首页> 外文期刊>Journal of Agricultural and Food Chemistry >Effect of Alkali and Enzymatic Pretreatments of Eucommia ulmoides Leaves and Barks on the Extraction of Gutta Percha
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Effect of Alkali and Enzymatic Pretreatments of Eucommia ulmoides Leaves and Barks on the Extraction of Gutta Percha

机译:杜仲叶和树皮的碱和酶法预处理对杜仲提取的影响。

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This paper exploited a novel method of single solvent recycling plus enzymatic pretreatment.Petroleum ether(60-90°C)was an ideal solvent to extract Eucommia gum at high temperature(~ 80°C)and to precipitate the gum(flocculent)as the temperature of the solution fell to below 40°C.The gutta percha was almost completely precipitated from solution as the temperature cooled down to below 0°C.After filtration and recovery of the precipitated gum,the filtrate,petroleum ether,was applied to an activated carbon column to remove dissolved impurities and reused for next gutta percha extraction.Because impurities were kept in solution,the precipitated gutta percha was highly pure.In an experiment of enzyme hydrolyzing the plant cell wall,cuticle layers on the surfaces of leaves prevented cellulase from approaching to and hydrolyzing the cellulose of the cell wall.NaOH(1%)at 70°C efficiently degraded the cuticle layer,which greatly improved the enzymatic hydrolysis of cellulose within eucommia leaves.Gutta percha that was extracted from the alkali-and cellulase-treated leaves had a degree of polymerization as high as in the leaves,and the yield increased from 2.5% of milled leaves up to over 3.2%.The tensile strength of obtained gutta percha increased from 0.02 MPa of milled Eucommia leaves to 60.5 MPa,the breakage extensibility ranged from about 0 to 24%,and the tearing strength ranged from 0.5 to 36 kN/m.
机译:本文探索了一种单溶剂循环再用酶法预处理的新方法。石油醚(60-90°C)是在高温(〜80°C)下提取杜仲胶并沉淀出胶凝剂(絮凝剂)的理想溶剂。溶液温度降至40°C以下。随着温度冷却至0°C以下,牙胶几乎完全从溶液中沉淀出来。过滤并回收沉淀的胶后,将滤液,石油醚加到活性炭柱去除溶解的杂质,然后再用于下一步牙胶的提取。由于将杂质保留在溶液中,沉淀的牙胶的纯度很高。在酶水解植物细胞壁的实验中,叶片表面的表皮层阻止了纤维素酶的降解。从接近和水解细胞壁的纤维素开始。在70°C的NaOH(1%)有效降解了表皮层,从而大大改善了杜仲叶中纤维素的酶促水解作用。 es。从经碱和纤维素酶处理的叶片中提取的牙胶具有很高的聚合度,其收率从碾碎的叶片的2.5%增至3.2%以上。 Percha从碾碎的杜​​仲叶的0.02 MPa增加到60.5 MPa,断裂伸长率约为0至24%,撕裂强度为0.5至36 kN / m。

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