密胺塑料中三聚氰胺在食品模拟物中的迁移规律研究

采用超高效液相色谱串联质谱(UPLC-MS/MS)法,研究食品模拟物种类、接触时间、接触温度、乙酸浓度、乙醇浓度、重复使用和微波加热等迁移条件下,密胺塑料中三聚氰胺在水、4%乙酸(w/v)、10%乙醇(v/v)、95%乙醇(V/V)和异辛烷等5种食品模拟物和牛奶样品中的迁移规律。结果表明:模拟物的属性对迁移行为有显著影响,迁移量随温度的升高和时间的增加而变大。酸性食品和牛奶中的三聚氰胺迁移风险较高,且需控制密胺塑料的使用温度、盛放时间、重复使用次数及微波加热功率和时间以降低密胺塑料中三聚氰胺迁移风险。     

白酒塑料包装中增塑剂的迁移行为

采用气相色谱-质谱法研究了市售白色塑料酒壶中邻苯二甲酸二(2-乙基己烷)酯(DEHP)、邻苯二甲酸二异壬酯(DINP)和邻苯二甲酸二丁酯(DBP)在不同浸泡时间和温度以及不同酒精度条件下向白酒中迁移量的变化规律。结果显示,相同条件下,DEHP的迁移量最大;3种邻苯二甲酸酯(PAEs)向白酒中的迁移量与酒精度数和浸泡时间均成正比;当浸泡温度高于常温时,PAEs的迁移量将随着温度的增加而增加。因此,市售白色塑料酒壶在贮藏高度数酒时,不宜在高温条件下长期贮藏,以免白酒中PAEs含量过高而对饮酒者造成不良的健康风险。     

聚丙烯餐盒服役过程化学物质总迁移规律研究

通过试验模拟了聚丙烯餐盒与食用油接触、微波加热、臭氧消毒,以及餐饮配送服务公司使用情况,研究了其在上述服役过程中正己烷、体积分数4%乙酸总迁移量的变化规律。研究发现在酸性食品模拟物乙酸溶液中,聚丙烯餐盒化学物质总迁移量虽有变化,但均未超过标准限值;在油性食品模拟物正己烷溶液中,随着循环次数增加,聚丙烯餐盒化学物质总迁移量明显增大,出现了超过标准限值的现象,其中臭氧消毒对化学物质总迁移量影响最大,微波加热次之。     

一次性塑料饭盒中双酚A在食品模拟溶剂中的迁移

文章研究了一次性塑料饭盒中的双酚A在不同食品模拟溶剂条件下的迁移规律.实验采用高效液相色谱法对在不同食品模拟溶剂中迁移的双酚A进行了检测.结果表明,双酚A在不同食品模拟溶剂中的迁移量,主要受温度、溶剂极性及萃取方式的影响.随着水浴温度的升高,双酚A迁移量逐渐增加,但由于双酚A易挥发,温度过高时,溶出物中双酚A的量反而减小;相同温度时,在不同食品模拟溶剂中,溶剂极性越小,溶出物中双酚A的迁移量越高;溶剂相同时,不同萃取方式下的迁移量不同,实验表明：一次性塑料饭盒中的双酚A用微波萃取比水浴加热萃取时的迁移量明显增加.     

Migration of plasticizer di-2-ethylhexyl phthalate from PVC packaging material into cured meat

利用增塑剂DEHP的皂化反应,采用膜/肉接触的比色管模式和气相色谱法,研究了温度、时间、脂肪含量和加工方式等因素对PVC膜中的增塑剂DEHP向广式腊肠迁移的影响。结果表明：随着温度的升高,时间的延长,脂肪含量的增加,DEHP向肉中的迁移量均会增大;在紫外照射、微波辐射和高温蒸煮等条件下,DEHP的迁移量也会增加,其中微波辐射的作用较为明显,如微波照射18 s后,DEHP的迁移量高达189.3342 mg/kg,紫外光照射48 h后,迁移量是173.5921 mg/kg。同时研究了DEHP迁移溶出后,PVC膜的拉伸性能、断裂伸长率、透氧率和透湿率等性能的变化。结果表明：当增塑剂DEHP迁移溶出后,PVC膜的阻隔性和力学性能也发生了明显的变化,随着时间的延长、迁移量的增大,其PVC膜的拉伸强度逐渐升高,断裂伸长率逐渐降低,PVC膜的透氧率和透湿率也降低。     

