氮对纤维藻生长、油脂积累及营养吸收的影响

为研究氮源及氮浓度对一株淡水富油纤维藻(Ankistrodsemus sp.)生长、油脂积累及营养吸收的影响。以3N-BBM为基础培养基,采用单因素实验分别考察了尿素、氯化铵、硝酸钠及亚硝酸钠以及硝酸钠浓度对纤维藻生长、油脂积累及营养吸收的影响。结果表明:四种氮源对纤维藻生长和生物量影响较小,但对油脂积累影响较大。该藻在尿素中的生物量浓度最高(2.87g/L),在硝酸钠中的油脂含量(30.17%)和油脂产量(0.81g/L)最高。硝酸钠浓度为0.3mmol/L时,该藻较难存活,浓度为3.0mmol/L时其生长较差,但油脂含量(37.37%)和油脂产量(0.89g/L)最高;浓度在9.0~30.0mmol/L时,纤维藻生物量较高,但油脂含量和油脂产量较低。综合生物量和油脂含量考虑,该纤维藻最适生长和油脂积累的氮源为硝酸钠且最适浓度为3.0mmol/L。     

10种热带富油微藻生物量、总脂含量 及脂肪酸组成分析

微藻生物柴油是当前生物能源中最具发展潜力的一种新型能源,为更好地开发微藻生物柴油,筛选出适合制备生物柴油的富油微藻,以10种热带富油微藻为研究对象,对其生物量、总脂含量及脂肪酸组成进行分析。通过甲醇-氯仿(体积比为2∶1)称量法测定10种热带富油微藻中的总脂含量,将从微藻提取的油脂经过甲酯化反应后,采用气相色谱-质谱联用(GC-MS)分析油脂中脂肪酸组成及含量。结果表明,10种热带富油微藻中Chlorella vulgaris CJ15和Desmodesmus sp.WC08更适合制备生物柴油。     

不同营养条件对热带海洋富油微藻生长和油脂产量的影响

以热带海洋富油微藻XG01(琴式菱形藻,Psammodictyon panduriforme)为研究对象,测定了培养基中不同质量浓度的氮盐、磷酸盐和硅酸盐对藻株XG01生长和油脂产量的影响,确定了最佳培养条件,氮盐(硝酸钠)、磷酸盐(磷酸二氢钠)和硅酸盐(九水偏硅酸钠)的最佳质量浓度分别为300、10 mg/L和20 mg/L。在最佳培养条件下,藻株XG01的生物量达0.85 g/L,藻细胞内的油脂含量和油脂产量分别为48.21%和0.41 g/L。     

影响富油微藻高密度培养及产油因素研究进展

微藻具有诸多优良特性,是生物柴油最具潜力的原料之一。但大规模培养微藻制备生物柴油尚需解决优良藻种的选育、高密度培养、细胞采收、脱水及高效生物反应器设计等技术问题。该文从藻种、营养因素、培养条件、营养方式及培养模式等方面,阐述了当前影响富油微藻高密度培养和油脂积累因素的研究概况,以期为微藻培养及微藻油脂生产研究者提供参考。     

氮、磷源及海盐对微茫藻细胞生长和油脂积累的影响

为研究营养成分对一株淡水富油微茫藻(Micractinium reisseri)细胞生长和油脂积累的影响.以BG11为基础培养基,分别考察了氮源、磷浓度及海盐浓度的影响.实验结果表明,氯化铵为微茫藻细胞生长和油脂积累的最适氮源,以其为氮源时,微茫藻的油脂产量是原培养基中以硝酸钠为氮源时的1.6倍,缺氮培养条件下,微茫藻细胞油脂含量最高,但生物量较低;培养基中的磷浓度为80mg/L时,微茫藻总脂产量达到最高,为原培养基中磷浓度(40mg/L)时的1.4倍;添加适量海盐能够促进微茫藻的生长,同时该株微茫藻可以耐受比较高的海盐浓度(20g/L),其最适生长和油脂积累的海盐浓度为10g/L,在此浓度下,其总脂产量最高,是未添加海盐时的2.5倍.     

