In vitro antioxidant potential and inhibitory effect of seaweed on enzymes relevant for hyperglycemia

Hizikia fusiforme, Capsosiphon fulvescens, Undaria pinnatifida sporophyll, and Undaria pinnatifida blade extracts were evaluated for in vitro antioxidant and antihyperglycemic activities. Seaweed extracts contained high levels of phenolic compounds (12.44 to 39.01 mg of gallic acid equivalents/g of extract) and exhibited multiple antioxidant activities. Extracts showed weak inhibition of α-amylase. However, all extracts showed pronounced inhibition of α-glucosidase with EC₅₀ values from 2.56 to 18.81 mg/mL. U. pinnatifida sporophyll and U. pinnatifida blade extracts both contained protocatechuic and syringic acids. p-Coumaric and ferulic acids were detected only in the H. fusiforme extract. Caffeic acid and epicatechin were the dominant phenoilc acids found in C. fulvescens extracts. A basis for further research is provided to establish the capability of seaweed extracts as hypoglycemic agents or functional food ingredients.     

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%.     

体外模拟消化条件下岩藻黄素产品抗氧化活性的变化

目的 评价岩藻黄素产品在消化系统中的稳定性及变化规律。方法 本文考察了在体外消化模拟状态下岩藻黄素产品中岩藻黄素含量变化, 并采用测定其对DPPH自由基清除能力、铁离子还原能力(ferric ion reducing antioxidant power, FRAP)与氧自由基吸收能力 (oxygen radical absorbance capacity, ORAC)这3种抗氧化指标来评价岩藻黄素产品的抗氧化能力变化。结果 随着人工模拟胃肠消化过程时间的增加, 岩藻黄素产品中岩藻黄素的含量呈下降趋势, 但岩藻黄素微囊粉较岩藻黄素油悬液对岩藻黄素表现出良好的包埋与保护作用。在胃肠消化过程中, 岩藻黄素微囊粉与油悬液对DPPH自由基清除能力、FRAP铁离子还原能力与ORAC氧自由基吸收能力等抗氧化活性指标均有所降低, 其中岩藻黄素微囊粉较油悬液稳定, 表现出较好的抗氧化活性。结论 岩藻黄素微囊粉产品比油悬液产品在消化体系中具有更好的稳定性。     

Chemical compositions,fine structure and physicochemical properties of kudzu (Pueraria lobata) starches from different regions

Three commercial kudzu starches from Vietnam, Japan and Korea were used to determine chemical compositions, isoflavone compounds, fine structure and physicochemical properties. The kudzu starch from Vietnam had polygonal granules, whereas the kudzu starches from Japan and Korea contained both polygonal and spherical granules. Total protein, lipid, ash and phosphorus contents present in these kudzu starches were less than 1% (starch basis). The kudzu starch from Vietnam and Korea contained both daidzein and daidzin, whereas the kudzu starch from Japan had only daidzein. These starches had similar actual amylose contents (22.2–22.9%). However, λ_max, blue value and apparent amylose contents of the kudzu starch from Vietnam were lower than those from Japan and Korea. Amylose molecules of the kudzu starch from Vietnam had the largest average degree of polymerization (DP_n) and number of chains (NC), followed by the kudzu starches from Japan and Korea. Amylopectin molecules of the kudzu starch from Vietnam also had the largest DP_n and NC, followed by the kudzu starches from Korea and Japan. X-ray diffraction patterns of the kudzu starches from Vietnam, Japan and Korea were A-type, C-type and B-type, respectively. The kudzu starch from Vietnam was found to have the specific characteristics such as significantly high gelatinization temperature, transition enthalpy and degree of crystallinity as compared to the kudzu starch from Korea and Japan.     

