压力、温度对穿心莲内酯超临界CO2萃取-结晶的影响

以穿心莲浸膏为原料，进行了穿心莲内酯的超临界CO₂萃取结晶分离纯化。考察了单因素参数压力、温度对穿心莲内酯纯度、结晶量等的影响。结果表明：超临界CO₂萃取结晶穿心莲内酯的纯度在结晶板上呈梯度分布；在25 MPa以下，压力升高，结晶板上部晶体纯度升高，而结晶量先增后减；在结晶板下部穿心莲内酯的纯度和结晶量都是先升高后降低；温度在一定范围内能提高晶体纯度，且有利于缩短萃取结晶时间。     

夹带剂对超临界CO2萃取结晶穿心莲内酯的影响

以穿心莲内酯粗品和高纯品(纯度分别为30%和95%)为原料,采用超临界CO2萃取结晶法,考察了乙醇、丙酮、异丙醇与乙酸乙酯四种夹带剂对超临界CO2萃取结晶穿心莲内酯的结晶率、纯度、晶型和形貌等的作用规律.结果:因乙酸乙酯分离纯化综合效果较好,且既能与前处理工序中选择的浸提溶剂相统一,减少采用多种溶剂存在的污染,又能保持晶体优良晶型和结晶品质,所以优先选择了乙酸乙酯为夹带剂.     

穿心莲内酯超临界CO2重结晶工艺初探

采用单因素实验法探讨超临界CO₂重结晶压力、温度、时间对穿心莲内酯的纯度和结晶率的影响，并借助扫描电镜进行晶体形貌考察，利用高效液相色谱仪进行纯度检测。结果表明，采用超临界CO₂重结晶技术得到的穿心莲内酯晶体形貌更加细小，并呈絮状分布在结晶板上；选择较佳纯化工艺参数为重结晶压力14 MPa，温度55℃，时间60 min，CO₂流量20 L/min时，得到的穿心莲内酯纯度达90%以上，结晶率超过45%。     

响应曲面法建立超临界CO2萃取结晶穿心莲内酯工艺模型

以穿心莲内酯含量为30%的穿心莲浸膏为试验原料，采用响应曲面分析法(Response Surface Methodology，RSM)建立了超临界CO₂萃取结晶穿心莲内酯结晶率的二次多项数学模型，验证了数学模型的有效性，并探讨了萃取结晶压力、温度、时间对结晶率的作用规律。根据该模型进行了工艺参数的优选，以结晶率为指标，试验所得穿心莲内酯超临界CO₂萃取结晶优化工艺条件为：压力20.88 MPa，温度50.27℃，时间97.02 min，该条件下结晶率高达74.77%。     

乙醇溶剂与超临界CO2相结合提取高纯度卵黄磷脂的研究

采用乙醇溶剂首先提取蛋黄粉中的卵黄油，然后用超临界CO₂萃取方法脱除卵黄油中的中性脂肪，获得高纯度的卵黄磷脂。考察了工艺参数对提取效果的影响。试验表明：在乙醇溶剂提取卵黄油阶段，乙醇浓度是影响卵黄油提取率的最主要因素，温度是影响卵黄磷脂提取率的最主要因素；在超临界CO₂萃取阶段，磷脂的溶解度随萃取温度的升高而降低，中性脂质在55℃时溶解度最大。采用此工艺，卵黄磷脂得率为17.66%，纯度94.41%，且不含胆固醇。     

超临界CO2萃取万寿菊花中叶黄素的研究

采用超临界CO₂萃取技术,研究了从万寿菊花中萃取叶黄素的工艺条件。对影响超临界CO₂萃取叶黄素的各种因素,包括分离参数、原料含水率、粉碎粒径，超临界萃取温度、压力、流速、时间等因素进行了考察,得到较佳的萃取工艺条件为:原料含水率10.92％，粒径40目，萃取温度60℃，压力30 MPa，CO₂流速15 L/h，分离釜Ⅰ温度40℃，压力6 MPa，分离釜Ⅱ温度20℃，时间为6 h。     

