高压协同中温杀菌对PA/PE包装材料的影响

以蒸馏水、橄榄油、3%(体积分数)乙酸及15%(体积分数)乙醇为食品模拟物,研究超高压协同中温杀菌对PA/PE包装材料的影响,处理压强分别为200,300,400 MPa,加压的初始温度分别为10,30,50℃,保压时间为15 min。通过电镜观察材料的结构变化,得到杀菌处理后材料的机械性能及阻隔性能,并进行DSC热性能分析,进一步验证材料性能变化的原因。结果表明:30℃的初始温度下高压处理,能保证材料结构完整性,10℃时材料结构损伤最严重,出现气泡和白色条纹;包装蒸馏水的材料结构损伤最严重,包装橄榄油的材料几乎没有结构损伤。50℃时材料机械性能及阻隔性能下降较明显(P0.05),30℃时材料阻隔性能无显著变化(P0.05),而且包装橄榄油的材料阻隔性能增强,经DSC分析,发现材料结晶度增加。30℃/400 MPa/15min的杀菌条件在保证杀菌效果显著的基础上,可以确保PA/PE包装材料不受到结构及性能的破坏。     

超高静压对食品真空复合包装膜材料性能及微观结构影响的初探

食品包装材料性能及结构变化会影响食品的质量安全及货架期,探索超高静压对食品包装材料性能及结构变化对了解超高静压对包装材料作用效应机理及包装材料选择是有益的。选择2种食品包装最为常用的未拉伸聚丙烯/尼龙/聚乙烯(CPP/nylon/PE)和聚丙烯/铝/聚乙烯(PP/Al/PE)复合包装膜为研究对象,探讨了不同超高静压强对包装材料拉伸强度、拉伸伸长率、热封强度、透气性、透湿性的变化等影响,并对超高静压对包装材料断面结构的影响进行了环境扫描电镜(ESEM)观察。试验结果表明:(1)超高静压处理对CPP/nylon/PE和PP/AL/PE复合材料拉伸强度影响变化不显著;(2)经超高静压处理后,CPP/nylon/PE伸长率及透氧系数变化显著(P<0.05);(3)经超高静压处理后,PP/Al/PE热封强度、透湿率变化显著(P<0.05)、伸长率及透氧系数变化极显著(P<0.01);(4)在一定压强的超高静压处理会使复合膜结构产生膜间裂缝及Al膜内部裂缝。对CPP/nylon/PE在300-600MPa,PP/AL/PE在200-600MPa,基本上是压强越大,裂缝就越严重。     

四种聚合物包装材料对亚麻籽油氧化产物的影响研究

为了探究聚合物包装材料对食用油氧化的影响,以亚麻籽油和不同聚合物包装材料(聚酰胺(PA),聚乙烯(PE),聚对苯二甲酸乙二醇酯(PET)和聚丙烯(PP))为研究对象,探讨在室温和60℃条件下四种聚合物包装材料表面和颗粒对亚麻籽油初级氧化产物及挥发性产物的影响。利用接触角测量仪、傅里叶变换红外光谱仪及气相色谱-质谱联用仪对材料表面特性、亚麻籽油初级氧化产物及挥发性产物进行了测定。结果表明:包装材料亲水性顺序为PET PP PE PA;在不同温度的氧化条件下,材料表面和颗粒对亚麻籽油产生氢过氧化物速率顺序均为PP PA PE≈PET和PA PP≈PE PET;不同聚合物表面对亚麻籽油在室温及60℃条件下产生挥发性物质总量影响顺序分别为PP PET≈PE PA和PP PA PET PE。聚合物的亲水性对亚麻籽油氧化变化有较大影响,且不同温度下对氧化产物的影响具有一定差异性。     

不同包装材料对大米恒温恒湿贮藏品质的影响

分别采用聚偏二氯乙烯(PVDC)和聚乙烯/尼龙/聚丙烯(PE/PP/PA)包装材料对大米进行包装,在恒温恒湿(温度37℃,湿度70%)贮藏条件下,研究不同包装材料对大米贮藏品质的影响。试验结果表明,这两种包装材料的大米水分均有所降低,蒸煮品质下降,淀粉酶活力和脂肪酶活力呈先升高后降低的趋势,脂肪酸值升高;PVDC包装材料组各项指标变化程度均低于PE/PP/PA包装材料组。在恒温恒湿贮藏条件下,PVDC包装材料能更好地延长大米保质期。     

包装与贮藏温度对蚕豆采后品质的影响

为明确适宜于鲜食蚕豆采后贮藏的温度与自发气调包装材料,以无保鲜膜包装的蚕豆为对照,研究了(1.0±0.5)℃下聚乙烯(PE)、聚氯乙烯(PVC)、微孔(W)3种保鲜膜包装和(5±1)℃PE保鲜膜包装对蚕豆硬度、色泽、水分含量等品质指标的影响。结果表明,(1.0±0.5)℃下采用PVC保鲜膜包装的蚕豆品质优于其它处理,蚕豆贮藏28d,仍保持较好品质。     

