纳米活性果蔬保鲜膜的制备研究

以LDPE/LLDPE为基体材料,添加B型纳米活性分子筛,考察其对包装膜物理性能、力学性能和透气、透湿性能的影响.结果表明:保鲜包装膜的拉伸强度下降,撕裂性能、抗摆锤冲击强度和热封强度上升;保鲜膜的透明性有所下降.保鲜膜的透气和透湿性能大幅提高,非常利于果蔬的保鲜.     

纳米活性果蔬保鲜膜的制备研究

以LDPE/LLDPE为基体材料,添加B型纳米活性分子筛,考察其对包装膜物理性能、力学性能和透气、透湿性能的影响。结果表明:保鲜包装膜的拉伸强度下降,撕裂性能、抗摆锤冲击强度和热封强度上升;保鲜膜的透明性有所下降。保鲜膜的透气和透湿性能大幅提高,非常利于果蔬的保鲜。      

PU膜层压水刺黏合衬的加工工艺研究

以粘胶纤维水刺黏合衬、TPU和PU膜为材料,采用层压的方式制备复合织物,分析了黏合衬、PU膜及复合织物的强伸性、悬垂效果、透气透湿及防水效果,以TPU用量、温度及复合压力为变化参数探讨其对复合织物服用性能的影响.研究结果表明:黏合衬与PU膜复合后,复合织物的拉伸断裂强力变化较大,但悬垂性变化较小,而防水效果有所改善,透湿、透气效果比高透PU薄膜要小,综合而言,当TPU用量为15 g/m2、复合压力为5 MPa、复合温度为75℃时,复合织物的各项性能都比较好.     

纳米银/低密度聚乙烯复合食品包装薄膜的表征及性能

将纳米银(Ag)或助剂(光稳定剂783、抗氧剂B900)通过熔融共混的方法添加到低密度聚乙烯(low density polyethylene,LDPE)基材中,再通过挤出机造粒,吹膜机吹塑成薄膜,即制得纳米Ag/LDPE复合食品包装薄膜。借助扫描电子显微镜(Scanning Electron Microscope,SEM)分析了薄膜中纳米银的粒径分布情况;借助原子力显微镜(Atomic Force Microscope,AFM)分析了薄膜的表面微观形貌;对薄膜的力学拉伸性能、透湿性能、透光性、颜色做了相关的测试分析。结果表明,添加纳米银或光稳定剂783、抗氧剂B900会增加LDPE膜的粗糙度,降低LDPE膜的透光性;添加纳米银降低薄膜的断裂伸长率,增加LDPE膜的粗糙度,且使材料颜色偏暗偏黄;所添加的助剂对材料的颜色无影响,但会增加膜的粗糙度。      

生姜精油微胶囊薄膜包装对秋葵保鲜效果的影响

采用壳聚糖-明胶为壁材,以生姜精油为芯材,通过喷雾干燥的方法制备生姜精油微囊,并将其作为抗菌剂加入低密度聚乙烯(low-density polyethylene,LDPE)和乙烯-醋酸乙烯酯(ethylene-vinyl acetate,EVA)中,通过共混挤出、挤出流延工艺制备聚乙烯-生姜精油微囊活性包装。通过扫描电子显微镜测定添加有生姜精油微囊的LDPE/EVA薄膜微观结构,研究微囊的添加对LDPE/EVA薄膜性能的影响,并以空白LDPE/EVA薄膜及添加有壳聚糖-明胶微球的LDPE/EVA薄膜为对照,对秋葵进行保鲜实验。结果表明,生姜精油微囊加入后LDPE/EVA薄膜完整性良好,微囊的加入使薄膜透湿性增强[(2. 60±1. 607) g/(m·Pa·s)],透氧性增加[(3 166. 75±4. 98) cm³/(m²·24 h·0. 1 MPa)]。含有生姜精油微囊的LDPE/EVA薄膜相较于对照组能在4℃的贮藏条件下有效调控包装袋中气体含量(生姜精油微囊组12 d时O₂与CO₂体积比接近...     

