Physical Properties of Beeswax,Sunflower Wax,and Candelilla Wax Mixtures and Oleogels

To be able to tailor and optimize the physical properties of oleogels for various food applications, more information is needed to understand how different gelators interact. Therefore, the objectives of this study were to evaluate the interactions between binary mixtures of beeswax (BW), candelilla wax (CLW), and sunflower wax (SFW) in pure form as well as in 5% wax oleogels made with soybean oil, in terms of their crystallization and melting properties, crystal morphology, solid fat content, and gel firmness. CLW:BW mixtures had eutectic melting properties, and oleogels from these mixtures with 40:60 to 90:10 CLW:BW were firmer compared to oleogels made with one wax. The main components in SFW and BW appeared to cocrystallize or crystallize at the same temperature, but nonlinear changes in melting point and solid fat content profile of oleogels prepared with the mixed waxes indicated that SFW dominated oleogel formation. In addition, oleogels prepared with mixtures of SFW and BW had lower firmness compared to oleogels prepared with one wax, indicating an incompatibility between the two waxes. The main wax components in SFW and CLW never cocrystallized, and low levels of CLW appeared to prevent SFW from forming a crystalline platelet network. This resulted in low firmness of oleogels made from mixtures of 90:10 to 60:40 SFW:CLW compared to oleogels prepared with one wax. However, the firmest oleogels of all mixtures were made from 10:90 SFW:CLW. Changes in gel firmness and melting properties with mixed wax oleogels were likely to be due to changes observed in the crystal size and morphology. In addition, the firmest gels were shown to result from mixtures that were predicted to have >40% hydrocarbon content, and a high hydrocarbon to wax ester ratio, but minor components such as free fatty acids and fatty alcohols may have also influenced firmness.     

Effects of Conjugation between Proteins and Polysaccharides on the Physical Properties of Emulsion-Based Edible Films

The effects of conjugation between protein (soybean or peanut protein isolates) and polysaccharides (dextran or gum acacia) with different glycation time (0–32 hours) on the physical properties of emulsion-based edible films containing beeswax as dispersed phase were studied. Both the reaction time and type of polymers significantly (P < 0.05) affected the emulsifying properties of conjugates. Pearson's correlation analysis showed that the emulsifying activity index (EAI), emulsifying stability index (ESI), and droplet size of emulsions were in strong correlation with the physical properties of films, such as whiteness index, transparency, water vapor permeability, surface hydrophobicity, thermal stability, and mechanical properties. Furthermore, even though glycation could significantly (P < 0.05) affect intermolecular interactions between polymers in films, there was no strong correlation between the intermolecular interactions and the physical properties of films. Therefore, the emulsifying properties of conjugates are essential for preparing emulsion-based edible films.     

Physical Properties of Candelilla Wax,Monoacylglycerols, and Fully Hydrogenated Oil Oleogels

Oleogels have been studied in the past decade due to their potential to replace saturated fat in foods. Oleogelators have been mostly studied alone or in binary systems. Sometimes a single oleogelator cannot achieve all the technological properties necessary for a specific food application. Thus, the aim of this work was to investigate the interaction between candelilla wax (CLX), monoacylglycerols (MAG), and a fully hydrogenated oil (hardfat [HF]) in soybean and high‐oleic sunflower oils and to evaluate their physical properties. The concentration of the total oleogelator was between 5% and 10%, from pure CLX (5%), sample OP, up to many combinations of MAG, HF, and CLX samples O1, O2, O3, O4, O5, and O6. Samples were evaluated according to their microstructure, melting properties, rheological behavior, hardness, oil‐binding capacity (OBC), and thermal stability. Results showed that the addition of MAG and HF to CLX created a softer gel but improved its rheological properties. Changes in the physical properties were related to the various proportions of CLX, MAG, and HF rather than the overall concentration of structuring agents. For example, for a total concentration of 5% of the structuring agent, a decrease in the CLX concentration from 5% to 3% and the addition of HF and MAG resulted in a softer crystalline network. Increasing the overall concentration of oleogelators by increasing the amount of HF and/or MAG and maintaining the concentration of the CLX constant did not improve the hardness of the gel. This study showed that at least 3% of CLX must be added to the system to obtain a semisolid material independently of the amount of MAG and/or HF added.     

