食品添加剂领域标准化工作的现状分析和对策建议

标准化是我国应对食品安全问题的重要举措。本文由"塑化剂"事件谈起,全面剖析了我国食品添加剂领域标准化工作现状和存在的问题,并探讨了如何加强该领域标准化工作的对策建议。     

高掺量粉煤灰砌块制备的实验研究

重点研究了高掺量粉煤灰砌块制备的新工艺,并采用正交分析方法对影响高掺量粉煤灰砌块强度和水化效果的几种因素进行了分析,得出了最佳的试验配方和加工工艺。     

改良剂对速冻水饺冻裂率及褐变的影响研究

研究变性淀粉、硬酯酰乳酸钙-钠(CSL-SSL)、抗坏血酸(VC)、复合磷酸盐对速冻水饺冻裂率及色泽褐变的影响,结果表明:各种成分的最佳加入量:变性淀粉5%,CSL-SSL 0.2%,抗坏血酸0.025%,复合磷酸盐0.25%.     

高效液相色谱法快速测定饮料中的苯甲酸、山梨酸和糖精钠

将饮料样品定量稀释后，用针筒式水膜过滤器处理后，直接进样，外标法进行液相色谱定性、定量分析。用此方法进行了不同水平的加标回收率测试，证明方法快捷可靠，非常适用于大量的样品的快速测定。     

一种新型油井水泥降失水剂的室内评价

聚乙烯醇（PVA）分子中有大量的羟基存在，可以作为油井水泥的降失水剂。选择了一种交联剂与PVA反应，以提高PVA的降失水功能。加入交联剂的PVA17-88降失水剂的降滤失机理是：在过滤介质与滤饼之间形成一层致密的薄膜，阻止了水泥浆中的水向地层流失。实验表明，单纯地用PVAl7-88作为油井水泥的降失水剂时，降失水效果不明显，而加入少量交联剂后，可以使PVAl7-88的加量减少大约55％；交联剂的加量为2．0％PVA时为最佳加量；加入交联剂与不加入交联剂的PVA17-88降失水剂相比，其耐温和耐盐能力都有所提高，前者的使用温度至少超过90℃，后者接近80℃。     

Oxidation of Benzaldehyde to Benzoic Acid

Benzaldehyde was oxidized to benzoic acid using Na₂WO₄·2H₂O as a catalyst. Different factors, such as different acidic additives, the reaction time, the amount of catalyst, and hydrogen peroxide dosage, on the isolated yield of benzoic acid were investigated. The effects of surfactants on yield of benzoic acid were also discussed in the acid-free system. The results indicated that both acidic additives and surfactants in an acid-free system can effectively improve the isolated yield of benzoic acid, especially non-ionic surfactants, such as β-CD. The product was determined by IR and m.p.     

Insights into the influence of additives on the thermal gradient induced migration of lubricant

Thermo‐capillary migration is a phenomenon that the thermal gradients will drive a liquid to flow from warm to cold regions. It is of great importance to prevent the lubricant migration on rubbing surfaces in the cases where the amount of lubricant is limited. In this paper, four different lubricant additives are incorporated into one base oil, and the effects of additives on the migration behaviour and surface tension coefficient are investigated. The functional mechanisms of additives are discussed. The experimental results demonstrate that the additives have remarkable influences on the migration performance of lubricant. The migration behaviour shows the relation to not only the surface tension coefficient, but also the actions between the additive and substrate. This should be considered in the designing process of an anti‐migration lubricant. Copyright © 2016 John Wiley & Sons, Ltd.     

Development of a new silicone‐base transdermal therapeutic system. II. Study of trifunctional ingredients

The effect of two trifunctional silicon compounds was investigated on the polarity behavior of silicone elastomers by investigating the swelling properties in solvents of various polarity. The properties of the silicone elastomer were also influenced by methyltrimethoxysilane (MTS) and N‐[(aminoethyl)aminopropyl]trimethoxysilane (GF‐91) if they were used together with the networking agent. The cooperative effect of the polar liquid ingredients [glycerol, ethylene glycol, propylene glycol, poly(ethylene glycol) 400] and GF‐91 as well as the dissolution of the liquid ingredients from the silicone elastomer were studied. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1187–1194, 2001     

Stability of hydroperoxide lyase activity from Amaranthus tricolor (Amaranthus mangostanus L.) leaves: influence of selected additives

BACKGROUND: Hydroperoxide lyase (HPL) has potential value for the flavour additive industry. Currently, the production and application of HPL suffer from stability problems. The objective of this study was to investigate the stabilisation of HPL preparation from Amaranthus tricolor leaves by the addition of selected chemical additives. RESULTS: Amaranthus tricolor leaves were identified as a particularly rich source of 13‐HPL activity. The addition of 100 g L^?1 sucrose and trehalose to microsomal HPL prior to lyophilisation could retain nearly 100% enzymatic activity, compared to only 20% for the lyophilised control. The lyophilised microsomal HPL containing sucrose maintained full activity for even 40 days storage at ? 20 °C. For HPL solution, glycerol was effective for long‐term stability at ? 20 °C. Moreover, poyols (sucrose and trehalose) and amino acid (glycine) enhanced the thermostability of HPL, while KCl and polyol mannitol decreased the thermostability of HPL. CONCLUSION: The flavour‐producing enzyme HPL, found in the leaves of Amaranthus tricolor, was stabilised by the addition of chemical additives. Copyright © 2010 Society of Chemical Industry     

Thermal and Electrical Properties in Plasma-Activation-Sintered Silicon Carbide with Rare-Earth-Oxide Additives

This study investigates the thermal and electrical properties of SiC ceramics with a combination of Y₂O₃ and rare-earth-oxide additions as sintering additives, by comparing four types of SiC starting powders varying in particle size and chemical composition. The powder mixtures were plasma-activation sintered to full densities and then annealed at high temperatures for grain growth. The thermal conductivity and electrical resistivity of the SiC ceramics were measured at room temperature by a laser-flash technique and a current–voltage method, respectively. The results indicate that the thermal conductivity and electrical resistivity of the SiC ceramics are dependent on the chemical composition and particle size of the starting powders. The thermal conductivities observed for all of the annealed materials with a rare-earth La₂O₃ sintering additive were >160 W·(m·K)⁻¹, although low electrical resistivity was observed for all materials, in the range 3.4–450 Ω·cm. High thermal conductivity, up to 242 W·(m·K)⁻¹, was achieved in an annealed material using a commercial 270 nm SiC starting powder.