海泡石填充PE保鲜膜的研制及其在平菇保鲜中的应用

以LDPE/LLDPE(4:1)为基材,选择具有调湿性能的酸活化海泡石为无机填充剂,针对改善薄膜的透气性和透湿性,制备了不同添加量的海泡石PE保鲜膜.结果表明:随着海泡石添加量的增多,薄膜的拉伸强度和断裂伸长率不断降低,但薄膜的透氧率和透湿性能得到改善.通过对平菇保鲜实验,证明酸活化处理的海泡石填充膜对平菇的保鲜效果优于未包装的对照组.以填充40份酸活化处理的海泡石填充膜包装的平菇保鲜效果最好,其包装的平菇的呼吸高峰出现最晚,且呼吸峰值最低(383.6mL/kg·h),第6d的失重率为5.34%,在15℃左右下可保鲜7d,比未包装的对照组延长了5d.     

海泡石填充PE保鲜膜的研制及其在平菇保鲜中的应用

以LDPE/LLDPE(4:1)为基材,选择具有调湿性能的酸活化海泡石为无机填充剂,针对改善薄膜的透气性和透湿性,制备了不同添加量的海泡石PE保鲜膜。结果表明:随着海泡石添加量的增多,薄膜的拉伸强度和断裂伸长率不断降低,但薄膜的透氧率和透湿性能得到改善。通过对平菇保鲜实验,证明酸活化处理的海泡石填充膜对平菇的保鲜效果优于未包装的对照组。以填充40份酸活化处理的海泡石填充膜包装的平菇保鲜效果最好,其包装的平菇的呼吸高峰出现最晚,且呼吸峰值最低(383.6mL/kg.h),第6d的失重率为5.34%,在15℃左右下可保鲜7d,比未包装的对照组延长了5d。      

高透聚氨酯薄膜层压罗纹针织物服用性能研究

以2+2双罗纹针织物、热熔胶TPU和高透PU膜为原材料,采用层压复合的方法制备防水透湿复合织物,分析双罗纹针织物、高透PU膜及复合织物的拉伸性能、悬垂性、透气性,以及防水透湿效果,并通过改变TPU用量、温度及复合压力探讨对复合织物各项性能的影响。研究结果表明:双罗纹针织物与PU膜复合后,复合织物的强伸性有所提高,但悬垂性有所降低,防水效果明显比双罗纹针织物要好,透湿、透气效果比高透PU薄膜小一些。综合而言,当TPU用量为32 g/m2,复合压力为8 MPa,复合温度为80℃时,复合织物的复合效果最好。     

如何获得软包装材料最准确的热封性能

1软包装封口强度封口强度是包装材料的一个重要性能指标。任何一种软包装材料都要被做成包装袋来包装各种商品,商品包装又都要采用热封或粘接来封口,达到包装目的。封口要有一定的强度才能够承受一定重量的内装物的压力,保证商品在流通过程中不开裂。热封是利用外界条件(电加热、超声波等)使塑料薄膜的封口部位变成黏流状态,借助刀具压力使薄膜融合为一体,冷却后才能保持一定的强度。热封工艺有三大因素:热封温度、压力和时间,其中主要是温度。根据材料的不同和料袋的运动状态需要不同的热封因素,三者必须协调配合才能获得较好的热封参数。…     

添加PBAT的PLA/PHB复合材料的性能研究

为探讨添加不同比例的PBAT对PLA/PHB复合薄膜性能的影响,将PBAT按一定比例与PLA/PHB共混,采用挤出吹塑法制得薄膜并测定其DSC、SEM、力学性能、透湿、透氧性能及其可降解性能。结果表明,PBAT含量为10%时,薄膜的透湿、透氧性能最好;PBAT含量为20%时,拉伸强度由原来的35.86MPa下降到20.75MPa,降幅达42%;而断裂伸长率随PBAT含量增加而增大;此外,其降解失重率也随PBAT含量的增大而变大。按一定比例在PLA/PHB中添加PBAT可以改善材料的性能。     

