红外光谱法鉴别天然肠衣真伪的研究

为了快速准确地鉴别天然肠衣,为天然肠衣提供可靠快速的检测手段。采用红外光谱法对天然肠衣进行测定,通过比较天然肠衣和样品肠衣的红外谱图的相似性和特定谱峰相似性,对样品肠衣的真伪进行鉴别。天然肠衣在3296、2961、2927、2852、1663、1558、1457、1403、1339、1240、1083、675cm-1处有较强的特征吸收峰。根据谱图对比分析和特征谱峰相似性能快速确定样品肠衣的真伪,红外光谱法可以作为天然肠衣真伪鉴别的一种快速检测方法。     

纺织用薄膜材料定性鉴别方法研究

采用手感目测法、显微镜法、燃烧法、溶解法、红外光谱法和差示扫描量热法对两种纺织用薄膜材料进行了定性分析。结果表明,手感目测法和显微镜法的结合可判定样品是否为薄膜材料,溶解法、红外光谱法和差示扫描量热法可定性鉴别纺织用薄膜材料的主要组成成分,该研究可以为纺织用薄膜材料提供定性鉴别的依据。     

衰减全反射傅里叶红外光谱在纤维鉴别中的应用

比较了纤维素纤维的衰减全反射红外光谱法(ATR)和溴化钾压片法测试的红外光谱图,两种制样方法得到的红外光谱图特征峰位置一致,特征谱带明显.用ATR测试了不同种类的纺织纤维的红外光谱,得到了常见纤维的衰减全反射红外光谱图,为单一纤维的定性鉴别奠定了基础.探讨了差谱分析技术在二组分混纺织物定性分析上的应用,分析了两种未知成分样品的衰减全反射红外光谱,在有效确定某一组分为参比光谱的基础上,利用差谱分析技术,能快速、有效地进行二组分混纺织物的定性分析.     

纤维定性鉴别的显微红外光谱法

红外光谱法是鉴别纤维的有效方法之一,难以通过手工拆分且难以用溶解法分离的混合纤维样品、微量的纤维样品等可以使用显微红外光谱法进行定性鉴别,该方法更为直接,是现有纤维定性鉴别方法的有效补充。通过采集单根纤维样品的红外光谱,可以定性鉴别纤维。     

红外光谱法检测食盐中微塑料研究

目的：建立食盐中微塑料红外光谱检测方法。方法：利用PS、PVC、PE、PP、PET和PA标准品建立微塑料红外光谱标准图谱。制备食盐样本及阳性模拟样品借助红外光谱仪寻找微塑料,将试验得到的图谱与标准图谱进行匹配度检测。结果：食盐样品中未发现微塑料颗粒,食盐阳性模拟样品检验结果显示,本方法的回收率在74%～96%,相对标准偏差RSD(n=6)为9.73%。将得到的谱图与标准谱图进行比对,6种微塑料的匹配度均大于74%。结论：红外光谱法可检测食盐中的微塑料,此方法操作简便,回收率高。本次试验为我国对食盐中微塑料检验技术奠定了基础。     

人造革与合成革类别及常用指标的检测研究

采用溶解法、红外光谱法、近红外光谱法对人造革与合成革种类的鉴别进行了研究,通过6种溶剂的考察,发现二氯甲烷可以作为鉴别PVC人造革与PU合成革的溶剂;采用近红外光谱法和红外光谱法,用QC比较检索算法建立的定性模型可以成功预测PVC人造革和PU合成革的种类,具有简单、快速、准确的特点。对人造革、合成革常用指标按照不同检测标准进行了试验,结果表明,摩擦色牢度采用纺织品测试方法更为合理;pH值、甲醛及禁用偶氮染料选用皮革的测试标准更为合适。     

