共查询到18条相似文献，搜索用时 203 毫秒
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为了探讨超临界CO2干燥罗非鱼的机理,该文基于微分床的质量守恒定律建立了超临界CO2干燥罗非鱼片的传质数学模型,通过Matlab软件对其干燥过程进行了数值模拟,分析了干燥室内超临界CO2中的溶质质量分数和罗非鱼片中的溶质质量分数随干燥时间和干燥床高度变化的规律,揭示溶质在超临界CO2干燥过程中的传质模式。结果表明:在超临界CO2干燥罗非鱼片的过程中,溶质传质主要以对流扩散为主,而以轴向扩散为辅;数值模拟的结果与试验值拟合良好(R2=0.97),相对偏差的绝对值在10%以内,说明建立的传质数学模型能较好的模拟超临界CO2干燥罗非鱼片的过程。研究结果可为超临界CO2干制罗非鱼片的工业化生产的过程控制提供参考。 相似文献
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不同干燥方法对罗非鱼片品质和微观结构的影响 总被引：11，自引：5，他引：6
为了解不同干燥方法对罗非鱼片干燥后品质和微观结构的影响,采用热风干燥、真空冷冻干燥、超临界CO2干燥等3种方法对罗非鱼片进行干燥,研究其对营养成分、微生物、感官特征、复水性能、质构特征、微观结构等的影响。结果表明:与热风干燥和真空冷冻干燥相比,超临界CO2干燥的鱼片,粗蛋白含量高,脂肪含量较低;且在杀灭微生物方面有着显著的优势;但其鱼片的收缩率和复水特性稍差于真空冷冻干燥,而其感官、质构和微观结构等品质均与真空冷冻干燥的相当,而所有品质都明显优于热风干燥;结合经济性等综合考虑,罗非鱼片应用超临界CO2干燥是可行的。研究结果可为罗非鱼片干燥技术的选择提供参考。 相似文献
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超临界CO2连续浓缩鱼油EPA和DHA的研究 总被引：4，自引：0，他引：4
为了克服鱼油有效组分超临界CO2间歇萃取方法的缺点,设计建造了超临界CO2在内径14 mm、填料高1.8 m的填料塔中连续萃取浓缩鱼油有效组分的流程.根据单因素试验的结果,对工艺参数进行优化.设计了4因素3水平并考虑部分交互作用的正交试验方案,以综合指标进行评价,得到了优化工艺参数为:填料塔压为12.5 MPa;CO2流量为5 L/min;鱼油进料流量为0.8 mL/min;塔的温度分布为40～85℃.经方差分析得知,温度分布的影响对综合指标高度显著,鱼油进料流量对综合指标的影响显著,试验范围内的压力、CO2流量、压力和温度分布交互作用、温度分布和CO2流量交互作用以及压力和CO2流量交互作用对综合指标没有显著影响. 相似文献
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超临界CO2流体萃取海滨锦葵籽油的工艺条件优化 总被引：11，自引：5，他引：6
为了提高海滨锦葵籽的利用价值,开发生物柴油新原料,该文以海滨锦葵籽为原料,利用超临界CO2流体萃取技术提取海滨锦葵籽油。通过单因素试验及正交试验研究了萃取压力、萃取温度、CO2流量和萃取时间等因素对油脂得率的影响,确定了超临界CO2流体萃取技术提取海滨锦葵籽油的最佳工艺条件。结果表明,在试验范围内各影响因素对海滨锦葵籽油得率作用的大小依次为：萃取压力＞萃取温度＞CO2流量＞萃取时间。超临界CO2流体萃取技术提取海滨锦葵籽油的最佳工艺参数为：萃取压力25 MPa,萃取温度45℃,CO2流量21 kg/h,萃取时间为100 min,在该工艺条件下萃取3次,海滨锦葵籽油得率达到19.35%。 相似文献
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超临界CO2萃取毛竹笋油的工艺及产品成分 总被引：3，自引：4，他引：3
为优化超临界CO2萃取毛竹笋油的工艺参数,该研究通过单因素试验和正交试验考察了萃取压力、萃取温度、萃取时间和CO2流量等因素对毛竹笋油得率的影响,并利用气质联用（GC-MS）对毛竹笋油进行成分分析。研究确定超临界CO2萃取毛竹笋油的较佳工艺为：萃取压力25 MPa、萃取温度55℃、萃取时间2.5 h和CO2流量15 L/h,较佳工艺条件下笋油得率为5.74%;GC-MS分析毛竹笋油,共鉴定出17种组分,其中β-谷甾醇、9,12-十八碳二烯酸和9,12,15-十八碳三烯酸的相对含量分别为26.00%、10.50%和9.83%。 相似文献
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超临界CO_2杀灭大肠杆菌过程中菌体蛋白的变化 总被引：1，自引：0，他引：1
通过SDS-聚丙烯酰胺凝胶电泳,结合超临界CO2对大肠杆菌的杀菌曲线,研究超临界压力、温度和处理时间对大肠杆菌菌体蛋白的影响.结果表明:超临界CO2在杀灭大肠杆菌过程中,可显著降低菌体碱溶性(pH8.0)蛋白的溶解性,但对菌体总蛋白含量和种类没有影响;37℃下超临界CO2处理大肠杆菌30min,压力为10MPa时,大肠杆菌存活率为2.8%,菌体碱溶性蛋白的溶解性显著降低,当压力增加到50MPa时,大肠杆菌存活率和碱溶性蛋白溶解性变化不明显;超临界温度和处理时间对菌体碱溶性蛋白溶解性的影响与大肠杆菌在超临界CO2中的存活趋势基本一致,随处理时间的延长和温度的增加大肠杆菌存活率逐渐降低到0,碱溶性蛋白溶解性逐渐降低,直至部分蛋白带消失,但菌体总蛋白含量和种类并没有明显变化;升高温度比增加压力更能显著地导致菌体碱溶性蛋白变性,溶解性下降. 相似文献
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为了获得脉冲真空浸渍预处理条件对热泵干燥罗非鱼片品质的影响,以白度、脱水效率指数(DEI,dehydration efficiency index,)、Ca2+-ATPase活性、复水率和质构为检测指标,结合综合评分,进行了以循环率(真空维持时间/常压维持时间)、循环次数、真空压力和海藻糖浓度为预处理变化条件下单因素影响的系列试验。结果表明:在其他条件不变的情况下,每个单因素均有一个使干燥品质达到最佳的因素范围和最佳值。循环率在4∶4~5∶1min/min之间变化时,其综合品质较好,且以循环率为4∶2min/min时,综合评分达到最高。循环次数在3~5之间变化时,其综合品质与对照组相比提升幅度较高,且循环次数为4时,综合评分最高。脉冲真空压力在4~16 kPa之间变化时,对热泵干燥罗非鱼片的综合品质的提升效果较好,且真空压力为10 kPa时,综合评分最高。海藻糖质量浓度在90~170 g/L的范围内变化时,综合品质的提升效果较好,且海藻糖质量浓度在130 g/L时综合评分值最高。与常压渗透对照组相比,各品质指标都得到了不同程度的提升,各指标达到的最大升幅分别为:白度17.9%,复水率80%,Ca2+-ATPase活性93.6%,差异显著(P0.05)。脉冲真空条件下的浸渍预处理可以有效提升热泵干燥罗非片的综合品质,研究结果为改善同类产品干燥的预处理工艺提供参考。 相似文献
