基于紫外可见光谱技术和色素组成区分橄榄油与其他食用油

目的 通过紫外可见光谱技术和色素组成,探究区分橄榄油与其他食用油的方法。方法 选择市售橄榄油(特级初榨橄榄油、混合橄榄油)和其他食用油(菜籽油、玉米油、葵花籽油、大豆油、花生油、调和油)作为研究对象,分别在220~800 nm的波长范围内进行全光谱扫描以及在波长为450 nm和670 nm处进行光度测量;通过比较不同食用油的紫外可见吸收光谱并结合主成分分析(principal component analysis, PCA)和偏最小二乘法判别(partial least squares discriminant analysis, PLS-DA)对不同橄榄油和其他食用油进行比较区分。结果 通过观察比较各食用油紫外可见吸收光谱的最大吸收波长所在位置,可以对不同食用油进行初步区分。并且PCA和PLS-DA结果显示,以波长450 nm和670 nm处的吸光度A450和A670以及A450/A670为变量,可用于区分不同橄榄油和其他食用油。结论 基于紫外可见光谱技术对不同食用油中色素的检测结果可以对食用油进行分类,并且A450、A670和A450/A670可以作为区分橄榄油与其他食用油的标记。     

红外和紫外可见分光光谱法初步鉴别餐饮废油

目的建立简便、快速的餐饮废油、生物柴油以及合格食用油的鉴别检测方法。方法选择市售普通食用油、餐馆用油、生物柴油和餐饮废油(包括潲水油和煎炸老油)为研究对象,以1745 cm-1波数处的共有吸收峰为基准,比较各油脂红外光谱特征吸收峰相对强度;在230~800 nm范围内,比较各油脂的紫外可见吸收曲线,对油脂品质进行比较鉴别。结果比较红外图谱发现,各油脂在3473、3008、1652 cm-1附近对1745 cm-1的吸收峰相对强度差别较大,可以此作为判别依据;通过观察比较各油脂在紫外可见光谱图中的起始和终止吸收波长,以及在668 nm处是否有较高的吸光度或特征吸收峰,可对油脂品质进行鉴别。结论综合红外和紫外可见两种光谱方法的检测结果,本方法可初步地快速鉴别合格食用油与餐饮废油。     

食用油抗紫外包装的研究

针对普通透明的聚对苯二甲酸乙二醇酯(PET)包装瓶难于解决食用油脂中VA在遇光照紫外线后分解流失的问题,本研究通过在普通PET瓶中添加不同种类及不同比例的抗紫外助剂,并通过对配方设计分析及紫外通过率分析,最终得出具有最佳抗紫外效果的包装材料。在不同的储存期经过对抗紫外包装材料内的油品质及VA的变化情况的比对验证,得出选用UV370助剂,添加比例为1.5%,此配方包材能使含有VA的食用油在18个月后VA留存率在77%以上。     

包装材料领域：食品塑料包装占巨大市场份额

美国麦利肯（Milliken）化工公司日前推出PET瓶用紫外吸收剂ClearShield，该产品是专门用于PET包装的均相液体聚合物，能阻挡波长390nm以内的所有紫外线。该产品使用方便，可直接使用，不需进一步配混成液体或固体母料，可以在成型时与树脂一起加入或在预成型阶段时加入。加入ClearShield的PET，注塑和吹塑成型时，不会产生弄脏设备的积垢，也不会延误生产时间。这种产品为透明聚合物，不影响PET瓶的透明性、光泽和瓶子质量，已被美国食品药品管理局（FDA）认可，适用于大部分食品和饮料的包装。     

一种食用油锁养保鲜生产工艺

为了解决食用油在储存过程中因发生各种变化而造成的品质下降问题,介绍了一种食用油的锁养保鲜生产工艺,包括全工段恒温灌装、充氮灌装和抗紫外瓶包装。实践证明,全工段恒温灌装有效避免了灌装油温过高产生负压造成的瓶内缩吸瘪,减少了标签不平整情况的发生;充氮灌装使食用油包装瓶内顶空残氧量低于6%,产品残氧量指标稳定;以色母为抗紫外助剂,制成的食品级食用油包装瓶可防止紫外线对食用油品质的影响。采用此生产工艺,可以有效提高食用油的品质并延长储存期。     

基于紫外光谱的花生油掺伪检测

为建立一种花生油掺伪检测方法,利用花生油和其他食用油在紫外光谱特征吸收峰不同,建立定量检测模型及并对模型进行验证分析。结果表明：花生油与其他食用油在280nm处特性吸收存在差异性,利用这一特性建立花生油掺伪定量分析模型,其方程为y＝46.72x－27.51(y为掺伪比例/%;x为吸光度),相关系数为0.9779,标准差为3.099%。盲样验证预测值与实际掺伪值高度线性相关,相关系数为0.9841,标准差为3.849%,检出限约为10%,相对误差均小于15%。紫外光谱花生油掺伪快速检测方法是可行的。     

