海带褐藻糖胶的复合酶法与热水法提取比较研究

目的对复合酶法与热水法提取海带褐藻糖胶的效率和提取物结构进行比较。方法分别采用复合酶法与热水法提取海带褐藻糖胶;环境扫描电镜(ESEM)比较两种方法对海带细胞壁组织显微结构的影响;采用高效液相色谱(HPLC)分析两种方法提取物的单糖组成。结果复合酶能温和高效地破碎海带的胞壁组织结构,使褐藻糖胶快速溶出,复合酶法与传统热水法比较有更高的褐藻糖胶得率和一次提取率,分别达2.36%±0.15%(以海带干重计)和84.89%。结论复合酶法提取海带褐藻糖胶效率较高,所制备的褐藻糖胶甘露糖和硫酸根含量较高。     

几种褐藻多糖硫酸酯粗提物的降血脂作用

褐藻多糖硫酸酯是一类独特的水溶性硫酸杂多糖,具有多种生物活性。研究用复合酶法提取分离羊栖菜褐藻多糖硫酸酯,利用动物试验,分析羊栖菜褐藻多糖硫酸酯和日本厚叶海带、真海带、大连厚叶海带、裙带菜的褐藻多糖硫酸酯对小鼠的降血脂作用。动物实验结果表明,日本厚叶海带、真海带和羊栖菜高剂量组、裙带菜低剂量组的褐藻多糖硫酸酯显著降低了TC、TG水平;大连厚叶海带和羊栖菜低剂量组、裙带菜高剂量组的褐藻多糖硫酸酯显著降低了TG水平;各褐藻多糖硫酸酯组均显著降低了LDL-C水平。比较5种褐藻多糖硫酸酯对小鼠体内抗氧化酶的影响,表明日本厚叶海带和羊栖菜的褐藻多糖硫酸酯各剂量组均显著降低了MDA水平;日本厚叶海带、真海带和大连厚叶海带的高剂量组均显著升高了SOD水平,而羊栖菜和裙带菜褐藻多糖硫酸酯的低剂量组具有同样作用;除羊栖菜低剂量组,其余各组均显著升高了GSH-Px水平;同样,除日本厚叶海带和羊栖菜高剂量组,其余各组均显著升高了NO值。研究结果显示这5种褐藻多糖硫酸酯具有较好的降血脂、抗氧化作用。     

海中蔬菜香

裙带菜 裙带菜就是俗称的海白菜。裙带菜和海带一样，都是褐藻植物。裙带菜长得和海带很像，它的叶片较海带薄，外形很像破的芭蕉叶，颜色为黄褐色。     

4种大型褐藻类菌胞素氨基酸的提取工艺优化及鉴定

类菌胞素氨基酸（mycosporine-like amino acids,MAAs）是小分子、水溶性代谢产物,广泛存在于大型褐藻中。以羊栖菜、海带、马尾藻和裙带菜4种大型褐藻为原料,采用单因素和正交试验验,分析提取温度、提取时间、提取次数和液料比对MAAs提取率的影响。结果表明,提取温度、提取时间和液料比对4种大型褐藻MAAs得率影响较大。对于羊栖菜、海带、马尾藻和裙带菜MAAs提取而言,适宜提取温度、提取时间和液料比依次为40、45、45℃和40℃;2、2、2 h和 3 h;25、20、25 mL/g和 20 mL/g,MAAs得率分别可达到 31.40%、46.71%、8.29%和 21.92%。通过对 4种大型褐藻MAAs提取物进行紫外波长扫描、高效液相色谱和质谱测定,并参考研究报道,鉴定它们中MAAs组成,主要包括palythine、palythenic acid、porphyra-334和shinorine。同时,根据palythine等4种类菌胞素氨基酸单体化合物（mycosporine-like amino acid,MAA）摩尔消光系数,可计算出4种大型褐藻MAAs提取物中MAA含量。其中,羊栖菜和马尾藻中palythenic acid含量较高,是此种MAA的理想来源。该文提出了羊栖菜、海带、马尾藻和裙带菜MAAs优化提取工艺,并第一次明确此4种大型褐藻MAAs组成。     

菠萝叶纤维素超级微晶的制备及其结构特性的研究

对菠萝叶纤维分别通过NaOH、HNO3、HCl进行预处理,然后用64%H2SO4水解,运用扫描电镜、透射电镜、Zeta电位-粒度分析仪、红外光谱和X射线衍射对其结构与特性进行表征。结果表明,可制备出长度分布为300~700nm,直径分布约为20~50nm的棒状菠萝叶纤维素超级微晶;与原纤维素相比,菠萝叶纤维素超级微晶的晶型仍为纤维素I型,但结晶度由57.8%增加到82.7%。     

