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%。     

羧甲基纤维素钠在食品工业中应用及研究现状

羧甲基纤维素钠是葡萄糖聚合度为100-2000纤维素衍生物,属于改性天然纤维素,在食品工业中有着广泛应用。该文综述羧甲基纤维素钠的结构和性质,制备方法及其在食品工业中应用,并展望其发展前景。     

Development of Antibacterial Carboxymethyl Cellulose‐Based Nanobiocomposite Films Containing Various Metallic Nanoparticles for Food Packaging Applications

In this study, silver (Ag), zinc oxide (ZnO), and copper oxide (CuO) metallic nanoparticles were used in preparation of carboxymethyl cellulose (CMC) nanobiocomposite films. Scanning electron microscopy (SEM), X‐ray diffraction (EDXA), water vapor permeability (WVP), ultraviolet and visible light (UV–Vis) spectroscopy, and mechanical and microbial tests were used to determine the characteristics of the obtained active films. SEM results showed that the CMC nanobiocomposite films had roughness deflection levels and the EDXA test confirmed the presence of Ag, ZnO, and Cuo nanoparticles in the biopolymer tissue. UV–Vis spectroscopy confirmed that with addition of metallic nanoparticles to the pure CMC film, absorption rate increased and WVP decreased. In the mechanical tests, addition of nanoparticles also increased the tensile strength of the films, and the nanobiocomposite films exhibited higher resistance compared to the pure CMC film. Films incorporating metallic nanoparticles showed antibacterial properties against Escherichia coli and Staphylococcus aureus growth. Thus, nanobiocomposite films can be used as active packaging films and could increase the shelf‐life of the food.     

石墨烯/低密度聚乙烯复合包装膜中2种抗氧化剂向食品模拟物异辛烷的迁移

建立高效液相色谱法检测石墨烯/低密度聚乙烯复合食品包装薄膜中2种抗氧化剂(Irganox1076、Irgafos168)的方法。考察时间、温度以及石墨烯和石墨烯微片的存在对2种抗氧化剂向脂肪类食品模拟物异辛烷迁移的影响,同时分析2种不同抗氧化剂在迁移中的相互作用。结果表明,2种抗氧化剂的迁移会随着迁移温度的升高以及迁移时间的延长而增加直至达到迁移平衡;2种抗氧化剂之间存在协同作用,在迁移过程中会相互影响;石墨烯及石墨烯微片纳米粒子的团聚现象和吸附作用抑制了食品包装中的Irganox1076、Irgafos168两种抗氧化剂向异辛烷中的迁移。     

羧甲基化改性纳米甘薯渣纤维素的表征

以甘薯渣为原料,利用超声辅助酸法从薯渣中提取纳米纤维素,用羧甲基化对纳米纤维素进行亲水性改性,并对其理化性质进行表征。结果表明,羧甲基纳米纤维素仍为典型的球形粒子,粒径集中分布在30~50nm,与原纳米纤维素相比,表面结构更加疏松,化学反应活性增强;改性纳米纤维素的晶型结构发生了变化,结晶度明显降低,结晶指数由原来的73.27%下降到52.83%,但其热稳定性提高;改性纳米纤维素的实测纯度99.5%,黏度25 mPa·s,是一种高纯度极低黏度的纳米级羧甲基纤维素,可用做食品级添加剂。     

玉米秸秆制备羧甲基纤维素的研究及结构表征

以玉米秸秆为原料,采用溶媒法制备羧甲基纤维素,在单因素实验的基础上,利用响应面法对羧甲基纤维素的制备工艺进行优化。最佳工艺条件为：氯乙酸添加量为2.67g、反应时间1.5h、反应温度63℃,此条件下制备的羧甲基纤维素取代度为1.071。使用扫描电镜、傅里叶变换红外光谱仪、X-射线衍射仪、热重分析仪对玉米秸秆粉、玉米秸秆纤维素及羧甲基纤维素的形貌及结构进行了表征：提取的纤维素的结构没有遭到破坏,结晶度提高。制备的羧甲基纤维素因羧甲基基团的引入,导致表面疏松,热分解温度降低。     

