南美白对虾虾壳甲壳素的提取工艺及结构分析

Preparation and Structural Characterization of Chitin from Shrimp Shell of Penaeus Vannamei

为探究南美白对虾虾壳甲壳素提取工艺条件及其对甲壳素结构的影响,测定分析不同NaOH浓度和处理温度对虾壳中蛋白质的脱除效果,不同HCl浓度及处理温度、不同酸及不同固液比的乙酸对虾壳中矿物质的脱除效果,比较虾壳经不同处理后的甲壳素结构。结果表明,南美白对虾虾壳的组成成分为:水10.45%、蛋白质29.80%、矿物质37.25%、甲壳素20.49%、色素2.01%。脱蛋白质的最佳条件为NaOH浓度2.0 mol/L,处理温度70 ℃;HCl脱盐的最佳条件为HCl浓度1.0 mol/L,处理温度25 ℃;同等条件下柠檬酸、乳酸和HCl的脱盐效果基本相当,脱盐率均高于90%,乙酸的脱盐率仅为78.74%,但增加乙酸溶液添加量可使脱盐率提高至94.87%。扫描电镜结果表明,虾壳表面为无机盐与蛋白质的混合物,内部为蛋白质与甲壳素的扭曲网状结合物。红外光谱结果表明,不同处理制备的甲壳素的红外谱带大致相同,但在峰形、峰数上还存在一些差异。虾壳甲壳素的提取工艺条件不仅影响甲壳素的纯度,对其分子结构也会产生一定的影响。

In order to explore the process conditions for preparation chitin from shrimp shell of Penaeus vannamei,and their influence on the structure of chitin,the deproteination of different NaOH concentrations and temperatures,the demineralization of different HCl concentrations,temperatures,acids and solid to liquid ratios of acetic acid were measured.Furtherly,the structure of chitin prepared under different conditions were compared.Results indicated that the shrimp shell contains water 10.45%,protein 29.80%,mineral 37.25%,chitin 20.49%,pigment 2.01%.The optimal conditions were NaOH concentration 2.0 mol/L,treatment temperature 70 ℃ for deproteinization,and HCl concentration 1.0 mol/L,treatment temperature 25 ℃ for demineralization.The demineralization rate of shrimp shell treated separately by HCl,citric acid and lactic acid was about the same and higher than 90%,but 78.74% when it was acetic acid under the same conditions.If acetic acid solution was added more,the demineralization rate could be increased to 94.87%.The scanning electronic microscope results showed that the mixture of inorganic salts and proteins were in the shell surface,but in the inner surface,it was a conjugate of proteins and chitin with net structure.Infrared spectrum results showed that the spectrum bands of chitin prepared by different treatments were roughly the same,but there were some differences in peak shape and peak numbers.It could be concluded that not only chitin purity but also the structure was affected by the process conditions for extraction chitin from shrimp shell.