Exotic fruits as a source of important phytochemicals: Improving the traditional use of Rosa canina fruits in Portugal

Several exotic fruits are used in folk medicine as potential sources of healthy compounds. Rosa canina L. (dog rose) fruits and other parts used to be widely consumed in rural areas from Portugal. The present work intends to highlight the presence of bioactive compounds in those different parts, in order to improve their use based on scientific studies. The antioxidant activity was screened through: radical scavenging effects, reducing power, and inhibition of lipid peroxidation in brain homogenates. Phytochemical characterization included determination of sugars by HPLC-RI, fatty acids by GC-FID, tocopherols by HPLC-fluorescence, phenolics, flavonoids, carotenoids, chlorophylls and ascorbic acid, by spectrophotometric techniques. Galls revealed the highest antioxidant potential, ripen hips showed the highest tocopherols and ??-carotene contents, as also the most adequate n-6/n-3 fatty acids ratios. Unripe hips gave the highest levels of ascorbic acid and petals revealed the highest concentration of sugars. Ethnobotanical studies conducted have mentioned different use-reports for seeds, petals, flowers and galls, as well as for fruits in different stages of maturity and, therefore, the comparison between chemical compounds and antioxidant properties of those different parts is a key-point of the present study. Furthermore, the levels of antioxidants found would make them suitable sources of compounds to be used commercially to retard rancidity in fatty materials in food manufacturing, to reduce the effects of ageing and to help to prevent oxidative-stress related diseases such as cancer and heart disease.     

滁菊的功能成分及其体外抗氧化活性

为明确滁菊中抗氧化活性物质的含量及其抗氧化能力,对其进行进一步的开发利用,对滁菊（Chrysanthemum morifolium Ramat）酚类、多糖、类胡萝卜素提取物抗氧化能力及含量进行研究。结果表明：滁菊总酚和黄酮含量较高,分别为53.67 mg/g和70.32 mg/g,高于大洋菊等菊花;多糖和类胡萝卜素含量较低。3 种提取物中,酚类抗氧化能力最强,对1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）和2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)（2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),ABTS）阳离子自由基的清除能力分别为208.79 mmol/g和160.23 mmol/g,对Fe3＋的还原能力达到238.35 mmol/g,高于杭白菊等菊花。采用高效液相色谱法测定了滁菊酚类及类胡萝卜素单体组成,初步鉴定出滁菊含有绿原酸、儿茶素、咖啡酸、阿魏酸、金丝桃苷、槲皮素6 种单体酚,以及叶黄素和β-类胡萝卜素2 种类胡萝卜素单体。酚类物质中绿原酸含量最高,达到813.21 mg/g;金丝桃苷次之,达到408.17 mg/g;类胡萝卜素中叶黄素含量最高,为78.6 mg/g。在不考虑协同作用情况下,酚类物质中绿原酸对Fe3＋还原能力、DPPH及ABTS阳离子自由基清除能力的贡献均最大,类胡萝卜素中叶黄素对DPPH自由基的清除能力贡献最大。     

‘金丝小枣’在生长与成熟过程中活性成分及抗氧化活性变化规律研究

本文以6个不同生长与成熟期（S1^S6）的‘金丝小枣’为研究对象,通过高效液相色谱测定分析了枣果中的维生素C、酚类物质、环核苷酸、三萜酸、α-生育酚和β-胡萝卜素,同时采用分光光度计法测定了其在不同生长与成熟期的总酚、总黄酮含量以及枣果抗氧化活性。研究结果表明:随着枣果的生长成熟:其总酚、总黄酮、α-生育酚和β-胡萝卜素以及FRAP值、清除DPPH·以及ABTS+·自由基能力均呈现下降趋势;儿茶素和表儿茶素是枣果在生长与成熟过程中主要酚类物质。三萜酸含量在枣果的S3^S4期时最高,而c AMP和c GMP则随着枣果的生长成熟逐渐积累。      

Liaison of phenolic acids and biological activity of escalating cultivars of Daucus carota

