Optimisation,characterisation and quantification of phenolic compounds in olive cake

The phenolic compounds in extracts from pressed olive cake were investigated. Free phenolic compounds were extracted from olive cake using methanol. To liberate bound phenolic compounds, the olive cake was subjected to basic and acidic hydrolysis followed by methanol extraction. The individual phenolic compounds and antioxidant activity of the extracts were determined. The highest total phenolic content and antioxidant activity were obtained using methanol extraction for 12 h at 70 °C. The RP-HPLC profiles for full-fat and defatted olive cake showed that protocatechuic acid, hydroxybenzoic acid, sinapic acid, p-coumaric acid, rutin and hesperidin were the predominant free phenolic compounds. Meanwhile, syringic acid, sinapic acid, caffeic acid and protocatechuic acid were the predominant bound phenolic acids. A positive correlation was observed between total phenolic content and antioxidant activity. The results indicated that most of the phenolic compounds in olive products were present in their free forms (75–90% of total phenolic content), while bound phenolic compounds were only a small proportion (10–25%) of total phenolic content.     

15种柑橘果皮中酚酸的含量测定

采用反相液相色谱法(RP-HPLC)测定了15种柑橘果皮中7种酚酸的含量,并用数学统计的方法分析了各种酚酸含量和总酚酸含量的差异性,旨在寻找酚酸提取的新来源,为柑檑资源的合理开发利用和抗氧化活性的研究提供参考。结果表明:酚酸在柑橘果皮中主要以可溶性酚酸形式存在,且肉桂酸类酚酸的含量要高于苯甲酸类酚酸的含量。在可溶性酚酸中,阿魏酸和芥子酸是柑橘果皮中最主要的酚酸;而不可溶性酚酸则以阿魏酸含量最高,原儿茶酸含量最低。对于总的酚酸含量而言,朱红果皮柑橘含量最高为6857.88μg/g(干重);胡柚果皮中最低,仅为549.62μg/g(干重)。     

响应面分析优化福林酚法测定樱桃酒中总酚的含量

本研究采用福林酚法测定樱桃酒中总酚的含量,并通过响应面法优化其工艺参数。在单因素实验基础上,以福林酚试剂用量、碳酸钠浓度、显色温度、显色时间和碳酸钠用量为影响因素,樱桃酒总酚含量为指标,响应面法进行分析和优化。结果表明,优化后得到最佳条件为:福林酚试剂2.1 mL、碳酸钠浓度63 g/L、碳酸钠用量8.32 mL,在25℃件下反应1.4 h,总酚含量为1085.2±0.16 mg/L。此回归模型拟合性良好,可用于预测总酚含量。根据此线性回归方程测定12个品种樱桃酒中总酚含量最高的为俄罗斯酸樱桃(1495.0 mg/L),雷尼含量最低(442.8 mg/L)。福林酚法操作简单,可用于不同品种樱桃酒总酚含量的测定。     

甘蔗不同组织中游离态和结合态酚酸的分布及抗氧化活性

为了探讨甘蔗不同组织中酚酸的存在形式,本文利用反相高效液相色谱法(RP-HPLC)对蔗汁、蔗叶及蔗渣三个组织中游离态和结合态的酚酸进行了定性和定量检测分析。结果表明,甘蔗组织中的酚酸主要以结合态形式存在,但其在甘蔗三个组织中的含量和存在形式有差别。甘蔗叶、蔗渣中游离的酚酸含量最高,蔗汁较低。蔗汁、蔗叶及蔗渣中总游离态酚酸含量分别为317.18 mg/kg(干固物),1568.37 mg/kg(干基)及1504.57 mg/kg(干基);总结合态酚酸含量分别为740.32 mg/kg(干固物),2725.41 mg/kg(干基),2452.13 mg/kg(干基)。在蔗汁中,咖啡酸、没食子酸主要以游离态存在,阿魏酸、香豆酸主要以结合态存在,而在蔗叶和蔗渣中,咖啡酸、阿魏酸、香豆酸主要以结合态形式存在。甘蔗不同组织中游离态酚酸的DPPH和ABTS自由基清除活性优于结合态酚酸,不同组织中的游离态酚酸和结合态酚酸含量分别与抗氧化活性呈正相关性。     

