南通坛紫菜多糖的黏度性质及其抗氧化活性

以南通洋口港坛紫菜为原料,利用水提法从紫菜中提取紫菜多糖,通过Sevage法除蛋白、活性炭脱色对其进行纯化。利用流变仪测定浓度、温度以及剪切速率对紫菜多糖黏度的影响探讨其黏度性质,并采用清除.OH自由基、O2-.自由基和DPPH.自由基模型对其体外抗氧化活性进行评价,并与VC进行了比较。结果表明:紫菜多糖溶液的黏度随着浓度和温度的升高而升高,随着剪切速率的增加而降低,多糖溶液表现为"非牛顿型流体",且具有"假塑性";紫菜多糖对.OH自由基、O2-.自由基以及DPPH.自由基都具有一定的清除能力,随着多糖溶液质量浓度的增大而增加,其中对O2-.自由基清除能力相对较强,当紫菜多糖溶液质量浓度为5 mg/mL时,对羟基自由基、超氧阴离子自由基、DPPH自由基的清除率分别为53.4%、78.9%和43.1%,但是与VC相比,紫菜多糖的抗氧化作用较弱。     

坛紫菜R-藻红蛋白的稳定性研究

为了揭示坛紫菜R-藻红蛋白（R-PR）的环境稳定性变化规律,分别研究了不同光照强度、温度、pH和金属离子条件下坛紫菜R-藻红蛋白光谱特性的影响。研究结果表明：坛紫菜R-藻红蛋白在40℃以下、弱光（2000lux以内）及pH5.0～8.0条件下相对稳定,光谱特性基本无变化;其中4℃、pH7.0的避光条件下R-PE尤为稳定;高温、紫外线、酸碱环境均影响坛紫菜R-PE稳定性,导致在565nm和498nm处特征吸收峰发生显著减弱并逐渐消失。坛紫菜R-藻红蛋白的两种藻胆色素的热稳定性关系为：藻尿胆素〉藻红胆素。此外,Fe2＋、Fe3＋、Cu2＋对坛紫菜R-PE的稳定性的破坏作用显著,而Ca2＋、Mg2＋、Zn2＋、Mn2＋对其稳定性影响较小。     

Effects of Different Short-Term UV-B Radiation Intensities on Metabolic Characteristics of Porphyra haitanensis

The effects of ultraviolet (UV) radiation, particularly UV-B on algae, have become an important issue as human-caused depletion of the protecting ozone layer has been reported. In this study, the effects of different short-term UV-B radiation on the growth, physiology, and metabolism of Porphyra haitanensis were examined. The growth of P. haitanensis decreased, and the bleaching phenomenon occurred in the thalli. The contents of total amino acids, soluble sugar, total protein, and mycosporine-like amino acids (MAAs) increased under different UV-B radiation intensities. The metabolic profiles of P. haitanensis differed between the control and UV-B radiation-treated groups. Most of the differential metabolites in P. haitanensis were significantly upregulated under UV-B exposure. Short-term enhanced UV-B irradiation significantly affected amino acid metabolism, carbohydrate metabolism, glutathione metabolism, and phenylpropane biosynthesis. The contents of phenylalanine, tyrosine, threonine, and serine were increased, suggesting that amino acid metabolism can promote the synthesis of UV-absorbing substances (such as phenols and MAAs) by providing precursor substances. The contents of sucrose, D-glucose-6-phosphate, and beta-D-fructose-6-phosphate were increased, suggesting that carbohydrate metabolism contributes to maintain energy supply for metabolic activity in response to UV-B exposure. Meanwhile, dehydroascorbic acid (DHA) was also significantly upregulated, denoting effective activation of the antioxidant system. To some extent, these results provide metabolic insights into the adaptive response mechanism of P. haitanensis to short-term enhanced UV-B radiation.     