Effect of Pasteurization, High-Pressure Processing, and Retorting on the Barrier Properties of Nylon 6, Nylon 6/Ethylene Vinyl Alcohol, and Nylon 6/Nanocomposites Films

ABSTRACT:  This study determined the impact of pasteurization, high-pressure processing (HPP), and retorting on the barrier properties of nylon 6 (N6), nylon 6/ethylene vinyl alcohol (N6/EVOH), and nylon 6/nanocomposite (N6/nano) materials. The pasteurized and high-pressure treated films were coextruded with low-density polyethylene (PE) as the heat-sealing layer. The retorted films were coextruded with polypropylene (PP). Oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) of the samples were measured after pasteurization (75 °C for 30 min), HPP (800 MPa for 10 min at 70 °C), and retorting (121 °C for 30 min) treatments. These were compared with the thermal characteristics and morphologies of the samples using differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Results showed that OTR of N6 and N6/Nano increased after HPP (16.9% and 39.7%), pasteurization (13.3% and 75.9%), and retorting (63.3% and 112.6%), respectively. For N6/EVOH, a decrease in OTR after HPP (53.9%) and pasteurization (44.5%) was observed. The HPP treatment increased the WVTR of N6 (21.0%), N6/EVOH (48.9%), and N6/Nano (21.2%). The WVTR of N6, N6/EVOH, and N6/Nano increased by 96.7%, 43.8%, and 40.7%, respectively, after pasteurization. The DSC analyses showed that the enthalpy and percent crystallinity increased (2.3% to 6.5%) in the N6/Nano when compared with the N6 material after each treatment. Retorting caused a decrease (3.5%) in the percent crystallinity of the polypropylene material. HPP did not cause major morphological changes to the samples. Results of the barrier studies were influenced by the crystallinity changes in the materials as seen in the XRD diffractograms.     

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     

超高压对低盐海藻鸡肉糜品质的影响

为探究超高压对低盐海藻鸡胸肉糜的影响,考察了不同压力（0.1～500 MPa/10 min）和保压时间 （0～25 min/300 MPa）时肉糜的色泽、盐溶蛋白溶解度、蒸煮损失率、持水性、冻融损失率、质构以及流变特 性的变化规律。结果表明：随着压力的升高,肉糜亮度（L*）和白度（W）先降低后增加,在200 MPa时最低, 红度（a*）逐渐上升;100～300 MPa超高压处理对盐溶蛋白溶解度无显著影响（P＞0.05）,压力大于300 MPa 时盐溶蛋白溶解度显著降低（P＜0.05）;蒸煮损失率和冻融损失率随压力的升高呈先降低后增加趋势,在压力 为300 MPa时达到最低值;与0.1 MPa处理组相比,100～500 MPa压力处理使肉糜持水性显著升高（P＜0.05）; 硬度和弹性随着压力的增加先升高后降低,在200～300 MPa时达最大值,200、300 MPa处理组间无显著差异 （P＞0.05）;与0.1 MPa处理组相比,超高压处理能够改善海藻鸡胸肉糜的储能模量（G’）和相位角正切值 （tan δ）。保压时间对低盐海藻鸡胸肉糜色泽、盐溶蛋白溶解度、蒸煮损失率无显著影响（P＞0.05）;随着保压 时间的延长,肉糜的持水性、G’、tan δ值和质构得到改善,但保压时间过长（25 min）可破坏肉糜的硬度和弹性。 本研究表明超高压处理能够改善低盐海藻鸡胸肉糜的品质,为新型肉制品的开发提供了理论依据。     

Effect of High-Pressure Food Processing on the Physical Properties of Synthetic and Biopolymer Films