红外光谱法检测聚氯乙烯塑料中的邻苯二甲酸酯

塑料食品包装材料的主成分为聚氯乙烯,同时需要添加部分塑化剂以改善塑料的加工性能和制品的柔韧性,如果食品包装材料中邻苯二甲酸酯类塑化剂含量超标,将对人体产生损害。基于食品安全的角度,国内外对食品包装材料中邻苯二甲酸酯类塑化剂的含量有明确限定。红外光谱法是一种根据样品红外特征法检测样品含量的一种非破坏性方法,能够对快餐盒中的邻苯二甲酸酯进行快速检测,以鉴定快餐盒的安全性,从而进一步保障公众的食品安全。     

傅立叶红外光谱(ATR)法鉴别塑料奶瓶

研究使用傅立叶红外光谱(ATR)法对PP和PC两种材质的塑料奶瓶快速鉴别的方法。利用ATR法对送检的两件塑料奶瓶样品进行鉴别。结果表明,ATR法具有分析时间短、样品需求量小,几乎不破坏样品,不消耗检材,快速简便,分析结果满意等优点。     

皮革的红外光谱与拉曼光谱鉴别方法

皮革的材质鉴别是皮革及皮革制品检测中的基础项目,现行标准中鉴别皮革类别的主要方法有感官法、显微镜法和扫描电镜法,研究中的方法还有红外光谱法、DNA鉴别法等。研究使用红外光谱法和拉曼光谱法鉴别人工革和天然皮革,结果表明红外光谱可用来区分天然皮革、聚氯乙烯人工革和聚氨酯人工革,使用ATR附件采集样品的红外光谱法方便快捷;拉曼光谱也可用来区分天然皮革、聚氯乙烯人工革和聚氨酯人工革,采集谱图过程方便快捷且不受样品中水分的影响,谱峰尖锐,易于识别。     

食品添加剂部分氢化木松香季戊四醇酯的测定与表征

建立了食品添加剂部分氢化木松香季戊四醇酯定性表征和定量分析方法。采用红外光谱法、环球法对部分氢化木松香季戊四醇酯进行定性分析,采用化学滴定法对其酸值进行定量分析,结果表明食品添加剂部分氢化木松香季戊四醇酯红外光谱与FCC标准谱图一致,软化点及酸值也符合FCC要求。     

固相微萃取-气相色谱-质谱法测定食品塑料包装袋中6 种酞酸酯类化合物

建立固相微萃取-气相色谱-质谱同时测定食品塑料包装袋中6 种酞酸酯类化合物的分析方法,并对固相微萃取方式、萃取溶剂、萃取头涂层、萃取温度等参数进行优化。采用85 μm PA固相微萃取纤维头、正己烷为萃取溶剂,90 ℃平衡5 min后萃取吸附30 min,在250 ℃进样口解吸5 min后供气相色谱-质谱分析。结果表明：该方法的线性范围为0.25～50 mg/L,方法检出限为0.049～0.920 mg/L,回收率为82.2%～109.0%,相对标准偏差（n=6）为4.0%～12.0%,该方法能很好地富集基体中的目标化合物,满足食品塑料包装袋中多种酞酸酯类化合物的分析要求。     

毛细管气相色谱法测定塑料包装及包装内食品中酞酸酯

建立了用毛细管气相色谱-氢火焰离子化检测器测定塑料食品袋及袋内包装食品中5种酞酸酯(邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二丁酯(DBP)、邻苯二甲酸二正辛酯(DOP)和邻苯二甲酸二(2-乙基己基)酯(DEHP))的方法。样品用无水乙醇超声提取,经干燥脱水过0.45μm滤膜过滤,直接注入气相色谱仪进行分析。用保留时间定性,外标法定量。5种酞酸酯的回收率为71.5%～125.5%;精密度(RSD)为1.6%～3.2%;DMP、DEP、DBP、DOP和DEHP的检测限分别为0.18、0.13、0.13、0.15和0.14ng。该方法准确度和灵敏度高,样品用量少,前处理简单,可同时测定塑料食品袋及包装内食品中5种酞酸酯。     

