Phenolic compositions and antioxidant activities of Maya nut (Brosimum alicastrum): Comparison with commercial nuts

The goal of the present study was to investigate the antioxidant activity and total phenolic content (TPC) of Maya nut (Brosimum alicastrum) in comparison with commercially available nuts (i.e. walnut, almond, and peanut). Results indicated that Maya nut had the highest TPCs among these nuts. Maya nut also possessed strong 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and 2.2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) scavenging activities and ferric reducing antioxidant power (FRAP) (p < 0.05) as compared to walnut, almond, and peanut. Five phenolic acids (gallic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid, and p-coumaric acid) and one flavonoid ((-)-epicatechin) were identified and the phenolic content ranged from 6.5 to 326.2 µg/g.     

凤头姜醇溶和水溶黄酮的抗氧化作用

比较凤头姜水溶和醇溶黄酮对超氧阴离子自由基、1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基、2’-联氨-双-3-乙基苯并噻唑啉-6-磺酸(2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),ABTS)自由基的清除能力和总抗氧化能力(铁离子还原能力法),同时用VC和2,6-二叔丁基对甲酚(butylated hydroxytoluene,BHT)作对照。结果表明:在DPPH自由基清除能力测定中,水溶黄酮的抗氧化效果强于醇溶黄酮和BHT,但弱于VC,水溶和醇溶黄酮的半抑制浓度(half maximal inhibitory concentration,IC_(50))分别为585.75μg/m L和1 013.45μg/m L;在ABTS+·、超氧阴离子自由基清除能力和总抗氧化能力测定中,醇溶黄酮的抗氧化效果均强于水溶黄酮、VC和BHT,醇溶和水溶黄酮对ABTS+·的IC_(50)分别为21.90μg/m L和87.54μg/m L;在超氧阴离子自由基清除能力测定中,水溶和醇溶黄酮的IC_(50)分别为26.56μg/m L和22.29μg/m L;在铁离子还原能力测定中,水溶黄酮和醇溶黄酮的TEAC1 000分别为45.78μg/m L和36.42μg/m L。综合研究发现,凤头姜水溶黄酮和醇溶黄酮在不同抗氧化体系中的抗氧化效果存在差异。     

Isolation And Identification Of An Antioxidant Peptide Prepared From Fermented Peanut Meal Using Bacillus Subtilis Fermentation

In order to recover and utilize peanut protein resource, peanut meal was fermented using Bacillus subtilis to prepare antioxidant peptides in this study. The antioxidant activities of the peanut peptides were evaluated via six in vitro tests, namely, 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) scavenging activity, inhibition of linoleic acid autoxidation, reducing power, and metal chelating capacity. The peanut peptides showed 63.28% of scavenging effect on 1,1-diphenyl-2-picrylhydrazyl radical, 70.67% of scavenging effect on 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and 39.32% of superoxide anion radical scavenging activity at 1.0 mg/ml, and 62.69% of inhibition on linoleic acid autooxidation at 0.8 mg/ml. Besides, the peanut peptides exhibited 32.8% of reducing power and 60.44% of Fe²⁺-chelating capacity at 2 mg/ml. Then the peanut peptides were desalted with macroporous resin; the fraction eluted with 75% ethanol showed the highest scavenging activity on 1,1-diphenyl-2-picrylhydrazyl radical. This fraction was subject to further purification using gel filtration chromatography and reverse phase-high performance liquid chromatography. At last, a peptide was gained, and it was identified to be Tyr-Pro with matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry. The results indicated that it is feasible to prepare natural antioxidants from peanut meal using B. subtilis fermentation.     

东北6 种红树莓叶酚类化合物的鉴定及抗氧化活性分析

以东北地区6 种不同品种的红树莓营养叶片为原料,采用分光光度法测定总酚、总黄酮和原花青素含量;使用3 种方法评价体外抗氧化活性并分析抗氧化活性与总酚、总黄酮和原花青素含量的相关性;采用超高效液相色谱-串联质谱法鉴定多酚类物质。结果表明,6 种红树莓叶片总酚含量高于总黄酮与原花青素含量。欧洲红的总酚与总黄酮含量最高,分别为（5.56±0.06）mg/g和（3.77±0.06）mg/g;哈瑞泰兹的原花青素含量最高为（3.06±0.04）mg/g。3 种抗氧化能力评价方法中,红树莓叶提取物对2,2’-联氮-双-(3-乙基苯并噻唑啉-6-磺酸二铵盐)（2,2’-azino-bis(3-ethylbenzthiazoline-6-sulphonate),ABTS）阳离子自由基清除能力与1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除能力具有极显著正相关性,相关系数为0.992;红树莓叶提取物中总酚含量和对ABTS阳离子自由基清除能力与对DPPH自由基清除能力的相关性显著,相关系数分别为0.886和0.891。超高效液相色谱-串联质谱法检出红树莓叶提取物中的13 种多酚类物质,其中有6 种酚酸和7 种类黄酮,主要酚酸为鞣花酸、绿原酸、没食子酸等;主要类黄酮为芦丁、儿茶素、表儿茶素、金丝桃苷等。     

