Determination of phenolic compounds in wines: Influence of bottle storage of young red wines on their evolution

Various analytical methods based on the HPLC-DAD technique were used to determine 38 phenolic compounds in red wines. While anthocyanins and hydroxycinnamic acids were determined by direct injection of wine samples, hydroxybenzoic acids, catechins, procyanidins and flavonols required an analytical pretreatment involving liquid–liquid partitioning with ethyl ether followed by solid-phase extraction on C₁₈ mini-columns. The proposed analytical methods were used to establish the phenol composition of Mencía and Brancellao, two varietal young red wines, and its influence on colour stability during storage in bottles for one year. At the end of malolactic fermentation, Mencía wine was found to contain much greater amounts of anthocyan pigments than was Brancellao wine. This resulted in a higher colour density but a weaker hue in Mencía wine than in Brancellao wine. Phenolic compounds evolved similarly in both wines during storage; changes in such compounds involved a decrease in the levels of monomeric anthocyanins, phenolic acids, epicatechin and flavonols, and an increase in those of procyanidins. The absence of a relationship between the changes in colour density and monomeric anthocyanins in both wines suggests that copigmentation and polymerization with other phenolic compounds (viz. phenolic acids, catechins and/or flavonols) prevail over degradation of the pigments.     

The phenolic compounds of blackcurrant juice and their protective effect on ascorbic acid

Summary. The anthocyanins, flavonols and other phenolic compounds present in blackcurrant juice have been characterized and estimated using column, paper and thin-layer chromatography, and absorption spectrophotometry. New minor phenolic compounds isolated and identified include 5-methyl quercetin, quercitrin, dactylifric acid and p -coumaric acid. the presence of previously reported phenolic compounds in blackcurrant juice has been confirmed. A quantitative assessment of anthocyanin and other phenolic substances has been made.     

Influence of the refrigeration technique on the colour and phenolic composition of syrah red wines obtained by pre-fermentative cold maceration

The vinification technique called pre-fermentative cold maceration is used to enhance the anthocyans diffusion from the skins to the must, increasing the pigments extraction. For using this technique the application of low temperatures is needed. In this study, two different refrigerating methods (dry ice and cooling of grapes) have been assessed regarding the colour and the phenolic composition of the Syrah wines elaborated by applying pre-fermentative cold maceration. Results showed more intense and stable colours when grapes were previously refrigerated in cold-storage rooms, which showed higher values of chroma and more red-bluish hues. As regards phenolic composition, the cold maceration technique used yields to significant differences among the levels of phenolics, having higher levels of anthocyanins and some non-coloured phenols as flavonols in PR wines. Regarding the colour-composition relationships, it has been highlighted the importance of the co-pigments such as flavonols and cinnamic acids for classify the two groups of samples.     

正交优化超声辅助双水相法粗提雪菊色素

研究超声辅助正丙醇(NPA)/(NH4)2SO4双水相技术对雪菊色素的粗提工艺。以(NH4)2SO4质量分数、NPA质量分数、雪菊粉末用量、超声温度、时间及p H为考察因子,以总黄酮为指标,选择差示分光光度法测定粗提物中色素含量,并以单因素试验为基础设计正交试验优化提取工艺,发现雪菊色素主要集中于上相。在最佳水平,建立20.0 g ATPS,(NH4)2SO4质量分数29%、NPA质量分数23%,雪菊粉末用量0.08 g,调pH3,温度60℃下超声提取60 min;雪菊色素得率240.1469 mg/g,RSD为4.414%。与传统提取法相比,超声辅助NPA/(NH4)2SO4双水相粗提雪菊色素时间短、温度低、效率较高,可以实现雪菊色素粗提物的提取分离,且差示分光光度法用于雪菊色素的检测可信度较高,为雪菊色素粗提工艺提供一种新途径。     

The profile in polyphenols and volatile compounds in alcoholic beverages from different cultivars of mulberry