ABSTRACT:  The effect of high-pressure processing on 2 plastic food packaging films, a biopolymer (PLASiOx/PLA) and a synthetic polymer (PET-AlOx), was studied. Samples in direct contact with olive oil, as a fatty food simulant, and distilled water, as an aqueous simulant, were subjected to a pressure of 500MPa for 15 min at 50 °C. The mechanical, thermal, and gas barrier properties of both films were evaluated after the high-pressure processing (HPP) and compared to control samples that have not undergone this treatment. Significant changes in all properties were observed in both films after the HPP treatment and in contact with the food simulants. In both films an induced crystallization was noticed. In the PLASiOx/PLA film the changes were larger when in contact with water that probably acted as a plasticizer. In the PET-AlOx film the changes in properties were attributed to the formation of pinholes and cracks during the HPP treatment. In this film, most of the properties changed more in the presence of oil as the food simulant.     

木薯淀粉对改善可食性羧甲基纤维素膜性能的研究

文中对木薯淀粉改善可食性羧甲基纤维素膜的性能进行研究。结果表明:随着木薯淀粉添加量的增多,羧甲基纤维素膜的抗拉强度和水溶性逐渐减小,而断裂伸长率和透明度逐渐增大,透油率变化不大。当木薯淀粉的添加质量在0%-15%内,随着木薯淀粉添加量的增大,膜的水蒸气迁移率逐渐减小,当添加量超过15%时,膜的水蒸气迁移率逐渐增大。综合膜的各项性能得出,木薯淀粉的添加量不宜超过15%。     

Effects of High-Pressure Processing on the Cooking Loss and Gel Strength of Chicken Breast Actomyosin Containing Sodium Alginate

The effects of high-pressure processing (HPP) (0–400 MPa for 10 min) on the cooking loss (CL), gel strength, and thermal gelling mechanism of chicken breast actomyosin solution containing 0.5 % (w/v) sodium alginate (AS-SA) were investigated. The results showed that HPP could significantly increase (P?相似文献   

Effect of high pressure treatment on the quality of rainbow trout (Oncorhynchus mykiss) and mahi mahi (Coryphaena hippurus)

ABSTRACT:  High pressure processing (HPP) is becoming a promising seafood preservation method. The objective was to investigate the effect of HPP on quality of rainbow trout and mahi mahi during cold storage. Skinless fillets treated with different pressures (150, 300, 450, and 600 MPa for 15 min) and stored at 4 °C were analyzed at 1, 3, and 6 d storage. Red muscle was analyzed for lipid oxidation products by measuring thiobarbituric reactive substances (TBARS) and whole muscle was analyzed for total aerobic count, texture profile analysis, and color. A pressure of 300 MPa effectively inactivated the initial microbial population in rainbow trout (6-log reduction). However, inactivation of the initial population on mahi mahi was only about 4-log reduction at the same pressure. Microbial growth was significantly retarded after HPP. Color results showed that redness ( a * value) of rainbow trout at 300 MPa and above was significantly ( P < 0.05) lower compared to mahi mahi. TBARS values for rainbow trout increased with increased pressure, whereas the same trend was not seen for mahi mahi where maximum oxidation was found at 300 MPa and then declined. This study demonstrates the usefulness of HPP in seafood processing and the influence of species variation on processing parameters. The optimum HPP conditions for influencing lipid oxidation, microbial load, and color changes were found to be 300 MPa for rainbow trout and 450 MPa for mahi mahi.     