超声强化超临界CO2萃取人参皂苷的研究

为了探讨超声波对超临界CO₂萃取(SCE)的影响，考察了在不同萃取温度、萃取压力、萃取时间和流体流量下，有、无超声时超临界CO₂萃取人参皂苷的萃取率。试验结果发现，超声强化超临界CO₂萃取(USCE)的合适萃取温度比没加超声(SCE)时的低10℃；在各自合适的萃取压力下，USCE的皂苷萃取率是SCE的1.64倍；CO₂流体的流量大更有利于USCE。在SCE中，超声的加入能明显提高产物的萃取率和生产效率，降低生产能耗和节     

超临界CO2萃取大蒜精油及油树脂的研究

研究了大蒜精油及油树脂的超临界CO₂提取工艺，探讨了粒度，萃取及分离的温度、压力和时间对各萃取率的影响，建立了萃取温度、压力与各萃取率的数学模型。确定了超临界CO₂同时提取大蒜精油及油树脂的优化工艺条件。     

超临界CO2提取分离银杏叶药用成分的工艺研究

该文从理论与实践两方面着手，研究探讨超临界CO₂提取分离银杏叶药用成分的适用性和可操作性，提出溶剂浸提与超临界流体萃取相结合的生产工艺，既可降低生产成本，保证产品质量，又可大幅度削减设备造价，为超临界流体萃取技术的实际应用创造条件。     

用超临界CO2脱除绿茶浓缩液中咖啡碱的工艺研究

对绿茶浓缩液中咖啡碱的超临界CO₂萃取工艺进行了研究，通过4因素正交试验探讨了浓缩液的浓度、操作压强、操作温度、萃取时间对咖啡碱脱除率的影响。结果表明，超临界CO₂萃取技术可以有效地脱除绿茶浓缩液中大部分的咖啡碱，在此基础上完成了用超临界CO₂脱除绿茶浓缩液中咖啡碱的连续作业试验，从而获得了加工脱咖啡碱绿茶浓缩液或速溶绿茶的新工艺。     

Andrographis paniculata (Burm. f.) Wall. ex Nees (kalmegh), a traditional hepatoprotective drug from India

Andrographis paniculata [(Burm. f.) Wall. ex Nees, family Acanthaceae], commonly known as kalmegh is used both in Ayurvedic and Unani system of medicines for a number of ailments related to digestion, hepatoprotection, hypoglycaemic and as anti-bacterial, analgesic, anti-inflammatory, vermicidal and antipyretic. Although kalmegh is extensively used in Indian Systems of Medicine, but it is not yet cultivated on a large-scale. The supply of herb is met from the wild growing populations which is now under constrain due to over-collection. Considering its value as a drug raw material, genetic variability of A. paniculata was augmented from different geographical regions of India by explorations and was conserved at the National Gene Bank, NBPGR, New Delhi. The therapeutic activity of the herb has been attributed to andrographolide, a bicyclic diterpenoid lactone present in the whole herb. Thirty germplasm collections of A. paniculata were evaluated for bioactive compound andrographolide to find out superior genotype for high drug yield. The andrographolide content in the germplasm was quantitatively analyzed by high performance thin-layer chromatography (HPTLC) at 232 nm. Results indicated wide variability among thirty accessions of A. paniculata for andrographolide content which ranged from 0.72 to 2.99 % on dry weight basis. DIVA-GIS analysis of A. paniculata germplasm for andrographolide content showed that diverse accessions of A. paniculata exist in three Indian states of Orissa, Tamil Nadu and Kerala. Promising accessions having high andrographolide content were identified; IC520361 (2.99 %), IC520395 (2.86 %), IC399125 (2.81 %), IC369404 (2.77 %) and IC520394 (2.61 %). Due to the economic importance of the drug, these promising collections can be exploited for large-scale cultivation for their pharmacologically important constituents mainly andrographolide content and also can serve as potential source for breeding and improvement of cultivars for obtaining higher drug yield.     