超声波萃取-气相色谱法测定塑料袋袋装食品中邻苯二甲酸酯

采用超声波萃取-气相色谱法测定经塑料食品袋盛装后食品中邻苯二甲酸酯(PAEs)含量。取烧饼、麻花和馒头样品用同种塑料食品袋与纸袋分别盛装30 min,进行检测。PAEs添加回收率在84．1％～107．8％之间,标准偏差在1．6％～6．7％之间。测定结果表明,经塑料袋盛装后食品PAEs含量均有不同程度提高:PAEs对温度高食品污染程度大;且PAEs对油脂含量高的食品污染程度比油脂含量低的污染程度大;PAEs对食品表面污染程度大于内部。     

Nanoclay migration from food packaging materials

A recent trend is to use nanocomposites materials for food-packaging applications. Different kinds of nanoparticles are incorporated into the polymers to improve their characteristics, and, among them, nanoclay is used to improve their barrier properties to gases. In this work, the results of migration studies with different food simulants (ethanol 10% and acetic acid 3%), temperatures and times (40ºC for 10 days and 70ºC for 2 h) from two commercialised LDPE nanocomposite bags are presented. The migration solutions thus obtained were analysed by ICP-MS to evaluate the amount of aluminium which migrated into the solutions both in dissolved form and as a part of nanoparticles. Aluminium migration was observed for both samples with a maximum migration value of 51.65 ng cm^–2 for the Aisaika bags and 24.14 ng cm^–2 for the Debbie Meyer bags. The presence of spikes working in single-particle mode using ICP-MS indicated that part of this aluminium was present as nanoparticles. The size and morphology of the nanoclay, in both the original material and the migration solutions, was studied by scanning electron microscopy coupled to energy-dispersive X-ray diffraction (SEM-EDX). In this manner, nanoparticles of different morphologies and sizes were found to migrate into the food simulants.     

Sensory methods and electronic nose as innovative tools for the evaluation of the aroma transfer properties of food plastic bags

Despite the key role of the sensory quality for food acceptance, the aroma transfer properties of food packaging materials have not yet been studied using sensory approaches. This research investigated the suitability of sensory and electronic nose methods to evaluate the aroma transfer properties of plastic materials that come in contact with food. Four (W, X, Y, and Z) commercial freezer bags (polyethylene) for domestic uses were compared. The degree of the aroma transfer through the materials was estimated as the sensory contamination of an odor absorber food (bread) by an odor releaser food (onion), separated by the bags and stored under frozen conditions. Bread samples were analyzed by means of an electronic nose, and 42 assessors used three different sensory methods (triangle, scoring, and partial sorted Napping tests). From the triangle test, none of the plastic bags acted as a complete aroma barrier, showing a sensory contamination of bread stored in all four materials. Partial sorting Napping results clearly described the sensory contamination of bread as “onion flavor”, due to the aroma transfer from the odor releaser food to the odor absorber food through the plastic bag. Scoring tests showed significant (p < 0.0001) differences of aroma transfer properties among the plastic bags, revealing the highest aroma permeation for W (3.1 ± 0.1), the lowest aroma transfer for X and Y (2.0 ± 0.1), and intermediate aroma transfer properties for Z (2.6 ± 0.1). Electronic nose data were in good agreement with the sensory responses, and a high correlation with the scoring data was observed (R² = 0.988). The presented approaches had suitable results to provide meaningful information on the aroma transfer properties of freezer plastic bags, and could advantageously be applied in the future for analyzing other finished food containers (e.g. plastic trays, boxes, etc.) or packaging materials of a different nature (multilayer plastic films, biodegradable materials, composites, etc.).     