Abstract: Mulberry fruits have different chemical compositions because of cultivar variation. In this study, polyphenol profile and volatile composition of alcoholic beverages produced from different mulberries of Da 10, Hongguo 2 hao, and Hongguo 1 hao were investigated. Statistically significant differences were detected in the chemical composition of the analyzed alcoholic beverage samples. The beverage of Da 10 possessed the highest content of total phenols, total flavonoids, and total anthocyanins, which was determined by spectrophotometry analysis, contrarily Hongguo 1 hao beverage showing the lowest. Phenolic acids and flavonols were analyzed by high performance liquid chromatography analysis. Protocatechuic acid was the main phenolic acid in all analyzed alcoholic beverage samples, and its concentration ranged from 8.20 mg L^?1 (Hongguo 1 hao beverage) to 29.98 mg L^?1 (Da 10 beverage). High level of flavonols was found in both Da 10 and Hongguo 2 hao beverage samples, whereas Hongguo 1 hao beverage sample was characterized with lower level of flavonols. Furthermore, volatile compounds were analyzed by solid phase microextraction‐gas chromatography mass spectrometry analysis. The amount of esters varied widely among the 3 alcoholic beverage samples. The concentration of aliphatic alcohols in Hongguo 2 hao and 1 hao beverage samples was higher than Da 10 sample, whereas Da 10 beverage sample contained more aromatic alcohols than the others. Hongguo 1 beverage sample showed the highest concentration of acetic acid. This study demonstrated that quantitative differences of phenolic compounds and volatile compounds among cultivars were significant, which highly affected the quality of alcoholic beverage from mulberry. Practical Application: Mulberry fruits had different chemical compositions because of cultivar variation. The analyzed Da 10 cultivar of mulberry appeared to be a good raw material for alcoholic beverage‐making because of its high level of total sugar and acidity. This study demonstrated that alcoholic beverages from mulberry contain high amounts of polyphenols. These bioactive compounds may act synergistically to promote health, and reduce risk factors of chronic diseases.     

Effects of exogenous abscisic acid on phenolic characteristics of red <Emphasis Type="Italic">Vitis vinifera</Emphasis> grapes and wines

The effects of exogenous abscisic acid (ABA) on phenolic characteristics of grapes and wines were investigated in Vitis vinifera cvs. Merlot and Cabernet Sauvignon. Exogenous ABA treatment at veraison significantly improved phenolic contents, mainly anthocyanins and flavonols, and antioxidant properties of the grape skins, but had no effects on total phenolics and antioxidant activities in the seeds or on basic fruit qualities. The wines made from ABA-treated grapes were also consequently enhanced in total phenolics, anthocyanins, flavonols and antioxidant activities. The proportions of methylated anthocyanins in the skins and acylated anthocyanins and derived pigments in the wines were decreased to some degree by exogenous ABA treatment. No distinct relationships were observed between ABA concentrations and phenolic characteristics, and the effects were observed even with 200 mg/L ABA. The results revealed that exogenous ABA applied at veraison offered opportunities to improve phenolic contents and nutritional values of grape skins and wines.     

Analysis of pigmented polymers in red wine by reverse phase HPLC

A reverse phase HPLC method has been developed for the quantitative analysis of pigmented poly-phenolic polymers in red wines. Pigmented polymers were well separated from anthocyanins and other simple wine pigments and eluted last as a single peak. The polymeric and polyphenolic nature of this peak was confirmed by its precipitation with gelatine and its behaviour during ultrafiltration and chromato-graphy on Sephadex LH20. This method correlates well with spectrophotometric measures of total pigmented polymers and indices of wine age. The proportion of the pigmented material incorporated into polymers increased with increasing wine age.     

Antimicrobial activity of the polyphenolic fractions derived from Grewia asiatica,Eugenia jambolana and Carissa carandas

Crude methanolic extracts from Grewia asiatica, Eugenia jambolana and Carissa carandas were separated into four major fractions viz. phenolic acids, flavanols, flavonols and anthocyanins which were then analysed for their total phenolic, flavonoid contents, and antimicrobial effects. In addition, anthocyanin fraction was also analysed for total anthocyanins, total colour and polymeric pigments. Total phenolics and flavonoids were highest in the fractions from E. jambolana and lowest in C. carandas, the order being phenolic acid > flavanols > flavonols > anthocyanins in all fruits. All fractions showed significant antibacterial activity except anthocyanin. Being the most active, phenolic acid fractions were also tested for their antifungal activity, the fractions of C. carandas and G. asiatica substantially inhibited all the tested fungal species. These results are being reported for the first time.     