Antioxidant Properties of Phenolic Compounds in Renewable Parts of Crataegus pinnatifida inferred from Seasonal Variations

In this study, the effect of seasonal variations on Crataegus pinnatifida, changes in antioxidant activity and active components in C. pinnatifida leaves, roots, twigs, and fruits from May to October were investigated. Through correlation analysis of climatic factors and 7 phenolic compounds yield, the phenolic compounds content was positively correlated with temperatures and daytime. The correlation coefficient of temperatures and daytime were 0.912 and 0.829, respectively. 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging, 2,2′‐azino‐bis 3‐ethylbenzothiazoline‐6‐sulphonic acid (ABTS) radical scavenging and reducing power tests were employed to evaluate the antioxidant activity of the C. pinnatifida. C. pinnatifida leaves exhibited significant advantages in terms of higher phenolic contents and excellent antioxidant activities. Principal component analysis (PCA) revealed that 2 main PC characterize the C. pinnatifida phenolic composition (82.1% of all variance). C. pinnatifida leaves in September possessed remarkable antioxidant activity. The results elucidate that C. pinnatifida leaves, as renewable parts, are suitable for application as antioxidant ingredients.     

The fucoidans from brown algae of Far-Eastern seas: Anti-tumor activity and structure–function relationship

The sulfated polysaccharides from brown algae – the fucoidans – are known to be a topic of numerous studies, due to their beneficial biological activities including anti-tumour activity. In this study the effect of fucoidans isolated from brown algae Saccharina cichorioides, Fucus evanescens, and Undaria pinnatifida on the proliferation, neoplastic transformation, and colony formation of mouse epidermal cells JB6 Cl41, human colon cancer DLD-1, breast cancer T-47D, and melanoma RPMI-7951 cell lines was investigated. The algal fucoidans specifically and markedly suppressed the proliferation of human cancer cells with less cytotoxic effects against normal mouse epidermal cells. The highly sulfated (1 → 3)-α-l-fucan from S. cichorioides was found to be vitally important in the inhibition of EGF-induced neoplastic transformation of JB6 Cl41 cells. In colony formation assay the fucoidans from different species of brown algae showed selective anti-tumour activity against different types of cancer, which depended on unique structures of the investigated polysaccharides. These results provide evidence for further exploring the use of the fucoidans from S. cichorioides, F. evanescens, and U. pinnatifida as novel chemotherapeutics against different types of cancer.     

Salmonella, Escherichia coli O157:H7 and E. coli biotype 1 in a pilot survey of imported and New Zealand pig meats

A pilot survey for the pathogens Salmonella and Escherichia coli O157:H7, and E. coli biotype 1 was conducted on 100 New Zealand-produced (domestic) pig carcasses and 110 imported pig meat samples over an 8-month period to assess the likelihood of introduction of novel pathogen strains into New Zealand (NZ), and as a guide for development of a domestic pork National Microbiological Database programme. Salmonella was not isolated from domestic pig carcasses or from pig meat imported from Canada and the USA. The prevalence of Salmonella in imported pig meat was 3.6% (95% CI 1.0–9.0) with positive samples detected from Australian pig meat. The prevalence of E. coli O157:H7 on domestic pig carcasses was 1% (95% CI 0.03–5.4) while the overall prevalence of E. coli O157:H7 in imported pig meat was 1.8% (95% CI 0.2–6.4), detected mainly from Australian but not from Canadian or US pork. All except three samples have an E. coli biotype 1 count of <100 CFU cm⁻² or g⁻¹, indicating good hygiene quality of domestic and imported pig meat. The results demonstrated that importation of uncooked pig meat is a potential route for the introduction of new clones of Salmonella and E. coli O157:H7 into New Zealand.     

Varieties of antioxidant and antibacterial properties of Ecklonia stolonifera and Ecklonia kurome products harvested and processed in the Noto peninsula,Japan

Ecklonia stolonifera and Ecklonia kurome are traditional edible brown algae in the fisheries towns in Far East Asia. In the Noto Peninsula area, Ishikawa, Japan, both the Ecklonia are called ‘kajime’ and people believe that the algae improve the property of blood. To determine the varieties of antioxidant and antibacterial properties E. stolonifera and E. kurome products, assays for total phenolic content and antioxidant activities, including DPPH radical-scavenging activity, superoxide anion radical-generated by non-enzymatic system, ferrous-reducing power and WST-8, a tetrazolium salt, redox activity of four dried and two boiled E. stolonifera, and four dried and two raw E. kurome preparations were tested in this study. Furthermore, antibacterial activity of the products was tested. Though the total phenolic content, the antioxidant activity and the antibacterial activities of E. stolorifera and E. kurome products were high, these properties were varied by manufacturers or each product. Especially, two dried and two boiled products of E. stolonifera showed low activities. The results of this study indicate that the contents of functional compounds and their activities were affected or decreased greatly by the processing method.     

