Oxidative stabilization of cold‐pressed sunflower oil using phenolic compounds of the same seeds

It is known that sunflower seeds are rich in phenols, constituting approximately 1–3 g per 100 g of seeds. The principal phenol is chlorogenic acid (CGA), followed by caffeic acid (CA) and lower quantities of several other compounds. On the contrary, it is known that phenols are present only in trace amounts in cold‐pressed sunflower seed oils. In this study, the possibility of improving the oxidative stability of cold‐pressed sunflower oil is evaluated using phenolic substances constitutive of seeds. Phenols, extracted from two different dehulled sunflower seed samples, were identified, measured and added to a cold‐pressed sunflower oil and compared with butylated hydroxyanisole (BHA), pure CGA and pure CA. Raw phenolic extract (RPE) was composed of CGA exclusively, whereas CA was present only in traces in its free form was not present. On the contrary, hydrolysable phenol acids (HPAs) were constituted prevalently from CA, released by CGA alkaline hydrolysis. The stabilization effect on oil oxidation at 110 °C was evaluated as 41% and 118% for RPE and HPAs respectively with respect to the control. At 30 °C, no significant differences were recorded between the two seed extracts. Their antioxidant effect was lower than that at 110 °C and evaluated to be, on average 13%. In comparison with BHA, at 30 °C, both seed extracts were more effective than this synthetic phenol; at 110 °C, the antioxidant effect of RPE and BHA was similar, whereas HPA was significantly more effective than BHA. In conclusion, this study demonstrates that the phenols present in sunflower seeds can be considered natural antioxidants suitable for stabilizing the oxidation of cold‐pressed sunflower oil, at both low and high temperatures. Copyright © 2003 Society of Chemical Industry     

Comparison of the antioxidative properties of caffeic and chlorogenic acids

The antioxidative properties of caffeic and chlorogenic acids during autoxidation of triacylglycerols of sunflower oil at 100 °C were compared. The effects of the two acids within the concentration range 2.8–56.5 × 10⁻⁴ M (50–2000 ppm) were investigated. The stabilization factor (F) as a measure of the effectiveness of the antioxidants and the oxidation rate ratio (ORR) as a measure of their strength were determined. It was found that at concentration 2.8 × 10⁻⁴ M, the effectiveness and the strength of the two acids were practically the same, while at higher concentrations caffeic acid appeared as a much more effective and stronger inhibitor. The analysis of the kinetic data obtained showed that chlorogenic acid and its radicals participated more readily in side reactions with the hydroperoxides and the lipid substrate than caffeic acid and its radicals did.     

The content of chlorogenic acids in tropical fruits

This work investigates the content of feruloylquinic (FQA), caffeoylquinic (CQA) and dicaffeoylquinic (diCQA) acids in the peel, pulp and seed of 22 tropical fruits from Brazil. 3‐CQA, 4,5‐diCQA and 4‐ and 5‐FQA were not detected in any of the fruits analysed. Relatively small amounts of 4‐CQA (4.0–48.7 mg kg^?1) were found in the peel and/or pulp of seven of the fruits; only the peel of Artocarpus heterophyllus was significantly (p < 0.05) richer in this acid (1000 mg kg^?1). The distribution of 3,4‐ and 3,5‐diCQA in different parts of the fruits was relatively poor, only reaching levels of up to 16.4 mg kg^?1. The peel of A heterophyllus also showed the highest amount of 5‐CQA (13 000 mg kg^?1), while the seed of most fruits generally contained a lower amount of this acid than the peel or pulp. On the basis of the 5‐CQA content found in the pulp, 15 of the fruits were classified as follows: very low concentration (4.4–15.8 mg kg^?1), low concentration (28.9–66.4 mg kg^?1), medium concentration (132 mg kg^?1), high concentration (473–474 mg kg^?1) or very high concentration (1730 mg kg^?1); however, no 5‐CQA was detected in the pulp of the other seven fruits. Thus 5‐CQA was the major chlorogenic acid present in most of the tropical fruits studied and was generally accompanied by small amounts of 4‐CQA and 3,4‐ and 3,5‐diCQA. © 2002 Society of Chemical Industry     

葵花籽粕的综合利用

对从葵花籽粕中提取绿原酸和葵花籽分离蛋白的制备工艺进行了研究。通过实验,获得了提取绿原酸和蛋白质的最佳工艺参数。采用50%乙醇,料液比1∶12,浸提1.5h,温度50℃,pH4.0首先提取绿原酸,然后用1mol/LNaCl溶液,料液比1∶10,时间1h,温度50℃,pH9.0提取葵花籽分离蛋白。     