The objective of the present study was to analyze and compare the phenolic compounds and their antioxidant capacities of new lines of Dacus carota. The selected cultivars showed high variation in the contents of total phenolics (30.26–65.39 mg/100 g FW) and total ascorbic acid (41.12–58.36 mg/100 g FW). Analysis on RP-HPLC revealed that hydroxycinnamic acids and its derivatives were major phenolic compounds present in D. carota extracts, whereas 5-caffeolquinic acid was a major hydroxycinnamic acid (ranged from 30.26 to 65.39 mg/100 g FW). DCP cultivar showed high total antioxidant capacity (77.69 mg/100 g), 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging capacity (52.36 mg/100 g), superoxide radical scavenging capacity (53.69 mg/100 g), and hydroxyl radical scavenging capacity (51.91 mg/100 g). A linear relationship was found between total phenolic acid contents and antioxidant capacity. Both phenolic compounds and antioxidant capacities varied significantly (ρ < 0.05) among cultivars. DCP cultivar was found to be a rich source of phenolics and ascorbic acid with high antioxidant activity.     

The effect of plant regulators on the concentration of carotenoids and phenolic compounds in foliage of coriander

Foliage of coriander crop is a rich source of pro-vitamin-A carotenoids and phenolics of relevance to human health. Foliar-application of plant growth regulators – methyl jasmonate and salicylic acid, differentially elicited total carotenoids, β-carotene, lutein, chlorophylls, total phenolics and chlorogenic acid in coriander, GS4 Multicut and Mahak, the cultivars with high and low carotenoids respectively. Carotenoids and total phenolics increased 6.8 and 3 folds respectively when treated with methyl jasmonate (10 μmol/L), whereas salicylic acid (500 μmol/L) showed 5.4 and 3.5 folds of respective compounds. These treatments also enhanced levels of β-carotene, lutein, chlorophylls and chlorogenic acid, as observed by HPLC/MS analyses. Carotenoid and phenolic extracts of the best treatments showed significant increase in hydroxyl and superoxide radical scavenging antioxidant activities compared with controls. The observations made here indicate that the precise use of plant growth regulators is a simple method for naturally augmenting the nutritionally important compounds in coriander crop.     

Antioxidant activity and contents of essential oil and phenolic compounds in flowers and seeds of Alpinia zerumbet (Pers.) B.L. Burtt. & R.M. Sm

Alpinia zerumbet leaves and rhizomes have been extensively studied for their chemical compositions and biological activities. However, less attention has been given to its flowers and seeds. In our study, essential oil, total phenolics and antioxidant capacities assayed by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and β-carotene bleaching methods were evaluated in flowers and seeds of A. zerumbet. In addition, their phenolic composition was determined by GC–MS and HPLC. 1,8-Cineol, camphor, methyl cinnamate and borneol were the major constituents in flower oils, whereas the main components in seeds oil were α-cadinol, T-muurolol, α-terpineol, δ-cadinene and terpinene-4-ol. The results showed that the hexane extract of flowers contained a significantly higher quantity of dihydro-5,6-dehydrokawain (DDK) than that of seeds. Total phenolic contents of flower and seed extracts were measured as 56.7 and 13.7 mg gallic acid equivalent per gram extract, respectively. The ethyl acetate extract of flowers and seeds possessed a high antiradical activity and prevented the bleaching of β-carotene. The HPLC analysis indicated that p-hydroxybenzoic acid, ferulic acid and syringic acid were the predominant phenolics in the ethyl acetate extract of flowers, whilst p-hydroxybenzoic acid, syringic acid and vanillin were the major phenolics in seeds.     

油茶籽油不同形态酚类化合物的抗氧化互作关系

本研究首先对油茶籽油中游离酚（free phenolics，FP）、酯化酚（esterified phenolics，EP）及不溶性结合酚（insoluble-bound phenolics，ISP）含量及主要物质组成进行分析，并通过测定铁离子还原能力、2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)阳离子自由基清除能力、1,1-二苯基-2-三硝基苯肼自由基清除能力及β-胡萝卜素漂白能力对其中FP、EP及ISP的抗氧化活性及互作关系进行研究。结果表明，油茶籽油总酚含量为（137.97±5.14）mg/kg，其中ISP含量显著高于FP及EP（P＜0.05），占油茶籽油总酚的47.74%。另外，FP中以苯甲酸衍生物含量较高（主要为异香兰素及甲基香兰素），EP中主要为水杨酸，ISP中主要为3,4-二羟基扁桃酸。3 种形态酚类化合物在不同机制下的抗氧化能力不同，且呈现质量浓度依赖效应。FP＋ISP组合及EP＋ISP组合在抗氧化互作方面表现出一定的协同或相加作用，且后者复配组合的抗氧化活性更强；而FP＋EP组合和FP＋EP＋ISP组合则表现出拮抗或相加作用。     