正交试验法优选坛紫菜多糖的提取工艺

目的：对常规法提取紫菜多糖的工艺进行优化；方法：L16（4^4）正交试验及方差分析；结果：影响紫菜多糖热水提取的主要因素为醇沉浓度，其次是浸提时间，再次是浸提温度和料液比；结论：常规法提取紫菜多糖的优选方案为浸提温度80℃、浸提时间1．5h、料液比1：20、醇沉浓度90％。     

紫菜酶解物的制备及其特性

坛紫菜用纤维素酶和木瓜蛋白酶分别或联合处理,考察了提取物的得率、DPPH自由基清除率、氨基酸组成、蛋白溶解性和乳化性等性质.结果发现,利用木瓜蛋白酶对紫菜进行酶解时,固形物提取率稍微高于纤维素酶,利用这两种酶进行复合酶解时虽然可以提高紫菜的固形物得率,但不会改变蛋白提取率.紫菜酶解物的DPPH自由基清除率与蛋白含量之间存在显著的正相关关系,可能与提取物中具有抗氧化活性的氨基酸含量增加有关.另一方面,紫菜经复合酶酶解4h以上,提取物的蛋白溶解性在任一pH下都接近100％.而且,紫菜酶解物的乳化性在pH9最好,但乳化稳定性在pH7最低.     

利用扩增片段长度多态性(AFLP)研究坛紫菜的遗传变异

应用AFLP技术对浙江普陀列岛、渔山列岛和南麂列岛野生坛紫菜、福建野生厚型及薄型以及栽培坛紫菜的两个表型分化类型进行了研究。结果表明：坛紫菜的遗传变异较为丰富，共记录了528个位点，其中16个为单态位点，其余的为多态位点，多态位点比例达到96.97%。其遗传距离与地域分布正相关，说明不同的环境因素可能是造成坛紫菜遗传变异的主要因素。对遗传距离进行UPGMA和Neighbor-joining聚类分析表明具有薄型叶片性状的浙江野生坛紫菜和福建野生薄型坛此菜聚合，而福建野生厚型与栽培具厚型叶片，当地俗称为木耳菜的样本聚合。该结果基本清楚地反映了坛紫菜表型特征的分化。栽培薄型叶片俗称鸡毛菜样本在不同聚类方法中分别于外侧并入不同的分支。在福建野生坛紫菜与养殖坛紫菜的AFLP图谱中仅发现了三条与叶片性状相关的谱带：具有厚型叶片性状的坛紫菜共有的ACC-CAA(100)和ACT-CAG(232)，具有薄型叶性状的坛紫菜共有的ACC-CAA(490)。     

微波辅助提取紫菜多糖的工艺研究

紫菜多糖具有多种生理活性,研究其提取工艺具有重要意义.采用微波辅助提取技术和间断式微波辐射加热方法,探索了紫菜粗多糖的提取新工艺.试验研究了不同的微波功率、处理时间、料液比对紫菜多糖提取率的影响.在单因素试验的基础上,通过L9(3 3)正交试验优化了提取条件,取得了微波辅助浸提紫菜多糖的最佳工艺参数,即微波功率120W、提取时间8min、料液比1:30,在此条件下,紫菜多糖提取率为8.478%.     

Separation and purification of Porphyra haitanensis polysaccharide and its preliminary structural characterization

Porphyra haitanensis polysaccharide was separated and purified by microwave-assisted extraction with sequential DE-52 anion-exchange chromatography and Sephadex G-100 size-exclusion chromatography. The maximal yield of polysaccharide was 3.6% by microwave-assisted extraction. After purification, three polysaccharide components (PY1, PY2, and PY3) were obtained. PY1 had α-glycosidic bonds, whereas PY2 and PY3 had the β-amide pyranose. Sulfate groups and 3,6-anhydrogalactose were presented in three purified polysaccharide components. PY1 contained galactose and a little of xylose and arabinose. PY2 contained galactose and a little of arabinose, xylose, glucose, and mannose. The contents of sulfate groups, 3,6-anhydrogalactose, and galactose were also determined.     

微波消解-ICP-AES法测定坛紫菜中重金属及近年坛紫菜金属污染调查

以东海海域某养殖场中坛紫菜为原料,采用微波消解法-ICP-AES标准曲线法对坛紫菜中铝(Al)、锌(Zn)、铜(Cu)、镉(Cd)、砷(As)、铬(Cr)和铅(Pb)7种金属元素含量进行测定。各金属元素加标回收率为95.63%~105.3%,说明微波消解-等离子电感耦合等离子体原子发射光谱法(ICP-AES)能够实现对坛紫菜重金属元素的快速精确检测。另外,监测了近5年来坛紫菜的金属污染情况,结果发现呈显著上升趋势(P0.05,RSD1.89%),并且2012年不同嫩度的紫菜中金属含量呈现一水二水三水四水的现象(P0.05,RSD1.89%),应引起重视和治理。