不同品种紫薯抗氧化物质及体外抗氧化活性比较

为比较福建产区主栽紫薯抗氧化物质成分含量及其体外抗氧化活性,对7个不同品种紫薯中总酚、总黄酮、总花色苷及花青素组分进行了分析,并测定其清除自由基活性。结果表明:福宁紫3号紫薯中所含抗氧化活性成分如总酚、总黄酮、总花色苷和花青素的含量均为最高。通过高效液相色谱法分析测定紫薯中含有的花青素单体主要为飞燕草色素、芍药色素和矢车菊色素,不同品种紫薯中花青素组成及含量表现出的一定的差异性。福宁紫3号紫薯表现出较强的自由基清除活性,0.5 mg·L-1紫薯鲜样提取液DPPH自由基、OH自由基及ABTS清除率分别达到88.4%、49.1%、90.1%。 相对于其他品种,福宁紫3号紫薯在抗氧化活性成分含量及体外抗氧化活性方面表现最佳。     

紫皮百香果精粉酚类物质剖析及抗氧化活性评价

本研究采用紫皮百香果果肉、果皮及整果为原料,经真空微波提取、浓缩及干燥后制备成3种百香果精粉,分别剖析其总酚、总黄酮、花青素、酚类化合物组成,并采用DPPH、ABTS+和FRAP方法测定其抗氧化能力。结果表明：百香果果肉、果皮和整果精粉中总酚含量依次为126.37、230.34、497.82 mg GAE/100 g DW,总黄酮含量分别为10.06、168.74、426.48 mg RE/100 g DW;果皮和整果精粉花青素单体有矢车菊素、锦葵素、芍药素和飞燕草素4种,其中矢车菊素含量最高,分别为106.82、77.15 mg/100 g DW;3种精粉中酚类物质主要有儿茶素、异荭草素、芦丁和槲皮素等14种;果肉、果皮及整果精粉皆具抗氧化能力,且它们的抗氧化活性与酚类化合物含量呈正相关。     

响应面分析优选紫背天葵紫色素提取工艺

采用响应面分析法,以紫背天葵中紫色素含量为指标,考察超声时间、料液比、提取次数等因素对紫背天葵紫色素含量测定的影响,优选三峡库区紫背天葵紫色素的提取工艺条件。优选出三峡库区紫背天葵紫色素的最佳工艺为超声时间为15min,提取2次,料液比1∶20(g/mL),该条件下三峡库区紫背天葵紫色素的含量为2.783mg/g鲜重。     

紫马铃薯花色苷的提取纯化与鉴定

对超声波辅助提取紫马铃薯花色苷工艺条件进行优化,并用NKA-9大孔吸附树脂进行纯化,液相色谱结合紫外-可见光谱扫描分离和鉴定花色苷组成。结果表明：花色苷最佳提取条件为料液比1:50(2.5g/100mL柠檬酸溶液)、超声功率400W、提取温度45℃、提取时间10min,以干质量计算紫马铃薯种花色苷含量为1.362mg/g;用NKA-9大孔吸附树脂纯化,8倍柱床体积洗脱出占总量98.35%的的花色苷,花色苷纯度达到90.23%;高效液相色谱鉴定出紫马铃薯含有5种组分,其中3种分别是矢车菊素-3-葡萄糖苷、矢车菊素-3-芸香糖苷和芍药-3-葡萄糖苷,其含量分别为0.27、0.057mg/g和0.46mg/g,三者总和占马铃薯中总花色苷含量的57.78%。马铃薯中含量最高的花色苷成分出峰保留时间为12.224min,其结构未知。     

HPLC-MS法鉴定不同品种紫甘薯中花色苷组成

采用HPLC-MS法鉴定中国5个主要紫甘薯种植品种中花色苷的含量及组成,结果从5种紫甘薯中鉴定出10种花色苷,其中从紫薯038和济18中鉴定出一种新花色苷组分,其质荷比为1 083.结合保留时间、紫外光谱和质谱等信息,推测其可能为芍药素3-阿魏酰—羟基苯甲酰槐糖苷-5-葡糖苷.5种紫甘薯中花色苷的含量各不相同,其中紫薯038的总花色苷含量最高(9.66 mg/g),济18的花色苷含量最低(1.71 mg/g).     