射频处理对花椒粉品质及EVOH/PA包装薄膜性能的影响

为了避免二次污染,在实际生产中产品多以预包装形式进行射频处理,研究射频处理对内装物及外部包装材料的影响尤为重要。本文以花椒粉为原料,EVOH/PA薄膜为外部包装材料,采用6 kW,27.12 MHz的射频设备进行杀菌,研究射频过程中影响其升温速率的关键因素。结果表明:在25～40 mm的射频极板间距下,随着极板间距的升高,电场强度变小,射频输出功率降低,包装件的升温速率下降。在相同的极板间距条件下,随着花椒粉含水率的升高,介电损耗因子增加,包装件的升温速率提高。还研究了射频处理不同温度的花椒粉的菌落总数及最佳杀菌温度下的颜色改变情况,结果表明,当射频处理温度80℃时,花椒粉基本无细菌检出,且此处理温度未对花椒粉色泽产生显著影响。射频处理未对EVOH/PA包装薄膜的力学性能和阻隔性能产生显著性影响,说明其可作为预包装花椒粉新型杀菌方式。     

冷链物流中包装材料对黄鳍金枪鱼品质的影响

为研究物流过程中包装材料对黄鳍金枪鱼品质的影响,模拟了4℃物流过程(120h)中对照组、PE包装组和纳米包装组的质构(硬度和弹性)、持水力、TBA、肉色【a*和高铁肌红蛋白(MetMb)】以及组胺的变化情况。结果显示:随着贮藏时间的延长,3个试验组的硬度、弹性、持水力和a*值均呈下降趋势;TBA值、MetMb和组胺均呈增加趋势。上述理化指标中黄鳍金枪鱼品质最好的是纳米包装组,其次是PE包装组,最后是对照组。在4℃冷链物流中PE包装材料和纳米包装材料对黄鳍金枪鱼品质的劣化均有缓冲作用,其中纳米包装材料的效果比PE包装材料好。     

不同包装对冷藏和货架期黑布朗李果实品质及乙烯释放速率的影响

黑布朗李分别经PE、PVC和微孔膜包装后在0℃贮藏,以无包装为对照,研究不同材料包装对冷藏及货架期(25℃)黑布朗李果实品质的影响。结果表明,包装可以显著(p0.05)降低果实失重率,对果实贮藏期品质具有良好的影响;PVC包装能显著地降低包装内O_2体积分数(p0.05),提高CO_2体积分数,并能够有效地延缓货架期李果实硬度下降,维持较高的SSC;PE包装的李果实软化缓慢,与其他组果实相比转色指数最高。PE、PVC和微孔膜包装均能有效地抑制贮藏过程中李果实乙烯的释放速率。     

不同透明包装对榨菜品质的影响

以刚腌制好的原味榨菜片为原料,选用7种常用的透明包装材料,并以非透明包装材料(BOPP/PET/PE)作对照,按普通榨菜的生产工艺制作包装榨菜样品,采用现代分析方法对在自然条件下贮存的该包装榨菜进行品质分析研究。结果表明:采用A透明材料(PET/PA/RCPP)包装的榨菜的色泽、气味、总酸、氨基态氮、还原糖、VC等品质指标均优于除对照组外的其他包装组,但与对照组相比,A材料包装榨菜的色泽、气味等感官品质稍差,总酸、VC、氨基态氮、还原糖含量与对照组榨菜相差较小,没有统计学意义;PA/RCPP组、PA/CPE组保存榨菜品质的能力较差,其他4种透明包装材料(PET/PE(大)、PET/PE(小)、BOPP/PE、BOPP/CPP包装的榨菜在100d后其色泽和气味劣变得让人难以接受。因此,A透明包装材料是能很好保持榨菜品质的透明包装材料。通过对包装材料的基本性能测试得出,透明材料的厚度越大、透氧率越小,越有利于榨菜保持良好的品质;其透光率对榨菜品质的影响不太明显。     

不同阻隔性包装材料对生菜保鲜效果的影响

为了研究不同阻隔性包装材料对采后生菜保鲜效果的影响,选择低密度聚乙烯膜(LDPE)、聚乙烯膜(PE)、高密度聚乙烯膜(HDPE)、乙烯—乙烯醇共聚物/聚乙烯复合膜(EVOH/PE)4种包装材料对生菜进行气调包装,并设置无包装组作为对照,置于4℃的冷库中贮藏。贮藏期间,定期对各组生菜感官、失重率、叶绿素含量、相对电导率以及袋内气体组分等指标进行测定。结果表明,第6天时,对照组生菜因失水严重而失去商品价值;EVOH/PE组中O_2即将耗尽,CO_2比例达到20.3%,袋内出现酒精气味;其它3组袋内O_2比例均先降低,在小范围内呈波动性变化,CO_2比例先升高后相对平稳。HDPE组贮藏时间达18d,保鲜效果最好。阻隔性适宜的包装材料可以有效提高生菜的保鲜效果,延长保鲜期。     

