A mass transfer model applied to the supercritical extraction with CO2 of curcumins from turmeric rhizomes (Curcuma longa L)
A mass transfer model applied to the supercritical extraction with CO2 of curcumins from turmeric rhizomes (Curcuma longa L)
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DOI：
10.1590/s0104-66322000000300007
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发表时间：
2000-09-01
影响因子：
1.2
通讯作者：
Araújo, ME
中科院分区：
文献类型：
--
作者：
Chassagnez-Méndez, AL;Corrêa, NCF;Araújo, ME
国际市场对食品工业中使用人造色素的限制越来越多，这增加了含有天然色素的原材料的重要性。在众多具有潜在应用价值的天然物质中，姜黄(Curuma Longa L)是黄色素的重要天然来源之一。姜黄素类化合物由三种不同的色素(姜黄素、去甲氧基姜黄素和双去甲氧基姜黄素)组成。这些色素主要用于食品工业，作为柠檬黄等合成染料的替代品。超临界CO2萃取姜黄素可以作为一种替代方法来获得姜黄素，因为天然色素通常是不稳定的，因此在高温下用有机溶剂萃取时会降解。在超临界萃取中试装置上进行了萃取实验，考察了干燥前处理对萃取率的影响，分析了萃取过程中的传质动力学和萃取物中姜黄素的含量。采用分光光度法对提取液和残留固体中的姜黄素进行了化学鉴定。固相内的传质符合线性一级脱附模型，气相中的传质符合对流传质模型。实验结果表明，在343K下进行干燥前处理，超临界萃取过程中姜黄素类化合物的浓度分布较高。
Increasing restrictions on the use of artificial pigments in the food industry, imposed by the international market, have increased the importance of raw materials containing natural pigments. Of those natural substances with potential applications turmeric rhizomes (Curcuma longa L), are one of the most important natural sources of yellow coloring. Three different pigments (curcumin, desmetoxycurcumin, and bis-desmetoxycurcumin) constitute the curcuminoids. These pigments are largely used in the food industry as substitutes fur synthetic dyes like tartrazin. Extraction of curcuminoids from tumeric rhizomes with supercritical CO2 can be applied as an alternative method to obtain curcuminoids, as natural pigments are in general unstable, and hence degrade when submitted to extraction with organic solvents at high temperatures. Extraction experiments were carried out in a supercritical extraction pilot plant at pressures between 25 and 30 MPa and a temperature of 318 K. The influence of drying pretreatment on extraction yield was evaluated analyzing the mass transfer kinetics and the content of curcuminoids in the extracts during the course of extraction. The chemical identification of curcuminoids in both the extract and the residual solid was performed by spectrophotometry. Mass transfer within the solid matrix was described by a linear first-order desorption model, while that in the gas phase was described by a convective mass transfer model. Experimental results showed that the concentration profile for curcuminoids during the supercritical extraction process was higher when the turmeric rhizomes were submitted to a drying pretreatment at 343 K.