Assessment of phenolic content and free radical-scavenging capacity of some Thai indigenous plants

Ethanolic extracts from various parts of 26 Thai indigenous plants were examined for phenolic constituents and free radical scavenging capacity, to determine their potential as a source of natural antioxidants. Total phenolic content and total flavonoid content were evaluated according to the Folin-Ciocalteu procedure, and a colorimetric method, respectively. The results showed that total phenolic compounds and flavonoid content were higher in seed extracts of berries used in wine production, while the levels in extracts obtained from herbs and vegetables were lower. Chewing plants which have an astringent taste gave a significantly higher total phenolic content and flavonoid content. Antiradical activity determined from 1/EC₅₀ by the DPPH radical-scavenging method was highest in wine production seeds and chewing plants. The correlation coefficient from regression analysis showed a positive relationship between total phenolic and total flavonoid content (r = 0.9). The results suggest that ethanolic extracts of some Thai indigenous plants exhibit a potential for use as natural antioxidants.     

不同品种甜樱桃中不同形态酚酸的比较及其抗氧化性分析

为研究不同品种对甜樱桃酚酸类物质及其抗氧化性的影响,本文采用超高效液相色谱-串联质谱法(UPLC-MS/MS)对5个不同品种甜樱桃,包括彩虹、艳阳、萨米脱、23-51和瓦列里中的游离型、游离酯型和结合型酚酸进行了测定和分析。结果表明,不同樱桃品种间酚酸含量差异较大,5个樱桃品种酚酸总量在115.96~704.94 mg/kg FW之间。其中瓦列里中酚酸总量最高,其次是萨米脱和23-51,艳阳和彩虹中酚酸总量最低。对于三种不同形态酚酸,游离型和游离酯型酚酸含量较高,而结合型酚酸含量较低。不同品种樱桃中的游离型酚酸以新绿原酸为主,可占游离型酚酸总量的90%以上;游离酯型酚酸和结合型酚酸均以咖啡酸含量最高,可占各自形态酚酸总量的50%以上。不同品种中瓦列里樱桃酚酸提取液的DPPH自由基清除能力和FRAP均最高,抗氧化性指标的测定结果与酚酸类物质含量呈现较高的一致性。偏最小二乘判别分析表明,新绿原酸和咖啡酸是区分五个樱桃品种贡献最大的物质(VIP得分>1),且这两个物质均在瓦列里中含量最高。甜樱桃酚酸含量与品种有关,并与其抗氧化特性相一致。     

提取溶剂对青稞提取物总酚、黄酮含量及其抗氧化活性的影响

以3种不同的青稞为原料,采用不同的提取溶剂(水、60%乙醇、60%甲醇、60%丙酮、95%乙醇、100%甲醇、100%丙酮)对青稞进行提取。对各提取物的总酚、总黄酮进行测定,同时采用3种抗氧化方法:二苯代苦味酰自由基(DPPH)、2,2’-联氨-双(3-乙基苯并噻唑啉-6-磺酸)二胺盐自由基(ABTS)和总抗氧化能力(FARP)评价青稞提取物的抗氧化活性。结果表明,95%乙醇和60%丙酮更有利于青稞多酚的提取。藏青2000的各溶剂提取物的总酚、总黄酮及抗氧化活性普遍高于相应溶剂的循化蓝青稞和香格里拉绿青稞。藏青2000的60%丙酮提取物含有最高的总酚含量,达到211.92mg GAE/100g DW;在60%乙醇提取时具有最高的总黄酮含量,达到60.11mg RT/100g DW;在60%乙醇提取时具有最强的DPPH清除能力,达到80.08%;而用60%丙酮提取时,具有最强的ABTS清除能力和总抗氧化能力,分别达到了1.85,9.28 mmol TEAC/100g DW。总酚含量与抗氧化活性均具有显著的相关性,FRAP法与DPPH、ABTS法具有极显著的相关性。综上表明,青稞富含总酚成分,是一种潜在的天然抗氧化剂资源。     

