Lipid hydrolysis and oxidation on the surface of milled rice

The changes in milled rice FFA content and composition and in conjugated diene (CD) content and bacterial, yeast, and mold counts were determined at 24, 37, and 50°C and 70% RH over 50 d. There was a rapid rate of FFA formation during the first few days of storage, which was optimal at 37°C, but that slowed after 2, 4, and 5 d at 37, 24, and 50°C, respectively. There was a second increase in FFA after about day 12 that increased with increasing temperature, indicating nonlipase hydrolysis. Linoleic and oleic acids were the main components of the total FFA produced on the surface of milled rice. The pattern of CD development followed that of FFA increase. Bacterial growth correlated with increased FFA levels after 12 d of storage, suggesting that bacterial lipase rather than bran lipase may be responsible for rice lipid hydrolysis     

Corrosion control of Cu-Ni alloys in neutral chloride solutions by amino acids

The corrosion inhibition of Cu-Ni alloys was investigated in aqueous chloride solutions using amino acids as environmentally safe materials. The corrosion rate was calculated in absence and presence of the corrosion inhibitor using polarization and impedance techniques. The inhibition efficiency of the different amino acids was also calculated.The experimental results have shown that a simple amino acid like glycine can be used as efficient corrosion inhibitor for the Cu-Ni alloys in neutral chloride solutions. An inhibition efficiency of about 85% could be achieved at very low concentrations of the amino acid (0.1 mM). For low Ni content alloy (Cu-5Ni), 2.0 mM cysteine shows a remarkable high (∼96%) corrosion inhibition efficiency. The experimental impedance data were fitted to theoretical data according to a proposed equivalent circuit model for the electrode/electrolyte interface, and the mechanism of the corrosion inhibition process was suggested. Different adsorption isotherms were tested and the corrosion inhibition process was found to depend on the adsorption of the amino acid molecules and/or the deposition of corrosion products on the alloy surface. The adsorption free energy of cysteine on Cu-5Ni (−37.81 kJ mol⁻¹) reveals a strong physical adsorption of the inhibitor on the alloy surface.     

Monooxygenase system of <Emphasis Type="Italic">Bacillus megaterium</Emphasis> ALA2: Studies on palmitic acid oxidation products

We identified many novel oxygenated FA produced from linoleic acid by microbial strain ALA2: 12,13,17-trihydroxy-9(Z)-octadecenoic acid (12,13,17-THOA); 12,13,16-trihydroxy-9(Z)-octadecenoic acid (12,13,16-THOA); 12-hydroxy-13,16-epoxy-9(Z)-octadecenoic acid; and 12,17;13,17-diepoxy-16-hydroxy-9(Z)-octadecenoic acid. 12,13,17-THOA, the main product, inhibits the growth of some plant pathogenic fungi. Recently, we reclassified strain ALA2 as Bacillus megaterium ALA2 NRRL B-21660 and opened a possible link with the well-studied catalytically self-sufficient P450 monooxygenase of Bacillus megaterium ATCC 14581 (NRRL B-3712) and B. subtilis strain 168 (NRRL B-4219). Now we have found that strain ALA2 also oxidizes palmitic acid into three oxygenated products: 13-, 14-, and 15-hydroxy palmitic acids. This indicates that strain ALA2 also possesses a monooxygenase system similar to the abovementioned well-known strains. These data facilitate studies on the oxygenase system of strain ALA2.     

柱前衍生化RP-HPLC测定中药野马追中的氨基酸

采用柱前衍生反相高效液相色谱法(RP HPLC)测定了江苏地产药材野马追茎叶及其花蕾中的总氨基酸和游离氨基酸。用邻苯二甲醛(OPA)与一氯甲酸芴甲酯(FMOC)联用全自动柱前衍生化反相高效液相色谱仪,liozosphezeC18柱,pH=7.2的醋酸钠缓冲溶液和甲醇为流动相,流速为1.0mL/min,荧光检测器,波长为Ex=340nm、Em=450nm,样品中的氨基酸在30min内得到分离和检测。结果表明:野马追茎叶及其花蕾中含17种氨基酸,游离氨基酸17种,总氨基酸含量分别为2.40%和6.51%,游离氨基酸含量分别0.185%和0.508%,半胱氨酸(cys)和谷氨酸(glu)含量较高,其中7种为人体必需氨基酸。     