Mechanism of inhibition of rice bran lipase by polyphenols: a case study with chlorogenic acid and caffeic acid

ABSTRACT:  Rice bran is a byproduct obtained from the rice milling industry, and to arrest lipolysis caused by lipolytic enzyme, rice bran lipase (RBL) was inactivated by inhibitors such as polyphenols. This study describes the inhibition and interaction of enzyme with chlorogenic acid (CGA) and caffeic acid (CA). The inhibition of the enzyme was competitive in nature in both CGA and CA. The inhibition constant K _i of the reaction was found to be 1.8 and 1.5 μM for CGA and CA, respectively. Fluorescence emission measurements indicated a decrease in the fluorescence emission intensity and a red shift in the emission maximum as these ligands concentrations are increased, indicating the minor changes in the tryptophan environment and the effect of binding that is stronger in the case of CA compared to CGA with RBL. Far UV-circular dichroic data suggest that there are no significant changes in the conformation of the enzyme as a result of binding of CGA or CA. The instability of the enzyme in the presence of these polyphenols has been indicated by decrease in apparent thermal transition temperatures of the enzyme from a control value of 60 °C as revealed by thermal denaturation measurements. These results demonstrate that both CGA and CA are inhibitors of RBL and bind to the enzyme through both hydrogen and hydrophobic interaction in bringing about inhibition with minor structural alterations. These inactivation phenomena of polyphenols that act as inhibitors on RBL can be utilized to prevent oxidation of the rice bran oil.     

Bioavailability and metabolism of chlorogenic acids (acyl‐quinic acids) in humans

Acyl‐quinic acids (chlorogenic acids) are produced by many plants, including fruits, vegetables, and herbal remedies, with coffee and maté particularly rich dietary sources. Epidemiological and intervention studies suggest that they can reduce the risk of developing type 2 diabetes and cardiovascular disease. This review addresses their metabolic handling after oral consumption to provide a mechanistic basis to explain their possible effects on health. Intact acyl‐quinic acids are absorbed only to a small extent in the small intestine, but the cinnamic acids are efficiently absorbed after hydrolysis by either digestive or microbial enzymes in the colon. Metabolism results in phenolic conjugates in the blood and urine, but varying dependent on the acyl‐quinic acid, and subject to significant interperson variability. The balance between hydrogenation and complete β‐oxidation of the cinnamic acids, both by liver and gut microbiota, determines the profile of metabolites. Pharmacokinetic data suggest that some metabolites are bound to human serum albumin and/or sequestered in tissues, and some exhibit biological activity in vitro, consistent with proposed protective action in vivo. Significant gaps in the literature include lack of plasma and urinary data for free‐living individuals, and pharmacokinetic data for groups who consume coffee or maté at regular short intervals. Data are required for cis isomers. There is a critical need for precise urinary biomarkers of consumption of acyl‐quinic acids, accounting for variability in individual metabolism and in beverage composition, thus facilitating better translation of urinary metabolite measurements into accurate coffee consumption data to improve the outcomes of future epidemiological and intervention studies.     

不同品种炒货葵花籽氧化稳定性研究

本研究以7个品种炒货葵花籽为研究对象,采用超声波从葵花籽仁提取油脂,用Schaal烘箱法进行加速氧化处理,比较加速氧化对不同品种葵花籽仁油脂过氧化值、酸值和碘值以及氧化后产生的共轭二烯与共轭三烯含量的影响,综合筛选出具有较高抗氧化稳定性的炒货葵花籽品种。结果显示,甘葵2号品种葵花籽仁油脂在氧化过程中过氧化值、酸值的变化量和氧化后产生的共轭二烯与共轭三烯的含量显著(p<0.05)低于其余各品种,碘值的变化量与LD5609、科阳7号葵花籽仁油脂无显著差异,但显著高于青花王、三道眉和青花品种,表明甘葵2号品种葵花籽抗氧化性较好。      

Quantitative UPLC‐MS/MS analysis of chlorogenic acid derivatives in antioxidant fractionates from dandelion (Taraxacum officinale) root

While qualitative studies have identified chlorogenic acids in antioxidant extracts, particularly ethyl acetate‐derived extracts, of Taraxacum officinale, quantitative analysis of these phenolic compounds remains largely unreported for this species. In this study, bioactivity‐guided fractionation of an antioxidant crude ethyl acetate extract (DPPH = 295.481 ± 0.955 mg TE g^?1 extract) from T. officinale root resulted in a number of reverse‐phase fractions that demonstrated high antioxidant activity (DPPH = 1058.733–1312.136 mg TE g^?1 extract), stronger than that of the synthetic antioxidant Trolox^®. UPLC‐MS/MS screening of these fractions for the presence of selected mono‐ and di‐caffeoylquinic acids revealed large quantities of 1,5‐dicaffeoylquinic acid present in several fractions (853.052–907.324 μg mg^?1), respectively. Due to the antioxidant potency and high levels of 1,5‐dicaffeoylquinic acid observed in these fractions, it was concluded that specifically this chlorogenic acid derivative is a major contributor to the antioxidant efficacy of dandelion root.     

