几种红藻琼胶的组分结构及理化性质的比较研究

IOCAS-IR > 海洋环流与波动重点实验室

	几种红藻琼胶的组分结构及理化性质的比较研究
	王璐
学位类型	博士
	1999
学位授予单位	中国科学院海洋研究所
学位授予地点	中国科学院海洋研究所
学位专业	海洋化学
关键词	琼胶海藻琼胶琼胶素理化性质化学结构比较研究
摘要	为了给生产不同用途的优质琼胶和琼胶素提供一些理论指导，本文以我国三种经济红藻龙须菜、石花菜、坛紫菜以及北朝鲜的伊谷草为研究对象，首次将这些不同种属的海藻放在一起进行了理化性质和化学组分结构方面的横向比较。测定了用不同方法处理海藻后提取琼胶样品的琼胶得率以及凝胶强度、凝固温度、融化温度等物理性质。同种方法提取琼胶以石花菜的琼胶得率为最高。坛紫菜琼胶凝固温度最高。龙须菜琼胶融化温度较高。碱处理对四种红藻琼胶的凝胶强度影响程度不一。碱处理后，琼胶的凝胶强度、融化温度和凝固温度都升高。对各琼胶样品的灰分、水解硫酸根、总糖及3,6-内醚半乳糖含量进行化学分析表明:龙须菜琼胶的灰分比石花菜琼胶和碱处理后的其它两种红藻琼胶高。坛紫菜琼胶的3,6-内醚半乳糖含量最高。碱处理对不同红藻琼胶的灰分、水解硫酸根、3,6-内醚半乳糖含量影响不同。同种方法处理海藻，所得琼胶的这些化学成分含量大小顺序也不一样。总糖含量测定结果都相当高，各琼胶样品的主要成分为多糖。对8个琼胶样品进行了~（13）C-NMR谱和IR光谱的测定。~（13）C-NMR谱表明所有测试样品均以无取代琼胶糖为主要成分，不含红藻淀粉。无碱法坛紫菜琼胶还含有一定量的琼胶糖前体及很少量的6-甲氧基-D-半乳糖-3,6-内醚-L-半乳糖；稀碱法坛紫菜不含琼胶糖前体，但仍含6-甲氧基-D-半乳糖-3,6-内醚-L-半乳糖；稀碱法伊谷草琼胶含有少量D-半乳糖-2-甲氧基-3,6-内醚-L-半乳糖。实验中的龙须菜琼胶无甲氧基取代。IR光谱表明除无碱法坛紫菜琼胶外，各样品都有较尖锐的3,6-内醚半乳糖吸收峰。无碱法坛紫菜琼胶硫酸基的吸收峰较强，硫酸基取代主要在6位。稀碱法伊谷草琼胶的硫酸基取代主要在D-半乳糖的4位。碱处理前，石花菜琼胶、龙须菜琼胶及坛紫菜琼胶都有弱的肽键吸收峰。碱处理可消除6位硫酸基和少量的蛋白质。对所有理化性质数据两两进行相关性分析。有负相关性的最为：硫酸根含量与3,6-内醚半乳糖含量、总糖含量与硫酸根含量、3,6-内醚半乳糖含量与灰分、总糖含量与灰分、琼胶得率与灰分；有正相关性的量为：硫酸根含量与灰分、凝固温度与3,6-内醚半乳糖含量、凝胶强度与3,6-内醚半乳糖含量、凝胶强度与总糖含量。综合考察认为，我国的三种琼胶海藻均为优质的琼胶原料。提取琼胶时，石花菜不用碱处理，龙须菜和坛紫菜则必须经过碱处理。从灰分和硫酸基含量角度分析，石花菜琼胶优于坛紫菜琼胶，后者又优于龙须菜琼胶。凝固温度与甲氧基含量及其位置有关。
其他摘要	In order to offer some theoretic guidance for preparing high quality agars suitable for different usages, comparative studies on the agars extracted from Gracilaria lemaneiformis, Gelidium amansii, Porphyra haitanensis, and Ahnfeltia sp. are carried out in this thesis. 1) Agar yield (AY) of Gelidium amansii is of the highest among the four agarophyta. Agar from Porphyra haitanensis (PA) ha the highest gelling temperature(T_g). Agar from Gracilaria lemaneiformis (GA) has rather higher melting temperature(T_m) than others. The influences of alkali pretreatment on AY, T_g, and T_m are dissimilar for different agarophyta. Gel strength (GS), T_g and T_m rise after the alkali pretreatment. 2) Among the gels, ash and sulfate contents of GA are of the highest. 3,6-anhydro-galactose (3,6-AG) content (C_(36)) of PA is of the highest. The influences of alkali pretreatment on ash, sulfate, and 3,6-AG contents are dissimilar for different agarophyta. Total carbohydrate contents (C_c) of all the samples are very high due to the purity of the agar samples and the system error of the phenol-sulfate method. 3) The ~(13)C-NMR spectrum of 8 samples show the major signals characteristic of the agarobiose repeating unit. Floridean starch is not detected. PA without alkali pretreatment (UPA) has distinct signals corresponding to precursor of agarose and weak signals related to 6-OCH_3-D-galactose-3,6-anhydro-L-galactose. PA with dilute alkali pretreatment (DAA) has weak signals related to 6-OCH_3-D-galactose-3,6-anhydro-L-galactose. Agar from Ahnfeltia sp. with dilute alkali pretreatment (DAA) has weak signals assigned to D-galactose-2-OCH_3-3,6-anhydro-L-galactose. The IR spectrum of 8 samples show that all but UPA have distinct absorption bands assigned to of 3,6-AG. UPA has pronounced band corresponding to sulfate linked to the C_6 of galactose. DAA has weak band corresponding to sulfate linked to the C_4 of D-galactose. Agars from Gracilaria lemaneiformis, Gelidium amansii, and Porphyra haitanensis without alkali pretreatment (UGA, UGEA, and UPA) have weak signals corresponding to peptide bond. The signals related to C_6 of galactose and peptide bond disappear after alkali pretreatment. 4) Negative correlations included: sulfate content (C_s) and C_(36); C_c and C_s; ash content (C_a) and C_(36); C_c and C_a; AY and C_a. Positive correlations included: C_s and C_a; T_g and C_(36); GS and C_(36); GS and C_c. The three economic agarophyta in our country are all high quality resources of agar. Before extraction, the alkali pretreatment is unnecessary for Gelidium amansii, while essential for Porphyra haitanensis, and Gracilaria lemaneiformis. At the C_a and C_s point of view, GEA is better than PA, which is better than GA. T_g is affected by the location and quantity of OCH_2 substituent.
页数	26
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/465
专题	海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	王璐. 几种红藻琼胶的组分结构及理化性质的比较研究[D]. 中国科学院海洋研究所. 中国科学院海洋研究所,1999.

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