Modeling the Lysozyme Release Kinetics from Antimicrobial Films Intended for Food Packaging Applications

ABSTRACT: The aim of this work is to develop a mathematical model to predict the lysozyme release kinetics from crosslinked polyvinylalcohol (PVOH) into an aqueous solution. The model was developed by taking into account both the diffusion of water molecules into the polymeric film and the counter-diffusion of the incorporated antimicrobial agent from the film into the aqueous solution. In particular, it was considered that the lysozyme release from a swelling polymer could be regarded as "anomalous diffusion" with moving boundary conditions. The water sorption kinetics of 4 films, differing for the degree of crosslink, were determined at ambient temperature (25 °C). The results obtained by fitting the model to the experimental data are satisfactory.     

多糖基膜内抑菌剂向食品模拟体系中释放的规律

本文研究多糖基抑菌膜(低甲氧基果胶-羧甲基纤维素-山梨酸钾(LMP-CMC-Psb,LCP))内抑菌剂Psb在4℃下的释放动力学。分别探讨了基膜比例LMP:CMC(8:2、6:4、4:6)、Ca Cl2(1%、2%、4%、8%)、蒙脱土(MMT,1%、4%、8%、12%)及Psb(2%、5%、8%、15%)含量变化对Psb向食品模拟液(50%乙醇)中释放的影响;并使用Fickian第二定律方程和简化模型与Psb释放试验数据进行非线性最小二乘法拟合,计算得出扩散系数,进而评估Psb的扩散能力。结果表明:通过调整膜基质LMP和CMC的比例、改变Ca Cl2、MMT在基膜内的浓度可有效地控制Psb的释放速率;提高LMP比例、Ca Cl2和MMT含量均可降低Psb的扩散系数。通过Fickian第二定律拟合结果证实了Fickian模型与Psb的释放有很好的拟合度(R20.98%),说明该拟合具有一定可靠性,可以用来模拟Psb的释放。本文亦发现可通过使用简化模型对Psb的短期释放进行拟合而得的扩散系数评估Psb在抑菌膜内的释放规律,以缩短试验时间。该抑菌材料有望作为可控释放包装体系用于包装食品。     

桑葚花青素共混羧甲基纤维素膜的性能研究及应用

以羧甲基纤维素为成膜基材,桑葚花青素为指示剂制备包装指示膜,研究不同质量分数的桑葚花青素对膜性能的影响.结果表明,添加桑葚花青素后,膜的拉伸强度、阻湿性、阻光性均有所提高,但断裂伸长率略有下降.桑葚花青素降低了膜的水蒸气透过率,质量分数为0.3％时膜的水蒸气透过系数达到最低值[1.39×10-10 g/(cm·s·Pa...     

Release Kinetics of Nisin from Chitosan–Alginate Complex Films

Understanding the release kinetics of antimicrobials from polymer films is important in the design of effective antimicrobial packaging films. The release kinetics of nisin (30 mg/film) from chitosan–alginate polyelectric complex films prepared using various fractions of alginate (33%, 50%, and 66%) was investigated into an aqueous release medium. Films containing higher alginate fractions showed significantly lower (P < 0.05) degree of swelling in water. Total amount of nisin released from films into an aqueous system decreased significantly (P < 0.05) with an increase in alginate concentration. The mechanism of diffusion of nisin from all films was found to be Fickian, and diffusion coefficients varied from 0.872 × 10^?9 to 8.034 ×10^?9 cm²/s. Strong complexation was confirmed between chitosan and alginate polymers within the films using isothermal titration calorimetry and viscosity studies, which affects swelling of films and subsequent nisin release. Complexation was also confirmed between nisin and alginate, which limited the amount of free nisin available for diffusion from films. These low‐swelling biopolymer complexes have potential to be used as antimicrobial packaging films with sustained nisin release characteristics.     

