Continuous production of structured phospholipids in a packed bed reactor with lipase from <Emphasis Type="Italic">Thermomyces lanuginosa</Emphasis>

The possibilities of producing structured phospholipids between soybean phospholipids and caprylic acid by lipase-catalyzed acidolysis were examined in continuous packedbed enzyme reactors. Acidolysis reactions were performed in both a solvent system and a solvent-free system with the commercially immobilized lipase from Thermomyces lanuginosa (Lipozyme TL IM) as catalyst. In the packed bed reactors, different parameters for the lipase-catalyzed acidolysis were elucidated, such as solvent ratio (solvent system), temperature, substrate ratio, residence time, water content, and operation stability. The water content was observed to be very crucial for the acidolysis reaction in packed bed reactors. If no water was added to the substrate during reactions under the solvent-free system, very low incorporation corporation of caprylic acid was observed. In both solvent and solvent-free systems, acyl incorporation was favored by a high substrate ratio between acyl donor and phospholipids, a longer residence time, and a higher reaction temperature. Under certain conditions, the incorporation of around 30% caprylic acid can be obtained in continuous operation with hexane as the solvent. Presented at the 95th American Oil Chemists' Society Annual Meeting and Expo in Cincinnati, Ohio, May 10, 2004.     

Acidolysis of babassu fat catalyzed by immobilized lipase

The lipase-catalyzed interesterification of oils and fats gives products that are unobtainable by chemical interesterification methods. Acidolysis of babassu fat and palmitic acid, catalyzed by immobilized lipase (Lipozyme; Novo Industri, Bagsveard, Denmark), was studied. The reactions were performed at 65°C with 5% w/w enzyme for 4 h. The molar proportions of babassu fat/palmitic acid were 1∶0.1, 1∶0.3 and 1∶0.5. At the end of the reaction period, the catalyst particles were removed by filtration, and the residual oil was extracted with organic solvent (diethyl ether). The recovered particles were then reused. The palmitic acid content of babassu fat before and after acidolysis changed from 10 to 22% at a molar proportion of 1∶0.5. The equilibrium was attained in about 4 h. The original water and enzymatic activities of Lipozyme were maintained after acidolysis. Water sorption isotherms of the immobilized enzyme were determined at 25, 35 and 45°C. From the temperature dependence of the isotherms, isosteric heats of sorption were evaluated by means of the Clausius Clapeyron equation. Monolayer moisture content was calculated by means of the B.E.T. and Guggenhein-Anderson-De Boer analyses. Paper presented at the International Meeting on Fats and Oils Technology, Universidade Estadual de Campinas, Brazil, 1991.     

含甲基丙烯酸叔丁酯单元聚合物的合成及其酸解性能研究

本研究合成了甲基丙烯酸叔丁酯(TBMA)单体及其均聚物,并与甲基丙烯酸(MAA)共聚合成了二元共聚物。同时以对甲苯磺酸作为酸源,比较系统地研究了聚合物中甲基丙烯酸叔丁酯单元的酸姐情况及其影响因素。研究表明,酸含量的增加和烤版温度的适当升高对甲基丙烯酸叔丁酯单元的酸解有利,烤版时间对甲基丙烯酸叔丁酯单元的酸解比例有一定影响。     

稀酸预处理玉米芯提取木糖的研究

通过单因素实验法和正交实验法优化了以玉米芯为原料制备木糖实验过程中各工艺参数,包括固液比、酸浓度、处理温度以及处理时间。结果表明,稀酸预处理过程各因素对玉米芯木糖提取率影响程度由大到小的顺序为:处理温度酸浓度处理时间。且在降低酸浓度和减少反应时间的情况下,仍可使木糖得率达到较高的水平,优化的实验条件为:固液比1∶10,酸浓度1. 2%,处理温度120°C,处理时间90 min。在此条件下,木糖得率可达86. 36%。     

Sn-2位富含棕榈酸甘油三酯的酶法制备研究

以棕榈硬脂为原料,以非专一性脂肪酶Novozym 435作催化剂,将棕榈酸作为酰基供体与棕榈硬脂进行酸解反应,制备Sn-2位富含棕榈酸的甘油三酯,为下一步制备母乳脂肪替代油脂提供原料。首先,通过单因素实验确定了各因素的范围,再应用Box-Behnken中心组合实验设计建立二次多项数学模型,进行响应面分析。结果表明,当棕榈酸与棕榈硬脂质量比1.09∶1,反应时间9.9h,反应温度54.7℃,加酶量21.9%时,反应所得甘油三酯中Sn-2位棕榈酸可达到60.59%,可满足下一步制备母乳脂肪替代油脂的要求。     

Lipase-catalyzed acidolysis of sunflower oil: Kinetic behavior

In the present study, sunflower oil was modified with a palmitic–stearic acids blend by means of an immobilized sn-1,3 specific lipase (Lipozyme RM IM) to produce structured lipids. Products were analyzed to determine fatty acid incorporation (F_M) into triacylglycerol structure and to quantify by-products as monoglycerides (MG) and diglycerides (DG). The effects of the reaction conditions (temperature, time, incorporated water) on enzymatic acidolysis were studied. Nonlinear regression methods were employed to fit experimental data with kinetic models proposed in the literature. The disappearance of reactant fatty acids (RF) over time was successfully modeled by a Ping-Pong Bi-Bi mechanism. F_M was also represented with a lumped parameter model of the enzymatic mechanism. Maximum RF disappearance and F_M onto sunflower oil glycerides increased with increasing reaction temperature. MG and DG concentrations in water-free systems were stabilized in low levels, while the incorporation of water to the reaction mixture produced a considerable increase in DG formation principally. Kinetic and equilibrium parameters showed temperature dependencies.     

脱脂大豆粕硫酸酸解试验和利用

选择脱脂大豆粕硫酸酸解条件,底物浓度20％,5％的硫酸加酸量为1:5,酸解温度80℃,酸解时间8h,作酸解试验,可获得氨基酸含量(0.91g/100ml)、还原糖含量(8.7g/100ml)、可溶性固形物含量(20g/100ml)都较高的酸解液;利用酸解液调配酱油、饮料;利用粕渣粉作贫蛋白食品添加剂,蛋白质饲料,具有可行性并有很好的效益。     

电弧炉熔炼钛渣的物相组成及其与酸溶性的关系

电弧炉熔分金属化率大于９０％的球团，所得钛渣的∑Ｔｉ＿２Ｏ＿３／∑ＴｉＯ＿２在０．３～０．５，其酸解率较高。这是因为渣中有更多的黑钛石ｍ［（Ｍｇ，Ｆｅ，Ｍｎ）Ｏ·２ＴｉＯ＿２］·ｎ［（Ｔｉ，Ａｌ）＿２Ｏ＿３·ＴｉＯ＿２］，而黑钛石易于被酸溶解。若钛渣中有ＭｇＴｉ＿２Ｏ＿５型黑钛石，则可提高酸解率。