大豆蛋白粉的碱改性研究

用碱液对大豆蛋白粉改性,研究了加碱量、温度及时间对碱改性大豆蛋白液黏度的影响,并通过X射线衍射和红外光谱等表征手段考察了碱改性大豆蛋白粉的结晶性及蛋白质二级结构。结果表明,在加碱量4%(以大豆蛋白粉质量计)、温度60℃、时间0.5 h时,改性大豆蛋白液的黏度最大,改性大豆蛋白粉的结晶性遭到破坏,蛋白质二级结构中无规卷曲含量达到最大值。     

柚皮纳米纤维素的制备工艺优化及形态特征

该文以丰都红心柚的中果皮为原料,采用硫酸水解法制备柚皮纳米纤维素(nano-crystal cellulose,NCC)。以H2SO4浓度、反应温度、反应时间对得率的影响进行单因素试验和响应面优化分析,并对制备出的纳米纤维素结构进行扫描电镜、红外光谱和X-射线衍射等分析。在H2SO4质量分数为62%、反应温度为50℃、反应时间为78 min的条件下制备出的NCC得率最高,为63. 27%。通过扫描电镜观察得知柚皮NCC呈类球状结构均匀分布,粒径在100～200 nm;由红外光谱和X射线衍射鉴定出样品为纤维素Ⅰ型结构,结晶度达到53. 75%。相较于柚皮微晶纤维素(microcrystalline cellulose,MCC),制备出的NCC具有更规则的结构、更大的比表面积和更高的结晶度,使柚皮纤维素具有了更高的应用价值。     

海藻酒

海藻作为一种天然传统食品,营养价值很高,仅以褐藻类海带科的海藻裙带菜(undaria pinnatifida)为例,组成如下:水份15—18％,蛋白质10—16％,脂肪1—2％,糖类38—45％     

草酸水解法制备纳米纤维素

采用草酸水解漂白阔叶木浆的方法制备纳米纤维素。用红外光谱、原子力显微镜、X-射线衍射以及热重分析等技术方法对对制备的纳米纤维素进行表征。实验结果表明,50%浓度的草酸水解得到的纳米纤维素的平均粒径为43.7 nm,长度为521 nm,结晶度达72%,以纤维素I晶型存在;纳米纤维素的尺寸减小引起热稳定性下降。     

海带综合利用研究

海带作为天然的保健食品,含有多种有效成分。就海带的综合利用进行研究,开发了从海带联产褐藻糖胶、甘露醇、膳食纤维和海藻酸钠的综合利用工艺。每100g海带可得水提法褐藻糖胶9.29g(含量14.33%)或酸提法褐藻糖胶8.10g(含量26.88%)、甘露醇7.11g(含量96.55%)、膳食纤维5.24g、海藻酸钠11.86g(含量90.28%)。还进行了褐藻糖胶抗氧化性能研究(DPPH法),水提法提取的褐藻糖胶抗氧化性能优于酸提法。     

Oral Administration of Edible Seaweed Undaria Pinnatifida (Wakame) Modifies Glucose and Lipid Metabolism in Rats: A DNA Microarray Analysis

1 Scope

Wakame is an edible seaweed that is a common constituent in the Japanese diet. Previous studies showed that wakame consumption is associated with the prevention of metabolic syndrome, but the molecular mechanisms underlying the protective effects are poorly understood.

2 Methods and results

To determine if the expression of hepatic genes is affected by ingestion of the brown seaweed Undaria pinnatifida (wakame), rats were fed a diet containing 0, 0.1, or 1.0 g per 100 g dried wakame powder for 28 days. Administration of 1% wakame significantly decreased serum total cholesterol levels. Hepatic gene expression was investigated using DNA microarray analysis, and the results showed that wakame suppresses the lipogenic pathway by downregulating SREBF‐1. Moreover, bile acid biosynthesis and gluconeogenesis were promoted by upregulation of the PPAR signaling pathway, which leads to a reduction in the accumulation of cholesterol and promotion of β‐oxidation.

3 Conclusions

These results suggest that wakame ingestion affects glucose and lipid metabolism by altering the expression of SREBF‐1 and PPAR signal‐related genes.     