Determination of antioxidant activity and antioxidant content in tomato varieties and evaluation of mutual interactions between antioxidants

Major antioxidants and antioxidant activity in eight varieties of tomatoes were determined. Hydrophilic and lipophilic antioxidant activity (HAA and LAA) was determined by the ABTS assay and ascorbic acid and carotenoid contents were determined by HPLC-DAD. The HAA has far more significant impact on total antioxidant activity (83%) as compared with LAA. HAA was increasing during all ripening stages and was strongly correlated with ascorbic acid content (r = 0.83). During the ripening the LAA was increasing till the III. stage of maturity and then decreased. The main carotenoids determined in the red-fruit tomatoes were lycopene, β-carotene and lutein. The content of lycopene has been increasing equally during the ripening. β-Carotene and lutein were intensively synthesized between the I. and II. stage of maturity. Among ascorbic acid, α-tocopherol, lycopene, β-carotene and lutein standards ascorbic acid was determined as the most efficient antioxidant followed by α-tocopherol and β-carotene. Antioxidant activity of ascorbic acid, α-tocopherol, β-carotene and lutein grew equally with increasing concentration, however lycopene was the most effective in its lowest concentration. The analysis of two-component mixtures showed significant synergism between lycopene-lutein, lycopene-β-carotene and α-tocopherol-β-carotene.     

Changes in the contents of antioxidant compounds in pepper fruits at different ripening stages,as affected by salinity

The interest in the consumption of pepper fruits (Capsicum annuum L.) is, to a large extent, due to its content of bioactive nutrients and their importance as dietary antioxidants. A greenhouse experiment was carried out to determine the effects of salinity and different ripening states of pepper fruits on several compounds with antioxidant properties. Fruits from plants grown under three saline treatments (0, 15, and 30 mM NaCl) were collected at three maturity states (green, turning, and red). Antioxidant activity in the hydrophilic (HAA) and lipophilic (LAA) fractions, lycopene, β-carotene, ascorbic acid, total phenolic compounds and reducing sugars were determined. From the nutritional point of view, the red state was the most appropriate state of maturation, since red peppers had the highest levels of lycopene, β-carotene, and sugars and the highest antioxidant activity for both hydrophilic and lipophilic fractions. The effect of salinity depended on the maturity state of the peppers: it had no effect on HAA, β-carotene or sugars, but decreased ascorbic acid and total phenolic compounds, and increased LAA and lycopene. The use of a moderately-saline water was beneficial when peppers were harvested in the red state, by increasing HAA and LAA in fruits, with no significant effects on other parameters.     

Anthocyanins,Antioxidative, and Antimicrobial Properties of American Cranberry (Vaccinium macrocarpon Ait.) and their Press Cakes

ABSTRACT: Amounts of total phenolics, anthocyanins, and ascorbic acid in 4 American cranberry varieties harvested at 4 stages of maturity were measured. The larger amount of phenolic compounds was found in berries of “Black Veil” cultivar (504 mg/100 g) at II stage of maturity. Significantly larger amounts of anthocyanins were determined in the overripe berries of the cultivars “Ben Lear” and “Black Veil.” The amount of ascorbic acid in berries increased during ripening from I to III stage, and slightly decreased in the overripe berries. The biggest quantities of ascorbic acid were found in the ripe berries of “Ben Lear” cultivar (15.8 mg/100 g). The distribution of anthocyanins pigments was determined by HPLC‐UV/MS in mature berries. The composition of individual anthocyanins in berries was quite similar in all the studied cranberry cultivars. While skins of cranberries are rich in anthocyanins and other phenolic compounds, the extracts of the by‐products of cranberries juice—berry cakes, were analyzed and obtained results were compared with the properties of extracts made from whole berries. The anthocyanins and total phenolics content, radical scavenging activity, antimicrobial activity of the whole berries, and their press cakes extracts were measured. All investigated extracts from berries and their press cakes showed good radical scavenging activity and revealed antimicrobial properties. It was found that Bacillus cereus (ATCC 10876) and Micrococcus luteus (ATCC 9341) were the most sensitive among 10 tested Gram‐negative and Gram‐positive bacteria.     

