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以改性淀粉为成膜基材,甘油和羧甲基纤维素钠(CMC)为添加剂制备可食膜,研究了改性淀粉及复合膜的相关结构和性能。将壳聚糖与淀粉共混,进行干热改性得到改性淀粉,采用溶液共混法将改性淀粉糊化液、甘油及CMC搅拌混合,随后流延成膜;通过红外光谱、X射线衍射方法对改性淀粉的结构进行了分析,通过热重分析、扫描电镜对改性淀粉及复合膜的结构进行了分析,并研究了甘油及CMC含量对复合膜性能的影响。结果表明,壳聚糖干热改性淀粉属于以物理反应为主的改性,其有助于改善复合膜的物理性能,甘油降低了复合膜的机械强度和阻水性,但CMC可增强膜的机械强度。当甘油含量为20%,CMC含量为60%时,壳聚糖干热改性淀粉复合膜的综合性能达到最佳。 相似文献
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以壳聚糖为原料经改性制备的巯基化壳聚糖为成膜基质,再添加结冷胶、甘油、氯化钙和纳他霉素,通过流延成膜制备复合膜。以膜的拉伸强度、断裂伸长率、水蒸汽透过率以及透光率为考查指标,对结冷胶、甘油、氯化钙和纳他霉素进行单因素实验,然后通过Plackett-Burman(PB)试验和最陡爬坡试验确定对膜拉伸强度影响显著的因素以及最佳试验范围。最后以拉伸强度为评价指标进行响应面试验,得出二次响应预测模型,优化出了复合膜的最佳配比。结果表明:单一壳聚糖膜拉伸强度为0.928 MPa,但断裂伸长率仅为5.91%;单一巯基化壳聚糖膜拉伸强度仅为0.350 MPa,断裂伸长率为14.47%。当基础膜液中巯基化壳聚糖0.20 g,改性条件为结冷胶0.18 g,甘油1.00 g,氯化钙0.17 g,纳他霉素0.01 g时,复合膜的拉伸强度最大,达到4.986±0.087 MPa;改性壳聚糖复合膜的拉伸强度得到显著提高(P<0.05)。本研究结果为改性壳聚糖复合膜的制备、复合膜综合性能提高以及在食品保鲜领域的应用提供理论支撑。 相似文献
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以壳聚糖(CS)为原料经咖啡酸改性制备咖啡酸接枝壳聚糖(CA-g-CS)复合膜,并与聚乙烯(PE)膜、CS膜对比,研究CA-g-CS复合膜对薏仁米保鲜效果的影响。结果表明:与PE膜和CS膜相比,CA-g-CS复合膜的水蒸气渗透率和抗拉强度更优,分别为3.55×10-8 g·mm·h-1·cm-2·Pa-1和20.74 MPa;与PE膜相比,CA-g-CS复合膜包装的薏米仁在贮藏4个月后,其脂肪酸值、过氧化值和丙二醛含量分别降低了31.04%、18.18%、27.63%;CA-g-CS复合膜包装的薏仁米在贮藏期间微生物数量低于PE膜和CS膜,且CA-g-CS复合膜包装的薏仁米中脂肪酸组成及相对含量与新鲜薏仁米近似。表明CA-g-CS复合膜有利于减缓薏仁米贮藏期间脂质氧化。 相似文献
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茶多酚改性胶原蛋白-壳聚糖复合膜对冷藏斜带石斑鱼的保鲜效果 总被引:2,自引:0,他引:2
研究茶多酚改性后的胶原蛋白-壳聚糖复合膜对冷藏斜带石斑鱼的保鲜效果。在4℃冷藏条件下,采用空白对照、胶原蛋白-壳聚糖复合膜、茶多酚改性胶原蛋白-壳聚糖复合膜3种方式处理样品并贮藏20 d,以K值、肌动球蛋白含量、巯基(—SH)含量、Ca~(2+)-ATPase活性以及p H值、硫代巴比妥酸(thiobarbityric acid,TBA)值、挥发性盐基氮(total volatile basic nitrogen,TVB-N)值、菌落总数、感官评定值作为研究指标。结果表明:胶原蛋白-壳聚糖复合膜、茶多酚改性胶原蛋白-壳聚糖复合膜处理组斜带石斑鱼的巯基含量、肌动球蛋白含量、Ca~(2+)-ATPase活性和感官评定值均显著高于对照组(P0.05),而K值、p H值、TVB-N值、菌落总数均显著低于对照组(P0.05),且茶多酚改性胶原蛋白-壳聚糖复合膜处理组的效果优于胶原蛋白-壳聚糖复合膜处理组,其中3个处理组的TBA值的差异性不显著(P0.05)。茶多酚改性胶原蛋白-壳聚糖复合膜处理组鱼肉的肌动球蛋白变性和巯基含量降低缓慢、Ca~(2+)-ATPase活性下降受到阻碍、TVB-N值等理化指标变化以及细菌总数生长受到抑制。说明在4℃冷藏条件下,茶多酚改性胶原蛋白-壳聚糖复合膜处理组能有效延缓斜带石斑鱼的腐败变质,保鲜效果更明显。 相似文献
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壳聚糖-肉桂醛复合抗菌降解膜的制备及性能 总被引:1,自引:0,他引:1
为改善壳聚糖膜的抗菌效果,将肉桂醛添加到壳聚糖基膜中制成壳聚糖-肉桂醛复合膜,研究肉桂醛体积分数对复合膜的物理性质、力学性能、水蒸气透过系数、官能团结构、结晶程度、微观结构以及抗菌性能的影响。结果表明:随着肉桂醛体积分数的增加,复合膜的色差、水蒸气透过系数和断裂伸长率减小,膜的厚度显著增加;当肉桂醛体积分数为2%时,膜的抗拉强度最大,为(15.77±1.13)MPa;根据傅里叶变换红外光谱分析,壳聚糖与肉桂醛有较好的相容性;肉桂醛体积分数的增加会导致膜表面结晶程度、裂纹、粗糙程度增加;复合膜的抑菌性能也随着肉桂醛体积分数的增大而显著增大。该研究可为壳聚糖-肉桂醛复合降解膜的应用提供理论依据。 相似文献
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本文采用溶胶-凝胶法制备了纯壳聚糖膜及纳米TiO2/壳聚糖复合膜,用X-衍射(XRD)、红外光谱(FI-RT)、扫描电镜(SEM)进行表征,并测试了TiO2/壳聚糖膜的热稳定性及机械性能。X-衍射(XRD)表明,添加TiO2改变了壳聚糖原来的排列;红外(FT-IR)分析表明,壳聚糖复合膜中存在Ti—O键;扫描电镜(SEM)表面,纳米TiO2较好地分散在壳聚糖中,形成无机粒子嵌入式有机/无机网络结构,有机相为连续相,分散性较好;通过测试复合膜的起始和终止分解温度表面,加入纳米TiO2能够提高了壳聚糖分子链加热过程中断裂所需要的能量,提高了壳聚糖纳米二氧化钛复合膜的热稳定性;拉伸测试表明,添加适量纳米TiO2后能提高断裂强度。 相似文献
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纳米TiO2改性壳聚糖膜的制备及性能初探 总被引:1,自引:0,他引:1