Chemical composition characteristics of the longissimus and semimembranosus muscles for pigs from New Zealand and Singapore

A range of composition characteristics of the longissimus (LL) and semimembranosus (SM) muscles were compared between pigs raised in intensive and extensive production systems in New Zealand (NZ), and pigs raised in an intensive system in Indonesia for supply to the Singapore market (n = 8/group). Ultimate pH was slightly higher for the Singaporean LL muscles (P < 0.05), while LL muscle of the NZ extensive group was redder (higher a^∗ values) and contained more fat (P < 0.05). Muscle iron levels were highest for the NZ extensive group and lowest for a lighter group within the Singapore pigs (P < 0.05). Differences in fatty acid concentrations, which were also measured in a sample of the belly cut, could largely be attributed to the effects of diet, with higher levels of alpha linolenic acid for the NZ extensive group (P < 0.05) due to linseed in the diet, and much higher levels of linoleic acid and the P:S ratio for the Singapore group (P < 0.05). Some statistically significant differences in amino acid concentrations were shown between muscles and groups, but they were not large. With respect to compounds with potential bioactive properties, coenzyme Q_10, and taurine levels were higher in pork from NZ pigs, and carnosine levels were highest for the NZ intensive group (P < 0.05). The LL muscle contained more coenzyme Q₁₀ and taurine, but less carnosine than the SM muscle (P < 0.001). It is concluded that some of these composition differences in the pork from the muscles and groups compared may be of commercial importance, but several are likely to have been due to dietary or weight differences.     

岩藻黄素产业化技术研究进展

岩藻黄素（Fucoxanthin）,又称岩藻黄质、褐藻黄质、褐藻黄素,是一种具有抗氧化活性的天然类胡萝卜素,主要来源于褐藻、微藻（如微藻、金藻）等海洋藻类。岩藻黄素具有较大的市场开发潜力,但产业化程度较低,针对这一问题,该文首先概述了岩藻黄素物化特性及抗氧化、抗肿瘤、抗肥胖、抗炎等功能特性,并对岩藻黄素生产的上游开发和下游加工技术研究现状进行综述性介绍,详细介绍了岩藻黄素的上游开发（生物合成途径、生产藻类筛选、培养方法及条件）和下游加工技术（提取纯化方法、稳态化制剂、产品生产技术）,指出目前存在的技术瓶颈并提出可能的解决方案,最后分别介绍了岩藻黄素在食品、化妆品和医药等领域的应用现状。该文将为未来岩藻黄素产业化技术研究提供借鉴价值。     

Minerals,polysaccharides and antioxidant properties of aqueous solutions obtained from macroalgal beach-casts in the Noto Peninsula,Ishikawa, Japan

To clarify the useful properties of the macroalgal beach-casts for food, we determined mineral, water-soluble polysaccharide and total phenolic compound contents and antioxidant properties of aqueous solutions obtained from frond of eight brown and four green algae. These algae were washed ashore from the East Sea (the Sea of Japan) to the northeast beaches of the Noto Peninsula in autumn. There were fresh and large amounts of Ecklonia stolonifera (Es), Ecklonia kurome (Ek), Sargassum ringgoldianum subsp. coreanum (Sr) and Sargassum macrocarpum on the beaches. Potassium, magnesium and calcium ions were high in Sr-solution. High molecular weight water-soluble polysaccharide, mainly alginates, and relative viscosity were also high in Sr-solution. Both Es and Ek solutions showed high contents of total phenolic compounds and high antioxidant activities, including DPPH radical- and hydroxyl radical-scavenging and ferrous reducing power. On the other hand, the highest superoxide anion radical-scavenging activity was in the Sr solution. In the case of Sr, the same antioxidant properties were also found in the aqueous solution obtained from stem. These results suggest that some macroalgal beach-casts, especially Sr, can be utilised as new natural resources for functional foods, cosmetics, medical applications and fertilizer instead of being processed to landfill or incineration.     