Antioxidant constituents in some sweet pepper (Capsicum annuum L.) genotypes during maturity

Changes in total phenolics, antioxidant activity (AOX), carotenoids, capsaicin and ascorbic acid were monitored during three maturity stages in 10 genotypes of sweet pepper. In an attempt to explain the variations during maturity stages (green, intermediate and red/yellow), the data was expressed both on fresh and dry weight basis. All the antioxidant constituents (phenolics, ascorbic acid and carotenoids) and AOX, when expressed on fresh weight basis in general, showed an overall increasing trend during maturity in all the genotypes studied. On dry weight basis, phenolic content declined in majority of the genotypes during maturity to red stage. This decline was significant (P<0.05) in Parker, Torkel, HA-1038 and Flamingo. Genotype Flamingo and Golden Summer had the highest phenolic content of 852.0 mg 100 g⁻¹ and 720.5 mg 100 g⁻¹, at their final red and yellow maturity stages, respectively. With maturation, most of the cultivars showed a declining trend with regard to capsaicin content while total carotenoids and β-carotene content increased significantly. Anupam was a promising genotype in terms of both total carotenoids and β-carotene content. Ascorbic acid content declined progressively with advancing maturity. Genotype HA-1038 had the maximum content (3030 mg 100 g⁻¹ dwb) at the green stage. AOX in general, increased with maturity and registered a 1.30-1.95fold increase from green to red stage.The study proposes the nutritional significance of consuming sweet peppers at the red maturity stage because of enhanced functional properties. Overall genotype Flamingo and Anupam represent superior genotypes for both nutrition and germplasm improvement.     

蓝莓叶不同溶剂提取物抗氧化活性研究

研究蓝莓叶不同溶剂提取物中总酚和黄酮的含量以及抗氧化活性。分别用水、甲醇、乙醇、乙酸乙酯、氯仿、石油醚等不同极性溶剂提取蓝莓叶中的活性物质,采用Folin-Cioeaile法、三氯化铝显色法分别测定不同提取物中总酚和黄酮的含量;应用1,1-二苯基-2-三硝基苯肼（DPPH）自由基和2,2-联氮基双（3-乙基苯并噻唑啉-6-磺酸）二铵盐（ABTS）自由基清除体系及β-胡萝卜素-亚油酸体系评价其抗氧化活性,考察活性物质含量与抗氧化活性的关系。结果表明,蓝莓叶提取物的抗氧化活性随提取溶剂极性的减小而减小。水提取物具有较强的抗氧化活性,其清除DPPH·和ABTS+·的EC50分别为（12.78±0.10）、（6.35±0.03）μg/mL,抑制β-胡萝卜素淬灭IC50值为（25.33±0.02）μg/mL。含量测定显示水提物中总酚含量最高,为（264.67±0.29）mg/g,而甲醇提取物中黄酮含量最高,为（68.94±0.08）mg/g,相关性分析表明,不同溶剂提取物抗氧化能力差别较大,总酚和黄酮含量与抗氧化能力具有相关性,提示水可作为蓝莓叶抗氧化活性物质提取的优选溶剂,而总酚和黄酮含量可作为蓝莓叶抗氧化提取物的质量评价指标。      

Antioxidant Bioactive Compounds in Selected Industrial Processing and Fresh Consumption Tomato Cultivars

Four selected fresh consumption tomato varieties, harvested at different ripening stages (green, breaker, pink, red) and five industrial processing tomato varieties, harvested at red ripe stage, were analysed for lycopene and its isomers, β-carotene, total and individual phenolics, vitamin C and hydrophilic antioxidant activity. Tomato variety and ripening stage significantly affected carotenoids, total phenolic compounds and hydrophilic antioxidant activity when fresh consumption tomatoes were compared. The average of total lycopene content at the different ripening stages was 0.63, 12.20, 26.76 and 116.66 mg/kg of fresh weight (FW). Vitamin C ranged from 2.79 (breaker Cherry Pera) to 297.62 (red Cherry Pera) mg/kg FW. In green and breaker tomatoes, a positive correlation of hydrophilic antioxidant activity with vitamin C and chlorogenic acid was observed. However, in industrial tomato varieties (red ripe stage) and fresh consumption varieties harvested at pink and red stages, hydrophilic antioxidant activity was correlated with total phenolics and rutin. Tomato varieties for industrial processing did not show significant differences in total phenolic compounds and lycopene content. Lycopene ranged from 83.17 to 97.60 mg/kg FW, while total phenolic compounds varied between 257.91 and 284.13 mg/kg FW. Chlorogenic acid and rutin were the most abundant individual phenolics found in all the samples studied. Moreover, the content of total phenolics was always significantly correlated with the content of rutin. The amounts of all individual phenolics were affected by variety, with the exception of ferulic acid. Generally, these individual phenolics were more abundant in green and intermediate ripening stages, decreasing in full red tomatoes.     

