Inactivation Kinetics of Enzymes by Using Continuous Treatment with Microbubbles of Supercritical Carbon Dioxide

ABSTRACT Enzyme inactivation using a new apparatus for continuous treatment with microbubbles supercritical carbon dioxide (SC-CO₂) was investigated. D value of a-amylase (5.0±1.2 min) subjected to microbubbles of SC-CO₂ treatment (microbubbles-SCT) at 35 °C, 30 MPa was lower than that (227 ± 15.9 min) subjected to heat treatment (HT) at 70 °C. D value of acid protease was reduced by microbubbles-SCT at 50 °C, 30 MPa (15.4 ± 4.1 min), compared to HT at 50 °C (233 ± 15.2 min). The activation energy for the inactivation of acid protease (135 ± 8.3 kJ mol^-1) by microbubbles-SCT was 1 half of that (259 ± 9.0 kJ mol^-1) by HT. These results indicated that continuous treatment with microbubbles of SC-CO₂ was effective for enzyme inactivation.     

Enzyme Inactivation in Food Processing using High Pressure Carbon Dioxide Technology

High pressure carbon dioxide (HPCD) is an effective non-thermal processing technique for inactivating deleterious enzymes in liquid and solid food systems. This processing method avoids high temperatures and exerts a minimal impact on the nutritional and sensory properties of foods, but extends shelf life by inhibiting or killing microorganisms and enzymes. Indigenous enzymes in food such as polyphenol oxidase (PPO), pectin methylesterase (PME), and lypoxygenase (LOX) may cause undesirable chemical changes in food attributes, showing the loss in color, texture, and flavor. For more than two decades, HPCD has proved its effectiveness in inactivating these enzymes. The HPCD-induced inactivation of some microbial enzymes responsible for microbial metabolism is also included. This review presents a survey of the published knowledge regarding the use of HPCD for the inactivation of these enzymes, and analyzes the factors controlling the efficiency of HPCD and speculates on the underlying mechanism that leads to enzyme inactivation.     

Deodorization of Fish Sauce by Continuous-Flow Extraction with Microbubbles of Supercritical Carbon Dioxide

Volatiles were removed from fish sauce by continuous‐flow extraction with microbubbles of supercritical carbon dioxide. The extraction was done at 35 °C and CO₂/sample flow ratio of 0.14 and 0.29 under pressures of 10 to 30 MPa. After the treatment at a CO₂/sample flow ratio, 0.29 at 10 MPa, remaining percentage ((the concentration in treated sample/that in untreated one) × 100) was 5.2% trimethylamine, 8.0% S‐methyl ethanethioate, 30% dimethyldisulfide, 55 to 61% aliphatic aldehydes, and 25 to 42% carboxylic acids. The increase in CO₂ flow rate improved the extraction efficiency significantly, but no effect of pressure was observed. The odor intensities of treated samples were between 1/4 and 1/8 of the untreated fish sauce.     

CO2超临界流体介质中制革酶脱毛的研究

对CO2超临界流体代替水作介质下的制革酶脱毛进行了研究,并与常规条件下以水作介质进行的有温有浴酶脱毛和堆置酶脱毛作了对比。结果表明：在CO2超临界流体介质中进行制革酶脱毛是可行的,其脱毛分析液的总蛋白含量和羟脯氨酸含量分别约为常规酶脱毛的2倍和1～2倍,其脱毛分析液的酶活力损失低于常规酶脱毛。CO2超临界流体介质中酶脱毛后铬鞣的革,在本实验条件下其收缩温度达到95℃左右,高于常规酶脱毛后铬鞣的革。本实验中较为理想的在CO2超临界流体介质中进行制革酶脱毛的超临界反应条件为：反应压力8．5MPa、反应温度37℃、反应时间2h、AS1．398蛋白酶用量200单位／g皮。     