Water vapor and oxygen permeability of wax films

The water vapor (WVP) and oxygen (O₂P) permeabilities of beeswax (BW), candelilla wax (CnW), carnauba wax (CrW) and microcrystalline wax (MW), formed as freestanding films, were determined. CnW and CrW both had small values for O₂P (0.29 and 0.26 g·m⁻¹·sec⁻¹·Pa⁻¹ × 10⁻¹⁴, respectively), which are less than half the value for high-density polyethylene and about a decade greater than the value for polyethylene terephthalate. O₂P values for BW and MW were about 6−9× greater than those of CnW and CrW. WVP of CnW was 0.18 g·m⁻¹·sec⁻¹·Pa⁻¹ × 10⁻¹², which is about one-half the value for CrW and MW and about one-third the value for BW. The WVP of CnW was somewhat less than that of polypropylene and somewhat greater than that of high-density polyethylene. Differences in permeabilities among the wax films are attributed mainly to differences in chemical composition and crystal type as determined by X-ray diffraction.     

费-托合成蜡的性质及应用展望

结合费托合成工艺原理及现状介绍了费-托合成蜡的生产过程及性质,并对不同厂家生产的费-托合成蜡的性质进行了分析比较,同时简要介绍了费-托合成蜡的改性方式及改性后费-托合成蜡的性质。通过分析费-托合成蜡在不同行业的实际应用现状,展望了费-托合成蜡的发展前景。     

海藻酸/羧甲基纤维素共混膜的结构与性能研究

用溶液共混法制备了海藻酸/羧甲基纤维素共混膜,通过红外光谱、X-射线衍射、原子吸收光谱、扫描电镜、热分析等对共混膜的结构进行了表征,并测定了不同配比共混膜的透光率、拉伸强度、断裂伸长率、水蒸汽透过率和吸水率.结果表明:共混膜中海藻酸和羧甲基纤维素之间具有较强的相互作用和良好的相容性.共混膜具有良好的力学性能,在生物材料...     

铁电薄膜的材料系统与功能性质

集成铁电体把铁电材料与集成半导体技术联合起来,以发展出一批新的电子器件.铁电薄膜在其中发挥着非挥发性记忆、热释电、压电、光折变、抗辐射、声学的和/或介电的功能性质.在不同的器件应用中,铁电薄膜的材料体系是不相同的.在非挥发性存贮器(NVRAM)中,PZT薄膜面临着SrBi2Ta2O9(SBT)系列铁电体的强力挑战;Ba1-xSrxTiO3(BST)则可能出现在下一代高密度动态随机存贮器(DRAM)中.金属氧化物电极和/或过渡层可以克服Pt电极面临的一些问题,并有助于铁电薄膜的外延生长.     

石蜡复合相变材料的研究进展及其热学性质

石蜡作为相变储能材料具有不存在过冷及析出现象,性能稳定,无毒,无腐蚀,价格便宜等优点。石蜡复合相变储能材料弥补了石蜡作为相变储能材料的缺点,改进了在实际应用中相变材料的效果,并且扩大了石蜡相变储能材料应用的领域。主要介绍了国内外对石蜡复合相变储能材料的研讨及相关热学性质。     

新型汽车防锈蜡的研制及性能研究

对乳化蜡的配方及乳化工艺条件进行了研究,当石蜡质量分数为10%～20%、氧化石蜡质量分数为3%,采用复合乳化剂硬脂酸与三乙醇胺（其质量比为5∶2,用量为7%）,在85℃、800～1000r/min的条件下乳化20～30min可制得稳定性高、分散性好的乳化蜡。以此乳化蜡为原料,采用复合防锈剂,当防锈剂A与防锈剂C质量比为3∶1、加入量为6%时,可制得pH值为8～8.5、氨味小、半透明的防锈蜡,其主要性能与国外先进同类产品指标接近。     

Properties and Biodegradability of Films Based on Cellulose and Cellulose Nanocrystals from Corn Cob in Mixture with Chitosan