产油脂微藻的分离、鉴定及筛选

微藻油脂是生产生物柴油的重要原料,同时也是生产不饱和脂肪酸的原料来源之一。本文以广州市华南理工大学校内东湖为采样点,筛选鉴定湖中存在的微藻并研究其生长和油脂积累特性,旨在筛选出水体中可能存在的富油微藻以便后续研究分析。研究共筛选出6株绿藻,18Sr DNA鉴定显示6株绿藻中DH1、DH2、DH6均属于小球藻属,DH3、DH4、DH5均属于栅藻属,后分析构建了6株微藻进化发育树。通过藻细胞胞内油脂含量测定,表明DH1、DH2与DH6均能较好地积累油脂,尤其是DH2与DH6两株微藻。培养25 d发现其最大生物量(细胞数)分别达到2.14×10~7个/m L和2.74×10~7个/m L,油脂产量分别达到103.89 mg/L和131.69mg/L,藻细胞油脂百分含量均超过30%,表明该两株微藻是潜在的较为理想的产油微藻,可作为生物柴油制备的备用藻种资源。     

7种富油微藻的超临界提取及脂肪酸分布特征

富油微藻是制备生物燃料和提取高附加值不饱和脂肪酸的理想原料。为筛选具有高产油潜能的微藻,开发经济高效的微藻油脂提取工艺和检测方法,本文对7种富油微藻进行超临界CO2提取,并结合三氟化硼-甲醇衍生化、GC-MS分析了各微藻提取物中的35种脂肪酸组成和含量。结果表明,添加乙醇夹带剂后,各藻类的油脂收率由54.60 % ~ 82.16 %提高至75.61 % ~ 104.46 %。微藻中共检出18种脂肪酸,C16 ~ C18系列脂肪酸含量均在55.97 %以上,其中小球藻、三角褐指藻和青岛大扁藻的单不饱和脂肪酸含量分别为36.25 %、31.81 %和26.85 %,是生物柴油理想的替代品。牟氏角毛藻的不饱和脂肪酸UFAs含量达到91.15 %,可作为绿色医疗保健品的重要来源。     

几种天然有机物在食品抗氧化中的应用

<正>在油脂及富油的食品中,为了延长其货架期,添加少量抗氧化剂是十分必要的,否则油脂会被空气中的氧气氧化生成有害于人体的过氧化物。     

前处理条件对超临界CO_2萃取隐甲藻油脂的影响

对于超临界CO2 流体萃取油脂 ,物料的前处理是非常重要的。本实验探讨了隐甲藻藻粉的含水量、超声波破碎细胞壁和蒸炒技术处理藻粉细胞对超临界CO2 油脂萃取的影响。藻粉的水分含量小于 3 9% ,有利于藻细胞中油脂的提取 ;超声波破碎藻细胞壁 ,有利于藻细胞油脂的萃取 ,最大油脂萃取率达 85 % ;蒸炒技术处理藻细胞 ,可使细胞蛋白变性 ,起到调节油脂结构 ,凝集油脂的作用 ,适宜的蒸炒温度为 95～ 1 0 0℃。     

培养条件对蛋白核小球藻生长及油脂合成的影响

以富油蛋白核小球藻为出发藻株,研究自养、异养和混养培养模式对小球藻生物量和油脂含量的影响,以及异养发酵培养基葡萄糖质量浓度、氮源种类及质量浓度对小球藻生长的影响。结果表明,与自养和混养培养模式相比,采用异养发酵方式培养蛋白核小球藻可获得最大的生物量和油脂含量。通过气相色谱法测得异养蛋白核小球藻油主要脂肪酸为棕榈酸(36.07%)、油酸(34.26%)、亚油酸(20.17%)和亚麻酸(6.12%)。经单因素试验优化得到最适蛋白核小球藻生长异养发酵培养基的葡萄糖质量浓度为60 g/L,最适的氮源为酵母粉,质量浓度为4 g/L,在此条件下经192 h发酵,蛋白核小球藻生物量可达12.43 g/L,油脂产量为5.45 g/L。研究结果表明,异养发酵培养获得的蛋白核小球藻油是一种潜在且可再生的新油源。     

热带海洋产油脂微藻的筛选与鉴定分析

采用平板分离法从三亚亚龙湾海水样品中,分离获得1株热带海洋产油脂微藻,油脂含量高达34.05%,油脂产量为0.184 g/L。利用扫描电镜形态观察与分子鉴定相结合的技术手段,确定了该热带海洋产油脂微藻属于双眉藻属的Amphora Montana。     

Nutrient Composition of Chlorella spp. and Monodus subterraneus Cultured in a Bubble Column Bioreactor