豆渣一锅法均相制备羧甲基纤维素的研究

本研究在均相条件下通过一锅法合成羧甲基纤维素(carboxymethyl cellulose, CMC)。豆渣(soybean dregs, SD)溶解在6%NaOH/4%尿素水溶液得到碱纤维素,一步完成纤维素的提纯和碱化,再以氯乙酸钠为醚化剂制备CMC。经正交实验确定制备CMC的优化反应条件,并对其特性进行分析。结果表明:在55℃下醚化3 h,68℃保温1 h,豆渣添加量6.8 g,氯乙酸钠和纤维素摩尔比为4∶1,NaOH的浓度为1.5%时,得到取代度为0.51的淡黄色中性CMC,其溶解度为83.88%;红外光谱分析发现在1 608.12 cm~(-1)处出现的新吸收峰,表明有羧甲基基团成功引入;~1H NMR中化学位移的改变证明有羧甲基取代纤维素链上的羟基;热重分析表明制备CMC有良好的热稳定性;扫描电镜显示CMC由表面平滑的大颗粒结构转变成表面凹凸不平的短棒状。     

海藻酸钠微囊化JS25噬菌体的制备、表征及其在食品模拟体系中的释放

通过海藻酸钠微囊化JS25噬菌体,并对制备的JS25噬菌体微囊粉进行结构表征和稳定性分析,通过构建不同的食品模拟体系分析JS25噬菌体微囊粉的释放规律。结果表明,海藻酸钠和CaCl2组成的体系能有效地构建JS25噬菌体微囊粉,通过响应面优化试验得到海藻酸钠和CaCl2添加量分别为3.72、2.55?g/100?mL时,JS25噬菌体包埋率可达88.38%;该条件下的JS25微囊粉粒径分布在20～90?μm之间,且呈正态分布;并且与浮游态噬菌体相比,微囊化的JS25噬菌体稳定性显著增加至35?d（4?℃和20?℃）。另外,JS25微囊粉在不同食品模拟体系中均可迅速释放,呈现先增加后稳定的趋势,在8?min后释放率均达75%以上。说明该工艺可以有效固定JS25噬菌体,并且对噬菌体效价影响较小。因此,海藻酸钠微囊化JS25噬菌体可以用于JS25噬菌体微囊粉的生产加工。     

微波条件下微波纸中邻苯二甲酸酯向食品模拟物Tenax的迁移

研究250W和600W微波加热功率条件下微波纸中5种邻苯二甲酸酯向食品模拟物Tenax迁移的规律,并与常规高温迁移实验的结果比较。结果表明:微波加热条件下的迁移受加热功率、加热时间、迁移物分子结构、相对分子质量和极性等因素影响。与常规高温迁移相比,微波加热能加速物质迁移,说明迁移过程也受加热方式影响,微波加热可作为加速纸质包装中有害物质迁移的实验方法。     

Oral Toxicity of Cold Plasma‐Treated Edible Films for Food Coating

No prior research has investigated whether the cold plasma treatment (CPT) resulted in the formation of toxic compounds. Therefore, this study carried out the experiment to check the safety of edible films treated with cold plasma by examining their acute and subacute oral toxicity in a rat model. Single‐dose acute (5000 mg/kg body weight) and 14‐d subacute (1000 mg/kg body weight/day) oral toxicity of cold plasma‐treated edible films was assessed for male and female Sprague–Dawley (SD) rats. Rats administered 5000 mg/kg of edible film did not show the signs of acute toxicity or death after 14 d of observation. Similarly, no signs of acute toxicity or death were recorded during 14 d in rats administered 1000 mg/kg/day of edible film treated with cold plasma. Although changes in the levels of several blood components (hematocrit, hemoglobin, bilirubin, creatinine, and aspartate aminotransferase) of samples were observed, the changes compared to the control were considered to be toxicologically irrelevant as their levels were within normal physiological ranges. Macroscopic analysis showed there were no changes in color or texture of representative liver sections of SD rats following the oral administration of edible films with CPT (F‐CP) or without CPT (F‐NT). The results demonstrate that the cold plasma‐treated edible film possessed very low toxicity, suggesting that CPT does not generate harmful by‐products in the edible film.     