本文采用溶胶-凝胶法制备了纯壳聚糖膜及纳米TiO2/壳聚糖复合膜,用X-衍射(XRD)、红外光谱(FI-RT)、扫描电镜(SEM)进行表征,并测试了TiO2/壳聚糖膜的热稳定性及机械性能.X-衍射(XRD)表明,添加TiO2改变了壳聚糖原来的排列;红外(FT-IR)分析表明,壳聚糖复合膜中存在Ti-O键;扫描电镜(SEM)表面,纳米TiO2较好地分散在壳聚糖中,形成无机粒子嵌入式有机/无机网络结构,有机相为连续相,分散性较好;通过测试复合膜的起始和终止分解温度表面,加入纳米TiO2能够提高了壳聚糖分子链加热过程中断裂所需要的能量,提高了壳聚糖纳米二氧化钛复合膜的热稳定性;拉伸测试表明,添加适量纳米TiO2后能提高断裂强度. 相似文献
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ABSTRACT: Quinoa protein concentrate was hydrolyzed with alcalase to obtain a hydrolysate that was fractionated by ultrafiltration using 10000- and 5000-molecular-weight cutoff membranes. Functional properties of the protein concentrate, protein hydrolysate, and membrane permeates were compared at different pH values. Protein solubility of the hydrolysate and membrane permeates were significantly higher ( P = 0.05) than that of the protein concentrate. The protein concentrate had a significantly higher ( P = 0.05) emulsifying activity index than the protein hydrolysate and membrane permeates. Membrane fractionation of the protein hydrolysate into lower-molecular-weight pep tides significantly reduced ( P = 0.05) foaming properties, but it improved radical scavenging activity and the ability to inhibit the activity of angiotensin-converting enzyme. 相似文献
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以玉米淀粉和玉米醇溶蛋白作为基础原料,研究可食性膜的成膜条件和膜性能。玉米淀粉液经糊化、掺入脱色的玉米醇溶蛋白、添加甘油增塑剂、匀浆、脱泡、成膜后,检测膜的抗拉强度、断裂伸展率、溶解度、透明度、微观表面特征。配制质量分数为4%、5%、6%、7%的玉米淀粉液分别制膜,检测并筛选一适宜浓度,同时筛选制备脱色玉米醇溶蛋白液。玉米淀粉糊化后,分别按其体积的0%、10%、15%、20%、25%、30%掺入脱色玉米醇溶蛋白液,制膜,筛选适宜掺入比例。测试筛选添加质量分数为1.0%、1.2%、1.4%、1.6%的甘油增塑剂的成膜效果。结果显示,添加玉米醇溶蛋白液能够提高抗拉强度和断裂伸展率,降低透明度和溶解度,但添加10%有反抗拉强度现象。筛选确定淀粉质量分数5%,按体积分数15%掺入含玉米醇溶蛋白0.5%的脱色液,添加1.2%的甘油增塑剂,获得的可食性淀粉-玉米醇溶蛋白膜具有良好的机械性能和表观特征。 相似文献
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超滤对罗非鱼下脚料蛋白酶解物功能特性的影响 总被引:2,自引:1,他引:1
以罗非鱼下脚料为原料,采用pH-stat法控制酶解,滤膜对罗非鱼下脚料胰蛋白酶水解产物(DH5.0%)进行超滤。1-2倍,乳化稳定性提高1.1倍;发池陛略有提高。制备5.0%的罗非鱼下脚料酶解蛋白。采用截留分子量为5kDa的超结果显示:蛋白回收率为89.21%,脱盐率为87.59%,乳化活性提高 相似文献
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以明胶为基体,甘油为增塑剂,石墨和氧化石墨烯(graphene oxide,GO)分别作为增强相,制备出一系列两种增强相的共混复合膜,探究两者与基体明胶的相容性,并通过测试复合膜的抗拉强度、断裂伸长率、热缩、SEM和透光率,用于研究不同的增强相复合膜性能及规律。结果表明:0.5% GO复合膜的抗拉强度(17.98 MPa)最大,比空白样(11.74 MPa)增加53.4%,10%石墨复合膜的断裂伸长率(57.30%)最大,比空白样(22.65%)增加153%;通过不同复合膜的SEM观察得出GO与基体的相容性优于石墨;5%的石墨含量热缩率最小,比空白样减小27%,但石墨复合膜的热缩率下降趋势比GO复合膜的下降趋势波动性大;随着GO和石墨含量的增大,透光率逐渐的降低,雾度逐渐增大。通过两者的对比得出:GO与明胶结合较好,两者相互结合成键,使得分子间作用力增强,结构稳定;石墨与明胶结合相容性不好,但石墨对基体明胶的保护较好。 相似文献
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低温是保障水产品质量安全的重要方法,然而仍有部分耐冷菌能适应低温环境,继续生长繁殖并最终导致水产品腐败变质。为了解不同培养温度对腐败希瓦氏菌生长动力学参数及细胞膜理化特性变化的影响,以水产品中典型的耐冷腐败微生物腐败希瓦氏菌模式菌株DSM6067为研究对象,对细菌的生长情况、细胞膜脂肪酸组成、膜蛋白含量、细胞微观结构和细胞膜流动性进行分析。结果表明,腐败希瓦氏菌模式菌株DSM6067分别在30,10℃和4℃培养条件下经3.35,25.94 h和122.03 h的延滞期后进入对数生长期;腐败希瓦氏菌虽在低温环境下培养增速较为缓慢,但能够适应低温环境继续生长。腐败希瓦氏菌在相应培养温度下的对数生长中期,30℃条件下细菌细胞膜不饱和脂肪酸总量仅43.36%,其中C16:1(棕榈油酸)为26.62%,而4℃培养下细菌细胞膜不饱和脂肪酸总量为51.04%,其中单不饱和脂肪酸C16:1含量高达46.66%,低温培养下细菌细胞膜中C16:1含量显著增加;细菌细胞膜蛋白表达量随培养温度的降低而有所上升;腐败希瓦氏菌微观结构观察显示,低温培养下的细菌细胞膜较为平滑,胞内空泡较少,细胞体积略大;在低温适应过程中,细菌细胞膜流动性增强。腐败希瓦氏菌细胞膜理化特性所产生的变化为细菌更好地适应低温环境生长提供了一定的物质基础。 相似文献