紫薯粉发酵工艺优化及抗氧化能力分析

以紫薯生粉为原料,对低糖酵母发酵制备高抗氧化活性紫薯粉的工艺条件进行优化,并探讨发酵前后总黄酮、总酚、花青素与抗氧化能力的变化。结果表明,低糖酵母发酵的最佳工艺条件为酵母添加量0.95%,料液比1022(g/mL)、发酵时间16h、发酵温度23℃,该条件下的紫薯粉抗氧化能力为404.94 mg VC/100g,总酚含量为123.85mg GAE/100g,总黄酮含量为610.64mg芦丁/100g,花青素含量为26.99mg/100g,其抗氧化能力显著提高,花青素的稳定性优于未发酵紫薯粉。     

不同真菌发酵对墨江紫米多酚及其抗氧化性影响的比较

研究探讨了墨江紫米中花色苷的种类,以及经过5种常用真菌(米曲霉疏展变种2083、米曲霉2011、米根霉3005、米根霉3079以及少孢根霉3152)发酵的墨江紫米中总酚含量、总黄酮含量、花色苷含量以及抗氧化性的变化。墨江紫米中含有4种花色苷,分别是矢车菊素-3,5-二葡萄糖苷、矢车菊素-3-葡萄糖苷、矢车菊素-3-芸香糖苷和芍药花青素-3-葡萄糖苷。墨江紫米的总酚含量、总黄酮含量、花色苷含量以及抗氧化性受到发酵菌株和发酵时间的影响,其中米根霉3005、少孢根霉和米曲霉疏展变种在4天发酵过程中均可以显著提高墨江紫米的上述指标(P0.05)。结果表明,墨江紫米,尤其是经真菌发酵一定时间的墨江紫米,可能是一个天然抗氧化剂的良好来源,可以作为一种营养品或功能性食品加以开发利用。     

紫薯的抗氧化及活性成分研究

以紫薯为原料,对其水分、脂肪、总灰分和矿质元素含量以及主要活性成分进行了测定,并对紫薯的体外抗氧化活性进行了评价。结果表明,紫薯中水分含量为69.10±0.64 g/100g鲜重、脂肪含量为0.21±0.02 g/100g鲜重、总灰分为1.23±0.02 g/100g鲜重。紫薯中矿质元素Ca的含量最高为137.8±1.4 mg/g干重,而硒元素的含量为0.3±0.1 mg/g干重。紫薯中总酚、总花色苷、总黄酮的含量分别为7.69±0.03 mg GA/g干重、1.80±0.02 mg/g干重、1.48±0.00 mg QU/g干重。通过UPLC–ESI–MS鉴定出7种紫薯花色苷和3种其他酚类物质,其中花色苷主要以peonidin 3–sophoroside–5–glucoside和cyanidin 3–sophoroside–5–glucoside为母核,同时带有一个或两个酰基化基团,主要为咖啡酸、阿魏酸和对羟基苯甲酸;其他酚类物质主要是绿原酸,含量为67.40±0.024 mg/g干重。紫薯对铁离子的还原能力为4.45±0.00μmol TE/g干重,对氧自由基的清除能力为38.7±1.90μmol TE/g干重。     

6 种东北地区红树莓果渣提取物的抗氧化活性差异

以东北地区6 种红树莓果实加工后的果渣提取物为实验材料,研究其总酚、总黄酮、原花青素、花色苷含量和体外抗氧化活性的差异。结果表明：宝石红果渣提取物中总酚、总黄酮和原花青素含量最高,分别为14.18、3.71、15.28 mg/g;哈瑞太兹果渣提取物中花色苷含量最高,为0.68 mg/g;菲尔杜德和野生果果渣提取物的总还原能力与VC接近;除哈瑞太兹外,其他品种红树莓果渣提取物对（1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基和2,2’-二氮-双（3-乙基苯并噻唑-6-磺酸）二铵盐自由基（2,2’-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical,ABTS+·）的清除率均大于VC。相关性分析结果表明红树莓果渣提取物的总还原能力与总黄酮、原花青素含量的相关性较大;对DPPH自由基的清除率与原花青素、花色苷含量的相关性较大;而对ABTS＋·的清除率与总酚和总黄酮含量的相关性较大。在6 个红树莓品种中,菲尔杜德和野生果果渣提取物具有较强的抗氧化活性。     

植酸处理对冷藏期间紫背天葵品质的影响

以紫背天葵为试材,采用不同浓度植酸(0、0.1、0.5和1mmol/L)处理并于低温下(10℃)晾干叶片表面明水,HDPE袋(15μm厚)挽口包装(500g/袋),并置于0℃下贮藏15d,每5d测定一次品质指标:腐烂指数、呼吸强度、花青素、叶绿素、氨基酸、总酚、游离酚、蛋白质、总糖和还原糖。结果表明,0.5mmol/L植酸处理组可有效抑制紫背天葵呼吸作用,减缓花青素的损失而有效保持其含量,保持较高的叶绿素含量,有效抑制总酚、游离酚、还原糖、总糖、氨基酸和蛋白质含量的降低,有效延长紫背天葵货架期。1.0mmol/L植酸处理组会对紫背天葵叶片产生灼伤,加速品质劣变。     