Application of high pressure processing for extending the shelf-life of sliced raw squid

This study was designed to evaluate the effect of high pressure processing (HPP) on the microbiological safety and quality of sliced raw squid during refrigerated storage. The sliced and vacuum-packed raw squid samples were treated at 200, 300, and 400 MPa for 20 min by using a custom-made high pressure processor. The numbers of psychrotrophic bacteria in the sliced raw squids treated at 200, 300, and 400 MPa were reduced by 0.5, 2.5, and >4.7 log CFU/g, respectively. The amounts of trimethylamine (TMA) produced in the sliced raw squids were reduced by 20, 33, and 51% at 200, 300, and 400 MPa, respectively, as compared to the control. The amount of total biogenic amines (BAs) in the control significantly increased up to 1.70 mg/g after 10 days of refrigerated storage, while that in the 400 MPa-treated squid sample gradually increased up to 1.33 mg/g. The autolytic activity values in the control, 200, 300, and 400 MPa-treated squid samples were 4.70, 2.28, 2.18, and 1.55 nkat/g, respectively, after 20 days of refrigerated storage. The HPP effectively retarded the microbial growth, TMA formation, autolytic activity in the sliced raw squids. Therefore, the HPP could be used as an effective processing tool for improving microbiological safety and quality of seafood.     

超高压处理对鲜切马铃薯质地及细胞壁多糖含量的影响

本文旨在探究鲜切马铃薯的质地随压力变化的规律及质地改变的机制。研究了超高压(HPP,100~600 MPa,10 min)对鲜切马铃薯色泽、硬度、咀嚼度、细胞壁相关酶活及多糖组成的影响。结果表明,HPP在压力≥ 500 MPa下对鲜切马铃薯的褐变抑制较好,300 MPa时褐变严重且程度高于空白。HPP相较传统热处理,能够更好的保持鲜切马铃薯的硬度及咀嚼度;但相比空白,HPP处理后硬度均有不同程度的下降,其中300 MPa时硬度下降最大,达到500 MPa时,硬度出现回升,咀嚼度在该压力下同样存在回升现象。HPP在一定程度上改变了马铃薯细胞壁相关酶活性及多糖含量,果胶甲酯酶(PME)活性在压力≤ 500 MPa具有稳定性,同时HPP可抑制多聚半乳糖醛酸酶(PG)和内切β-葡聚糖酶(Cx)活性,在压力100、500、600 MPa下提高β-葡糖苷酶及外切β-葡聚糖酶(C₁)活性;相比空白,HPP处理后鲜切马铃薯纤维素(CEL)、碱溶性果胶(NSF)、螯合性果胶(CSF)含量显著(P<0.05)提高,其中CSF含量在300 MPa下显著(P<0.05)低于空白水平,水溶性果胶(WSF)含量在100、600 MPa下显著(P<0.05)下降,其余压力下无显著变化,而经HPP处理后鲜切马铃薯半纤维素(HC)含量均显著(P<0.05)下降。经相关性分析,HPP处理后马铃薯硬度、咀嚼度与CSF、NSF、CEL含量呈显著或极显著正相关(P<0.05或P<0.01),与WSF含量呈极显著(P<0.01)负相关,与HC含量相关性不显著,PME活性对其质构指标影响较大。综上,超高压处理后细胞壁多糖组成及含量变化影响了鲜切马铃薯的质地。     

Effect of food ingredients and selected lipids on the physical properties of extruded edible films/casings

Films/casings produced using pectin (PN) and gelatin/sodium alginate blends (GSAB) containing 2.5 and 5% added corn oil (CO) or olive oil (OO) and non‐oil containing were manufactured using extrusion technology. Films/casings formed from PN and GSAB had great difference in properties of tensile strength, elongation, Young's modulus and puncture resistance. Quality and stability of films/casings were greatly enhanced on addition of oils. However, an oil addition of 2.5% was identified as optimal while 5% decreased the final films/casings quality. Oil addition increased (P < 0.05) films/casings thicknesses. Oil addition also decreased (P < 0.05) tensile strength, puncture resistance, Young's modulus and tear resistance of films/casings but increased their elongation properties, with the exception of converse effect of 2.5% CO on two films/casings. Olive oil and CO both reduced (P < 0.05) water vapour transfer rate (WVTR) of films/casings. However, no significant difference between films using different concentrations of oil was observed with respect to WVTR.