四种食用油共轭脂肪酸含量的比较

食用油中共轭脂肪酸的含量非常重要,他既是不饱和脂肪酸,又是必需脂肪酸,具有多种生理功能,是食用油营养价值评价重要因素之一。通过对几种市面上常见食用油甲酯化处理,比较其紫外吸收值,分析几种食用油共轭脂肪酸的含量高低,为人们对食用油的选择提供一个依据。     

UV-365光对不同瓶装大豆油酸价和过氧化值的影响

将紫外吸收剂UV-326引入PET容器中来减慢油脂氧化,以大豆油的酸值和过氧化值为指标,研究分析了一级大豆油分装在不同瓶体中其过氧化值、酸价随光照温度、光照时间、电流强度变化的基本规律,并对添加0.4%吸收剂UV-326的PET食用油瓶作油脂迁移实验。结果表明:紫外吸收剂UV-326在迁移达到平衡时的迁移量为14.85mg/kg,PET中紫外吸收剂对包装油脂食品风险很小,添加0.4%吸收剂UV-326的PET食用油瓶对紫外光有屏蔽作用,可降低大豆油脂的氧化程度。     

全冠机械——符合绿色环保的全电式吹瓶机

全冠(福建)机械工业有限公司,作为在PET全自动吹瓶设备专业制造公司,可以为客户提供PET瓶整厂规划,从瓶胚设计到吹瓶成型,为客户提供完整的服务,产品涉及汽水矿泉水瓶、果汁瓶、酒类瓶、食用油瓶、网球罐、农药瓶、化妆品瓶等宝特瓶吹瓶机,瓶子容量从50mL到20L,在包装饮料、食用油、食品、药品     

烷基酚聚氧乙烯醚的紫外光谱定性与定量分析

为探索烷基酚聚氧乙烯醚(APnEO)光谱检测方法,对壬基酚聚氧乙烯醚(NPEO)和辛基酚聚氧乙烯醚(OPEO)的紫外吸收特性进行比较研究.结果表明:NPEO、OPEO的紫外吸收光谱没有明显的差别,在275、224 nm附近均有特征吸收峰,可用于进行烷基酚聚氧乙烯醚的定性和定量分析;224 nm处的吸收,定量测定的灵敏度...     

植物防紫外线整理剂性能研究

对8种常见天然植物进行紫外线吸收剂的提取,并对提取液进行了紫外吸收光谱特性分析,确定了防紫外线整理剂的最佳方案。对真丝织物先用金属离子络合,再用防紫外线整理剂浸渍整理,测试其防紫外线性能。实验结果表明,不同植物提取液对紫外线的吸收效果不同,可选择黄柏、蒲公英和绿茶3种植物来制备防紫外线复配液,经其处理的丝织物防紫外线能力明显增强,该复配液可作为一种天然的紫外线吸收剂应用在纺织品上。     

大豆油阻湿包装的研究

针对一级大豆油在贮运过程中存在水分及挥发物含量不断升高这一问题,通过在PET中共混PEN的方法来改善原有PET油瓶的防潮功能。采用DSC方法对PET、PEN共混相容性进行试验分析。用扫描电镜对不同生产工艺条件下制得PET/PEN共混瓶坯的微观结构进行分析比较。试验通过对96g 5LPET和PET/PEN共混透明瓶透湿率的测定,同时对这两种瓶装一级大豆油进行加速试验,考察包装内一级大豆油水分及挥发物含量和油本身酸价的变化。结果表明,PET/PEN共混瓶可以有效提高原有PET瓶对油包装的阻湿性能。     

食用油掺伪餐饮业废油脂鉴别检测方法研究进展

综述了食用油掺伪餐饮业废油脂的鉴别检测方法。通过对油脂的常规理化指标、金属离子含量、电导率、十二烷基苯磺酸钠(SDBS)、黄曲霉毒素、挥发性物质、脂肪酸组成、胆固醇、红外及紫外特征吸收等指标进行定性定量分析,可以鉴别食用油是否掺伪。     

Evaluation of polyethylene terephthalate as a packaging material for premium quality whole pasteurized milk in Greece

Chemical, microbiological, and sensorial changes in premium quality whole pasteurized milk stored at 4 °C under fluorescent light for one day followed by storage in the dark for an additional 12 days was studied. Milk containers tested included 1 l bottles made of (a) clear PET + UV blocker, 350–400μm in thickness bearing a transparent label, (b) clear PET + UV blocker, 350–400 μm in thickness bearing a white colored label, (c) clear PET 350–400 μm in thickness. Milk packaged in 1 l coated paperboard cartons and stored under the same experimental conditions served as the “commercial control” sample. Data were obtained for lipid oxidation, lipolysis, proteolysis, vitamin A, E, and riboflavin content, microbial growth including mesophilic and psychrotrophic counts and sensorial attributes (odor and taste) of whole pasteurized milk. Results showed satisfactory protection of milk packaged in all containers with regard to microbiological and chemical parameters assessed over the 13 day period. Based on sensory analysis, the shelf life of premium quality whole pasteurized milk tested in the present study was 10–11 days for samples packaged in clear PET+UV bottles and 9–10 days for clear PET bottles and paperboard cartons. Vitamin A losses recorded after 10 days of storage were respectively 15.9, 20.6, and 14.3% for samples packaged in clear PET+UV protected bottles, clear PET, and control samples. Respective losses for Vitamin E were 26.4, 36.6, and 35.0% and for riboflavin 32.9, 38.3, and 32.5%. Clear PET + UV provided equal or better protection to milk as compared to the paperboard carton. Clear PET was the least effective in retaining light-sensitive vitamins. Based on spectral transmission curves of packaging materials tested, it is suggested that the use of a UV blocking agent in combination with a dark color pigmentation (blue, green etc.) in fresh milk packaging will provide a better protection to light-sensitive vitamins in cases where the expected shelf life of milk exceeds 5–6 days.     