Phenolic compound profile of selected vegetables frequently consumed by African Americans in the southeast United States

The phenolic composition of vegetables commonly consumed by African Americans in the southeast United States was analyzed with HPLC–MS. The vegetable samples included collard greens, mustard greens, kale, okra, sweet potato greens, green onion, butter beans, butter peas, purple hull peas, rutabagas, eggplant, and purslane. Five compounds out of total 29 peaks detected from the 12 samples – caffeic acid, ferulic acid, quercetin, kaempferol, and isorhamnetin – were identified. No gallic acid, p-coumaric acid, myricetin, luteolin, apigenin, hesperetin, naringenin, or flavanols was detected. The major flavonoids were isorhamnetin, quercetin and kaempferol. Isorhamnetin was found in kale, mustard greens, and purslane. The content ranged from 2.8 to 23.6 mg/100 g fresh edible part. Quercetin was found in collard greens, mustard greens, kale, okra, sweet potato greens, purple hull peas, and purslane. The content ranged from 1.3 to 31.8 mg/100 g with the highest content in kale and lowest content in purslane. Kaempferol was found in collard greens, mustard greens, kale, sweet potato greens, green onion, and purslane. The content ranged from 1.1 to 90.5 mg/100 g. Caffeic acid was only found in sweet potato greens. Ferulic acid was found in collard greens, mustard greens, kale, okra, purple hull peas, and purslane. Although some peaks were found in eggplant, butter beans, butter peas and rutabagas, these peaks were not identified due to lack of reference compound and no flavonoid or phenolic acid was quantified in these samples. The results suggest that these indigenous vegetables among African Americans are good sources of the phenolic compounds, which can be useful for the prevention of cardiovascular and other chronic diseases.     

Flavonoid content of several vegetables and their antioxidant activity

Several vegetables were selected to study their flavonoid contents and antioxidant activities. The results showed that both green and purple leaves of sweet potatoes (185.01 and 426.82 mg kg⁻¹ respectively) and the outer leaves of onion (264.03 mg kg⁻¹) possessed higher amounts of flavonoids, and more than 85% of free radical scavenging activities were evaluated by using 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH), superoxide and hydroxyl radicals. In addition, green leaves of sweet potatoes and the outer leaves of onion showed higher reducing power and higher antioxidant activity in a linoleic acid system as compared to cabbage, spinach, potato and crown daisy. Blanching of green leaves of sweet potatoes for 30–60 s retained more flavonoids and higher free radical scavenging activities as compared to more than 1 min of blanching. The storage test showed that green leaves of sweet potatoes stored at 4–10 °C maintained better quality than those stored at room temperature. © 2000 Society of Chemical Industry     

Composition and colour stability of anthocyanins extracted from fermented purple sweet potato culture

The components and colour stability of anthocyanins in purple sweet potato were investigated. Anthocyanins were extracted from fermented purple sweet potato culture fermented by Suzhou wine starter (Rhizopus 3.851, 3.866 and Saccharomyces cerevisiae). In these purple sweet potato anthocyanins (PSPAs), five major anthocyanins were detected by high performance liquid chromatography (HPLC). Cyanidin and peonidin were found to be the major anthocyanidins in PSPAs by acid hydrolysis of anthocyanins. PSPAs were more stable under the acid conditions (pH 2.0-4.0) than the subacid conditions (pH 5.0-6.0) as per UV-Vis absorption spectra and CIELAB colour coordinates.     

Fruit quality and bioactive compounds relevant to human health of sweet cherry (Prunus avium L.) cultivars grown in Italy

The fruit quality characteristics, phenolic compounds and antioxidant capacities of 24 sweet cherry (Prunus avium L.) cultivars grown on the mountainsides of the Etna volcano (Sicily, Italy) were evaluated. High-performance liquid chromatographic methods were used to identify and quantify sugars, organic acids and phenolics. A total of seven phenolic compounds were characterised as hydroxycinnamic acid derivatives (neochlorogenic acid, p-coumaroylquinic acid and chlorogenic acid) and anthocyanins (cyanidin 3-glucoside, cyanidin 3-rutinoside, pelargonidin 3-rutinoside and peonidin 3-rutinoside). The total anthocyanin content ranged from 6.21 to 94.20 mg cyanidin 3-glucoside equivalents/100 g fresh weight (FW), while the total phenol content ranged from 84.96 to 162.21 mg gallic acid equivalents/100 g FW. The oxygen radical absorbance capacity (ORAC) assay indicated that fruit of all genotypes possessed considerable antioxidant activity. The high level of phenolic compounds and antioxidant capacity of some sweet cherry fruits implied that they might be sources of bioactive compounds that are relevant to human health.     