Effect of sucrose ester addition on nucleation and growth behavior of milk fat-sunflower oil blends

The effects of addition of the sucrose esters (SE) P-1670, P-170, and S-170 to a high-melting fraction of milk fat (HMF) and its blends with sunflower oil (SFO) on nucleation and growth were studied by laser polarized light turbidimetry and polarized light microscopy (PLM). The three SE delayed nucleation of HMF at the temperatures selected. P-1670 did not modify average crystal size after 3 h at crystallization temperature (T(c)) or crystal size distribution and modified crystallization kinetics only slightly. P-170 and S-170, however, markedly diminished crystal size and narrowed crystal size distribution. Activation free energies of nucleation at equivalent supercooling, calculated using the Fisher-Turnbull equation, significantly increased with addition of SE. According to these results, among the mechanisms described in the literature for fats or emulsions, the cocrystallization hypothesis is the one that better described the effects of sucrose esters on crystallization behavior in these systems.     

Preparation of interesterified plastic fats from fats and oils free of trans fatty acid

Interesterified plastic fats were produced with trans-free substrates of fully hydrogenated soybean oil, extra virgin olive oil, and palm stearin in a weight ratio of 10:20:70, 10:40:50, and 10:50:40, respectively, by lipase catalysis. The major fatty acids of the products were palmitic (32.2-47.4%), stearic (12.0-12.4%), and oleic acid (33.6-49.5%). After storage at 5 degrees C (refrigerator temperature) or 24 degrees C (room temperature) for 16 h, the physical properties were evaluated for solid fat content, texture, melting, and crystallization behavior, viscoelastic properties, crystal polymorphism, and crystal microstructure. The interesterified fats contained desirable crystal polymorphs (beta' form) as determined by X-ray diffraction spectroscopy. They exhibited a wide plastic range of solid fat content of 52-58% at 10 degrees C and 15% at 40 degrees C. The physical properties were influenced by the ratio of palm stearin and olive oil. Harder and more brittle texture, crystallization and melting at higher temperature, higher solid fat contents, and more elastic (G') or viscous (G') characteristics were observed in the produced fats containing a higher content of palm stearin and lower content of olive oil. The produced fats stored at 5 degrees C consisted mostly of beta' form crystal together with a small content of beta form, while those at 24 degrees C had only beta' form. The produced fat with a higher amount of palm stearin appeared to have more beta' form crystal and small size crystal clusters. Thus, the physical properties of the produced plastic fats may be desirable for use in a bakery product.     

Effects of degree of enzymatic interesterification on the physical properties of margarine fats: solid fat content, crystallization behavior, crystal morphology, and crystal network

In this study enzymatic-interesterified margarine fats with different conversion degrees were produced in a packed-bed reactor. The effects of conversion degree on the formation of free fatty acids and diacyglycerols, solid fat content, crystallization behavior, microstructure, and crystal network were investigated, and the enzymatically interesterified products were compared with a chemically interesterified product. Formation of free fatty acids and diacyglycerols increased slightly with increasing conversion degree. The solid fat content was higher at 10 and 20 degrees C and lower at 30, 35, and 40 degrees C with increasing conversion degree. Increased conversion degree from the blend to products, measured by X-ray with addition of 50% of rapeseed oil for dilution, caused the content of beta to decrease from 100% to 33%, and 30% and eventually to pure beta' crystal. However, double chain packing was observed for both the blend and products. Isothermal crystallization kinetics was characterized by the Fisher-Turnbull model. The highest free energy was observed for the blend. A small deformation with oscillation tests shows a significant difference between the blend and interesterified products. The differences of microstructure between the blend, different conversion degree, and chemical randomized product were observed.     

