双乙酸钠在大空间下分解动力学研究

研究了在55、65、75、85、95、105、115℃的大空间条件下双乙酸钠的分解实验,确定其分解反应为零级反应,并根据不同温度下的分解速率系数求出双乙酸钠的分解动力学方程。      

食品添加剂双乙酸钠的合成动力学研究

以醋酸-烧碱法合成双乙酸钠。在不同的原料配比下,测定双乙酸钠产率与反应时间的关系,进而确定反应的初速率;在不同的反应温度条件下,测定双乙酸钠产率和反应平衡常数,以此确定动力学方程中的待定参数。结果表明:利用动力学方程推导出来的数据结果能较准确的对实验结果进行验证。     

双乙酸钠在调味品中的防腐作用

1国内外食品防腐剂应用现状及发展趋势食品防腐剂是食品保藏技术的重要内容，它能抑制或消灭食品中的各种杂菌，并使食品在保藏过程中有保鲜的效果。目前，我国食品防腐剂主要采用苯甲酸钠及山梨酸钾，但90％以上的食品及调味品采用的是苯甲酸钠。苯甲酸钠在工业生产中用催化氧化或空气氧化甲苯制取苯甲酸。再与碳酸氢钠反应制取苯甲酸钠。其作用机理是阻碍霉菌和细菌对氨基酸的吸收，抑制微生物细胞的呼吸酶、脱氨酶、大肠杆菌的氧化还原酶等的活性，干扰细菌体内的代谢过程。苯甲酸钠的每日容许摄取量ADI值为0～5mg／kg。由于苯甲酸钠价…     

双乙酸钠防腐剂在酱油生产中的应用

双乙酸钠是FAO、WHO及我国政府批准使用的食品防腐剂 ,它集安全性、有效性、经济性于一身 ,将其作为酱油生产中的防腐剂 ,用量为 0 .0 5 %～ 0 .1% ,取得了较好的效果     

双乙酸钠合成方法研究

双乙酸钠是一种较理想的食品、饲料添加剂。本文介绍了两种不同的双乙酸钠合成方法,并得到相应较佳的实验结果。     

新型食品添加剂双乙酸钠的合成研究

以醋酸和烧碱为原料、在水为溶剂的条件下制备双乙酸钠,系统地研究了原料配比、温度、时间等因素对产品质量及收率的影响,得到了最优化工艺条件。正交试验确定的优化合成条件是:n(醋酸)∶n(烧碱)=2.4∶1,反应温度100℃,反应时间120min。产物收率为94.15%,产品质量达到美国食品级标准。     

双乙酸钠的醋酸-碳酸钠法合成研究

以醋酸和碳酸钠为原料,在无溶剂的条件下制备双乙酸钠,系统地研究了原料配比、温度、时间等因素对产品质量及收率的影响,得到了最优化工艺条件。正交试验确定的优化合成条件是:n(醋酸):n(碳酸钠)=(3.8～3.9):1,反应温度90℃,反应时间180min。产物收率为94%,产品质量达到美国食品级标准。     

防霉剂双乙酸钠的特性及其应用

介绍了食品添加剂双乙酸钠的理化性质、安全性及产品标准以及在食品、粮食谷物和饲料中的应用及使用方法、抗菌机理等     

大蒜素在正戊烷和乙醇中的分解动力学研究

研究了大蒜素在正戊烷、乙醇溶剂中的分解动力学过程,拟合得到了动力学参数：大蒜素在正戊烷、乙醇溶剂中的分解活化能分别为56.0、72.0 kJ/mol,指前因子分别为9.2×105、1.5×106。采用B3LYP方法,在6-31+G(d,p)基组下计算了大蒜素与正戊烷、乙醇的相互作用能分别为1.12、31.18 kJ/mol,说明大蒜素与乙醇分子间存在较强的相互作用;采用自然键轨道理论分析了以乙醇为溶剂的体系中电子供体(Donor)轨道、电子受体(Acceptor)轨道以及它们之间相互作用的稳定化能,结果表明大蒜素分子中的氧原子的孤对电子O(13)对乙醇分子的羟基（O(21)-H(20)）的反键轨道稳定化能为45.45 kJ/mol,说明大蒜素与乙醇分子产生较强的氢键作用,分散了大蒜素分子中的氧原子上的负电荷,导致分子内质子转移能量升高,因而大蒜素在乙醇中具有更高热稳定性。     