Structural features,antioxidant and tyrosinase inhibitory activities of proanthocyanidins in leaves of two tea cultivars

In this study the structural features, antioxidant, and tyrosinase inhibitory activities of proanthocyanidins in leaves of two tea cultivars, namely Huangjingui and Qilan, were investigated. The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and thiolysis-high performance liquid chromatography-electrospray ionization mass spectrometry analyses confirmed that these proanthocyanidins were built up a mixture of procyanidins, propelargonidins, and prodelphinidins, with the predominance of procyanidins. The proanthocyanidins in leaves of Huangjingui and Qilan cultivars exhibited potent antioxidant activities with IC₅₀ values of 87.36 ± 0.83 and 97.33 ± 0.61 µg/mL in 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay, 43.57 ± 0.25 and 55.01 ± 0.22 µg/mL in 2,2’-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging assay, and with ferric reducing antioxidant power values of 4.83 ± 0.03 and 3.97 ± 0.02 mmol ascorbic acid equivalent/g in ferric reducing antioxidant power assay. It was also found that these proanthocyanidins had strong inhibition on tyrosinase activity with IC₅₀ values of 54.8 ± 1.27 and 20.0 ± 0.89 µg/mL for Huangjingui and Qilan cultivars, respectively. The results indicated that the proanthocyanidins in leaves of two tea cultivars could be considered as natural antioxidants and tyrosinase inhibitors applied in pharmaceutical and cosmetic industries in the future.     

豆芋异黄酮的制备及其对RIN-m5F细胞氧化损伤的保护作用

以豆芋（Apios americana Medik.）为原料,采用乙醇热回流提取、乙酸乙酯萃取,以异黄酮质量浓度为指标,优化大孔树脂富集工艺,并对得到的豆芋异黄酮（记为AI-3）抗氧化活性、α-葡萄糖苷酶抑制能力及对胰岛瘤细胞RIN-m5F氧化损伤的保护作用进行探究。结果：优化的D101型大孔树脂富集工艺为：上样质量浓度1.5 mg/mL,体积分数80%乙醇溶液（pH 6）洗脱,洗脱体积80 mL（4 倍柱体积）,所得AI-3得率为0.44%（占豆芋干基质量）,异黄酮质量分数50.83%;AI-3对1,1-二苯基-2-三硝基苯肼自由基、2,2’-联氮-双(3-乙基苯并噻唑啉-6-磺酸)阳离子自由基的半抑制质量浓度分别为19.51、3.40 μg/mL,铁离子还原抗氧化能力为387.83 μmol/mg,对α-葡萄糖苷酶活力的半抑制质量浓度为235.97 μg/mL;AI-3在0～300 μg/mL范围内,RIN-m5F细胞存活率同空白对照组相比无显著差异（P＞0.05）,且25～300 μg/mL时可极显著提高RIN-m5F氧化损伤细胞的存活率（P＜0.01）,300 μg/mL时细胞存活率达84.19%,高于阳性对照组。结论：D101型大孔树脂可有效富集豆芋异黄酮,所得AI-3具有较强的抗氧化、α-葡萄糖苷酶抑制活性及RIN-m5F细胞氧化损伤保护作用。研究结果为开发预防糖尿病等代谢综合征功能性食品提供了理论依据。     