Edible Japanese seaweed,wakame (Undaria pinnatifida) as an ingredient in pasta: Chemical,functional and structural evaluation

Wakame (Undaria pinnatifida) is edible seaweed rich in fucoxanthin; whilst, pasta is an important dish from nutritional and gastronomic point of view. Pasta was prepared with wakame as an ingredient at different levels. In vitro antioxidant properties, total phenolic content, fatty acid composition, fucoxanthin and fucosterol contents formed the major bio-functional characteristics analysed. Pasta with 10% wakame was acceptable sensorially. The total phenolic content varied between 0.10 and 0.94 mg gallic acid equivalents (GAE)/g, whilst total antioxidant activity varied from 0.16 to 2.14 mg ascorbic acid equivalents (AAE)/g, amongst different samples. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavenging activities of sensorily acceptable pasta were 7.71% and 4.56%, respectively. The sensorily acceptable pasta had a mild seaweed flavour with taste similar to control pasta, as assessed by panelists. The ratio of n-3 to n-6 fatty acid in seaweed incorporated pasta was 1:3.4 as compared to 1:15.2 in the control. Heat process involved in pasta preparation and cooking did not destroy fucoxanthin. Microstructure studies revealed the enhanced interaction between starch granules and protein matrix in pasta containing seaweeds up to 20%.     

The α-amylase and α-glucosidase inhibitory effects of Irish seaweed extracts

To date, numerous studies have reported on the antidiabetic properties of various plant extracts through inhibition of carbohydrate-hydrolysing enzymes. The objective of this research was to evaluate extracts of seaweeds for α-amylase and α-glucosidase inhibitory effects. Cold water and ethanol extracts of 15 seaweeds were initially screened and from this, five brown seaweed species were chosen. The cold water and ethanol extracts of Ascophyllum nodosum had the strongest α-amylase inhibitory effect with IC₅₀ values of 53.6 and 44.7 μg/ml, respectively. Moreover, the extracts of Fucus vesiculosus Linnaeus were found to be potent inhibitors of α-glucosidase with IC₅₀ values of 0.32 and 0.49 μg/ml. The observed effects were associated with the phenolic content and antioxidant activity of the extracts, and the concentrations used were below cytotoxic levels. Overall, our findings suggest that brown seaweed extracts may limit the release of simple sugars from the gut and thereby alleviate postprandial hyperglycaemia.     

Benthic marine and blue–green algal species as a source of choline

Species of red, brown and green seaweeds and blue-green algae were evaluated as sources of choline. A third of the seaweeds and all the blue-green algae gave very low values. Of the remainder, the brown seaweeds yielded contents between 0.1 to 6, the red 1 to 6 and the green 3 to 8 mg choline/g of dry alga. The seasonal variation was investigated in three brown algae. Commercial seaweed meals from Ascophyllum nodosum showed nearly constant levels of choline. The chromatographic behaviour of the choline-reineckate complex was also studied.     

Influence of different types and proportions of added edible seaweeds on characteristics of low-salt gel/emulsion meat systems

The effects of three different types of edible seaweeds, Sea Spaghetti (Himanthalia elongata), Wakame (Undaria pinnatifida), and Nori (Porphyra umbilicalis) added at two concentrations (2.5% and 5% dry matter) on the physicochemical and morphological characteristics of gel/emulsion systems were evaluated. The addition of seaweeds improved (P<0.05) water- and fat-binding properties except in the case of Nori added at 2.5%. Hardness and chewiness of the cooked products with added seaweed were higher (P<0.05), and springiness and cohesiveness were lower (P<0.05) than in control samples. Colour changes in meat systems were affected by the type of seaweed. The morphology of sample differed depending on the type of seaweed added, and this is the result of differences in physical and chemical characteristic of the seaweed powder used. In general, products formulated with the brown seaweeds (Sea Spaghetti and Wakame) exhibited similar behaviour, different from that of products made with the red seaweed Nori.     

Inhibition of fish oil oxidation and the radical scavenging activity of New Zealand seaweed extracts

This study describes the potential use of New Zealand seaweed extracts as antioxidants in fish oils. The extracts from two brown seaweeds (Ecklonia radiata, Macrocystis pyrifera) and two red species (Champia sp. and Porphyra sp.), were added to hoki (Macruronus novaezelandiae) oil and assessed by production of oxidation products in an elevated temperature (60 °C) storage trial. Antioxidant assays ORAC and DPPH were conducted to elucidate the radical scavenging activity of the seaweed extracts. The results showed that all the lipid-soluble seaweed extracts had some antioxidative capacity, with brown algae generally outperforming red algae species. Extracts from E. radiata performed best with significantly lower primary, secondary and total oxidation products, and higher DPPH radical scavenging ability than the commercial antioxidant, BHT. This study demonstrated the potential of brown algae seaweed extracts, in particular E. radiata, for use as antioxidants in fish oil products.     