高效液相色谱法测定糜子中酚酸类化合物

为探索糜子麸皮和糜米中酚酸类物质的成分和含量,采用福林-酚法和高效液相色谱法测定比较糜子麸皮 和糜米中自由酚含量和酚酸类物质的种类。结果表明：不同品种糜子麸皮之间自由酚含量差异不显著,糜米之间自 由酚法差异极其显著（P＜0.01）。同一品种糜子麸皮和糜米之间自由酚含量差异显著（P＜0.05）,糜子麸皮自由 酚含量远高于糜米。赤糜2号麸皮和糜米中自由酚含量最高,麸皮中为159.22 mg没食子酸/100 g,糜米中为47.98 mg 没食子酸/100 g。糜子中检测到的酚酸类物质有绿原酸、丁香酸、香草酸、p-香豆酸、阿魏酸。     

The role of olive β-glucosidase in shaping the phenolic profile of virgin olive oil

The main objective of this work was to investigate the biochemical factors directly affecting the phenolic profile of virgin olive oil (VOO) such as the content of phenolic glycosides and the β-glucosidase activity present in the olive fruit. The phenolic compositions of VOO from two olive cultivars, Arbequina and Picual, were studied throughout the ripening phase. Picual oils displayed significantly higher phenolic content than Arbequina oils at all ripening stages; however, the total phenolic content of Arbequina fruits was consistently higher than that of Picual fruits. The most abundant phenolic glucosides found in olive fruits were oleuropein, present in both cultivars, and demethyloleuropein, only detected in Arbequina fruits. Nevertheless, the content of phenolic glycosides can hardly be regarded as a limiting factor given that the total secoiridoid content in VOOs represents an average of 1–4% of the secoiridoid glycosides present in the fruits. Although the level of β-glucosidase activity does not seem to be a limiting factor in these two cultivars, experimental data on the selectivity of the enzyme towards olive phenolic glucosides and its product specificity suggest that olive β-glucosidase plays a critical role in shaping the phenolic profile of VOO. A hypothesis on the biochemical formation of the dialdehydic form of decarboxymethyloleuropein (3,4-DHPEA-EDA) from oleuropein is proposed.     

Changes of hydrogen peroxide and radical-scavenging activity of raspberry during osmotic, convective, and freeze-drying

This study was conducted to investigate the influence of different drying treatments on antioxidant (AO) activity and phenolic content of raspberry (Rubus idaeus), cultivar Willamette. Whole raspberry fruits were dried convectively (air-drying), osmotically, and freeze-dried. Acetone-water extracts of fresh and dried raspberries were assessed for total phenolic content by standard Folin-Ciocalteau method. Two AO assays were applied, a recently developed direct current (DC) polarographic assay based on decrease of anodic oxidation current of hydrogen peroxide and widely used radical scavenge against the 1,1-diphenyl-2-picrylhydrazyl (DPPH). Strong correlation has been obtained between both AO assays and total phenolic content. In addition, some individual phenolic compounds present in raspberry have been assessed using DPPH and DC polarographic assay. Comparison and evaluation of drying methods has been based on preservation of AO activity and total phenolic content. Obtained results confirmed superiority of freeze-drying; convective drying caused slight changes while osmotic dehydration showed a significant decrease of phenolic compounds and AO activity.     

基于UPLC-QTOF-MS和HPLC-QQQ-MS技术的鹰嘴豆酚类化合物定性、定量分析及其抗氧化能力研究

鹰嘴豆为一种高营养豆类植物。为深入了解其营养价值,用80%甲醇溶液提取酚类物质,对提取物中不同存在形态的酚类化合物及其抗氧化活性进行测定,并对其提取物进行酚类的定性及定量分析。结果表明,酚酸含量最高部分为糖苷键合态酚类物质(0.81 mg/g),黄酮含量最高部分为游离态酚类物质(0.26 mg/g),不同存在形式酚类物质含量及抗氧化能力不同;80%甲醇提取物通过UPLC-QTOF-MS定性分析,对其24种化合物进行鉴定,包括12种黄酮、4种酚酸;HPLC-QQQ-MS定量分析表明:对羟基苯甲酸、香豆酸、原儿茶酸类化合物含量丰富。     

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.     