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Turmeric oil was extracted from turmeric (Curcuma longa) with supercritical carbon dioxide in a semicontinuous-flow extractor. Extraction rate was measured as a function of pressure, temperature, flow rate, and particle size. The extraction rate increased with an increase in CO(2) flow rate and with a reduction of particle size. The effect of pressure and temperature on turmeric extraction suggested the use of higher pressure and lower temperature at which solvent density is greater and thus the solubility of the oil in the solvent is greater in the range of 313-333 K and 20-40 MPa. The major components ( approximately 60%) of the extracted oil were identified as turmerone and ar-turmerone by GC-MS. 相似文献
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Supercritical CO(2) extraction of beta-carotene and lycopene from tomato paste waste 总被引：6，自引：0，他引：6
Lycopene and beta-carotene were extracted from tomato paste waste using supercritical carbon dioxide (SC-CO(2)). To optimize supercritical fluid extraction (SFE) results for the isolation of lycopene and beta-carotene, a factorial designed experiment was conducted. The factors assessed were the temperature of the extractor (35, 45, 55, and 65 degrees C), the pressure of the extraction fluid (200, 250, and 300 bar), addition of cosolvent (5, 10, and 15% ethanol), extraction time (1, 2, and 3 h), and CO(2) flow rate (2, 4, and 8 kg/h). The total amounts of lycopene and beta-carotene in the tomato paste waste, extracts, and residues were determined by HPLC. A maximum of 53.93% of lycopene was extracted by SC-CO(2) in 2 h (CO(2) flow rate = 4 kg/h) at 55 degrees C and 300 bar, with the addition of 5% ethanol as a cosolvent. Half of the initially present beta-carotene was extracted in 2 h (flow rate = 4 kg/h), at 65 degrees C and 300 bar, also with the addition of 5% ethanol. 相似文献
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Yu J Dandekar DV Toledo RT Singh RK Patil BS 《Journal of agricultural and food chemistry》2006,54(16):6041-6045
Limonoid glucosides (primarily limonin 17-beta-D-glucopyranoside, LG) were extracted from grapefruit molasses by supercritical fluid extraction using a supercritical carbon dioxide-ethanol (SC CO(2)-ethanol) system. Extraction conditions to maximize the yield of LG were determined by varying pressure, temperature, ethanol concentration, and extraction time. The highest yield of LG at 0.61 mg/g molasses was obtained at a pressure 48.3 MPa, a temperature of 50 degrees C, 10% ethanol (X(Eth) = 0.1), and 40 min of extraction time at a flow rate of 5.0 L/min. The results demonstrated that SC CO(2) extraction of limonoid glucosides from grapefruit molasses has practical significance for commercial production. 相似文献