食品塑料包装中抗氧化剂迁移研究

利用高效液相色谱仪对高密度聚乙烯包装中抗氧化剂1076和抗氧化剂168在微波条件下向食物中的迁移行为进行了研究。研究结果表明,微波功率增大、微波时间延长都会使两种抗氧化剂向食物中迁移的程度变大。另外随着时间的延长,在微波加热初期两种抗氧化剂的迁移量显著增高,随着作用时间延长至20 min后,抗氧化剂向食物中的迁移率增加不再明显。两种抗氧化剂向不同食物中的迁移率也不一样,向猪肉中的迁移率最高,米饭次之,向果蔬类食品中的迁移率最小。     

开放式超声微波协同萃取测定PVC塑料中邻苯二甲酸酯类增塑剂研究

概述了邻苯二甲酸酯类(PAEs)作为聚氯乙烯(PVC)增塑剂的应用、危害,说明了PAEs的理化性质,详细归纳了超声波、微波、超声.微波协同萃取技术的应用及PAEs分析测定方法.通过优化超声波、开放式微波和超声.微波等方式萃取PVC塑料样品中的PAEs的萃取条件,比较了3种不同萃取方式的萃取效率.结果表明,超声.微波协同萃取是比较理想的萃取方式.利用该方法对2种实际塑料样品中PAEs的萃取和分析,成功地定量测定了PVC塑料样品中DEHP、DINP和DBP等邻苯二甲酸酯类增塑剂的含量.该法可用于塑料制品中各类邻苯二甲酸酯类增塑剂的快速萃取和分析.     

白酒包装材料中塑化剂的迁移研究

考察包装白酒的不同材料、不同酒精度、存放温度及与塑料制品的接触时间等对塑化剂迁移量的影响。结果表明,TPE相对于PP、PE、PET等材料,塑化剂迁移明显,且塑化剂迁移量随酒精度、存放温度以及接触时间总体上呈现增长趋势,特别是酒精度及存放温度的增加对塑化剂迁移量的影响较大。塑化剂的18种指标中,DBP迁移较为明显,DEHP、DIBP、DMEP也有不同程度的迁移,其他指标没有检出。直接接触酒体的包装材料、酒精度、存放温度、白酒与塑料制品的接触时间均会对塑化剂迁移造成显著影响。     

长时间高温加热对食用植物油脂酸价的影响

为研究高温加热对不同脂肪酸组成的食用油酸价的影响,用不同加热温度(180℃,220℃和260℃)及不同加热时间(0.5~10 h)分别加热棕榈油、玉米油和橄榄油,并测定其酸价。结果表明:经过加热处理的三种食用油与原油相比,酸值增大;随着加热温度的升高和加热时间的延长,食用油的酸价均明显升高;其中高温加热对玉米油的酸价影响最大。     

微波辅助离子液体法对纤维素的均相改性研究

以离子液体1-丁基-3-甲基咪唑氯盐（BMIMCl）为溶剂,采用微波辐射代替常规的加热技术,对纤维素进行均相改性研究。首先进行微波辐射下纤维素在离子液体中的溶解,研究微波辐射温度和溶解时间的影响;其次进行纤维素与氯乙酰氯在微波辅助离子液体中的均相乙酰化研究,利用FT-IR、1H-NMR对聚合物进行了表征,探讨微波辐射功率、反应温度、反应时间和氯乙酰氯用量对纤维素取代度的影响。结果表明,微波加热有利于纤维素溶解和酯化,辐射时间和温度提高均会增加纤维素溶解量,酯化剂用量和微波辐射时间对反应影响较大。     

The migration of plasticizers from poly(vinyl chloride) into edible oils

The migration of phthalate plasticizers from poly (vinyl chloride) into edible oils has been analyzed. The principal method used involved ¹⁴C-labeled dibutyl and dioctyl phthalates with detection by liquid scintillation spectrophotometry. In most cases, the migration of the main plasticizer was accompanied by the migration of the secondary plasticizer, when present, and by diffusion of the oil into the polymer. Comparison of the scintillation results with those obtained by weight loss measurements can give quantitative information on the amount of the liquid medium that diffuses during the migration process. The effect of the following factors on the migration process was examined; (a) the nature and acidity of the edible oil, (b) the composition and amount of phthalate plasticizer, (c) the amount of epoxy plasticizer, and (d) the temperature and time of contact.     