A comparative study on free and bound phenolic acid content and their antioxidant activity in bran of rice (Oryza sativa L.) cultivars of Eastern Himalayan range

In our study, seven most prevailing but unexplored indigenous rice cultivars of northeast India, situated in the Eastern Himalayan Range, were investigated for their phenolic acid profile, total phenolic content (TPC) and antioxidant capacities in free and bound phenolic extracts of their bran. HPLC studies showed the presence of ferulic, p‐coumaric, sinapic, caffeic, chlorogenic and vanillic acids, with ferulic and p‐coumaric acids being the dominant phenolic acids in the bound form. The lower EC₅₀ values of the bound extracts than the free extracts suggested the better radical scavenging activity of the bound extracts. Significant correlations were observed between TPC and phenolic acid content (HPLC‐DAD) of bound extracts, and between Trolox equivalents antioxidant capacity (TEAC) and phenolic acid content (HPLC‐DAD) of both free and bound extracts. The findings suggest that phenolic acids in the rice cultivars investigated were exclusively present in bound form and contribute significantly towards their antioxidant capacity.     

Tunisian table olive phenolic compounds and their antioxidant capacity

ABSTRACT:  For the 1st time, 4 olive cultivars, the Meski, Chemlali, Besbessi, and Tounsi, from the Tunisian market were investigated to evaluate the phenolic compounds' contribution in nutritional value of table olives. From the Meski cultivar, we have chosen 4 different samples to evaluate differences within the same cultivar. Basic characteristics and total phenolic content were evaluated in flesh and kernel. The highest value of flesh phenolic content was observed in sample M4 of the Meski cultivar; however, the lowest value was observed in the Besbessi cultivar and they were 1801 and 339 mg GA/100 g dry weight, respectively. The main simple phenolic compounds identified in flesh extracts are hydroxytyrosol, tyrosol, and vanillic acid. Oleuropein was not detected in any samples. The antioxidant activity of Tunisian olive flesh varies between 212 and 462 μM TEAC/g of dry weight. Antioxidant activity of olives was related to their phenolic content but we found a low correlation between phenolic content and TEAC.     

基于UPLC-Triple-TOF/MS核桃油酚类物质的鉴定与区分

针对机械压榨法（MP）、溶剂萃取法（SE）、水酶法（AEE）等制备的核桃油,本研究测定三种油的总酚含量（TP）并分析鉴定其酚类化合物;通过酚类物质差异对三种萃取方法的核桃油进行分类、鉴定。研究发现,三种萃取方法制得核桃油TP具有显著差异;SE核桃油TP最高（15.75 mg/kg）,AEE核桃油TP次之（11.05 mg/kg）,MP核桃油TP最低（9.20 mg/kg）;基于HPLC和UPLC-Triple-TOF/MS分析,核桃油共鉴定出15种酚类化合物,且三种核桃油酚类物质类别、丰度与含量差异显著;其中,MP核桃油的酚类化合物种类最丰富。基于代表性酚类化合物的含量及酚类物质类别的相对含量开展主成分分析,能成功区分三种萃取方法的核桃油。因此,本研究成功构建了核桃油酚类化合物数据库,并提出一种基于酚类化合物对植物油掺假鉴定的可行方案。     

Phenolic glucosides in bread containing flaxseed

Three phenolic glucosides, secoisolariciresinol diglucoside, p-coumaric acid glucoside and ferulic acid glucoside, were analyzed in commercial breads containing flaxseed. The total phenolic glucoside content ranged from 15 to 157 mg/100 g dry bread. Secoisolariciresinol diglucoside was the dominating phenolic glucoside with an average relative content of 62%, followed by p-coumaric acid glucoside (20%) and ferulic acid glucoside (18%). Strong positive correlations between the phenolic glucosides were found, indicating no major effect of raw material or bread-making process on the relative content of the phenolic glucosides in flaxseed.     