Compositional changes in seeds influenced by their positions in different whorls of mature sunflower head

The physicochemical characteristics of seeds located in different whorls of the sunflower (Helianthus annuus L) head at maturity have been studied. The proportion of filled seeds decreased from the peripheral to the central whorl, with a 10‐fold decrease in filled/unfilled seed ratio. The dry weight of seeds and kernels and the oil content of kernels decreased from the peripheral towards the middle and central whorls. However, the dry weight of seeds and kernels in the seed crop was significantly higher and the oil content lower than in the oil crop. The contents of starch, total soluble sugars and reducing sugars were lower in the oil crop than in the seed crop. The starch content of peripheral whorls in the seed crop was much lower than that of central whorls, with accumulation of total soluble sugars and reducing sugars, whereas much less variability was observed with respect to the position of seeds on the sunflower head in the oil crop. The mean proportion of membrane lipids was higher and that of triacylglycerols lower in the seed crop than in the oil crop. The proportions of 16:0 and 18:1 were higher in the seed crop, while that of 18:2 was higher in the oil crop. Copyright © 2003 Society of Chemical Industry     

高效液相色谱法测定马铃薯中绿原酸和原儿茶酸

目的:建立高效液相色谱法测定马铃薯块茎中绿原酸和原儿茶酸的含量,并测定了两种马铃薯贮藏期间绿原酸、原儿茶酸含量的变化。方法:采用高效液相色谱法梯度洗脱,使用反相C18色谱柱,以1%甲酸水溶液和100%甲醇为流动相,流速为0.8 m L/min,柱温:40℃,在326、280 nm波长处分别对绿原酸和原儿茶酸进行测定。结果:绿原酸、原儿茶酸分别在50~500、200~1000μg/m L范围内与峰面积线性良好,相关系数分别为0.9999、0.9992;精密度RSD均小于0.35%,稳定性RSD均小于1.68%,绿原酸、原儿茶酸重复性RSD分别为2.07%、3.58%,绿原酸、原儿茶酸平均加样回收率分别为98.29%、97.81%,RSD分别为1.46%、1.31%(n=5)。结论:该方法线性范围宽,分离效果好,快速、准确,可用于马铃薯块茎中绿原酸和原儿茶酸含量的测定。      

葵花粕中绿原酸检测方法的建立

在分析高效液相色谱法(HPLC)和紫外分光光度法(UV)的基础上,通过运用Origin8.0数据处理分析软件,建立了一种快速、有效、准确的葵粕绿原酸(CGA)检测方法。结果表明:这两种方法测定的已知浓度CGA的含量符合方程:Y=1.386+0.4082X+0.0132X2-8.438X3,R2=0.9856,其中X为UV测定结果,Y为HPLC测定结果,并通过验证,在5.5～33μg/mL浓度范围内,该方程准确可靠,从而可以实现UV法快速、准确地测量大批量样品中的CGA含量。     

Caffeine and chlorogenic acids intake from coffee brew: influence of roasting degree and brewing procedure

The influence of coffee cultivar, roasting degree and brewing procedure in the presence and transfer of caffeine and caffeoylquinic acids (CQAs) from ground roasted coffee to the brew was evaluated. Two coffee cultivars were roasted in three roasting degrees and brewed using two different procedures. Compounds were determined simultaneously by HPLC‐DAD. Caffeine levels ranged from 87.3 to 122.5 mg/100 mL for Coffea arabica cv. Catuaí Amarelo and from 123.3 to 192.0 mg/100 mL for C. canephora cv. Apoatã. The sum of CQA isomers ranged from 24.2 to 41.3 mg/100 mL for brews prepared with dark roasted coffee and from 187.7 to 295.6 mg/100 mL for light roasted ones. Brews prepared by boiling showed higher content of the compounds than the corresponding filtered ones. C. arabica cv. Catuaí Amarelo light roasted coffee brew presented the lowest caffeine/CQA ratio, regardless of the brewing procedure used, in comparison with the highest ratio of the dark boiled brews.     