微波条件塑料包装化学物质迁移研究

塑料广泛应用食品于食品包装中,并且常常会在塑料包装加工过程中添加许多化学添加剂以提高其性能,可能会对人的健康产生影响。就微波条件下塑料包装化学物质的迁移进行了研究,采用500,700,900W三个不同加热功率下分别对食品模拟物三种食用油(橄榄油、菜籽油和葵花籽油)的迁移率进行实验。以期对预防塑料包装危害产生积极影响。     

以橄榄油为模拟食品测定微波加热容器的总迁移量

本文以橄榄油为脂肪食品模拟物,对市售微波适用塑料容器中有害物质的总迁移量进行了测定。对照我国现行标准中正己烷模拟物的测定结果,发现以橄榄油为模拟物的方法测得样品合格率为20%,而以正己烷为模拟食品测得样品合格率为100%。说明我国现行的相关标准对评价微波加热容器的安全性还存在不足之处。     

Effect of heating rate on pyrolysis of low-grade pyrolytic oil

The low-grade pyrolytic oil produced from pyrolysis of municipal plastic waste in a commercial rotary kiln reaction system cannot be an acceptable fuel oil due to its low quality. Thus, the degradation of pyrolytic oil was conducted in a bench scale batch reactor, which was done by two experiment conditions of high heating rate (about 7 °C/min) and low heating rate (1.5–3.6 °C/min) up to 420 °C of reaction temperature. The characteristics of raw pyrolytic oil were examined and also the characteristics of products obtained by different heating rates were compared. Raw pyrolytic oil had higher H/C ratio and higher heating value than commercial oils, and also its peak range in GC analysis showed wide distribution including all the range of gasoline, kerosene and diesel. In the upgrading of pyrolytic oil, cumulative amount profile of product oil, as a function of reaction time, was similar in shape to the degradation temperature profile. All product oils obtained by different degradation temperature had higher H/C ratio and slightly higher heating value than those of raw pyrolytic oil. Also, the characteristics of product oils were influenced by heating rate and reaction temperature.     

Free radical polymerization of butyl acrylate in monodispersed droplets: Comparison between two heating strategies

Monodispersed droplets could be easily generated in coaxial microdevice, and a reaction based upon these discrete droplets is an attractive approach thanks to isolated reaction units, efficient mixing, and precise residence time control. In this work, free radical polymerization of butyl acrylate was conducted in monodispersed droplets of several hundred microns. Two different heating methodologies, microwave heating and conventional heating with oil bath were adopted to initiate polymerization, respectively. The polymerization under conventional heating could be regarded as an isothermal process, while the polymerization under microwave heating gradually underwent a temperature increase. So the poly (butyl acrylate) obtained by microwave heating has larger average molecular weight and higher polydispersity index. Meanwhile, the conversion of butyl acrylate was significantly improved by microwave heating compared with conventional heating, even though the reaction temperature under microwave heating might be lower than the temperature of the oil bath. This remarkable enhancement was a direct proof of the nonthermal effect of the microwave field for free radical polymerization. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Type of polypropylene material significantly influences the migration of antioxidants from polymer packaging to food simulants during microwave heating

Three different polypropylene materials, polypropylene homopolymer (PP), propylene‐ethylene random copolymer (PP‐R), and propylene‐ethylene copolymer (PP‐C) are commonly used in plastic containers designed for microwave heating of food. Migration of antioxidants, Irganox 1010 and Irgafos 168, from PP, PP‐R, and PP‐C during microwave heating in contact with different food simulants was investigated by utilizing microwave assisted extraction (MAE) and high performance liquid chromatography (HPLC). The polypropylene material significantly influenced the migration rate, which decreased in the order of increasing degree of crystallinity in the materials. PP homopolymer was the most migration resistant of the studied materials especially in contact with fatty food simulants. The use of isooctane as fatty food simulant resulted in rapid depletion of antioxidants, while migration to another fatty food simulant, 96% ethanol, was much more limited. Migration to aqueous and acidic food simulants was in most cases under the detection limits irrespective of microwaving time and temperature. The diffusion coefficients were similar to what have been found previously under similar conditions but without microwaves. The effect of swelling was shown by the large increase in the calculated diffusion coefficients when isooctane was used as food simulant instead of 96% ethanol. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Fatty Acid Composition and Antioxidant Activity of Tea (Camellia sinensis L.) Seed Oil Extracted by Optimized Supercritical Carbon Dioxide