植物黄酮醇提取方法研究进展

黄酮醇是自然界中重要的天然色素及生物活性物质之一,在食品及保健品开发中发挥着重要作用。了解植物黄酮醇提取技术的最新研究进展对于有效获取植物黄酮醇并促进其在相关领域的应用具有重要意义。本文综述了近年来国内外有关植物黄酮醇提取的不同方法,对不同提取方法的工作原理及其优缺点进行了剖析,并对本领域后续发展方向进行展望,以期为植物生物活性物质分离提取及应用研究提供理论依据及技术支持。     

奶油中人工色素检测方法概述

随着奶油在饼干、糕点、冷饮、果冻等食品中的普遍使用,对奶油中人工色素的检测已经成为一个亟需解决的问题。本文简单介绍了奶油的分类、可食用人工色素的分类及我国目前的使用标准,阐述了其对人们造成的危害,并对人工色素常规检测方法和快速检测方法进行了介绍。人工色素常规分析方法主要有高效液相色谱法、薄层层析法、极谱法、分光光度法和毛细管电泳法,快速检测法有免疫学检测法、超高效液相色谱法、合成色素快速检测仪法、快速检测试剂盒、拉曼光谱和近红外光谱分析技术等。同时对今后奶油中人工色素的快速检测技术进行了展望。     

延迟采收对酿酒葡萄类黄酮物质的影响

以梅鹿辄和赤霞珠葡萄为实验材料,研究延迟采收对葡萄类黄酮物质的影响。结果表明：延迟采收后酿酒葡萄果粒质量和果粒纵径均降低,可溶性固形物的含量增加,可滴定酸含量降低。梅鹿辄果皮中共检测出19 种花色苷、6 种黄烷醇和15 种黄酮醇,延迟1 周后,黄烷醇和黄酮醇含量增加,相较于对照分别增加了69%和1.67%,延迟2～3 周后黄烷醇和黄酮醇含量降低;而延迟采收后,花色苷含量下降。赤霞珠果皮中共检测出15 种花色苷、4 种黄烷醇和15 种黄酮醇,花色苷、黄烷醇和黄酮醇的含量在延迟3 周后显著增加,相较于对照分别增加了22%、102%、80%。     

三波长紫外分光法测定覆盆子黄酮的研究

以单波长紫外分光光度法测定覆盆子黄酮类化合物为基础,建立了三波长法定量测定覆盆子黄酮类化合物,经验证该法能有效消除杂质对定量测定的影响,平均加样回收率达到101.40％,加样回收标准偏差为2.29％,稳定性试验相对标准偏差4.90％,该方法便捷、准确,适合于覆盆子黄酮提取分离工艺探讨中快速检测黄酮含量.     

红花提取物抗氧化活性研究(英文)

本研究从红花提取物中分离并用质谱鉴定了四种黄色素。建立了一个快速测定红花提取物中黄色素的反相液相色谱方法,并对不同温度和时间加热对红花提取物中黄色素含量的影响及其动力学变化进行了研究。进一步采用清除DPPH自由基能力的方法测定红花提取物的抗氧化能力。结果显示随着温度的升高,红花提取物中黄色素的含量逐步减少,同时发现红花黄色素含量与其抗氧化能力有相关性。     

Determination of phenolic compounds of grape skins during ripening by NIR spectroscopy

The potential of near infrared spectroscopy (NIRS) to determine the content of phenolic compounds in red grapes has been evaluated. The near infrared spectra of intact grapes and grape skins throughout maturity were recorded using a fibre-optic probe and a transport quartz cup, respectively. Reference values of phenolic compounds were obtained by HPLC-DAD-MS. Modified Partial Least Squares (MPLS) regression was used to develop the quantitative models for flavanols, flavonols, phenolic acids, anthocyanins and total phenolic compounds. The procedure reported here seems to have an excellent potential for fast and reasonable cost analysis. The results of this work show that the models developed using NIRS technology together with chemometric tools allow the quantification of total phenolic compounds and the families of main phenolic compounds in grape skins throughout maturation. The validation of these models showed the best results for the determination of flavonols (differences between HPLC and NIRS of 7.8% using grapes and 10.7% using grape skins) in the external validation procedure. Good results in the external validation were also obtained for the determination of total phenolic compounds (differences of 11.7% using grapes and 14.7% using grape skins). The best results were generally obtained recording the spectra directly in intact grapes.     