超临界CO_2萃取在多不饱和脂肪酸纯化中应用

该文介绍超临界CO_2萃取在多不饱和脂肪酸纯化中应用,对超临界CO_2萃取多不饱和脂肪酸的相平衡基础研究和工艺研究现状进行详细介绍,并分析目前应用领域中存在问题,提出一些解决方法。     

Antimicrobial Effects of Pressured Carbon Dioxide in a Continuous Flow System

The application of microbubbles of pressured CO₂ greatly increased CO₂ concentration in the solution treated. By treatment at 6 MPa, 35°C and average residence time 15 min, L. brevis was completely inactivated at the level of dissolved CO₂,γ≧ 11 (γ, Kuenen's gas absorption coefficient). E. coli and S. cerevisiae required γ≧ 17, and T. versatilis required γ≧ 21 for complete inactivation. Z. rouxii could be sterilized at 20 MPa and 26. A comparison of the continuous and batch method showed that L. brevis was inactivated completely under pressured CO₂ > 0.16 g/cm³ with the continuous method and >0.9 g/cm³ with the batch method.     

玉米胚芽油的超临界CO2萃取

研究了超临界CO2流体萃取玉米胚芽油的条件,着重研究了萃取压力、温度、萃取时间和CO2流量对油脂萃取率的影响,优化了萃取工艺条件;萃取压力35MPa,温度50℃,时间3h,CO3流量34kg/h,并利用GC／MS分析了最佳条件下萃取的玉米胚芽油成分组成。并比较了超临界CO2萃取的玉米胚芽油样和乙醚萃取油样的理化性质。     

超临界流体对杉木渗透性改变的研究

利用超临界CO2流体,采用均匀设计方案对杉木进行处理,然后再对其渗透性进行测定,与未处理材的渗透性相比较.结果表明,经超临界CO2处理的杉木试材,其渗透性得到部分改善.     

超临界CO2萃取大蒜提取物

研究了超临界二氧化碳萃取大蒜精油的可行性 ,得出最佳的提取工艺条件为 15MPa,40℃。若只需得到蒜素可采用发酵醇提法预处理 ,这样所得蒜素的得率最高 ,可达 44 .5 7% ,若要得到大蒜精油必须进一步利用有机溶剂进行萃取 ,每千克大蒜可得大蒜精油 1.8g。同时对制得的大蒜精油进行了红外吸收光谱定性分析。     

超临界流体分离大豆磷脂酰胆碱

研究了超临界流体CO2 /乙醇分离大豆磷脂酰胆碱的影响因素。结果表明 :在温度 4 0℃- 6 0℃ ,压力在 15MPa - 2 5MPa ,乙醇浓度在 2 % - 2 0 %之间 ,较低的温度 ,较高的压力和较高的乙醇浓度有利磷脂酰胆碱含量的提高。在温度 4 0℃、压力 2 5MPa、乙醇浓度 15 % (v/v)下 ,磷脂酰胆碱含量可达 89% (TLC扫描法 )     

蚕蛹油超临界二氧化碳萃取研究

以蚕蛹为原料,采用正交试验,研究萃取温度、萃取时间、萃取压力等因素对超临界CO2萃取蚕蛹油影响。确定蚕蛹油超临界CO2萃取条件,即萃取温度35℃,萃取时间2h,萃取压力25MPa。     

大豆胚芽油的超临界CO2萃取研究

通过超临界CO2流体萃取大豆胚芽油的实验,探讨了萃取压力、萃取温度、萃取时间和CO2流量对大豆胚芽油萃取率的影响。结果表明,最适宜的萃取条件为萃取压力30MPa、萃取温度45℃、萃取时间120min、CO2流量25kg/h,在此条件下萃取率为91.38%;超临界CO2法得到的大豆胚芽油不饱和脂肪酸含量为84.2%,其中亚麻酸和亚油酸占74%,碘值为152gI/100g。     