POTATO FLAVOR AS RELATED TO CHEMICAL COMPOSITION

SUMMARY— A study was made on the relationship of flavor of potatoes to their phenolic and ascorbic acid content. Material for the study was from two main sources: (1) clones that are hybrids between varieties of Solanum tuberosum subsp. tuberosum grown in New York and varieties of Solanum tuberosum subsp. andigenum grown in Peru; (2) established commercial American varieties such as Ontario, Pontiac, and Katahdin. Bitterness and astringency were selected as the character notes most related to phenolic content. A significant correlation was found between phenolic content and bitterness and a highly significant correlation between phenolic content and astringency. No significant correlation was found between ascorbic acid content and flavor.     

壳聚糖澄清对沙棘果汁酚类成分的影响

通过Folin—ciocalteu比色法测定和HPLC检测分析，对壳聚糖澄清过程中沙棘果汁总酚含量以及一些酚类成分的变化进行了研究，结果显示：壳聚糖澄清对沙棘果汁中的酚类物质有所影响，总酚含量降低了17．2％，澄清后果汁中的儿茶酸、阿魏酸和香豆酸组分损失，没食子酸降低87％，槲皮素减少了62．5％，绿原酸含量变化不大。     

对比福林酚法和高效液相色谱法测定酒神菊属蜂胶和国产蜂胶中酚酸类化合物含量

目的 比较福林酚法和高效液相色谱法测定酒神菊属蜂胶和国产蜂胶中的酚酸含量的差异。 方法 采用福林酚法(Folin-酚法)测总酚酸, 以没食子酸为对照品, 765 nm下检测样品的吸光值; 采用高效液相色谱法(high performance liquid chromatography, HPLC)测总酚酸, 以绿原酸、咖啡酸、异绿原酸A、异绿原酸C、咖啡酸苯乙酯、阿替匹林C为对照品, 优化HPLC洗脱条件, 利用标准品的进样量和色谱峰面积进行线性拟合, 线性回归方程以计算各个单体的含量。结果 Folin-酚法下, 酒神菊属蜂胶总酚酸含量为5.71%~14.68%, 平均为11.34% (n=14), 国产蜂胶总酚酸含量为5.87%~28.99%, 平均值为16.98% (n=12); HPLC法下, 酒神菊属蜂胶总酚酸含量为2.13%~9.20%, 均值为5.71% (n=14), 国产蜂胶总酚酸含量为1.69%~9.13%, 均值为5.05% (n=12)。结论 2种蜂胶都含有比较高含量的酚酸类成分, 不同测定方法下酚酸类成分含量存在明显差异, 选择合适的方法用于检测蜂胶中的酚酸类成分含量显得尤为重要。     

不同品种啤酒大麦间游离酚类化合物及其相关酶类的研究

大麦中的酚类化合物及相关酶(如酚类合成酶苯丙氨酸解氨酶,酚类氧化酶过氧化物酶和多酚氧化酶)对大麦的生长发育、抗病特性及啤酒质量有重要影响。本文研究了16种不同品种、22种不同样本啤酒大麦中酚类物质的含量及相关酶活性的差异性和相关性,并测定了不同品种大麦的抗氧化活力。研究结果表明:不同品种和同一品种不同产地啤酒大麦的酚类化合物含量和酚类酶活性因品种特性和生长、种植条件而存在显著差异(P<0.05);游离总多酚含量和抗氧化力之间存在显著的正相关性(r=0.794);苯丙氨酸解氨酶活性并不与游离总多酚含量呈正相关性,过氧化物酶和多酚氧化酶的活性也不与总多酚含量呈相关性,这可能和大麦中同时存在酶类氧化酶和酚类合成酶有关。研究认为,通过测定大麦游离总多酚含量和DPPH自由基清除率可初步判断啤酒大麦的内源性抗氧化力,以此作为评价酿造原料品质的检测手段。