共查询到20条相似文献,搜索用时 390 毫秒
1.
试验研究可降解材料聚丁二酸丁二醇酯/聚对苯二甲酸-己二酸-1, 4-丁二醇酯(PBS/PBAT)共混改性薄膜对樱桃番茄保鲜效果的影响。新鲜樱桃番茄经预冷后用PBS/PBAT薄膜进行包装,在5℃相对湿度70%的冷鲜柜中进行保藏。贮藏期间对包装内气体组分,以及樱桃番茄的硬度、可溶性固形物、失重率、维生素C含量、丙二醛含量等指标进行测定,评估其保鲜效果。结果显示, PBS/PBAT薄膜良好的气体透过性使得包装袋内的CO_2和O_2的浓度始终稳定在适宜保鲜樱桃番茄的气氛范围内,有效地抑制了樱桃番茄的腐败变质,维持了其较好的感官品质和营养价值。通过单一变量对比分析可知,同种包装规格下, 90 g和120 g包装组的保鲜效果较好,贮藏期间的硬度、可溶性固形物、维生素C含量优于其他组,失重率最小,丙二醛含量最低。贮藏第31天时感官评分为6分,而其他组则均低于6分,失去食用价值。从经济角度考虑, 120 g包装组的效果最佳。 相似文献
2.
3.
研究聚对苯二甲酸-己二酸-1,4-丁二醇酯/聚己内酯(PBAT/PCL)共混薄膜对双孢菇保鲜效果的影响,将新鲜双孢菇在采摘后经预冷,在自发气调条件下于4℃相对湿度80%进行保藏,以未包装的双孢菇作为对照组。贮藏期间对感官、白度值(L*)、可溶性蛋白、多酚氧化酶、硬度等指标进行测定包装效果评估。结果表明,PBAT/PCL共混薄膜具有良好的透气性和选择透过性,包装后可形成适宜稳定的气氛条件,可有效抑制双孢菇褐变,维持其良好的感官和营养价值,有效延长贮藏期,是空白组的2倍多。 相似文献
4.
5.
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。 相似文献
6.
7.
《食品与发酵工业》2020,(9)
为探讨不同薄膜包装对樱桃番茄常温货架期保鲜效果的影响,以"千禧"樱桃番茄为试验对象,采用5种保鲜膜[聚乙烯(膜厚20μm):P1;低密度聚乙烯:P2;聚乙烯(膜厚13μm):P3;聚偏二氯乙烯:P4;聚氯乙烯:P5]包装樱桃番茄,通过评价常温贮藏期樱桃番茄的感官品质、包装膜内气体比例、果实呼吸速率和腐烂率,果实及果蒂失重率和色泽等品质指标,果蒂叶绿素含量、果肉可溶性固形物、可滴定酸和Vc等营养指标,筛选出适宜樱桃番茄的包装材料。结果表明:P1、P2、P3、P4包装膜均具有良好的保鲜作用,其中,P1、P2包装膜的保鲜效果更佳,主要表现在能够维持樱桃番茄良好的感官品质,以及在袋内形成高浓度CO_2和低浓度O_2的气体环境,抑制果实呼吸作用和腐烂,果实和果蒂的失水、变色和丙二醛产生,以及果蒂叶绿素降解,同时可保持果肉较高的可溶性固形物、可滴定酸和Vc等营养成分的含量。因此,P1、P2较适用于樱桃番茄的包装。 相似文献
8.
9.
《食品科学》2020,(17)
以‘美早’大樱桃为试材,聚乳酸(polylactic acid,PLA)/聚3-羟基丁酸酯-co-4-羟基丁酸酯(poly-3-hydroxybut-yrate-co-4-hydroxybutyrate,P34HB)为基材,硅藻土附载薄荷精油为缓释型抗菌剂,采用流延成膜工艺,制备PLA/P34HB、薄荷精油-PLA/P34HB、薄荷精油/硅藻土-PLA/P34HB 3种活性抗菌膜,对活性抗菌膜性能进行测定,并通过对樱桃在(4±1)℃下贮藏期间保鲜袋内顶空气体组成、质量损失率等理化指标的测定以及低场核磁共振(low field-nuclear magnetic resonance,LF-NMR)分析樱桃内部水分状态的变化,研究不同薄膜和对照(不加薄膜)对樱桃保鲜效果的影响。结果表明:具有硅藻土附载薄荷精油的薄膜相较于PLA/P34HB薄膜氧气透过率从250.37 cm~3/(m~2·d·0.1 MPa)增加到290.45 cm~3/(m~2·d·0.1 MPa),有利于维持樱桃品质。LF-NMR结果表明含有硅藻土附载薄荷精油的薄膜能很好地保持樱桃水分活度,在贮藏12 d时结合水峰面积比是CK组2倍左右,有效延缓了包装中樱桃的腐败,延长了保质期。 相似文献
10.