Adsorption isotherms of sesame oil in a concentrated miscella system

The adsorption of peroxides, unsaturated carbonyls, free fatty acids and carotenoids from unrefined sesame oil on vegetable carbon (5%, w/w) in a miscella system was studied. Three different solvent conditions (hexane/ethanol, 100:0, 95:5 and 75:25, vol/vol), combined in a factorial design with five levels of solvent (0, 10, 20, 30 and 40%, w/w), were used to develop the miscella. Equilibrium adsorption was not achieved during the 100 min of adsorption, mainly because the oil components were involved in oxidation reactions during the adsorption process. However, for a given solvent concentration, adsorption of the oil components showed a significant linear regression on their respective initial concentration in the miscella (C_i). Peroxides and carbonyls showed, at all solvent levels investigated, an affinity for the carbon more independent of their C_i than free fatty acids and carotenoids. In general, at the same C_i, a higher adsorption was achieved as solvent concentration increased. The results indicated that free fatty acid adsorption may depend on competitive adsorption based on molecule hydrophobicity. However, in spite of the higher hydrophobicity of carotenoids, compared with free fatty acids, they might not be competing for the same adsorbing sites. Ethanol showed a prooxidant effect that increased peroxide production during adsorption but did not affect the reaction involved in carbonyl production.     

Investigation of the effects of fatty acids on the compressive strength of the concrete and the grindability of the cement

In cement industry, a great energy consumption has been observed during grinding of clinker. To reduce this consumption, some waste products have been used as grinding aids.In this investigation, the effects of sunflower oil (SO), oleic acid (OA), stearic acid (SA), myristic acid (MA) and lauric acid (LA) on the fineness and strength of the cement have been examined. These aids were added into clinker in certain ratios based on the cement clinker weight and the grinding has been done for a definite time at the same condition.All of the fatty acids used increased the fineness as compared with the cement without the grinding additives. SO and OA decreased the strength significantly, LA decreased it to a lesser extent and SA increased it definitely according to the common cement. But MA did not alter the strength of the cement as much as SA. In addition, the covering of the balls influences the grinding of cement clinker unfavourably.     

Synthesis and characterization of dehydroabietic acid derivatives suitable for surfactant synthesis

The syntheses of derivatives of dehydroabietic acid suitable for further manipulation into surfactants are presented. The compounds are produced at very high yields and purity. They contain several different functional groups, e.g., carboxylic acid, amine, ester, alcohol, and an aromatic group. The functional groups are useful as the linking unit to the hydrophilic part in synthesizing surfactants.     

酚醛泡沫塑料研究

针对影响酚醛泡沫性能的诸多因紊的不确定性，对树脂粘度、发泡剂、固化剂、表面活性剂、工艺温度及其他因素对泡沫性能的影响进行了讨论。研究表明：当树脂粘度控制在2000-10000cps，发泡剂用量为3．7％-9．5％，固化剂用量为7．5%-2．5％，表面活性剂用量为3．5％-8.5％，发泡温度控制在70℃-80℃之间时，可制得质量较好的酚醛泡沫塑料。     

杂多酸催化合成丙烯酸异丁酯

研究了以磷钨酸为催化剂,以丙烯酸与异丁醇为原料反应合成丙烯酸异丁酯.结果表明,反应时间2.5h,催化剂的用量3.0g,酸醇比1:2为最适宜的反应条件,丙烯酸的酯化率可达97.2%.     

气相色谱-质谱联用法测定金属皂中的多环芳烃

建立了金属皂中16种美国环保局(EPA)优先监控的多环芳烃的气相色谱-质谱(GC/MS)联用测定方法,样品先用二甲基亚砜萃取,再用环己烷进行反萃取,经硅胶柱净化后,用GC/MS分离测定。优化了16种多环芳烃(PAHs)的分离测定条件,结果16种PAHs的平均回收率为75.32%￣98.72%,精密度实验相对标准偏差(RSD)为2.19%￣6.93%,检测限(S/N=5)为0.002￣0.010mg/kg。该方法灵敏度高、准确性好,完全可以满足金属皂中多环芳烃的检测要求。