Evaluation of nutraceutical properties of Laportea interrupta (L.) chew

In the present study Laportea interrupta was analysed for nutritional, antioxidant, and antipyretic properties. Leaves contained significant amount of carbohydrates (19.80 g/100 g), proteins (31.30 g/100 g), starch (15.40 g/100 g), essential amino acids, and minerals. Ethanol extracts of flowers and roots revealed high total phenolic (46.35 mg gallic acid equivalents/g of extract) and flavonoid contents (96.67mg rutin equivalents/g of extract) respectively. Antioxidant assays showed that ethanol root extract possessed a strong 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity (IC₅₀: 32.34 μg/mL), a 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) radical cation scavenging activity (1,072.57 μM trolox equivalents/g of extract), and a ferric reducing ability (9,456.01 mM Fe(II)/g of extract). Antipyretic studies revealed that ethanol root and leaf extracts at a dosage of 400 mg/kg in rats reduced the pyrexia induced by Brewer’s yeast by 68.0 and 57.4%, respectively. Thus, nutraceutical potential of L. interrupta and ethnobotanical information about its use as an antipyretic was confirmed.     

Phenolic compounds content and antioxidant activity in pomace from selected red grapes (Vitis vinifera L. and Vitis labrusca L.) widely produced in Brazil

The phenolic compounds content and antioxidant activity of pomace from the vinification of grape varieties widely produced in Brazil (Cabernet Sauvignon, Merlot, Bordeaux and Isabel) were investigated with a view to their exploitation as a potential source of natural antioxidants. Cabernet Sauvignon grape pomace was found to have the highest content of total phenolic compounds (74.75 mg gallic acid equivalent (GAE)/g), the highest antioxidant activity (determined using the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging methods; 485.42 and 505.52 μMol Trolox equivalent antioxidant capacity (TEAC)/g, respectively), and the highest reducing power (determined using the FRAP method; 249.46 μMol TEAC/g). The Bordeaux variety showed the highest oxidation inhibition power (41.13%), determined using the β-carotene/linoleic acid method and the highest content of total anthocyanins (HPLC; 29.17 mg/g). Catechin was the most abundant non-anthocyanic compound identified in the grape pomace (150.16 mg/100 g) for all varieties. In this study, pomaces of the red wine vinification of Cabernet Sauvignon and Bordeaux varieties showed the highest potential as a source of antioxidant compounds and natural colourants, respectively.     

Rose Petal Tea as an Antioxidant-rich Beverage: Cultivar Effects

ABSTRACT Twelve rose cultivars were selected by field tasting as potential sources of edible flowers. Hot water infusions (teas) of air‐dried petals of these cultivars were assayed for antioxidant activity, total phenols, and total anthocyanins contents. Their composition was analyzed by high‐performance liquid chromatography (HPLC). Green tea was tested in parallel as a reference antioxidant‐rich beverage. Rose petal teas from different cultivars exhibited scavenging capacity toward 2,2′‐azino‐bis‐(3‐ethylbenzothiazoline)‐6‐sulfonate cation radical (ABTS+) ranging between 712.7 and 1770.7 μM Trolox equivalents (TE) per gram of dry petals, as compared with 1227.6 μM TE/g dry weight in the green tea. The range of total phenols content in rose teas was 50.7 to 119.5 mg gallic acid equivalents (GAE) per gram of dry matter, as compared with 62.1 mg GAE/g dry weight in the green tea. The rose teas were rich in free gallic acid. The highest values of antioxidant activity, total phenols, and gallic acid contents were found in the cultivars San Francisco, Katharina Zeimet, and Mercedes and in the essential‐oil‐bearing rose Rosa damascena. The correlation coefficients between antioxidant activity, on the 1 hand, and the contents of total phenols and of gallic acid in various rose cultivars, on the other hand, were 0.79 and 0.81, respectively. No clear relationship between anthocyanin level and radical‐scavenging activity was revealed. Teas from different rose cultivars significantly differed in their sensory properties. It was concluded that dried rose petals may be used for preparing antioxidant‐rich caffeine‐free beverages, either separately or in combination with other herbal materials.     

Phytochemical Content,Antioxidant Properties,and Phenolic Profile of Tunisian Raisin Varieties (Vitis Vinifera L.)