The increase in consumer demand for more sustainable packaging materials represents an opportunity for biopolymers utilization as an alternative to reduce the environmental impact of plastics. Cellulose (C) and chitosan (CH) are attractive biopolymers for film production due to their high abundance, biodegradability and low toxicity. The objective of this work was to incorporate cellulose nanocrystals (NC) and C extracted from corn cobs in films added with chitosan and to evaluate their properties and biodegradability. The physicochemical (water vapor barrier, moisture content, water solubility and color) and mechanical properties of the films were evaluated. Component interactions using Fourier-transform infrared (FTIR) spectroscopy, surface topography by means of atomic force microscopy (AFM), biodegradability utilizing a fungal mixture and compostability by burying film discs in compost were also determined. The C-NC-CH compared to C-CH films presented a lower moisture content (17.19 ± 1.11% and 20.07 ± 1.01%; w/w, respectively) and water vapor permeability (g m⁻¹ s⁻¹ Pa⁻¹ × 10⁻¹²: 1.05 ± 0.15 and 1.57 ± 0.10; w/w, respectively) associated with the NC addition. Significantly high roughness (Rq = 4.90 ± 0.98 nm) was observed in films added to NC, suggesting a decreased homogeneity. The biodegradability test showed larger fungal growth on C-CH films than on CH films (>60% and <10%, respectively) due to the antifungal properties of CH. C extracted from corn cobs resulted in a good option as an alternative packaging material, while the use of NC improved the luminosity and water barrier properties of C-CH films, promoting strong interactions due to hydrogen bonds.     

淀粉基全生物降解膜的制备工艺研究

通过流延法制备了一系列的淀粉基全生物降解膜。膜的物理性能研究表明,制备膜的最佳料液浓度为8%,膜的物理性能随着搅拌速度和搅拌时间的增加而增强;红外光谱表征和力学性能测试表明,随着干燥温度的升高,膜的结晶结构和拉伸强度增加,但是断裂伸长率显著下降。     

The Effect of Addition of High-Melting Monoacylglycerol and Candelilla Wax on Pea and Faba Bean Protein Foam-Templated Oleogelation

Use of oleogels prepared from hydrocolloids has recently gained considerable attention as an alternative for trans and saturated fats. Lately, pulse proteins such as faba bean protein and pea protein have been successfully used to prepare oleogels using a foam-templated approach. Although the pulse proteins are healthy oleogelators, high oil loss and low quality of cake baked using pulse protein-stabilized oleogels due to its poor rheological properties challenged its use. The present study explored whether the addition of small amount of high-melting monoglyceride (MAG) or candelilla wax (CW) can be used to improve the oil binding capacity, rheological properties, and baking qualities of pulse protein-stabilized oleogels composed of 5% faba bean or pea protein concentrate with 0.25% xanthan gum foams. Different concentrations (0.5–3%) of MAG or CW were dissolved in canola oil at 80 °C, followed by addition into the freeze-dried protein-polysaccharide foams (pH 7) and quickly transferred to a refrigerator to facilitate the formation of oleogels. The crystallized additives were found to be reinforcing the protein foam network in the oleogels. With increase in concentration of CW and MAG, the oil binding capacity, firmness, cohesiveness, and storage moduli of the oleogels were increased. Oleogels with and without MAG or CW were then characterized and tested for their performance as a shortening replacer in model baked cakes. Findings showed improved textural properties of cake upon addition of MAG in the foam-templated oleogels, however, compared to the shortening, negative effect on cake hardness and chewiness was still observed with the oleogels.     

壳聚糖对玉米淀粉可食膜性能的影响

以玉米淀粉为原料,结合壳聚糖在增塑剂甘油的作用下通过溶液浇铸法制备了玉米淀粉/壳聚糖复合可食薄膜,采用红外光谱和扫描电子显微镜对薄膜结构和微观形貌进行了表征,研究了壳聚糖的含量对薄膜力学性能、水蒸气透过性、阻油性及抗菌性能的影响.结果表明,适量的壳聚糖可以较明显地改善薄膜的力学性能,提高其隔水和阻油性能;壳聚糖与淀粉质...     