The effect of multiwall Kraft paper or plastic bags on physico-chemical changes in milk powder during storage at high temperature and humidity

Plastic bags have recently been introduced as an alternative to multiwall Kraft paper bags in packaging milk powder in 25-kg sizes as it is thought that plastic bags are more durable and would preserve the quality of milk powders during storage better than paper bags. However, there is little scientific information available on the performance of plastic bags for milk powder storage. The aim of this study was to compare the properties of skimmed milk powder (SMP) packaged in plastic or paper bags. Commercially produced and packaged SMP in 25-kg plastic or paper bags was stored at 37°C and 90% relative humidity. Samples were analysed at intervals (0, 45, 90 and 135 days) for moisture, water activity, lactic acid content, pH, insolubility index, bulk density, flowability, dispersibility and particle size. The magnitude of change in the majority of SMP properties measured during storage suggests that plastic bags are similar to paper bags in maintaining milk powder quality during storage.     

Sorghum seed storage in Purdue Improved Crop Storage (PICS) bags and improvised containers

Seed storage is a major challenge for smallholder farmers in developing nations. Purdue Improved Crop Storage (PICS) bags effectively control the postharvest insect pests of cowpea and other crops. Farmers, encouraged by this success, have begun to expand the use of PICS bags for storing other crops. Little is known about how sorghum seed, one of these important crops, fares when stored under hermetic conditions. Accordingly, we stored sorghum seed for six months in either airtight containers (PICS bags or sealed plastic bottles) or open ones (woven polypropylene bags and open plastic bottles). Overall, sorghum seed stored in PICS bags and in sealed plastic bottles maintained its initial moisture level, germination rate and seed weight. Porous polypropylene bags and open plastic bottles lost moisture over six months. We conclude that sorghum seed can be safely stored in hermetic containers without any loss of quality for extended periods of time.     

环保纺织品购物袋的发展及性能研究

介绍了各国对塑料袋使用的规定以及各国环保纺织品购物袋的应用，并对环保纺织品购物袋与传统塑料袋的机械拉伸、撕裂和顶破强力进行数据测试，通过试验结果分析，对环保纺织品购物袋的机械性能进行了讨论、总结。     

超声波辅助解冻对南极磷虾品质及其后续冷藏特性的影响

为研究超声波辅助解冻对南极磷虾品质及其后续冷藏特性的影响,采用网袋和塑料袋两种方式包装冷冻南极磷虾虾块,分别进行静水解冻和超声辅助解冻,并通过感官评分、微生物生长情况、硬度、总挥发性盐基氮（total volatile basic nitrogen,TVB-N）含量、多酚氧化酶（polyphenol oxidase,PPO）和胰蛋白酶活力以及低场核磁共振氢质子信号强度等指标,分析南极磷虾解冻后的冷藏特性。结果表明,网袋包装和塑料袋包装的静水解冻时间分别为105 min和145 min,而超声波辅助解冻分别耗时65 min和75 min,解冻效率较高。各组样品解冻后在4℃冷藏条件下贮藏24 h后感官评分下降至不可接受值;解冻前、后及冷藏28 h内菌落总数均低于2.5(lg(CFU/g)),PPO活力、胰蛋白酶活力呈先升高后降低趋势,TVB-N含量持续上升;冷藏期间网袋包装南极磷虾品质劣变较塑料袋包装缓慢。综上,网袋包装的超声波辅助解冻不仅可以加快解冻速率,还兼具清洗作用,有利于提高磷虾的耐贮藏性。     

Effect of Packaging Material on Nitrate Nitrogen Content of Irradiated Potatoes

The effect of packaging materials on nitrate nitrogen content of irradiated potatoes was investigated. Tubers were irradiated at 10, 30 and 100 Krads and stored for 12 wk at 5°C in paper or plastic bags. Nitrate nitrogen content was significantly (p < 0.01) higher in tubers packaged in plastic as compared to those in paper bags. Irradiation significantly (p < 0.01) increased nitrate nitrogen content between the lowest and highest levels of treatment in tubers stored in both paper and plastic bags.