枇杷花不同花期醇提物抗氧化活性的比较

以不同花期(花蕾期、露白期、初放期、盛开期)枇杷花为对象,研究枇杷花开放过程抗氧化性变化规律。采用70%乙醇二次回流提取以及Folin-Ciocalteu比色法、硝酸铝比色法、Fenton体系法、普鲁士蓝法和ABTS法分析评价枇杷花在不同花期的黄酮、总酚含量和总抗氧化能力。结果表明:枇杷花从花蕾期到盛开期,黄酮和总酚含量、抗氧化性能整体呈先上升后下降的趋势,其中在露白期的黄酮、总酚和Vc含量最高,分别为13.39±0.45mg/g、76.06±1.18 mg/g和(2.73±0.28)10-2mg/g,差异性显著高于其他花期(P<0.05);露白期枇杷花对羟基自由基的清除率、总抗氧化能力、总还原力和DPPH自由基清除率达到最高,分别为49.91±0.34%、61.50±0.21 mmol/g、0.67±0.01、74.28±0.73%。枇杷花具有较好的抗氧化性能,以露白期的抗氧化性最好,枇杷花采摘时期及开发利用时期应以露白期为佳。     

Biological activity and composition of extract from aerial root of Ficus microcarpa L. fil.

Total phenolic content, antioxidant and antibacterial activities of Ficus microcarpa aerial roots were determined on methanol extract and its sub-fractions (hexane, ethyl acetate, n -butanol and water). The ethyl acetate fraction possessed the highest amount of phenolic compounds evaluated by Folin-Ciocalteu reagent method. It also showed the highest antioxidant activity when tested the following methods: DPPH, ABTS⁺ radical-scavenging, superoxide radical scavenging, reducing power and β -carotene linoleic acid bleaching. On the other hand, high phenolics content extracts (ethyl acetate, methanol and n -butanol) showed significantly higher inhibitory activity than low phenolics content extracts (water and hexane) against five tested Gram positive and Gram negative bacteria. Protocatechuic acid, catechol, p -vinylguaiacol, syringol, p -propylphenol, vanillin, p -propylguaiacol, isovanillic acid, 4- n -Propylresorcinol, syringaldehyde and oleanolic acid contained in ethyl acetate fraction were identified by GC-MS and HPLC based on their cochromatography with standard compounds. Protocatechuic acid, catechol and syringol exhibited nearly same antioxidant activity as did by positive control Trolox using the mentioned assays. Results here showed that the ethyl acetate fraction has strong antioxidant and antibacterial activities, which are correlated with its high level of phenolic compounds.     

Antioxidant activity and total phenolics of edible mushroom extracts

Methanol and water crude extracts from Shiitake mushroom (Lentinus edodes) and straw mushroom (Volvariella volvacea) were investigated for their antioxidant capacity in three different assays, namely, the β-carotene and linoleic acid system, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, and inhibition of hemolysis of rat erythrocyte induced by peroxyl radicals. Among the four mushroom extracts, the water extract from L. edodes showed the most potent radical scavenging activity in each assay, showing 75.9% (at 20 mg/ml) in the β-carotene bleaching method, 55.4% in the DPPH radical scavenging method (at 6 mg/ml) and 94.9% of inhibition of erythrocyte hemolysis (at 5 mg/ml). Total phenolics in the water extracts were higher than that of the methanol ones. Positive correlations were found between total phenolic content in the mushroom extracts and their antioxidant activities. Edible mushrooms may have potential as natural antioxidants.     