The nutritional composition of two marine microalgae, Chlorella spp. and Monodus subterraneus, cultured in an outdoor bubble column photobioreactor used in batch mode was analyzed. Nutrients are reported at different microalgal growth phases. The proximate composition (moisture, crude protein, available carbohydrates and saponifiable oil), fatty acid and carotenoids at different growth stages were determined. On average, the biomass contained high amounts of protein in the two analyzed microalgae for all growth stages. Chlorella spp. biomass contained α-linolenic acid as predominant fatty acid, while M. subterraneus biomass was rich in palmitic and eicosapentaenoic fatty acids, which reached a maximum EPA productivity at the exponential growth phase (65.0 mg· L^?1·day^?1). For both microalgae, carotenoid content was strongly influenced by the growth phase. Chlorella spp. biomass was found to be good sources of lutein and β-carotene, while M. subterraneus biomass exhibited high amounts of neoxanthin and β-carotene. A high carotenoid productivity was obtained for this microalgae at the stationary growth phase, with 19.4 mg·L^?1·day^?1. The results of this study clearly demonstrated the relevance of microalgae for potential use in functional foods, justifying their commercial production.     

Effects of dietary microalgae,other lipid sources,inorganic selenium and iodine on yolk n‐3 fatty acid composition,selenium content and quality of eggs in laying hens

BACKGROUND: This aim of this study was to investigate the effects of supplementing laying hen diets with different n‐3 fatty acid sources (linseed oil, fish oil and microalgae) on egg quality and fatty acid profile. The addition of inorganic selenium (Se) and iodine (I) and their effects on egg characteristics and Se concentration were also evaluated. RESULTS: A significantly lower egg weight was found in the control group and in groups fed a diet containing fish oil or a diet containing microalgae plus Se and I. Yolks from all supplemented diet groups exhibited a significant reduction in n‐6 fatty acid content compared with the control group. The docosahexaenoic acid (DHA) content of yolks was higher (P < 0.01) in all supplemented diet groups. Selenium supplementation increased the Se concentration (P < 0.001) in eggs. CONCLUSION: The results of this study provide evidence that an improvement in egg weight and in the DHA content of yolks can be achieved by feeding hens a microalgae‐rich diet, which avoids the unpleasant flavours associated with fish oil supplementation. Dietary inorganic Se, especially in combination with I, can enhance the concentration of Se in eggs. Copyright © 2009 Society of Chemical Industry     

Indigenous marine diatoms as novel sources of bioactive peptides with antihypertensive and antioxidant properties

Several bioactive compounds from microalgae have demonstrated diverse biological activities with positive effects on human health. However, the potential of bioactive peptides as functional foods is still undervalued. Therefore, the exploration of microalgae strains as sources of bioactive peptides could reveal strong and unique bioactivities, especially when these marine sources have never been explored before. For this aim, protein extracts from six indigenous marine diatoms were subjected to enzymatic hydrolysis using four proteases (flavourzyme, pepsin, papain and trypsin). The hydrolysates were then tested for angiotensin converting enzyme (ACE)-inhibitory, antioxidant and antihypertensive properties. Results showed that papain hydrolysates from all microalgae strains exhibited strong ACE-inhibitory activities and antioxidant properties. In particular, protein hydrolysates from Bellerochea malleus were found to reduce blood pressure properties of 17 mmHg after 5 days of oral administration to SHR animals. These results revealed the potential of bioactive peptides from indigenous marine diatoms for use as functional foods or nutraceuticals.     

寇氏隐甲藻不同破壁方法的研究

寇氏隐甲藻是海洋微藻的一种,在寇氏隐甲藻的细胞油脂中,二十二碳六烯酸的含量高达30%～50%。但长期以来,因为微藻的细胞壁很难破碎,导致油脂的提取率不高。运用超声波法、生物酶法,反复冻溶法等方法,对寇氏隐甲藻进行了破壁研究。结果表明,这些方法都对寇氏隐甲藻都具有一定的破壁作用,破壁后油脂的提取率也有了不同程度的提高,把酶法破壁和超声波法破壁结合起来,在酶解5 h后,再超声波1 h,破壁率可高达91.7%,油脂提取率提高了21.7%,破壁效果更为理想。     