双乙酸钠的防霉应用研究

研究了新型防霉剂双乙酸钠对黑曲霉、黑根霉、黄曲霉、球毛壳、扩展青霉等常见菌的抑制作用，并用目前应用广泛的防腐剂山梨酸钾与其作对照实验证明了双乙酸钠是一种优良的防腐剂．为其在食品、粮食、饲料等领域的防霉保鲜应用提供了一定的依据。     

食品添加剂双乙酸钠的无溶剂合成新工艺研究

用醋酸、固体烧碱为原料,无溶剂法合成食品添加剂双乙酸钠。探索最佳工艺条件为:醋酸烧碱投料摩尔比2.05-2.15:1,反应时间2h,反应温度110-120℃。产品收率达到97%以上,质量符合联合国粮农组织(FAO)和世界卫生组织(WHO)双乙酸钠食品添加剂质量标准。     

Gamma irradiation of fine-emulsion sausage containing sodium diacetate

Listeria monocytogenes, a psychrotrophic foodborne pathogen, is a frequent postprocess contaminant of ready-to-eat (RTE) meat products, including frankfurters and bologna. Ionizing radiation can eliminate L. monocytogenes from RTE meats. Sodium diacetate (SDA) incorporated into fine-emulsion sausages inhibits the growth of L. monocytogenes. Irradiation of L. monocytogenes suspended in SDA solutions resulted in synergistic reductions of the microorganism. L. monocytogenes populations were reduced by > 9 log10 units at a radiation dose of 1.5 kGy when suspended in 0.125% SDA solution. In contrast, the D10-values (the ionizing radiation doses required to reduce the population by 90%) were 0.58, 0.59, 0.57, and 0.53 kGy for L. monocytogenes populations suspended in emulsions containing 0, 0.125, 0.25, and 0.5% SDA, respectively. The D10-values for L. monocytogenes surface inoculated onto frankfurters dipped in 0, 0.125, 0.25, and 0.5% SDA solutions were 0.58, 0.53, 0.54, and 0.52 kGy, respectively. Postirradiation growth of L. monocytogenes suspended in beef bologna emulsion at 9 degrees C was dependent on SDA concentration and ionizing radiation dose. Very small, but statistically significant, changes in bologna redness, lipid oxidation, and shear force were observed for the beef bologna emulsion with the highest SDA concentration (0.5%) and irradiation dose (3.0 kGy). SDA can inhibit the proliferation of L. monocytogenes surviving the irradiation process with minimal impact on fine-emulsion sausage color, lipid oxidation, and firmness when used within regulatory limits.     

双乙酸钠对蛋糕防霉保鲜效果研究

通过稀释平板法定期检测蛋糕保藏过程中霉菌总数变化,研究了不同浓度的双乙酸钠对不同种类蛋糕防霉效果的影响.实验证明:双乙酸钠在普通面糊类蛋糕中的最佳防霉添加量为0.4%,此时蛋糕在常温下的霉菌超标时间为14 d,比不添加防腐剂的蛋糕延长10 d.0.4%双乙酸钠对三种不同配方蛋糕的防霉效果不尽相同,普通蛋糕优于戚风蛋糕,海绵蛋糕最差.     

Decomposition kinetics of dimethyl sulphide

Dimethyl sulphide is a well characterized off‐flavour in the brewing industry. The thermal re‐creation of dimethyl sulphide by the decomposition of dimethyl sulphide precursor in standardized wort is measured using pressure‐controlled boiling processes at different temperatures. The results are used for the calculation of decomposition speed constants and Arrhenius activation energies. Using these data the re‐creation of dimethyl sulphide during the wort production processes can be calculated and thereby optimized. Copyright © 2014 The Institute of Brewing & Distilling     

Protein variations in Listeria monocytogenes exposed to sodium lactate, sodium diacetate, and their combination

Most studies of the effect of adverse conditions on survival of Listeria monocytogenes have focused on stress caused by acid or sodium chloride. However, no information is available on resistance of this pathogen to stress caused by salts of organic acids. Sodium lactate and sodium diacetate are generally recognized as safe substances and are approved as ingredients for use in foods. We evaluated antilisterial properties of each of these salts and the enhanced inhibition effected by their combination in ready-to-eat meat products at pH 6.3. Changes in proteins found in this pathogen were studied in the presence of the salts in a chemically defined medium at the same pH using a proteomic approach. The total numbers of protein spots obtained from two-dimensional electrophoresis were 198, 150, and 131 for sodium diacetate, sodium lactate, and the control, respectively. Sodium diacetate treatment produced the highest number of unmatched proteins (124 versus 53 in lactate), the greatest increase in expression (20 versus 5 in lactate), and the highest number of novel proteins (90 versus 45 in lactate). The number of repressed proteins was highest in the combination treatment (41 versus -30 in the single salt treatment). Six proteins that increased or decreased by > or = 10-fold were further investigated; oxidoreductase and lipoprotein were upregulated, and DNA-binding protein, alpha amylase, and two SecA proteins were downregulated or completely suppressed by the salt treatment. Identification of all protein spots is essential for comparison with proteins induced or suppressed under other stress conditions.     