微波处理与热处理对牛奶包装材料机械性能影响的研究

研究了微波处理与热处理对于牛奶包装材料机械性能的影响。结果表明,微波处理和热处理均会影响牛奶包装的热封强度和拉伸强度。随着微波功率和处理时间的增加,三种被测材料的热封强度和拉伸强度均呈下降趋势,尤其是C的拉伸强度变化幅度最大;随着加热温度的增加,三者热封强度升高,除B膜外,拉伸强度同样呈现上升趋势;而随着加热时间的增加,A、B热封强度相对比较稳定,但是C的热封强度呈明显上升趋势,对于拉伸强度而言,除B平均值略高于初始值以外,A与C的拉伸强度均呈明显的随时间增加而上升的趋势。特别是高温、大功率、长时间处理对包装材料的影响尤为显著。     

中国食品塑料包装产品安全性分析及其对策研究

<正> 1.前言食品包装被称作是"特殊食品添加剂",它是现代食品工业的最后一道工序,在一定程度上,食品包装已经成为食品不可分割的重要组成部分,它起着保护商品质量和卫生,不损失原始成分和营养,方便贮运,促进销售,延长货架期和提高商品价值的重要作用。自从50年代聚偏二氯乙烯用于食品包装以来,塑料包装材料用于食品包装日益增多,由于塑料材料具有     

The use of mechanical analyses,scanning electron microscopy and ultrasonic imaging to study the effects of high‐pressure processing on multilayer films

The effects of high‐pressure processing (HPP) on the mechanical and physical characteristics of eight high‐barrier multilayer films were investigated. These films were PET/SiO_x/LDPE, PET/Al₂O₃/LDPE, PET/PVDC/nylon/HDPE/PP, PE/nylon/EVOH/PE, PE/nylon/PE, metallised PET/EVA/LLDPE, PP/nylon/PP and PET/PVDC/EVA. In addition, PP was evaluated as a monolayer film for comparison purposes. Pouches made from these films were filled with distilled water, sealed, then pressure processed at 600 and 800 MPa for 5, 10 and 20 min at a process temperature of 45 °C. Pouches kept at atmospheric pressure were used as controls. Prior to and after HPP, all films were tested for tensile strength, percentage elongation and modulus of elasticity (at 50 cm min^?1) and imaged by scanning electron microscopy (SEM) and C‐mode scanning acoustic microscopy (C‐SAM). Results showed no significant changes in tensile strength, elongation and modulus of elasticity of all films after HPP. However, significant physical damage to metallised PET (MET‐PET) was identified by SEM and C‐SAM. Thus it could be concluded that MET‐PET is not suitable for batch‐type high‐pressure‐processed food packaging. It can also be concluded that the other materials investigated during this study are suitable for batch‐type high‐pressure‐processed food packaging. Copyright © 2003 Society of Chemical Industry     

Effects of emerging food processing techniques on the packaging materials

In recent years, new food processing techniques are attracting a lot of attention. Since some of these techniques might require the processing of foods inside their package, it is important to understand the interaction between the package and the process itself. The main objective of this article is to review the information in literature about the effects of different processing methods on: (i) the structural, mechanical and barrier properties of the materials commonly used in food packaging; and (ii) the migration behavior of additives mainly from plastic packaging films.     

Computer simulation model development and validation for radio frequency (RF) heating of dry food materials

Radio frequency (RF) heat treatment has been identified as a novel pasteurization and non-chemical quarantine method for dry food materials. But the major obstacle of this treatment is non-uniform heating in these food materials. The objective of this study was to help understand RF heating process by developing a computer simulation model. A finite element based commercial software FEMLAB was used to develop the computer model for a 12 kW, 27.12 MHz parallel plate RF system. Wheat flour was selected as a model food to represent dry food materials. Dielectric properties of wheat flour were measured using an open-ended coaxial probe connected with impedance analyzer, whereas thermal properties were determined using a duel needle probe method. Simulated and experimented temperature profiles (°C) of wheat flour were compared in four different horizontal layers after 3 min of RF heating, with a fixed electrode gap of 155 mm. Both, simulated and experimental results showed that temperature values were higher at the mid layers followed by top and bottom layers. Corners were more heated than centers in each layer. Sensitivity analysis showed that temperature uniformity in the sample was most affected by top electrode voltage and sample dielectric properties. The developed model can further be used to study the effect of some important parameters such as sample size, position, shape, and dielectric properties on RF heating of dry food materials.     