地沟油与食用油理化指标的对比分析

根据食用动植物油脂检测的国家标准方法,对比分析了地沟油和食用油的感官指标,碘价、折光率、过氧化值、酸值和电导率等理化指标。结果表明,与食用油相比,地沟油的酸值和电导率明显增大,酸值和电导率可以作为鉴定地沟油的指标。     

Oleogel Fabrication Based on Sodium Caseinate,Hydroxypropyl Methylcellulose,and Beeswax: Effect of Concentration,Oleogelation Method,and Their Optimization

In the present study, the oleogel preparation with hydroxypropyl methylcellulose (HPMC) (0–2 g/100 g), sodium caseinate (CN) (0–4 g/100 g), beeswax (0–5 g/100 g), and oleogelation method (foam and emulsion template) was optimized using response surface methodology (RSM) to attain the desirable oil retaining ability, rheological, and textural characteristics. For all the chosen responses, the quadratic model was the best-fitting model with a determination coefficient of R² > 0.91. Results exhibited that the HPMC and CN concentrations were the most influential tested factors on the oil binding capacity, textural, and rheological characteristics of the oleogels due to the formation of more complex and strong network. There was a significant improvement in oil binding capacity and structure recovery of samples by beeswax addition. To produce oleogel similar to industrial shortening, the optimization method was done based on maximum oil binding capacity and thixotropic recovery and other responses were chosen equal to those of shortening values (ɳ_a = 330 Pa.s, G′ = 276,543 Pa, A value = 164,308 Pa s rad⁻¹, and firmness = 44.99 g). As regards the optimized level of structuring agents and responses (ɳ_a = 317 and 329 Pa.s, G′ = 249,782 and 260,997 Pa, A value = 180,022 and 180,373 Pa s rad⁻¹, and firmness = 44.37 and 36.98 g corresponding to Optimization 1 and Optimization 2, respectively), fabrication of oleogels with at least 90 g/100 g trans-free and low saturated oil and attributes close to industrial shortening is possible.     

非PVC多层共挤输液膜与碳酸氢钠注射液的相容性

研究非PVC多层共挤输液膜与碳酸氢钠注射液的相容性。配制碳酸氢钠注射液,分装于不同材质的非PVC多层共挤输液袋中,检测各项指标,并进行比较。碳酸氢钠注射液pH值随时间逐步升高,所选用包装材料对此有显著影响。适宜的非PVC多层共挤输液膜可用于碳酸氢钠注射液的包装。     

Effects of Polymer Additives and Dispersion State on the Mechanical Properties of Cellulose Nanocrystal Films

Films produced from colloidal and nanomaterial dispersions such as aqueous cellulose nanocrystal (CNC) dispersions tend to crack above a critical cracking thickness; this issue limits the ability to produce flow‐aligned CNC films at thicknesses above ≈50 μm. This research explores the effects of adding polyethylene oxide (PEO), flocculation with hydrochloric acid (HCl), and the combination of both methods on film cracking, mechanical properties, and mechanical anisotropy. Most research on CNC polymer composites focuses on composites where the polymer is the majority component. To the authors' knowledge there has been only one investigation of CNC films' mechanical anisotropy and no studies of using HCl flocculation to flocculate CNC dispersions prior to shear casting. PEO addition significantly reduces Young's modulus, tensile strength, and toughness, but enhances the Young's modulus anisotropy. Flocculation results in little property deterioration but nearly eliminates mechanical anisotropy. The combination of both techniques results in similar properties as flocculation alone. These findings highlight the trade‐offs between these two approaches and can be used to help guide further research on obtaining robust shear cast CNC films over a range of thicknesses.

     

十二烯基琥珀酸淀粉酯的制备及其性质研究

研究了反应温度、反应时间、体系pH、十二烯基琥珀酸酐用量等条件对酯化反应的影响。采用红外光谱对产品进行了结构表征,结果表明反应后淀粉分子上的确引入了烯基琥珀酸酐基团;用扫描电镜观察产品的颗粒形态,发现十二烯基琥珀酸淀粉酯(SSDS)颗粒表面受到一定程度的破坏。研究了SSDS的性质,结果表明SSDS乳化能力强,而且乳化稳定性比较好,SSDS糊符合假塑性流体特征。     

薄膜厚度对Al掺杂ZnO薄膜性能的影响

采用直流磁控溅射技术,以氧化锌铝陶瓷靶为靶材,在玻璃衬底上制备了ZnO：Al（ZAO）薄膜样品。在其他参数不变的情况下,由不同溅射时间得到了不同厚度的薄膜,研究了薄膜的结构性质、电学和光学性质随薄膜厚度的变化关系。实验结果表明：在薄膜厚度为500 nm时,ZAO薄膜具有最优化的光电性能,电阻率为1.68×10-3Ω.cm,可见光区平均透射率为90.3%。