Four raisin (Vitis vinifera L.) varieties, Chriha, Razeki, Assli, and Meski, were evaluated for total phenolic content, total o-diphenol content, total flavonoid content, total condensed tannin, total carotenoid content, and total anthocyanin content. Antioxidant potential was assessed by three assays: 2,2-Diphenyl-1-Picrylhydrazyl and 2,2’-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid radical scavenging capacity and ferric reducing power. Individual phenolic profiles were determined by high-performance liquid chromatography. The results revealed that the four raisin varieties had considerable phenolic content and antioxidant activity. Chriha had the highest total phenolic content (534.2 mg/g dry weight) while Meski had high total condensed tannin (208.6 mg CEQ/g dry weight), TAC (137 mg/100 g dry weight), total o-diphenol content (115.8 mg/g dry weight), total flavonoid content (93 mg CEQ/g dry weight), and total carotenoid content (33 mg/100 g dry weight). There were significant differences in phenolic content among the four varieties (p < 0.05). Meski had the highest 2,2-Diphenyl-1-Picrylhydrazyl scavenging capacity, while Chriha had adequate reducing power and 2,2’-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid scavenging capacity. The individual phenolic compounds (2.96–6.54 mg/g dry weight) were variety-dependent.     

Antibacterial and Antioxidant Activities in Extracts of Fully Grown Cladodes of 8 Cultivars of Cactus Pear

The antimicrobial and antioxidant activities of some cultivars of the nopal cactus have not been determined. In this study, 8 cultivars of nopal cacti from Mexico were assayed for phenolic content, antioxidant activities, and antimicrobial activities against Campylobacter Jejuni, Vibrio cholera, and Clostridium Perfringens. Plant material was washed, dried, and macerated in methanol. Minimum bactericidal concentrations (MBCs) were determined using the broth microdilution method. Antioxidant activities were quantitatively determined using spectrophotometric methods. The MCBs of the nopal cacti ranged from 1.1 to 12.5 mg/mL for c. jejuni, 4.4 to 30 mg/mL for V. cholera, and 0.8 to 16 mg/mL for C. perfringens in the cultivars Cardon Blanco, Real de Catorce, and Jalpa, respectively. High quantities of total phenols and total flavonoids were found in the Jalpa cacti (3.80 mg of gallic acid equivalent GAE/g dry weight [DW] and 36.64 mg of quercetin equivalents [QE]/g DW, respectively). 2,2‐Diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activities (RSA) were correlated to bioactive compound contents. The Villanueva cacti had the highest %RSA at 42.31%, and the lowest activity was recorded in Copena V1 at 19.98%. In conclusion, we found that some of the 8 cactus pear cultivars studied may be used for their antioxidant compounds or antimicrobials to control or prevent the contamination of foods.     

Phenolic acid composition and antioxidant capacity of acid and alkali hydrolysed wheat bran fractions

Phenolic acid concentrations, profiles and antioxidant capacity of acid and alkali hydrolysates from the bran of six wheat cultivars representing six Canadian market classes were determined. Aqueous ethanol was used to extract the free phenolics (FP) and diethyl ether to extract the insoluble bound phenolics released after acid and alkaline hydrolysis of the bran. Folin–Ciocalteu (FC) reagent was used to estimate the total phenolic content and HPLC-UV to detect and quantitate 14 phenolic acids and one lignan. trans-Ferulic acid was the dominant acid in the bran extracts but mass spectrometric analysis showed tryptophan to be dominant in the FP extracts. The antioxidant capacity of individual phenolic acids and extracts was assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), and 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) equivalent antioxidant assays. The FP extracts had the lowest average antioxidant capacity and the hydrolysates the highest. Based on the concentration of each phenolic acid in the extracts, and the antioxidant capability of each phenolic standard, trans-ferulic acid was the dominant contributor (66.4–95.5%) to antioxidant capacity of the wheat bran extract.     

Purification and identification of antioxidant peptides from corn gluten meal

Corn gluten meal was hydrolyzed by alkaline protease and Flavourzyme to obtain the antioxidant peptides. The antioxidant activities of the hydrolysates or peptides were evaluated by free radical scavenging capacity (1,1-diphenyl-2-picrylhydrazyl/2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt/hydroxyl radical/superoxide radical anion), metal ion (Fe²⁺/Cu²⁺) chelating activity and lipid peroxidation inhibitory capacity. The hydrolysates were separated by ultrafiltration, and those with molecular weight <10 kDa exhibited highest antioxidant activity in all relevant assays. The hydrolysates were subsequently purified by gel filtration chromatography, and fraction F3 showed the highest antioxidant activity. Three peptides were identified from fraction F3 using LC–ESI–Q–TOF MS/MS as Leu-Pro-Phe (375.46 Da), Leu-Leu-Pro-Phe (488.64 Da) and Phe-Leu-Pro-Phe (522.64 Da). These peptides exhibited good free radical scavenging activity and lipid peroxidation inhibitory effect. Thus, corn gluten meal may be used as a potential source of antioxidant peptides for food and nutraceutical applications.     