Control of Listeria monocytogenes in ready-to-eat meats containing sodium levulinate, sodium lactate, or a combination of sodium lactate and sodium diacetate

ABSTRACT:  This study investigated the use of sodium levulinate to prevent outgrowth of Listeria monocytogenes in refrigerated ready-to-eat (RTE) meat products. Turkey breast roll and bologna were formulated to contain 1%, 2%, or 3% (w/w) sodium levulinate, 2% sodium lactate, a 2% combination of sodium lactate and sodium diacetate (1.875% sodium lactate and 0.125% sodium diacetate), or no antimicrobial (control). Samples of the RTE products were sliced, inoculated with 10² to 10³ CFU/cm² of a 5-strain cocktail of L. monocytogenes , vacuum packaged, and stored at refrigeration temperature for 0 to 12 wk. Counts reached 10⁸ CFU/cm² on control turkey roll product after 8 wk, and over 10⁷ CFU/cm² on control bologna after 12 wk. Addition of 2% or more sodium levulinate to turkey roll and 1% or more sodium levulinate to bologna completely prevented growth of L. monocytogenes during 12 wk of refrigerated storage. A consumer taste panel with pathogen-free samples found no differences in the overall liking among the preparations of turkey roll or among preparations of bologna. These results show that sodium levulinate is at least as effective at inhibiting outgrowth of L. monocytogenes in RTE meat products as the current industry standards of lactate or lactate and diacetate, and levulinate addition does not alter the overall liking of the RTE meat products.     

醋酸酯淀粉对速冻调制食品中双乙酸钠测定的影响

淀粉变性方式众多,其中醋酸酯变性过程中加入了乙酸酐,反应过程中乙酸酐与醋酸酯淀粉在碱性条件下发生水解生成乙酸,从而影响了速冻调制食品中双乙酸钠的测定。为了明确速冻调制食品中双乙酸钠测定的干扰项,本文采用GB 5009.277-2016《食品安全国家标准食品中双乙酸钠的测定》对醋酸酯A-1和乙酰化二淀粉磷酸酯A-2两种木薯变性淀粉中双乙酸钠及添加不同比例淀粉的速冻调制食品中双乙酸钠含量进行测定,且检测了不同乙酰基取代度的变性淀粉乙酰基、双乙酸钠及乙酸本底含量。实验结果表明:淀粉经过乙酰化变性后,对食品中双乙酸钠的测定产生了显著的阳性干扰,其中速冻调制食品中双乙酸钠测定量与变性淀粉添加量呈线性正相关,同时变性淀粉中双乙酸钠含量与其乙酰化取代度显著正相关。综上所述,现行食品安全国家标准GB 5009.277-2016不适合添加了醋酸酯变性淀粉的速冻调制食品中双乙酸钠的测定。     

Inhibition of Listeria monocytogenes growth in cured ready-to-eat meat products by use of sodium benzoate and sodium diacetate

The effect of sodium benzoate (0.08 to 0.25%) in combination with different concentrations of sodium diacetate (0.05 to 0.15%) and NaClI (0.8 to 2%) and different finished product moisture (55 to 75%) on the growth of Listeria monocytogenes in ready-to-eat meat products was evaluated using a central composite design over 18 weeks of storage at 4 degrees C. The effects of these factors on time to growth were analyzed using a time-to-failure regression method. All main effects were significant except product moisture, which was significant when included in the two- and three-way interactions (P < 0.05). Sodium benzoate was more effective (lengthening time to growth) when used with increasing concentrations of sodium diacetate and salt and decreasing finished product moisture. The model indicated that low-moisture products, e.g., bologna or wieners, could have time-to-growth values longer than 18 weeks if they were formulated with 0.1% sodium benzoate and 0.1% sodium diacetate. Time to growth in high-moisture products, e.g., ham or cured turkey breast at 75% moisture, was predicted to be much shorter for the same basic formulation (0.1% sodium benzoate and 0.1% sodium diacetate). Consequently, high-moisture ready-to-eat products in which sodium benzoate is limited to 0.1% (current standard for generally recognized as safe) may need additional ingredients to effectively inhibit growth of L. monocytogenes.