Kinetic analysis of nonisothermal differential scanning calorimetry of 1,3-dipalmitoyl-2-oleoylglycerol

The crystallization of fats has been extensively studied because of its importance in the processing of food and food ingredients. Differential scanning calorimetry (DSC) is widely used in such studies. The aim of this study was to examine the determination of kinetic parameters from nonisothermal DSC crystallization of a model fat, 1,3-dipalmitoyl-2-oleoylglycerol. We applied peak and isoconversional methods to determine activation energies and compared these techniques with a nonparametric method, which separates the temperature dependence and degree of crystallization dependence of the crystallization rate. The Johnson-Mehl-Avrami-Erofeyev-Kolmogorov (JMAEK) model provided the best fit to the data, while the temperature dependence of the rate constant was best explained by a Vogel-Fulcher relationship, where the reference temperature was the melting point of the crystallizing species.     

黄米醇溶蛋白脱色工艺研究

该文采用有机溶剂、颗粒活性炭、凝胶层析、超临界CO₂流体萃取等方法，研究了黄米醇溶蛋白的脱色效果及脱色后蛋白的回收率。结果显示甲苯脱色效果好，蛋白质回收率较高，但工艺繁琐，成本高；凝胶层析费时，而且处理量有限，在生产中会受到限制；颗粒活性炭成本低，脱色效果较好，工艺简单，可大量处理样品；超临界CO₂流体萃取在脱色效果和蛋白质回收率上都优于其他方法，且不需后处理即可直接得到脱色蛋白成品。因此，颗粒活性炭、超临界CO₂流体萃取脱色工艺适合于不同层次的无色黄米蛋白的工业化生产。     

Comparative analysis of lipid composition and thermal, polymorphic, and crystallization behaviors of granular crystals formed in beef tallow and palm oil

Six rectangular block all beef tallow (BT)-based and all palm oil (PO)-based model shortenings prepared on a laboratory scale, respectively denoted BTMS and POMS, were stored under temperature fluctuation cycles of 5-20 °C until granular crystals were observed. The lipid composition and thermal, polymorphic, and isothermal crystallization behaviors of the granular crystals and their surrounding materials separated from BTMS and POMS, respectively, were evaluated. The changes of nanostructure including the aggregation of high-melting triacylglycerols (TAGs) and polymorphic transformation from β' form of double chain length structures to complicated crystal structures, in which the β and β' form crystals of triple and double chain length structures simultaneously coexist, had occurred in granular crystals compared with surrounding materials, whether in BTMS or in POMS. Consequently, a slower crystallization rate appeared in granular crystal parts of both model shortenings noted above, which would yield larger and fewer crystals indicated by the Avrami model analysis that would further aggregate to form large granular crystals.     

Kinetics of sucrose crystallization in whey protein films

The kinetics of sucrose crystallization in whey protein isolate (WPI) films was studied at 25 degrees C in four different relative humidity environments: 23, 33, 44, and 53%. The effects of protein matrix, crystallization inhibitors, and storage environment on the rate constants of sucrose crystallization were determined using the Avrami model of crystallization. It was found that a cross-linked, denatured whey protein (WP) matrix more effectively hindered sucrose crystallization than a protein matrix of native WP. The crystallization inhibitors tested were lactose, raffinose, modified starch (Purity 69), and polyvinylpyrrolidone (Plasdone C15). Raffinose and modified starch were determined to be the more effective inhibitors of sucrose crystallization. At lower relative humidities (23, 33, and 44%), the cross-linked protein matrix played a more important role in sucrose crystallization than the inhibitors. As relative humidity increased (53%), the crystallization inhibitors were more central to controlling sucrose crystallization in WPI films.     

尿素包接法预浓缩鱼油生理活性组分的研究

为了提高鱼油中生理活性组分ＥＰＡ和ＤＨＡ的含量，以鱼油乙酯为原料，将其与饱和的尿素－乙醇溶液进行包合作用，而使鱼油中的饱和脂肪酸成结晶析出，以达到预浓缩的目的。随着尿素与鱼油乙酯摩尔比的增加，或结晶温度的降低，容易获得ＥＰＡ和ＤＨＡ含量在７０％以上的制品。