《食品与发酵工业》2019,(20):100-105
为提高自发气调包装(spontaneous control modified atmosphere packaging,SMAP)保鲜效果,采用化学改性方法制备高气体透过性及二氧化碳/氧气(CO_2/O_2)选择性的可降解聚乳酸嵌段物(PLGLx G20),制备薄膜并用于樱桃番茄的低温SMAP包装,通过对包装内气体浓度、果实的感官品质、营养成分等分析考察薄膜的保鲜效果。结果显示,储藏初期CO_2浓度迅速升高,O_2浓度迅速降低,约5 d后包装内的气体达到平衡,其CO_2浓度随着PLGLx G20的CO_2透过系数的增大呈阶梯型减小,薄膜表现出对内部气体的控制能力。与无包装和聚乳酸包装组相比,PLGLx G20包装内维持了相对低O_2高CO_2的气体环境,其中PLGL35G20包装在6 d后达到较适宜番茄保鲜的体积分数为3%~5%CO_2和3%~4%O_2平衡浓度,抑制了强烈的有氧呼吸,果实在20 d内维持了较好的感官品质和营养成分。该研究表明,PLGLx G20薄膜对果蔬具有良好的保鲜效果,对拓宽可降解材料在食品包装中应用具有一定意义。 相似文献
11.
为获得高质量的聚乳酸/聚(3-羟基丁酸-co-3-羟基戊酸共聚酯)(PLA/PHBV)双组分生物降解纺粘非织造材料,对PLA/PHBV母粒的相对分子质量及分布、熔体指数、热力学、结晶和流变性能进行了研究,并对PLA/PHBV纺粘纤维的热力学和结晶性能进行了探讨。结果表明:PLA/PHBV母粒重均分子质量约为120 000,分布指数为1.99;热失重起始热分解温度为285℃,适宜纺粘非织造挤出加工,合适的纺粘加工温度约为210℃。PLA/PHBV熔体在剪切速率小于1 000 rad/s时,表观黏度对剪切速率变化敏感;熔体对温度的敏感程度随着剪切速率的增大而降低。纺粘加工工艺对PLA/PHBV原料的热力学和结晶性能影响显著。与PLA/PHBV母粒相比,纺粘纤维结晶度下降明显,但非晶区取向程度提高。 相似文献
12.
13.
针对聚(3-羟基丁酸-co-3-羟基戊酸共聚酯)(PHBV)热稳定性差、易分解的问题,通过与聚乳酸(PLA)采用熔融共混的方法制备了不同混合比例的的PHBV/PLA共混物,借助差示扫描量热仪、热重分析仪、动态热机械分析仪和X射线衍射仪研究了PHBV/PLA共混物的相容性、热学性能和结晶性等,并用热台偏光显微镜观察了PHBV/PLA共混物的动态热结晶过程。结果表明:PHBV/PLA共混物呈现分离的熔融温度和玻璃化转变温度,X射线衍射曲线上没有出现新的衍射峰,说明PHBV和PLA的相容性较差;PLA的加入提高了PHBV的热稳定性能,拓宽了PHBV的熔融加工窗口;随着共混物中PLA比例的增加,共混物的结晶相由“海-岛”相逐渐变成两聚合物分别连续成相。 相似文献
14.