野生蓝果忍冬多酚鉴定及其抗氧化、降血糖活性

目的：对野生蓝果忍冬进行多酚成分鉴定和抗氧化、抗淀粉酶活性研究。方法：以我国小兴安岭地区的野生蓝果忍冬果实为材料,通过固相萃取技术分离纯化得到花色苷和非花色苷分离液,测定分离液中的化学成分,并测定多酚粗提液中总酚和总花色苷含量,抗氧化活性（1,1-二苯基-2-三硝基苯肼自由基清除能力、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、氧自由基吸收能力）,抗α-淀粉酶、α-葡萄糖苷酶活性和脂肪酶活性。结果：野生蓝果忍冬果实中含有丰富的花色苷和非花色苷多酚,尤其是矢车菊素-3-葡萄糖苷和山柰酚-3-芸香糖苷含量很高;蓝果忍冬多酚粗提液中总酚含量为82.7 mg/100 g,总花色苷含量为49.8 mg/100 g,具有较强的抗氧化活性;对α-淀粉酶、α-葡萄糖苷酶活性的半抑制质量浓度分别为0.39 mg/mL和0.933 mg/mL,对脂肪酶活性的半抑制质量浓度为12.31 mg/mL,说明蓝果忍冬可以作为一种有前景的淀粉酶抑制剂。     

分子量对酪蛋白多肽抗氧化活性的影响

在对酪蛋白酶解产物制备工艺进行优化的基础上,对不同分子量抗氧化肽(>3ku,1～3ku,<1ku)的抗氧化活性进行了评价。首先对酶的种类、酶底物比及水解时间进行了单因素实验,最终确定采用碱性蛋白酶,在pH8.0,55℃,底物浓度5%,酶底物比0.192AU/g的条件下,酶解4h所得水解物抗氧化活性最高。经过超滤和凝胶过滤层析分离获得不同分子量的抗氧化肽,并采用2,2′-连氮基-双-(3-乙基苯并二氢噻唑啉-6-磺酸)二铵盐(ABTS+.)、羟自由基和超氧自由基清除活性评价其抗氧化性。结果表明,ABTS+.清除活性与分子量呈负相关(r=-0.898,p<0.01),分子量低于1ku组分活性最强(2mg/mL,Trolox当量为2.08±0.05mmol/L);分子量低于3ku的抗氧化肽羟自由基清除活性较高(IC50:1～3ku,4.43±0.03mg/mL;<1ku,4.35±0.06mg/mL);分子量高于3ku组分主要分布在3～5ku,超氧自由基清除活最强(10mg/mL,66.1%±1.0%)。     

Isolation and Identification of Phenolic Antioxidants in Black Rice Bran

Black rice bran contains phenolic compounds of a high antioxidant activity. In this study, the 40% acetone extract of black rice bran was sequentially fractionated to obtain 5 fractions. Out of the 5 fractions, ethyl acetate fraction was subfractionated using the Sephadex LH‐20 chromatography. The antioxidant activity of phenolic compounds in the extracts was investigated by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical assay, 2,2‐azino‐bis‐(3‐ethylenebenzothiozoline‐6‐sulfonic acid) (ABTS) radical cation assay, reducing power. The subfraction 2 from ethyl acetate fraction had the highest total phenolic contents (TPC) (816.0 μg/mg) and the lowest EC₅₀ values (47.8 μg/mL for DPPH radical assay, 112.8 μg/mL for ABTS radical cation assay, and 49.2 μg/mL for reducing power). These results were 3.1, 1.3, and 2.6 times lower than those of butylated hydroxytoluene (BHT), respectively. At a concentration of 100 μg/mL, the antioxidant activity and TPC of various extracts was closely correlated, with correlation coefficients (R²) higher than 0.86. The major phenolic acid in subfraction 2 was identified as ferulic acid (178.3 μg/mg) by HPLC and LC‐ESI/MS/MS analyses. Our finding identified ferulic acid as a major phenolic compound in black rice bran, and supports the potential use of black rice bran as a natural source of antioxidant.     