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Asavasanti S Ersus S Ristenpart W Stroeve P Barrett DM 《Journal of food science》2010,75(7):E433-E443
The impact of pulsed electric fields (PEF) on cellular integrity and texture of Ranchero and Sabroso onions (Allium cepa L.) was investigated. Electrical properties, ion leakage rate, texture, and amount of enzymatically formed pyruvate were measured before and after PEF treatment for a range of applied field strengths and number of pulses. Critical electric field strengths or thresholds (E(c)) necessary to initiate membrane rupture were different because dissimilar properties were measured. Measurement of electrical characteristics was the most sensitive method and was used to detect the early stage of plasma membrane breakdown, while pyruvate formation by the enzyme alliinase was used to identify tonoplast membrane breakdown. Our results for 100-μs pulses indicate that breakdown of the plasma membrane occurs above E(c)= 67 V/cm for 10 pulses, but breakdown of the tonoplast membrane is above either E(c)= 200 V/cm for 10 pulses or 133 V/cm for 100 pulses. This disparity in field strength suggests there may be 2 critical electrical field strengths: a lower field strength for plasma membrane breakdown and a higher field strength for tonoplast membrane breakdown. Both critical electric field strengths depended on the number of pulses applied. Application of a single pulse at an electric field up to 333 V/cm had no observable effect on any measured properties, while significant differences were observed for n≥10. The minimum electric field strength required to cause a measurable property change decreased with the number of pulses. The results also suggest that PEF treatment may be more efficient if a higher electric field strength is applied for a fewer pulses. 相似文献
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Superhydrophobic electrospun polyacrylonitrile nanofibre membranes have been prepared by surface coating of silica nanoparticles and fluorinated alkyl silane. The coated membranes were characterised by scanning electron microscopy, water contact angle, thermogravimetry analysis, Brunauer–Emmett–Teller, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and atomic force microscopy. It was shown that the loading of nanoparticle on the nanofibre membrane was controlled by the particle concentration in the coating solution, which played a critical role in the formation of superhydrophobic surface. Increased particle loading led to higher surface roughness and WCA. The nanoparticle coating had little influence on the porosity of the nanofibre membranes. However, overloading of the particles would affect the specific surface area of the nanofibre membrane. 相似文献