Cytoprotective effect of fucoxanthin isolated from brown algae <Emphasis Type="Italic">Sargassum siliquastrum</Emphasis> against H<Subscript>2</Subscript>O<Subscript>2</Subscript>-induced cell damage

In this study, the cytoprotective effect of fucoxanthin, which was isolated from Sargassum siliquastrum, against oxidative stress induced DNA damage was investigated. Fucoxanthin, a kind of carotenoid, was pretreated to the medium and the protective effect was evaluated via 2′,7′-dichlorodihydrofluorescein diacetate, 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide, and comet assays. Intracellular reactive oxygen species were over produced by addition of hydrogen peroxide (H₂O₂), but the production was significantly reduced by the treatment with fucoxanthin. The fucoxanthin strongly enhanced cell viability against H₂O₂ induced oxidative damage and the inhibitory effect of cell damage was a dose-dependent manner. Furthermore, a protective effect against oxidative stress-induced cell apoptosis was also demonstrated via nuclear staining with Hoechst dye. These results clearly indicate that fucoxanthin isolated from S. siliquastrum possesses prominent antioxidant activity against H₂O₂-mediated cell damage and which might be a potential therapeutic agent for treating or preventing several diseases implicated with oxidative stress.     

岩藻黄素提取与分析方法研究进展

岩藻黄素是一类主要存在于海藻中的类胡萝卜素,其在抗癌、抗氧化、抗肥胖、调血脂、治疗认知功能障碍等方面具有重要的生理活性。该文综合并分析国内外相关文献,从岩藻黄素的提取、分离纯化及含量测定等方面的最新研究进展进行系统的阐述,以期为岩藻黄素的有效开发利用提供技术支撑。     

Supercritical carbon dioxide fluid extraction of Hibiscus cannabinus L. seed oil: A potential solvent-free and high antioxidative edible oil

The supercritical fluid extraction (SFE) trends and antioxidant activities of Hibiscus cannabinus seed oils were studied. SFE results indicate that extraction pressure is the major factor determining the oil yield. In comparison, classic Soxhlet extraction (SOX/L) yielded higher oil content than SFE (P < 0.05). However, no significant differences in oil content were observed in SFE at 600 bars/80 °C, rapid Soxhlet extraction (SOX/S) and conventional ultra-sonic assisted solvent extraction (SONIC) (P > 0.05). Antioxidant activities of H. cannabinus seed oils were compared with 7 types of commercial edible oils. DPPH scavenging activity test indicated that H. cannabinus seed oil extracted by SFE at 200 bars/80 °C possessed the highest antiradical activity whereas beta-carotene bleaching (BCB) assay revealed that all H. cannabinus seed oils (except for SFE at 400 bars/80 °C and 600 bars/80 °C) exhibited higher antioxidant activity than all commercial edible oils (P < 0.05). Thus, SFE – H. cannabinus seed oil may serve as an excellent source of solvent-free edible oil with high antioxidant properties.     

Electrochemistry-guided isolation of antioxidant metabolites from Sargassum elegans

Electrochemical techniques offer a rapid and simple alternative method for the analysis of bioactive compounds with antioxidant properties in crude samples. In this study we use square wave and cyclic voltammetry methods to guide the isolation of antioxidant natural products from the marine brown alga, Sargassum elegans (Suhr). Four pure antioxidants were isolated and identified by standard spectroscopic techniques as sargaquinoic acid, sargahydroquinoic acid, sargaquinal and fucoxanthin.     

Comparison of chemical profile and antioxidant properties of the brown algae

Six brown algae, Sargassum vestitum, Sargassum linearifolium, Phyllospora comosa, Padina sp., Hormosira banksii and Sargassum podocanthum, were investigated for the chemical profile and antioxidant activity. The results showed that the extracts H. banksii, S. vestitum and Padina sp. indicated the significantly higher total phenolic compound (TPC) and antioxidant activities (ABTS, DPPH and FRAP) compared to the other species (P < 0.05) and comparable to positive controls: butylated hydroxytoluene, ascorbic acid and alpha‐tocopherol at the concentrations (0.06–1 mg mL^?1). Fucoxanthin was also found in six species and isolated for evaluating antioxidant activity. In addition, the phenolic compounds were mainly responsible for antioxidant activity of the extracts, while fucoxanthin showed quite high antioxidant activity. It is suggested that S. vestitum, H. banksii and Padina sp. have the potent for extracting bioactive components and further applications in food and pharmaceutical industries.     

