragrant, and the other three are probably residues from solvents used to clean and protect the mould at the small-scale production facility. Finally, benzene and styrene were also found as migrants from rPET. These migrants appear to originate from heat-induced reactions within the PET matrix, which involve contaminants. The formation of benzene in rPET is attributed to polyvinylchloride as contaminant. The migrated amounts of benzene from the PET bottles with recycled content to the water simulant are relatively small (0.03–0.44 μg·L⁻¹) after 10 days at 40°C. Consequently, the margin of exposure is 3.10⁵–8.10⁶. Hence, the level of concern for the public health is low, and the migrated amount represents a low priority for risk management. The FCM legislation demands a risk assessment for migrating NIAS. Depending on the underlying data and exposure scenario, different threshold limits in the food can be derived which can still be considered as safe.     

Using sliding mode observers to estimate BtuB concentration from measured vitamin B12 concentration

A simple model for the B₁₂ ‐riboswitch regulatory network in Escherichia coli is first described and the same analysis is applied when changing the strain to Salmonella enterica. Model validation is undertaken by linking the dynamics of the riboswitch model to bacterial growth and comparing the results obtained with in vivo experimental measurements. Measurements of bacterial growth are relatively straightforward to obtain experimentally, but experimental measurements relating to the operation of the riboswitch are more difficult. Using the validated model, sliding mode observer design methods are used to estimate BtuB given measurements of the concentration of vitamin B₁₂. The sliding mode approach is selected because of its inherent robustness properties as well as for the ease of implementation. Validation of the estimates of BtuB produced by the observer is undertaken by comparing the BtuB and vitamin B₁₂ concentrations estimated from the observer with green fluorescent protein production and the concentration of vitamin B₁₂ obtained experimentally. These experimental results also provide further validation of the underpinning mathematical model. The results establish that using a sliding mode observer as a soft sensor is a useful approach to explore the operation of a vitamin B₁₂ riboswitch given measurements of the concentration of vitamin B₁₂.Inspec keywords: macromolecules, variable structure systems, observers, proteins, genetics, biologyOther keywords: underpinning mathematical model, sliding mode observer, BtuB concentration, Escherichia coli, Salmonella enterica, bacterial growth, vitamin B₁₂ concentration, B₁₂ ‐riboswitch regulatory network     

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.     

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.     

Packaging materials for fermented milk: effects of material crystallinity and polarity on food quality

The ability of a packaging material to protect the food product and extend its shelf‐life depends on several material properties. In this work the effects of material crystallinity and polarity on the quality of fermented milk were studied. The fermented milk is a high‐quality Swedish product, similar to yoghurt. The quality of the food product was determined as a function of storage time by containing the liquid in pouches of different materials. The material crystallinity was varied by using very low‐density polyethylene, high‐density polyethylene and aluminium laminate as packaging materials. Aluminium was used on account of its ‘100%’ gas‐tightness. The polarity was varied by comparing an aliphatic polyketone with polyethylene of similar crystallinity. The carbon dioxide (CO₂) and oxygen (O₂) contents in the headspace of the pouches were determined. The food quality was determined by measuring whey syneresis, viscosity and the content of desired Bifidobacteria, as well as of undesired yeast and mould. A trained taste panel determined the degree of acidity and of the sparkling taste. It was found that the content of CO₂ increased and that of O₂ decreased in the pouches with increasing degree of crystallinity and increasing polarity. The sparkling taste of fermented milk was a clear function of the headspace CO₂ content. The data presented here could thus be used to ‘design’ a package for a desired sparkling taste of the fermented milk by selecting a certain material crystallinity. Whey syneresis, viscosity and content of Bifidobacteria were found to be independent of pouch material. While the degree of whey syneresis and the viscosity increased with increasing storage time, the content of Bifidobacteria slowly decreased. The content of yeast and mould in the liquid was below the existing limit values for foodstuffs. The degrees of acidity and sparkling taste were highest for the liquids contained in aluminium and polyketone pouches, although the differences in acidulous taste between the various pouch materials were small. Copyright © 2001 John Wiley & Sons, Ltd.     

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.     

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     

Translucent low-thermal expansion ceramics

The optical transmittance of pressureless sintered KZr₂P₃O₁₂ (KZP) ceramics was studied in the ultraviolet, visible light, and near infrared spectrum ranges. Thermal expansion, strength, and thermal shock resistance of the ceramics were also studied. KZP ceramics with different additives (0–8 wt% of MgO, ZnO or SrO) show a 30–70% transmittance from 0.4–2 m, a low thermal expansion coefficient and high thermal shock resistance. These polyfunctional ceramics might be useful as optical windows.     

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.

     

Effects of pre-strain applied at a polyethylene terephthalate substrate before the coating of TiO2 film on the coating film quality and optical performance

A mold was designed to create various strains in polyethylene terephthalate (PET) substrates before the deposition of TiO₂ film to simulate deposition process on a cylindrical drum. The residual stress of the PET substrate with TiO₂ film significantly increased with increasing strain, decreasing the radius of curvature. Compared to the as-received PET substrate, there was a noticeable increase in the surface roughness in the PET/TiO₂ specimens when a large strain was applied. The formation of voids or cavities in the TiO₂ layer significantly increased the roughness of the specimen. The mean cavity size and depth increased with increasing strain. For strains ≦ 4%, the specimen's hardness and Young's modulus factored by the voids/cavities increased with increasing surface roughness. The optical absorption increased with increasing surface roughness before becoming asymptotic to a constant value. The strain applied to the PET substrate before TiO₂ deposition greatly affects the optical reflection, transmittance, and absorption.