Phenolic Compounds and Antioxidant Capacities of 10 Common Edible Flowers from China

The free and bound phenolic compounds in 10 common Chinese edible flowers were investigated using reversed phase high‐performance liquid chromatography. Their antioxidant capacities were evaluated using 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical‐scavenging activity, 2,2'‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid) (ABTS) radical‐scavenging activity, oxygen radical absorption capacity (ORAC), ferric reducing antioxidant power (FRAP), and cellular antioxidant activity (CAA). Free factions were more prominent in phenolic content and antioxidant capacity than bound fractions. Paeonia suffruticosa and Flos lonicerae showed the highest total phenolic content (TPC) 235.5 mg chlorogenic acid equivalents/g of dry weight and total flavonoid content 89.38 mg rutin equivalents/g of dry weight. The major phenolic compounds identified were gallic acid, chlorogenic acid, and rutin. P. suffruticosa had the highest antioxidant capacity in the DPPH, ABTS, and ORAC assays, which were 1028, 2065, 990 μmol Trolox equivalents/g of dry weight, respectively, whereas Rosa chinensis had the highest FRAP value (2645 μmol Fe²⁺ equivalents /g of dry weight). The P. suffruticosa soluble phenolics had the highest CAA, with the median effective dose (EC₅₀) 26.7 and 153 μmol quercetin equivalents/100 g of dry weight in the phosphate buffered saline (PBS) and no PBS wash protocol, respectively. TPC was strongly correlated with antioxidant capacity (R = 0.8443 to 0.9978, P < 0.01), which indicated that phenolics were the major contributors to the antioxidant activity of the selected edible flowers.     

Evaluation of antioxidant activities of various solvent extracts of Carissa opaca fruits

The chloroform and aqueous fractions of Carissa opaca fruit, a traditional medicinal fruit in Pakistan possessed a high amount of total phenolic and flavonoid contents as compare to other solvent fractions with potent antioxidant activities in scavenging DPPH, superoxides, hydroxyl, hydrogen peroxide, ABTS radicals, and had strong iron chelating activity. On the other hand, the ethyl acetate fraction showed the highest inhibition of β-carotene linoleic acid peroxidation and phosphomolybdate assay. A high correlation coefficient existed between EC₅₀ values of DPPH, superoxides, hydroxyl, hydrogen peroxide, ABTS radicals, total phenolics and flavonoids, but a non significant correlation was found in the case of iron chelaters, β-carotene and phosphomolybdate assay. This study verified that the chloroform and aqueous fractions have strong antioxidant activities which were correlated with its high level of phenolics and flavonoids. These fractions can be used as a source of potential antioxidant or functional food material.     

Antioxidant, tyrosinase inhibitory, and acetylcholinesterase inhibitory activities of green tea (Camellia sinensis L.) seed and its pericarp

The present study evaluates antioxidant, tyrosinase inhibitory, and acetylcholinesterase (AChE) inhibitory activities of seed and its pericarp of tea plant (Camellia sinensis L.). Water and methanol extracts of tea seed and pericarp were prepared in a shaking incubator overnight at room temperature. The highest total phenolic contents, DPPH and ABTS radical scavenging activities, reducing power, β-carotene bleaching inhibition activity, highest tyrosinase inhibitory activity, and AChE inhibitiory activity were found in the methanol extracts of pericarp. Caffeine, gallic acid, several phenolic compounds, hydroxymethyl furfural, and fatty acid derived compounds were detected in the extract of tea seed and pericarp. The results indicate that seed and pericarp could be utilized as the potential resources for antioxidant ingredients in food industry. In addition, these compounds may protect Alzheimer’s disease as they had inhibitory activity of acetylcholine esterase.     

盐藻β-胡萝卜素提取及自由基清除能力研究

对盐藻β-胡萝卜素的微波提取工艺和提取液的自由基清除能力进行了研究。选择丙酮为提取溶剂,微波辅助提取盐藻β-胡萝卜素的最优条件为:微波功率500 W、液固比250 m L/g、提取温度40℃、提取时间8 min和搅拌速度180 r/min,此时盐藻β-胡萝卜素得率为1.13%,高于传统的溶剂浸提法;三种体外抗氧化体系（还原力、羟自由基清除能力和抗脂质过氧化能力）结果表明,微波提取和传统溶剂浸提得到的盐藻β-胡萝卜素提取液的还原力、羟自由基清除能力和抗脂质过氧化能力之间没有显著差异（p>0.05）,但2种提取液的自由基清除能力均高于同浓度的β-胡萝卜素标准品溶液,说明盐藻β-胡萝卜素提取液中还含有其他具有良好抗氧化活性的物质,但其自由基清除能力均低于同浓度的维生素C和BHT溶液。