Impact of processing treatments and packaging material on some properties of stored dehydrated cauliflower

Investigations were carried out to see the impact of blanching time, pretreatment and storage and packaging on the physico‐chemical properties of solar dehydrated cauliflower. The processing treatments selected for the study were blanching time of 3, 5, 7 and 9 min, potassium metabisulphite (KMS) pretreatment having 0.5%, 1.0% and 1.5% concentration level and storage in high‐density polyethylene, laminated aluminium foil and polypropylene. The cauliflowers were further processed and dehydrated in solar dryer before packing it into different packaging materials. Packed dehydrated cauliflower was stored for 6 months at room temperature. The stored cauliflower samples were tested periodically for their moisture content, rehydration ratio, rehydration coefficient, ascorbic acid and browning. Ranking of blanching time, chemical concentration level and packaging materials were statistically analysed by using SAS package. The samples with 9 min blanching time, followed by dipping in 1.0% KMS solution, and packed in laminated aluminium foil showed better results in comparison with other treatments.     

纳米纤维素的制备及其在食品包装材料中应用的研究进展

纳米纤维素作为包装材料的填充成分,可以提高材料的力学性能和阻隔性能,并可改善复合材料的热学性能及降解性能.本文简要介绍了纤维素及纳米纤维素,重点阐述了纳米纤维素的制备方法(化学法、生物法和物理机械法等)及其在食品包装材料中的应用(保鲜及抗菌包装材料、活性包装材料和高阻隔包装材料等).最后,对纳米纤维素在食品包装材料领域...     

超高压下食品组分与包装材料的相互影响

研究超高压技术对薄膜的结构和性能产生的影响及超高压作用下薄膜与食品模拟物的相互作用。对以大豆蛋白、油脂等食品组分为内容物的尼龙/聚乙烯(PA/PE)、聚酯/聚乙烯(PET/PE)两种聚合物包装材料进行超高压处理,并贮藏一定周期,测定不同压强及保压时间下食品内容物与包装材料在不同贮藏周期内的相互影响。结果表明:贮藏周期一定,经过超高压处理的两种聚合物包装材料的性能要优于未经过处理的;在保压时间一定的情况下,增加压力会提升食品组分的货架期,压力越高,效果越明显;在压力一定的条件下,保压时间的变化并未对食品组分、包装材料产生规律性的影响。压力和贮藏周期的变化对食品组分和包装材料会产生一定的影响。     

Physical and Mechanical Properties of Biobased Materials Starch,Polylactate and Polyhydroxybutyrate

Commercial and semi‐commercial biobased materials (Polylactate, PLA, polyhydroxy‐butyrate, PHB, wheat starch and corn starch) were investigated. Physical and mechanical characterisation (tensile strength, elongation, tear strength, compression, gas permeability (CO₂ and O₂) and water vapour permeability (WVP)) was examined. Tests on both films and cups show potential use of these materials for primary food packaging, especially PLA and PHB. An interesting O₂:CO₂ permeability ratio (1:7 to 1:12) was seen, which make these materials suitable for packaging of food with high respiration. The mechanical properties were comparable to conventional materials such as polyethylene (PE) and polystyrene (PS). The WVP measured on films ranged from 12.6 to 18.6 [g H₂O/(m² ? 24h)], and on cups the range was 2.2 to 10.5 [g H₂O ? 700 μm/(m² ? 24h)]. The WVP for the starch‐based materials seems to be the most crucial parameter, and needs improvement if these materials are to be used as food packaging.     

Overall migration from commercial coextruded food packaging multilayer films and plastics containers into official EU food simulants

The overall migration from a wide range of commercial five-layer coextruded packaging films into aqueous food simulants (distilled water, 3% aqueous acetic acid) and alternative fatty food simulant (iso-octane) was studied. The overall migration from commercial plastics cups (PS, HIPS, and PP) used for ice-cream or yogurt packaging into distilled water and 3% aqueous acetic acid was also studied. Test conditions for packaging material/food simulant contact and method of overall migration analysis were according to the EU directives and CEN-standards. The results showed that for all tested five-layer films and plastics (PS, HIPS, and PP) cups values of overall migration into aqueous simulants (0.11-0.79 mg/dm², 2.3-15.9 mg/l) and (<0.10-0.41 mg/dm², <0.80-3.1 mg/l) were significantly lower than the upper limit (10 mg/dm²) for overall migration from plastic packaging materials and articles into food and food simulants set by the EU Directive 90/128/EEC and their revisions. The overall migration values from five-layer materials into iso-octane were significantly higher (0.94-8.23 mg/dm², 18.8-164.7 mg/l) than the above values but are still lower than the upper limit for overall migration. Global migration values of five-layer films into aqueous food simulants seems to be independent of material thickness. In contrast, overall migration into iso-octane increases with film thickness.