气相色谱法测定烟草中的绿原酸

以正己烷及甲醇水溶液为萃取剂依次为烟草进行萃取,将萃取物烷基化后进行气相色谱分析,并对其中的主要成分绿原酸进行了定量分析。实验结果表明,本方法灵敏度高,重现性好。     

石河子部分地区葵花籽油反式脂肪酸含量与品质分析

以石河子部分地区居民常食用的不同品牌、不同渠道购买的葵花籽油为样品,测定分析其反式脂肪酸的含量及品质,比较全精炼加工食用油与原生态作坊式加工食用油的反式脂肪酸含量及品质的不同。结果显示:在26个被检测产品中有7个食用油产品总反式脂肪酸的含量在1%以上,1个在2%以上,多数为全精炼油产品,过度加工带来了反式脂肪酸含量的升高。该地区的作坊式压榨制油加工程度低,品质偏低;高级精炼油加工程度高,品质较高。23.1%的产品酸值和42.3%的产品过氧化值指标不符合国家标准。抽样的产品不合格率为76.9%,经常购买散装油的居民需要注意食用油品质和卫生安全等方面的问题。     

Decrease of the chlorogenic acid content in commercial sunflower meal using a polyphenol oxidase preparation secreted by the white‐rot fungus Trametes versicolor ATCC 42530

BACKGROUND: Sunflower meal (SFM) is a by‐product from the oil extraction process from sunflower seeds. The meal is used as a protein supplement in the livestock diet. However, relatively high levels of polyphenols, among which chlorogenic (CGA) and caffeic acids are in larger amounts, in the meal compromises its use for animal feed and human consumption. The aim of this work was to investigate an enzymatic process for upgrading the quality of SFM by decreasing its CGA content using an enzyme preparation from the white‐rot fungus Trametes versicolor. RESULTS: The effects of pH, temperature, enzyme and meal concentrations, and mass transfer on the decrease of the CGA content in SFM were investigated. It was found that: (1) the optimum pH and temperature were 3.4 and 45 °C, respectively. (2) The system was saturated with the enzyme when its concentration was 5 nkat/mL of liquid phase; (3) the agitation speed of the system influenced the extraction of CGA from the meal; and (4) the conversion of CGA in the SFM system increased in the presence of larger volumes of liquid phase. CONCLUSIONS: The enzyme preparation used in the experiments is able to decrease successfully the CGA content in SFM. Copyright © 2007 Society of Chemical Industry     

Phenolics in Aqueous Potato Peel Extract: Extraction, Identification and Degradation

Phenolics were extracted from potato peel waste using water or methanol. Phenolic acids in the extracts were quantified by HPLC. The greatest amounts of phenolic acids resulted when potato homogenate was refluxed with water for 30 min. yielding a total concentration of 48 mg/100g. Four phenolic acids (chlorogenic. gallic, protocatechuic, and caffeic) were characterized as major components. Aqueous extracts were stored 20 days and after 7 days at 25°C exposed to light, chlorogenic acid had degraded to caffeic acid.     

金银花饮料中绿原酸HPLC法的测定

目的建立金银花饮料中绿原酸含量的HPLC测定方法。方法采用ODS柱(C18,4.6mm×250,5μm),用乙腈:0.1%磷酸(15∶85)为流动相,流速1.0ml/min,紫外检测波长327nm。结果在选定的实验条件下,绿原酸在0.197～1.182μg的范围内呈良好的线性关系,r=0.9998,平均回收率为98.38%,RSD=0.88%(n=6)。结论此法简单、快速、准确,可作为该产品的质量测定方法。     

绿原酸影响氨基酸消减丙烯酰胺的研究

绿原酸是马铃薯中的主要酚酸。试验将丙烯酰胺分别与7种氨基酸进行高温加工处理,研究添加绿原酸对体系中丙烯酰胺消减的影响。结果表明,绿原酸促进丙烯酰胺的消减。加入绿原酸在160℃反应30 min后,丙烯酰胺消减率显著提高,为9.58%(天冬酰胺)～33.46%(半胱氨酸)。采用甘氨酸/丙烯酰胺体系,进一步研究绿原酸添加量、加热温度和时间对丙烯酰胺消减的影响,发现丙烯酰胺消减率随绿原酸添加量、加热温度的增加和时间的延长而提高。绿原酸与丙烯酰胺物质的量比25∶1,180℃反应60 min后,丙烯酰胺消减率达到66.9%。