超临界CO2法分离番茄中番茄红素的研究

本实验研究了超临界CO2工艺参数对成熟番茄中番茄红素、β-胡萝卜素和叶黄素溶解度的影响。提取压力范围为10～45MPa,温度范围为40～80℃。操作参数不同,番茄红素、β-胡萝卜素及叶黄素在超临界流体中的溶解度不同。实验证明,在35MPa、70℃时,提取物中番茄红素含量可达80.25%,从而省去了番茄红素的纯化过程。     

超临界CO2萃取辣椒红色素的研究

本文着重研究了以传统溶剂萃取法得到的辣椒油树脂为原料，以无毒、易得、价廉的ＣＯ２为萃取剂，采用超临界萃取的方法提取辣椒红色素。通过对萃取压力、萃取温度、萃取时间、ＣＯ_２流量等条件的试验，获得了最佳的工艺参数。试验结果表明，超临界萃取法具有工艺简单、操作安全、产品质量好、萃取效率高等优点。     

涤纶织物在超临界二氧化碳流体中的染色研究

利用在超临界二氧化碳流体中加入分散染料的方法,对涤纶织物的染色效臬进行了研究。考察了影响染色的三个主要因素（温度、压力、染色时间）对上染量的影响,并测定了涤纶织物的上染量和色牢度。实验结果表明,当超临界二氧化碳染色的工艺条件为温度90℃、压力28MPa、染色时间1h时,涤纶织物的染色质量较好。     

大豆蛋白纤维超临界二氧化碳染色探讨

介绍在超临界CO2中用分散活性染料对大豆蛋白纤维进行染色,通过正交试验得出优化染色工艺:染色压力为15MPa,染色温度为80 ℃,染色时间为20 min.     

超临界CO2和乙醇混合溶剂提纯磷脂酰胆碱的研究进展

综述了用超临界CO2(SC—CO2)和乙醇混合溶剂提纯磷脂酰胆碱的研究概况。用SC—CO2和乙醇混合溶剂萃取，可以制备高纯度的磷脂酰胆碱。另外，得到的产品没有有害溶剂的残留。可以用于医药行业。这种提纯方法和乙醇分提以及柱层析提纯法相比，具有更好的应用前景。     

蚕蛹油脂的超临界二氧化碳萃取工艺及分析

采用四因素三水平正交试验方案对超临界CO2 流体萃取蚕蛹油脂的工艺参数进行研究,考察温度、压力、CO2 流量和分离Ⅰ压力等参数对油脂萃取量的影响效果。结果表明：萃取压力30MPa、萃取温度40℃、CO2 流量25kg/h、分离Ⅰ压力9MPa 为最佳参数组合,此条件下油脂萃取率可达30.53%,影响油脂萃取量的主要因素是压力。并对其脂肪酸组成及理化性质指标进行分析和测定,结果表明所得油样中游离脂肪酸较少,有害的过氧化值低、不饱和脂肪酸含量高、无臭味。     

Triglyceride Content of Supercritical Carbon Dioxide Extracted Fractions of Beef Fat

Beef fat was fractionated using supercritical carbon dioxide at 40°C and pressures from 10.3–27.6 MPa. Extractions followed by one or two stage separation were collected at atmospheric pressure and ambient temperature. Triglyceride analysis of extracts using HPLC and evaporative light scattering detection resolved 15 major peaks. Triglyceride content (mg/g extract) was influenced by extraction conditions. Extraction at 27.6 MPa and separation at 20.7 MPa resulted in highest triglyceride concentration, while 13.8 MPa resulted in the lowest. Saturated and monounsaturated triglycerides were selectively extracted based on solvent density and molecular weight. Little selectivity of polyunsaturated triglycerides was observed for fractionating beef fat.     

超临界二氧化碳技术产业化若干问题的探讨

介绍了超临界二氧化碳技术及其工业化设备在国内的应用情况,进而阐述了有关超临界二氧化碳技术产业化应用过程中所面临的问题及解决方案,探讨了该技术在产业化过程中的经济可行性以及该技术在印染行业中的应用前景。