The influence of light and maturity on fruit quality and flavonoid content of red raspberries

The effects of various fruit maturities and different light intensities on berry fruit quality, antioxidant capacity and phytonutrient levels in red raspberries (Rubus ideaus L.) were determined. At harvest, immature berries contained significantly lower levels of sugars and acids than ripe berries. When berries were harvested at 5% or 20% maturity, they never developed the levels of soluble solids content (SSC) and titratable acid (TA) values observed in ripe berries at harvest. However, fruit harvested at 50% or more advanced maturity had the capacity of attaining comparable levels of SSC, TA and sugars as those harvested at 100% maturity. When 5% and 20% berries were stored under light, higher level of SSC and lower levels of TA values were observed than those kept in the dark. However, light condition showed little effect in 50% and 80% maturity fruit after 4 days at 24/16 °C (day/night). Ripe raspberries (100%) had stronger antioxidant activities and higher total anthocyanin content when compared with the pink stage (50% maturity). Fruit harvested at greener stages (5% and 20%) also consistently showed higher antioxidant activities and total phenolics than those harvested at 50%. Cyanindin-based anthocyanins increased during postharvest period. On the other hand, other polyphenols such as ellagic acid, quercetin 3-glucoside, quercetin derivative, and kaempferol 3-glucuronide were initially present at high levels but decreased drastically during storage. Red raspberries harvested at different developmental stages continued their development during storage even under the dark conditions. The antioxidant activity of red raspberries was directly related to the total amount of phenolics and flavonoids. Results of this study indicate that red raspberries harvested at 50% or more advanced maturity could develop comparable quality and antioxidant levels as those harvested at full maturity.     

Determination of antioxidative potential of lichen Usnea ghattensis in vitro

The study was aimed at evaluating the antioxidant activities of extract of Usnea ghattensis. The antioxidant activity, reducing power, superoxide anion radical scavenging and free radical scavenging activities were studied. The antioxidant activity increased with the increasing amount of extracts (2-20 mg/ml) added to the linoleic acid emulsion. Lipid peroxidation upto 73.3% was inhibited by the extract of 20 mg/ml and 39.2% by α-tocopherol at the same concentration. These effects were statistically significant (r²=0.876,P<0.01) when compared with control. However, the extract had no significant effect on superoxide anion scavenging by the PMS/NADH-NBT method. Like antioxidant activity, the reducing power and free radical scavenging activity of extract depends on concentration and increasing with increased amount of sample. The reducing power and DPPH radical-scavenging activity of U. ghattensis extract were found greater than the BHA and BHT. The results obtained in the present study indicate that U. ghattensis is a potential source of natural antioxidant.     

A survey of oysters (Crassostrea gigas) in New Zealand for Vibrio parahaemolyticus and Vibrio vulnificus

A microbiological survey was conducted to determine the levels of total and pathogenic Vibrio parahaemolyticus (Vp) and Vibrio vulnificus (Vv) in Pacific oysters (Crassostrea gigas) collected from commercial growing areas in the North Island, New Zealand.The survey was intended to be geographically representative of commercial growing areas of Pacific oysters in New Zealand, while selecting the time frame most likely to coincide with the increased abundance of pathogenic vibrio species. Vp was detected in 94.8% of oyster samples examined (n = 58) with a geometric mean concentration of 99.3 MPN/g, while Vv was detected in 17.2% of oyster samples examined with a geometric mean concentration of 7.4 MPN/g. The frequency of Vp positive samples was 1.7 fold greater than reported in a study conducted three decades ago in New Zealand. Potentially virulent (tdh positive) Vp was detected in two samples (3.4%, n = 58) while no trh (another virulence marker) positive samples were detected. 16 S rRNA genotype could be assigned only to 58.8% of Vv isolates (8:1:1 A:B:AB ratio, n = 10). There was a good agreement [98.2% of Vp (n = 280) and 94.4% of Vv (n = 18) isolates] between molecular tests and cultivation based techniques used to identify Vibrio isolates and there was a significant (R² = 0.95, P < 0.001, n = 18) linear relationship between the MPN estimates by real-time PCR and cultivation. There was no significant correlation between any of the environmental parameters tested and Vp or Vv concentrations.