乳清蛋白肽美拉德反应产物的抗氧化活性与稳定性

以乳清蛋白碱性蛋白酶水解物为原料与葡萄糖发生美拉德反应,制备得到乳清蛋白肽美拉德反应产物（whey protein peptide Maillard reaction products,WPP-MRPs）,并研究其抗氧化活性以及温度、pH值、光照、金属离子和过氧化氢对其抗氧化活性的影响。结果表明,WPP-MRPs具有较强的总还原力、羟自由基（·OH）清除能力和2,2’-连氮基-双-（3-乙基苯并二氢噻唑啉-6-磺酸）二铵盐自由基（ABTS+·）清除能力,且抗氧化活性随着WPP-MRPs质量浓度的增加而加强。WPP-MRPs在90～100 ℃时具有较高的活性;在碱性环境中的抗氧化活性大于在中性及酸性环境中;室外自然光照射会降低WPP-MRPs抗氧化活性;金属离子Cu2+、Fe2+、Fe3+和氧化剂--过氧化氢能够显著降低WPP-MRPs的抗氧化活性。     

Analysis of volatile compounds and antioxidant activity in rice extracts (Oryza sativa L.) extracted by various conditions

This study focused on the analysis of the volatiles present in rice extracts (Oryza sativa L.) produced under various extraction conditions (i.e. the range of temperature was 50, 60 and 70 °C, and particle size was whole, 355, and 710 μm) The main volatiles identified were ethyl palmitate, benzenemethanol, nonanal, hexanal and 3-methyl-1-butanol. The highest levels of flavour compounds extracted from rice cultivated in Icheon and Cheorwon were recorded at an extraction temperature of 70 and 60 °C, respectively, and at a rice particle size of 355 μm. Non-volatile rice extracts were tested for antioxidant activity using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays. The antioxidant activity of Icheon rice extracts at a concentration of 2000 ppm was found to be 84.33 and 84.39% in the DPPH and ABTS assays, respectively.     

美藤果粕可溶性膳食纤维的抗氧化及免疫活性评价

本研究对美藤果粕可溶性膳食纤维（sacha inchi soluble dietary fiber，SISDF）进行了抗氧化和免疫活性评价。利用离子色谱、凝胶色谱和傅里叶变换红外光谱等方法对SISDF结构进行表征。结果表明：SISDF的重均分子质量为401 479 Da，是以吡喃糖为主链的大分子多糖。单糖组成中，半乳糖醛酸相对含量最大（46.49%），其次为鼠李糖（18.95%）、木糖（17.60%）和半乳糖（11.25%）等；当SISDF的质量浓度为2 mg/mL时，1,1-二苯基-2-三硝基苯肼（2,2-diphenyl-1-picrylhydrazyl，DPPH）自由基清除率为68.57%、羟自由基清除率为69.83%、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）阳离子自由基清除率为70.35%，表现出一定的抗氧化能力；在62.5～1 000 μg/mL质量浓度范围内，SISDF能够极显著增强RAW264.7巨噬细胞的增殖活性和吞噬活性（P＜0.01），提升RAW264.7巨噬细胞的一氧化氮、白细胞介素（interleukin，IL）-1β、IL-6、肿瘤坏死因子-α（tumor necrosis factor-α，TNF-α）因子分泌水平。SISDF具有良好的抗氧化活性和免疫活性，具备开发为天然食品抗氧化剂和消炎保健品的潜力。     

食叶草的营养活性成分含量及生物活性分析

为探究食叶草的开发应用价值,测定了食叶草中的主要营养成分和活性成分含量,并通过检测食叶草提取物对自由基的清除能力、还原力和α-葡萄糖苷酶活性抑制能力,探究食叶草的抗氧化和降血糖活性。结果表明:食叶草中的总蛋白含量高达34.70 mg/100 mg (干重),必需氨基酸含量和药用氨基酸含量分别占总氨基酸含量的45%和65%,氨基酸比值系数分(SRC)超过68,表明食叶草具有较高的营养保健价值;总酚含量、总黄酮含量和超氧化物歧化酶比活力分别为11.35 mg GAE/g (干重)、3.56 mg RE/g (干重)和15.24±3.40 U/mg pro;苹果酸和草酸是食叶草中最主要的有机酸(～89.24%);食叶草提取物对1,1-二苯基-2-三硝基苯肼(DPPH)自由基和2,2-联氮-双-3-乙基苯并噻唑啉-6-磺酸(ABTS)自由基的半数抑制浓度(IC₅₀)分别为0.465 mg/mL和0.066 mg/mL,当还原力(吸光值)达到0.5时的提取物浓度(IC_0.5)为0.528 mg/mL,且α-葡萄糖苷酶活性抑制效果较好,体现出良好的抗氧化...