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H Qiuhui 《Journal of agricultural and food chemistry》1999,47(7):2705-2706
The chemical component of spirulina was determined by supercritical CO(2) extraction. The protein and essential amino acid contents of spirulina powder were not significantly decreased through supercritical CO(2) extraction, but the contents of total amino acid and lipids were reduced. The spirulina powder had a stench smell before, but not after, supercritical CO(2) extractions. The highest yield rate of lipids was obtained at an extraction pressure of 35 MPa and an extraction time of 4 h. The lipids could be used as additives of health foods containing gamma-linolenic acid. 相似文献
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An efficient supercritical fluid extraction (SFE) process with carbon dioxide (SFE-CO(2)) was developed for the extraction of natural vitamin E (V(E)) from wheat germ. Both the pretreatment of extracted wheat germ and extraction conditions were optimized to ensure maximal V(E) yield. The extraction was undertaken at the extracting pressure of 4000-5000 psi, the extracting temperature of 40-45 degrees C, and the carbon dioxide flow rate of 2.0 mL/min for 90 min. An optimized pretreatment of wheat germ was usually necessary with a particle size of 30 mesh and a moisture content of 5.1%. A yield comparison of V(E) and its isomers extracted by supercritical CO(2) with those by conventional solvent extraction suggested that this SFE process was a practical process prospectively superior to conventional solvent extraction to prepare V(E) from wheat germ. 相似文献
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Rozzi NL Singh RK Vierling RA Watkins BA 《Journal of agricultural and food chemistry》2002,50(9):2638-2643
Tomato seeds and skins acquired from the byproduct of a local tomato processing facility were studied for supercritical fluid extraction (SFE) of phytochemicals. The extracts were analyzed for lycopene, beta-carotene, alpha-carotene, alpha-tocopherol, gamma-tocopherol, and delta-tocopherol content using high-performance liquid chromatography-electrochemical detection and compared to a chemically extracted control. SFEs were carried out using CO(2) at seven temperatures (32-86 degrees C) and six pressures (13.78-48.26 MPa). The effect of CO(2) flow rate and volume also was investigated. The results indicated that the percentage of lycopene extracted increased with elevated temperature and pressure until a maximum recovery of 38.8% was reached at 86 degrees C and 34.47 MPa, after which the amount of lycopene extracted decreased. Conditions for the optimum extraction of lycopene from 3 g of raw material were determined to be 86 degrees C, 34.47 MPa, and 500 mL of CO(2) at a flow rate of 2.5 mL/min. These conditions resulted in the extraction of 61.0% of the lycopene (7.19 microg lycopene/g). 相似文献