Dietary fibre and physicochemical properties of edible Spanish seaweeds

 Total dietary fibre content of five edible marine Spanish seaweeds: Fucus vesiculosus, Laminaria digitata (Kombu), Undaria pinnatifida (Wakame), Chondrus crispus (Irish moss), and Porphyra tenera (Nori) ranged from 33.6 to 50% of which 19.6 to 64.9% was soluble. For brown algae, the soluble fibre obtained by the AOAC method followed by dialysis, contained uronic acids from alginates and neutral sugars from sulphated fucoidan and laminarin. For red seaweeds, the main neutral sugars corresponded to sulphated galactans: carrageenan (Chondrus) or agar (Nori), respectively. Insoluble fibres (12–40%) were essentially made of cellulose, plus residual fucose-containing polysaccharides, except for the red seaweed Nori, which contained an insoluble mannan and xylan. Protein content in powdered algae was higher in red (20.9–29.8%) than in brown seaweeds (6.9–16%), although protein digestibility was apparently low as inferred from preliminary in vitro results with Fucus and Laminaria. Ashes (21–39.8%) and sulphate content (2.8–10.5%) were high in all seaweeds. Minor components were lipids (0.2–2.5%) and extractable polyphenols (0.4%). Regarding the physicochemical properties, oil retention was low, while swelling, water retention, and cation exchange capacity were higher in brown algae, related to their higher uronic acid plus sulphate content. Received: 2 May 2000 / Revised version: 13 June 2000     

海丝纤维的生产方法

为了制备具有生物活性的功能性纤维,在溶剂法生产再生纤维素纤维的过程中,把海藻粉末与纺丝溶液混合,所得到的海丝纤维中分布了细小的海藻颗粒。介绍了利用溶剂法生产海丝纤维的基本原理,分析了海藻的种类、来源、组成及生物活性,以及在海丝纤维活化过程中,纤维中海藻粉末吸附银离子的性能。     

Comparative antioxidant activity of edible Japanese brown seaweeds

Japanese edible brown seaweeds, Eisenia bicyclis (Arame), Kjellmaniella crassifolia (Gagome), Alaria crassifolia (Chigaiso), Sargassum horneri (Akamoku), and Cystoseira hakodatensis (Uganomoku) were assayed for total phenolic content (TPC), fucoxanthin content, radical scavenging activities (DPPH, peroxyl radical, ABTS, and nitric oxide), and antioxidant activity in a liposome system. Among the solvents used for extraction, methanol was the most effective to extract total phenolics (TPC) from brown seaweeds. Among 5 kinds of brown seaweeds analyzed, methanol extract from C. hakodatensis was the best source for antioxidants. The high antioxidant activity of the extract was based not only on the high content of phenolics, but on the presence of fucoxanthin. No significant correlation (P > 0.05) was observed between TPC per gram extract with DPPH radical scavenging activity of the methanol extracts. These observed discrepancy would be due to structural variations in the phenolic compounds, and different levels of fucoxanthin in the extracts. The present study also demonstrated the synergy in the antioxidant activity of the combination of brown seaweed phenolics and fucoxanthin.     

In vitro determination of digestible and unavailable protein in edible seaweeds

Edible seaweeds are considered a complementary source of food protein for human and animal nutrition. The physiological effects of seaweed protein depend on the degree of enzymatic digestion of protein in the small intestine and bacterial fermentation in the large intestine. The objective of this work was to estimate total, digestible, fermentable and unavailable protein in some red and brown seaweeds. Brown seaweeds Fucus vesiculosus, Laminaria digitata and Undaria pinnatifida and red seaweeds Chondrus crispus and Porphyra tenera were treated with pepsin and pancreatin to separate digestible protein. Residues containing indigestible protein were inoculated for 24 h with rat caecal droppings, and protein contents were evaluated in the non‐fermented residue. Protein content in the seaweeds ranged from 8.9 to 25% of dry matter. Digestible protein was the major protein fraction (69%) only in P tenera; in the other seaweeds, this fraction ranged from 15 to 45%. Significant amounts of unavailable protein were found in all samples (2–24%). The distribution of total protein among the three fractions, ie digestible, fermentable and unavailable protein, could yield information about the physiological and metabolic consequences of the intake of seaweed proteins. © 2002 Society of Chemical Industry