Eun Joo Shin 《纺织学会志》2018,109(2):241-247
Poly(ethylene-3,4-dioxythiophene)/poly(styrene sulfonic acid)(PEDOT/PSS) water dispersions are commercially available, and various coating formulations for substrates, such as glass, plastics, and ceramics, have been suggested. Recently, it was found that the addition of a small amount of organic solvent, such as ethylene glycol (EG) and dimethylsulfoxide (DMSO), to the aqueous dispersion of PEDOT/PSS increases the conductivity significantly. This study examined how a combination of solvent addition affects the PEDOT/PSS conductivity of artificial leather (napping fabric with short fur). In addition, the sustainability of the PEDOT/PSS conductivity for the common use of artificial leather was investigated using abrasion and tension cycle tests. The electric conductivity of the leather increased in the order of EG < DMSO < EG + DMSO. The sustainability of the PEDOT/PSS conductivity in the case of EG + DMSO was superior to that of the EG or DMSO solvents. The padding process was found to be a more effective method for achieving durability against abrasion and tension cycle with a lower deposit weight than when using the coating process. The mechanical properties of the synthetic leather using the padding process also showed high performance compared to the coating process. 相似文献
15.
采用熔融共混法制备了质量比为100/0、75/25、50/50、25/75、0/100的熔喷非织造用PHBV/PLA共混材料,分别采用热重分析法(TG)、熔融指数法(MFI)、热台偏光镜法(POM)和毛细管流变法对共混材料的可纺性能进行了研究,并对其初生纤维的纺丝性能给予了初步评价。研究表明:PHBV的热稳定性差、加工窗口窄且熔体流动性差,PHBV/PLA共混材料的热稳定性和熔体流动性明显改善;PHBV结晶速率快, PLA对PHBV的结晶具有稀释作用;PHBV/PLA共混物为典型的切力变稀型流体,PHBV对温度和剪切速率变化敏感度高,PHBV/PLA共混材料的表观粘度随着PLA含量的提高而有所增大,但均小于纯PLA;PHBV纤维发粘现象严重,纺丝困难,随着共混材料中PLA含量的提高,纺丝性能提高,初生纤维表面变得光滑。 相似文献
16.
17.
采用未干的聚对苯二甲酰对苯二胺(PPTA)纤维,分别用阳离子染料和分散染料对其进行染色,探讨纤维含水率、染色温度、染料种类和用量对纤维染色性能的影响。结果表明:相比于干燥的PPTA纤维,用未干的PPTA纤维进行染色,可明显提高纤维的上染率和K/S值;染色纤维具有较高的耐皂洗色牢度和耐摩擦色牢度;同时,染色后不会影响纤维原有的力学性能。 相似文献
18.
Isolation of thermophiles degrading poly(L-lactic acid) 总被引:2,自引:0,他引:2
A thermophile, strain 93, which degrades poly(L-lactic acid) (PLA) film was isolated from 144 soil samples obtained from different locations by cultivation using an enrichment culture medium at 60 degrees C. Under this temperature condition, the strain grew on PLA and the dissolved total organic carbon (TOC) concentration in the medium changed according to the growth stage, i.e., after the TOC rapidly reached the minimum, it increased rapidly until it reached the peak and then decreased thereafter. For residual PLA, reduced viscosity decreased rapidly but weight decreased initially slowly with a gradually increasing rate. Gel permeation chromatograms showed a marked decrease in the main peak and the appearance of a new peak in the low molecular weight region. The strain was identified as Bacillus brevis, which has an optimum growth temperature of around 58 degrees C. 相似文献
19.
20.
Mine Y Fukunaga K Yoshimoto M Nakao K Sugimura Y 《Journal of Bioscience and Bioengineering》2001,92(6):539-543
The alpha-chymotrypsin-poly(ethylene glycol) complex, which was prepared by lyophilizing an aqueous solution, was found to have high catalytic activity in organic media even when the molar ratio of polymer/enzyme in its preparation stage is unity. In this study, we obtained freeze-dried complexes of lipases and poly(ethylene glycol) or poly(oxyethylene) detergents including newly synthesized gemini-type detergents, and their transesterification activity in organic solvents was evaluated. The freeze-dried lipase from Pseudomonas cepacia prepared by using each modifier showed enhanced transesterification activity, exhibiting a similar dependence on the concentration of the modifier in the preparation stage to that of the alpha-chymotrypsin-poly(ethylene glycol) complex; in contrasts, the one from Candida rugosa did not do so. 相似文献