Seeds are another product in addition to leaves (raw materials for teas) of tea (Camellia sinensis L.) plant. The great increase of tea consumption in recent years raises the challenge of finding commercial applications for tea seeds. In the present study, supercritical carbon dioxide (SC-CO(2)) extraction edible oil from tea seed was carried out, response surface methodology (RSM) was used to optimize processing parameters including time (20-90 min), temperature (35-45 °C) and pressure (50-90 MPa). The fatty acid composition and antioxidant activity of the extracted oil was also investigated. The highest yield of oil (29.2 ± 0.6%) was obtained under optimal SC-CO(2) extraction conditions (45 °C, 89.7 min and 32 MPa, respectively), which was significantly higher (p < 0.05) than that (25.3 ± 1.0%) given by Soxhlet extraction. Meanwhile, tea seed oil extracted by SC-CO(2) contained approximately 80% unsaturated fatty acids and showed a much stronger scavenging ability on the DPPH radical than that extracted by Soxhlet. SC-CO(2) is a promising alternative for efficient extraction of edible oil from tea seed. Moreover, tea seed oil extracted by SC-CO(2) is highly edible and has good antioxidant activity, and therefore may play a potential role as a health-promoting food resource in human diets.     

Rapid Salt‐Assisted Microwave Demulsification of Oil‐Rich Emulsion Obtained by Aqueous Enzymatic Extraction of Peanut Seeds

Aqueous enzymatic extraction (AEE) is an environmentally friendly edible‐oil‐extraction process that can also provide edible protein. However, the AEE process may form a stable emulsion in most cases, which seriously limits the large‐scale industry applications for producing vegetable oils. In this study, the salt‐assisted microwave radiation demulsification of the oil‐rich emulsion prepared with AEE from peanuts is investigated. The microwave demulsification method is compared with other conventional demulsification methods, including heating, and freezing–thawing. The salt‐assisted microwave demulsification of the emulsions shows a greater free oil yield than conventional heating demulsification. Moreover, the microwave demulsification shows a similar free oil yield in less time than freezing–thawing method. Under the optimal operating conditions of demulsification, the free oil yield can reach 92.3% with CaCl₂‐assisted microwave demulsification for only 2 min. In addition, the oxidative properties and the fatty acid compositions of the demulsified peanut oil are investigated. No significant difference in the fatty acid composition is observed among salt‐assisted microwave, freezing–thawing, and heating demulsified oil. The oxidative properties of the salt‐assisted microwave demulsified peanut oil is better than the conventional heating demulsified oil. Thus, salt‐assisted microwave demulsification provides a quick and effective demulsification method to obtain vegetable oils with high quality. Practical Applications: Aqueous enzymatic extraction (AEE) is an environmentally friendly edible‐oil‐extraction process. To solve the problem of stable emulsion formed during AEE process, the salt‐assisted microwave demulsification of the oil‐rich emulsion prepared with AEE is developed with high efficiency (demulsification for 2 min). In addition, the oxidative properties of the microwave demulsified oil is better than the conventional heating demulsified oil.     

Changes of vitamin E content in rice bran with different heat treatment

Oil yield from unheated rice bran was 17.6% whereas that of microwave‐heated rice bran increased to up to 18.4%. Content and composition of vitamin E in rice bran oil were affected by microwave heating. Especially, contents of α‐tocopherol, α‐tocotrienol, and γ‐tocotrienol as well as total vitamin E were significantly (P <0.05) increased when the rice bran was subjected to microwave heating for up to 30 s. When rice bran was heated in an electric roaster up to 20 min at 170 °C, 5 min at 180 °C, and 3 min at 190 °C, the total vitamin E content in rice bran oil increased significantly (P <0.05) followed by a considerable decline beyond those time points. Microwave heating was more effective for an increase in the vitamin E content than electric roaster heating. However, longer heating with both microwave and electric roaster caused a significant degradation of vitamin E resulting in a decreased content of total vitamin E.