微波纸中邻苯二甲酸酯向Tenax的迁移规律及预测

研究微波纸中邻苯二甲酸酯向食品模拟物Tenax（改性聚苯醚）迁移时的变化规律,并分别基于Fick第二定律和Weibull分布理论建立迁移预测模型。与迁移实验值相比,基于包装有限体积-食品有限体积体系和恶劣迁移条件下建立的Fick迁移模型,其预测值往往略高于实验值,其预测效果可用于评估食品安全并提供更高的安全阈值。基于实验经验建立的Weibull迁移模型,其迁移预测曲线能有效地描述真实地迁移过程。     

源于食品加工副产物纳米纤维素晶体的制备及其在食品中的应用

近年来,作为一种环境友好材料——纳米纤维素,其制备及在材料、食品、化工、医药等领域的应用备受人们关注,其中纳米纤维素晶体具有高长径比、高比表面积、高结晶度、高机械强度和良好的热稳定性等优良特性。在介绍纳米纤维素晶体制备方法的基础上,对源于食品加工副产物纳米纤维素晶体的理化特性(形貌、结晶度、稳定性等)及主要应用方面(作为食品包装材料增强剂、Pickering乳液稳定剂、食品配料等)进行了全面综述,并对纳米纤维素晶体研究存在的问题及今后的发展方向进行了展望。     

Stability Enhancement of Ocimum Sanctum Linn. Essential Oils Using Stearic Acid in Aluminum Carboxymethyl Cellulose Film‐Coated Gelatin Microcapsules

Holy basil essential oils (HBEO) can be used in many food applications due to antioxidant and antimicrobial attributes, but they are susceptible to degradation upon storage. Therefore, a protective system is required to extend their shelf life. HBEO was microencapsulated by coacervation using gelatin and the microcapsules were subsequently coated with stearic acid (1%, 2%, and 3%) in carboxymethyl cellulose emulsions. The results showed that HBEO contents decreased with increasing stearic acid concentrations from 76% to 59%. Fourier transform infrared spectroscopy analysis suggested that HBEO was stable during microencapsulation. After 3‐month storage, changes in appearance were detected in all samples, especially the uncoated and 3% stearic acid‐coated microcapsules. Additionally, the surface HBEO content increased significantly, consistent with a distinct increase in darkness and agglomeration. X‐ray diffraction analysis revealed the physical change of microcapsules, attributed to the renaturation of gelatin and recrystallization of stearic acid. The antioxidant activity of both non‐encapsulated and encapsulated HBEO after storage decreased significantly, except the microcapsule coated with 1% stearic acid (half maximal inhibitory concentration of 0.35 mg/mL), whereas the antimicrobial activity remained constant. The findings suggest that HBEO microcapsules coated with 1% stearic acid could serve as antioxidant and antimicrobial additives in food industries.     

食品智能控释技术及其在益生菌制品的应用

食品智能控释技术是指食品的功能属性成分通过对其在食品加工以及摄取过程的环境响应来控制功能属性成分的释放与否、释放速度以及释放程度.智能控释有利于食品成分在食品加工、储藏过程的稳定,也能使其充分赋予食品的功能属性.可应用于食品的智能控释技术包括微胶囊化技术、微球技术、纳米技术、脂质体技术、超分子形成法等.在益生菌制品中应用智能控释技术,可以提高益生菌加工和储藏过程的耐热、耐氧性能,摄入体内能耐受胃酸而不产生释放,确保最多的活菌到达肠道产生释放,从而发挥益生菌的最大功能活性。