Influence of PET and PET/PEN Blend Packaging on Ascorbic Acid and Color in Juices Exposed to Fluorescent and UV Light

ABSTRACT: Apple and orange juices packed in polyester bottles were stored in dark, intense fluorescent (1500 lux), and UV light conditions in temperature-controlled (22 °C) chambers and monitored more than 7 mo for ascorbic acid content and color changes. Polyester beverage bottles were made of polyethylene terephthalate (PET), or PET blended with 0.25%, 1%, and 4% polyethylene naphthalate (PEN). The cut-off wavelength ranged from 322 nm for PET to 373 nm for the 4% PEN/PET blend. Spectral irradiance, visible light intensity, and light distribution were evaluated in the light chambers and compared with supermarket display lighting and outdoor daylight conditions. Only the UV chamber and sunlight showed significant irradiance at wavelengths below 400 nm. Ascorbic acid (AA) degradation and concurrent color changes occurred in both juices during storage in all 3 lighting conditions and in all 4 bottle types. Zero-order reaction kinetics described the AA degradation rate for all treatments. Apple juice stored in UV had a significantly higher ( P < 0.05) AA degradation rate than juice stored in the dark or in fluorescent light. Under UV conditions, apple juice in PET/ PEN bottles had a lower AA degradation rate than the juice in PET bottles. AA degradation in orange juice was less affected by UV exposure than in apple juice. Both juices darkened over time when stored in dark and fluorescent conditions, whereas UV exposure caused some initial bleaching of color before darkening. The bleaching effect was reduced in apple juice stored in the PET/PEN bottles.     

Evaluation of polyethylene terephthalate as a packaging material for premium quality whole pasteurized milk in Greece

Chemical, microbiological and sensorial changes in premium quality whole pasteurized milk stored at 4 °C under fluorescent light was studied for a period of 13 days. Milk containers tested included 1 l bottles made of (a) clear PET + UV blocker, 350–400 μm in thickness bearing a transparent label, (b) clear PET + UV blocker, 350–400 μm in thickness bearing a white colored label, (c) clear PET 350–400 μm in thickness. Milk packaged in 1 l coated paperboard cartons and stored under the same experimental conditions served as the “commercial control” sample. Data were obtained for lipid oxidation, lipolysis, proteolysis, vitamin A, E and riboflavin content, microbial growth including mesophilic and psychrotrophic counts and sensorial attributes (odor and taste) of whole pasteurized milk. Results showed satisfactory protection of milk packaged in all containers with regard to microbiological and chemical parameters assessed over the 13-day period. Based on sensory analysis, the shelf life of premium quality whole pasteurized milk tested in the present study was 10–11 days for both samples packaged in clear PET + UV bottles and in paperboard cartons and 8–9 days for clear PET bottles. Vitamin E losses recorded after 10 days of storage were respectively 42.7, 53.6 and 43.9% for samples packaged in clear PET + UV protected bottles, clear PET and control samples. Respective losses for riboflavin were 38.7, 52.5 and 35.0%. Average losses for vitamin A were 20.6% for all packaging materials. Clear PET + UV provided equal or better protection to milk as compared to the paperboard carton. Clear PET was the least effective in retaining light-sensitive vitamins. Based on spectral transmission curves of packaging materials tested, it is suggested that the use of a UV blocking agent in combination with a dark color pigmentation (blue, green etc.) in fresh milk packaging will provide a better protection to light-sensitive vitamins in cases where the expected shelf life of milk exceeds 5–6 days.     

机织物孔隙率的测试方法及对紫外性能的影响

通过理论计算和透气率的比较,找出了一种新的方法,可以直观而有效地分析各种织物的孔隙率.同时,分析了孔隙率与织物的防紫外性能之间的关系.研究表明:图像处理方法测试的孔隙率具有很好的重现性.孔隙率和紫外透过率之间存在着线性关系,孔隙率越大,紫外透过率越大,相应的紫外防护性能就越差.     

新型PET瓶盖杀菌系统的研究与开发

PET瓶超净及无菌灌装技术已成为饮料行业的发展趋势。目前在PET生产线上对瓶盖的杀菌方式主要有紫外线杀菌、倒瓶热力杀菌、化学药剂杀菌等,都存在着杀菌不彻底或者收集处理困难以及成本高等问题。在研究各类杀菌方式、特点的基础上,文章提出了通过过氧化氢喷雾＋无菌热空气激发＋高强度紫外线结合杀菌的理论,开发一种杀菌彻底,残留少的新型PET瓶盖在线杀菌系统。