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The effects of the feed concentration (Cfeed) and particle size distribution (PSD) on the crossflow microfiltration (CFMF) of suspensions containing lactalbumin particles were investigated. Experiments were carried out in constant transmembrane pressure (TMP) mode using tubular ceramic membrane modules. All the important parameters: permeate flux, internal and surface fouling, cake mass, height, porosity, and PSD were estimated. The steady-state flux (Jss) decreased, and internal as well surface fouling and cake mass and height all increased with an increase in Cfeed from 0.65 to 2.5 gL−1. This was due to the availability of more particles to foul the membrane at higher Cfeed. However, above 2.5 gL−1 there was no significant effect of Cfeed on any of these parameters. The overall observed behaviour is attributed to steady-state membrane fouling resulting from the availability of sufficient particles for maximum possible deposition under the experimental conditions reached at 2.5 gL−1. The larger the feed particles, the higher was the Jss. However, the cake mass, height and porosity were not affected by the feed PSD. Significantly, addition of larger feed particles at the steady state increased the flux by about 6%. This behaviour is attributed to the scouring effect of the large particles on the cake surface. There is scope for looking at the possibility of using the scouring effect of large particles to improve the CFMF process performance. 相似文献
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Long‐zheng Zhou Fu‐sheng Chen Li‐hua Hao Yan Du Chen Liu 《Journal of food science》2019,84(10):2812-2819
This study was aimed to assess the effect of membrane structure on the stability of peanut oil bodies extracted by enzyme‐assisted extraction. The influence of pH, NaCl concentration, and temperature on the physicochemical properties of peanut oil bodies was characterized using ζ‐potential and particle size. The results indicated that the peanut oil bodies had strong stability (ζ‐potential, >20 mV) at pH values away from the isoelectric point (pH 4.8), at a low salt concentration (NaCl concentration, <10 mM), and in a certain temperature range (35 to 55 °C). The stable structure of the oil body was closely related to its structure. Phospholipids, along with membrane proteins, were major components of the oil body membrane. Therefore, the phospholipid composition and content were measured and the types of membrane proteins of the oil bodies were identified. The results showed that phosphatidylcholine and phosphatidylserine were major components of the oil body phospholipids. Two‐dimensional electrophoresis showed that the oil bodies contained both intrinsic proteins and extrinsic proteins, which might play an important role in the stability of oil bodies during enzyme‐assisted extraction processing. 相似文献