紫薯花色苷在贮藏过程中的降解特性

本研究通过高效液相色谱-串联质谱（high performance liquid chromatography-tandem mass spectrometry,HPLC-MS/MS）法分析鉴定‘鄂薯12号’紫薯的花色苷成分,采用pH示差法和HPLC法研究该紫薯花色苷提取液在4、20、35 ℃贮藏98 d期间总花色苷和各单体花色苷的变化规律,并在此基础上研究了花色苷的降解动力学以及褐变指数和聚合物颜色指数。结果表明：从‘鄂薯12号’紫薯提取物中鉴定出13 种花色苷,主要为矢车菊素-3-槐糖苷-5-葡糖苷和芍药素-3-槐糖苷-5-葡糖苷与对羟基苯甲酸、阿魏酸或咖啡酸形成的酰基化花色苷;贮藏期间总花色苷和各单体花色苷的含量呈下降趋势,花色苷的降解符合一级动力学模型;4、20 ℃和35 ℃贮藏条件下总花色苷半衰期分别为228.8、48.1 d和32.6 d;在相同糖苷配体情况下,矢车菊素类花色苷的半衰期要短于芍药素;在相同花色素配体情况下,酰基化花色苷的半衰期要长于未酰基化花色苷,且二酰化花色苷的半衰期长于单酰化花色苷;褐变指数和聚合物颜色指数随贮藏时间的延长和贮藏温度的升高而增大,并且聚合物颜色指数与花色苷含量之间呈指数关系。     

Antioxidant capacities and total phenolic contents of 56 vegetables

The antioxidant capacities and total phenolic contents of lipophilic and hydrophilic extracts of 56 commonly consumed vegetables were studied. The resulted showed that antioxidant capacities and total phenolic contents in the lipophilic fraction were higher than those in hydrophilic fraction. The different vegetables had diverse antioxidant capacities. The highest antioxidant capacities and phenolic contents were found in Chinese toon bud, loosestrife, perilla leaf, cowpea, caraway, lotus root, sweet potato leaf, soy bean (green), pepper leaf, ginseng leaf, chives, and broccoli, while the values were very low in marrow squash and eggplant (purple). Furthermore, several phenolic compounds were detected, and chlorogenic acid, gallic acid and galangin were widely found in these vegetables. The results provide support for dietary guidelines as well as epidemiological research.     

高效液相色谱法测定8 个彩色马铃薯品种中花青素种类和含量

采用高效液相色谱法,以表皮和薯肉为研究对象,定量分析8 个彩色马铃薯品种块茎中花青素的种类和含量。研究发现,彩色马铃薯块茎中最多含有6 种花青素,即飞燕草色素、矢车菊色素、矮牵牛色素、天竺葵色素、芍药色素和锦葵色素。紫色马铃薯块茎中主要花青素为矮牵牛色素、芍药色素和锦葵色素,红色马铃薯块茎中主要花青素是天竺葵色素和芍药色素。飞燕草色素和芍药色素广泛存在于彩色马铃薯（紫色和红色）块茎的表皮中,而红色马铃薯块茎中未检测到锦葵色素。品种之间差异显著（P＜0.05）,其中紫云1号的总花青素含量最高。块茎表皮的花青素含量约是薯肉的6～176 倍,且大部分品种的表皮花青素种类比薯肉多。彩色马铃薯块茎的表皮富含丰富的花青素,是天然色素和抗氧化剂的重要来源。     

Phenolic compounds in Chinese purple yam and changes during vacuum frying

Phenolic compounds and their changes during vacuum frying were investigated for a Chinese purple yam. Three cyanidin derivatives and one peonidin derivative were tentatively identified by HPLC–DAD–ESIMS analysis; sinapic acid and ferulic acid were identified by HPLC–DAD analysis with authentic chemicals. There were 31.0 mg/100 g (dry weight, DW) of total anthocyanin (ACN) and 478 mg/100 g DW of total phenolic content (TPC) in the fresh yam. Sinapic acid and ferulic acid were 135 and 31.3 mg/100 g DW respectively. The blanching process caused about 60% of ACN, and 30–50% of phenolic acids and TPC to be lost, which showed that anthocyanins were most vulnerable during blanching. The retention rate of the phenolic compounds during vacuum frying was 60–69%, indicating it was a practical technology for purple yam processing, on account of its impact on the phenolic compounds stability.