微藻油的提取与功能研究进展

海洋微藻中富含多种功能性特异的脂类物质,其提取方法和功能特性逐渐受到研究者的关注。本文综述物理法、化学法、物理化学法、生物法四种微藻油提取方法及其优缺点;阐述了微藻油中二十二碳六烯酸(DHA)、二十碳五烯酸(EPA)和角鲨烯的抗肿瘤、降血脂、增强智力、预防心血管疾病等功能;介绍了微藻油在食品、医药和养殖业的应用;提出了微藻油提取技术及其功能特性的发展趋势,并展望了微藻油的应用前景。     

复合VE对延长富含油脂食品保质期的影响

为了延长富含油脂食品的保质期,对VE、Vc、柠檬酸对炒制花生粉油脂氧化酸败的抑制作用进行了研究。通过跟踪样品中过氧化值(POV)的变化来检测炒制花生粉油脂的氧化酸败程度。结果表明,VE、Vc、柠檬酸对炒制花生粉油脂氧化酸败确实有抑制作用,Vc、柠檬酸对VE的抗氧化作用有协同增效的作用,直接添加适当比例的VE、Vc、柠檬酸到炒制花生粉当中,可以延长富含油脂食品的保质期。     

利用微藻培养生产DHA的进展

DHA(二十二碳六烯酸)是一种重要的必需多不饱和脂肪 酸。它具有多种与我们身体健康有密切关系的生理功能, 是婴幼儿健康成长过程中不可缺少的营养因子,同时对 防治心脑血管疾病和抗癌也有很好的功效。传统的DHA 产品主要来源于鱼油,但对鱼类的过度捕捞已造成严重 的环境和资源问题,并且鱼油含有多种有毒的有机污染 物(如二恶英)与重金属,从而使鱼油来源的DHA在质量 和安全性上备受质疑。目前,利用微藻生产DHA成为一 个新趋势。本文综述了微藻生产DHA的方法。     

大豆蛋白/壳聚糖凝聚法制备微藻油乳液及其稳定性研究

微藻油富含ω-3多不饱和脂肪酸二十二碳六烯酸(DHA)与二十碳五烯酸(EPA),在液体食品中的应用日趋广泛。但是微藻油极易在食品加工、保藏和消化过程中发生氧化劣变;同时脂溶性的微藻油难以添加至液体食品中。因此,改善和提高微藻油的稳定性是其应用到食品中的关键问题。本文利用大豆分离蛋白(SPI)/壳聚糖(CS)复合凝聚物(Coacervate)制备了微藻油乳液。由于乳液的氧化稳定性很大程度上依赖于其物理稳定性,本文系统研究了微生物谷氨酰胺转氨酶(m TGase)交联对微藻油乳液物理稳定性及氧化稳定性的影响。实验结果表明,在p H为6.0,CS/SPI比例为0.1 g/g,m TGase浓度为25 U/g SPI的条件下,m TGase对SPI/CS凝聚物的交联效果最好。m TGase交联明显改善了微藻油乳液的物理稳定性及氧化稳定性,并显著提高了微藻油的乳化效率。通过此方法制备的微藻油乳液产品可应用于豆奶等液体蛋白饮料从而达到强化DHA的目的。     

Preparation and Characterization of Novel Lipid Carriers Containing Microalgae Oil for Food Applications

This work investigated the suitability of lipid carriers as potential encapsulation method to improve the physical and chemical stability of microalgae oil high in docosahexaenoic acid (DHA). Lipid carriers with various oil contents were successfully prepared by a microfluidization method using stearic acid as solid lipid, microalgae oil as liquid lipid, and poloxamer 188 as surfactant. Results show that the mean particle diameter of the lipid carriers was in the range of 300 to 350 nm with the polydispersity index below 0.2. The lipid carriers were found to have spherical shape when examined under the transmission electron microscope. Data from the encapsulation efficiency and loading capacity indicate high distribution of microalgae oil throughout the lipid carriers and good physical stability as reflected by the particle size and size distribution during storage. Furthermore, the lower DPPH scavenging activity of lipid carriers compared with that of free microalgae oil suggests better chemical stability of microalgae oil encapsulated in lipid carriers. The addition of microalgae oil into lipid phase could disturb the crystalline order and form lattice defects to enable encapsulation of DHA as revealed by the results from differential scanning calorimetery. Current results suggest that this type of novel lipid carriers could be an efficient and promising carrier system for delivery of microalgae oil.