柴油催化氧化脱硫的研究

用溶胶-凝胶法制备HPWA/SiO2催化剂,用于直馏柴油进行了脱硫实验。实验考察了催化剂用量(以催化剂的质量相当于模型溶液的质量分数表示),O/S摩尔比(叔丁基过氧化氢与硫含量的摩尔比),反应温度和反应时间对脱硫效果的影响,得出最佳反应条件为催化剂用量5%,O/S摩尔比为7,反应温度为70℃,反应时间为2 h。实验结果表明该催化剂有很好的催化氧化作用,氧化后产物经过溶剂抽提,可将硫含量从350μg/g降到100μg/g。达到了国家标准。     

Ga2O3/凹凸棒石复合催化剂的制备和肉桂酸环己酯的催化合成

采用浸渍法由凹凸棒石负载氧化镓(Ga2O3)制备了Ga2O3/凹凸棒石复合催化剂。用IR、XRD、BET、TEM等对催化剂结构进行了表征,并通过肉桂酸环己酯的合成,对催化剂制备条件、催化活性和反应动力学特性进行了考察。结果表明,催化剂的最佳制备条件是Ga2O3负载量为催化剂总质量的10 %,焙烧温度450 ℃;在肉桂酸环己酯合成过程中,当n(肉桂酸):n(环己醇)=1:4.5(其中肉桂酸0.02 mol),催化剂用量0.5 g,反应温度130 ℃,反应时间70 min时,产品平均酯化率为95.0 %,催化剂经5次重复使用,酯化率仍达81.5 %;反应为准二级反应,表观活化能为90.78 kJ/mol,130 ℃时反应速率常数为1.03×10-2 L/(mol•min)。     

二氧化双环戊二烯反应液的高效液相色谱分析

采用高效液相色谱建立了快速分析二氧化双环戊二烯反应液中溶剂异丙苯、氧化剂过氧化氢异丙苯和反应副产物2-苯基异丙醇的新方法。以Agilent Eclipse XDB C18型色谱柱为分离柱,乙腈/0.1%(φ)磷酸为流动相,梯度淋洗,流量1.0 mL/min。实验结果表明,目标组分分离效果良好,且各目标化合物在各自配制的浓度范围内线性关系良好,回归系数均达到0.999 9,各目标组分的最低检出限为0.15～0.25 mg/L,加标回收率为101.9%～111.6%,相对标准偏差均不高于2.37%,定量结果准确可靠,数据精密度良好,为二氧化双环戊二烯生产企业提供了一种简便、快速、准确的分析方法。     

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     

过氧化氢异丙苯分解催化剂研究进展

介绍了固体酸催化剂的研究进展及硫酸催化工艺流程的改进情况。过氧化氢异丙苯（CHP）分解是异丙苯法生产苯酚丙酮的关键反应步骤,使用硫酸催化CHP分解反应存在反应安全性低、副产物多、设备腐蚀严重等诸多问题。作为硫酸的理想替代品,固体酸催化剂具有许多优点,但还需要对其活性、使用寿命及再生性能等进行深入研究。     

对甲苯磺酸催化合成乙酸环己酯

以乙酸、环已醇为原料,对甲苯磺酸为酯化催化剂合成乙酸环乙酯结果表明,在环已醇与乙酸物质的最比为（１．４～１．６）：１．０,反应时间２小时及适量催化剂、带水剂存在的下,酯化这到９７．３％,产品纯度不小于９８％,用于甲苯磺酸作酯化催化剂,共性能优于硫酸。     

A well balanced omega-6/omega-3 ratio in developing flax bolls after heating and its implications for use as a fresh vegetable by humans

Flax seed (Linum usitatissimum L.) can be used for both industrial and food products including a wide variety of nutraceuticals and health foods and for which a restricted and specific fatty acid (FA) profile is required. As functional foods, flax meal is provided to humans in the form of ground vacuum-packed grains or flaxseed-enriched baked products. However, no reports are yet available on the potential food use for fresh flax products. A comparative study was conducted using two flax cultivars, AC McDuff and Linola, to evaluate FA accumulation in developing bolls at 12 different developmental stages and to determine stages having well balanced omega-6/omega-3 FA ratio. The lipid hydroperoxide level in fresh bolls and seeds, and the cyanogenic glucoside content in developing bolls were also measured in AC McDuff following different heating treatments. The findings indicated and suggested that the use of flax bolls as health promoting vegetable can be considered if adequately processed and palatable food attributes are obtained.     

以酶催化氧化油脂的方法制备香味料的研究进展

脂肪氧合酶催化油脂中的不饱和脂肪酸生成氢过氧化物,氢过氧化物再在裂解酶的作用下,生成具有青草香、青叶香香气特征的挥发性醛类物质。主要论述了不饱和脂肪酸酶催化氧化的基本途径,脂肪氧合酶的制备及氢过氧化物的生成,裂解酶的制备及氢过氧化物的裂解过程。并介绍了酶催化氧化油脂生成香味料的现状,展望了其发展前景。     

Effect of γ-Oryzanol on the Flavor and Oxidative Stability of Refrigerated Cooked Beef

ABSTRACT: γ-Oryzanol and α-tocopherol were added to beef patties as natural antioxidants. Beef patties containing 100 ppm γ-oryzanol had higher oxidative stability ( P <0.05) during storage at 4 °C than did beef patties with other antioxidants and without antioxidant. Thiobarbituric acid-reactive substances (TBARS) values, warmed over flavor (WOF) scores, C-7 oxidized cholesterol derivatives (OCDs), and concentrations of both hydroperoxide and hexanal in the cooked beef containing γ-oryzanol were significantly lower than those of other treatments ( P < 0.05). All variables had similar trends during the refrigerated storage. Significant correlations were found between TBARS and C-7 OCDs, TBARS and WOF, hydroperoxide and hexanal, and hexanal and WOF ( P < 0.05).