粉色、黑色花生种皮色素的抗氧化活性及组分差异分析

为了深入了解粉色和黑色花生种皮色素的抗氧化活性及组分差异,采用高效液相色谱-高分辨飞行时间质谱(UPLC-Q-TOF-MS)联用仪分析了粉色和黑色花生种皮色素的组分,从粉色花生种皮色素中鉴定出(表)儿茶素和2种原花色素二聚体、1种原花色素三聚体和2种原花色素四聚,黑色花生种皮色素中鉴定出原花色素二聚体、三聚体、四聚体和2种矢车菊素、4种飞燕草素类组分。采用分光光度法测定了粉色、黑色花生种皮色素的抗氧化活性,粉色花生种皮色素的抗氧化能力为(17.46±1.88) U/mg,黑色花生种皮色素的总抗氧化能力(23.77±1.58) U/mg;黑色花生种皮色素对羟自由基和超氧阴离子的半抑制力IC₅₀分别为 0.58、1.79 mg/mL;粉色花生种皮色素对羟自由基和超氧阴离子的半抑制力IC₅₀分别为 0.39、1.41 mg/mL。2种不同颜色花生种皮色素的组分具有明显差异,其抗氧化活性也存在异同之处,黑色花生总抗氧化能力强于粉色花生种皮色素,而抑制羟自由基和超氧阴离子的能力弱于粉色花生种皮色素。     

Analytical problems in the study of flavonoid compounds in onions

Flavonoids, although potentially mutagenic, are widely thought to have beneficial effects in the diet resulting from their antioxidant and metal binding properties. Epidemiological evidence correlates diets rich in flavonoid compounds with a low risk of coronary heart disease. In the present work flavonoids (principally flavonols and anthocyanins) are studied in the onion, a major dietary source of flavonoids. This work concentrates on the development of methods to study flavonoids in their natural form in plant foods as conjugates. Two major components quercetin monoglucoside and quercetin diglucoside account for 80% of the total flavonoids in onions. Anthocyanins are only minor components of the flavonoid spectrum in the edible portion of red varieties. A preliminary study of flavonols in onions, which had been finely chopped, suggests that in most varieties there is only a small loss in total flavonol but that there is a progressive loss of the diglucoside component with an accompanying quantitative accumulation of the monoglucoside and the aglycone.     

三波长紫外分光光度法测定红车轴草异黄酮含量的研究

红车轴草乙醇提取液，颜色较深，背景吸收较大，以一般常用的单波长紫外分光光度法测定红车轴草异黄酮含量时，色素和醇溶性蛋白等杂质干扰严重。本文建立的三波长紫外分光光度法，能有效扣除色素和醇溶性蛋白等杂质的干扰，精密度实验的相对标准偏差为0．85％，平均加样回收率为103．95％，加样回收率的相对标准偏差为1．82％。本方法具有简便、快速、准确等特点。     

Characterization of the Residual Pink Color in Cooked Turkey Breast and Pork Loin

The residual redness was characterized in well cooked meat from turkey breast and pork loin. A simple method of scanning thin slices by transmission spectrophotometry was used to evaluate the meat pigments in situ. Absorption bands at 414, 520, and 550 nm of the spectra obtained from cooked meat led to the conclusion that residual pink color was caused by cytochrome c. The method was further modified to study the effect of air contact on meat color after cooking. Other pigments were spontaneously oxidized as soon as meat surface was exposed to air. The concentrations of hemoproteins in turkey and pork were determined and found to be related to cooked meat color.     

ATR-FTIR and Spectrometric Methods for the Assay of Crocin in Commercial Saffron Spices (Crocus savitus L.)

Attenuated total reflectance Fourier transform infrared spectrometric method for determination of crocin in commercial saffron samples was studied. Calibration models were built based on the peaks at spectral region of 1700–900 cm^?1 and spectral wavenumbers with correlation coefficient (r) greater than 0.99 were selected for quantification of crocin in the samples. The quantitative analysis of samples by attenuated total reflectance Fourier transform infrared was tested against reference UV-visible spectrophotometry method. Considerable correlation (r = 0.95) between both methods in prediction of crocin content among the saffron samples indicated that the proposed methodology has the potential application as a rapid screening tool.     

Phenolic profile and antioxidant activity of highbush blueberry (Vaccinium corymbosum L.) during fruit maturation and ripening

The phenolic profile and quantitative composition of blueberries as well as the corresponding antioxidant activity of blueberries is well documented. Unfortunately, little is reported on the development of phenolic compounds and antioxidant activity during fruit maturation and ripening. In the present study, the total phenolic content and main phenolic compounds of four highbush blueberry cultivars (Vaccinium corymbosum L.) were analyzed at five stages of maturation and ripening. Antioxidant activity was screened with electron spin resonance spectrometry and trolox equivalent antioxidant capacity (TEAC) assay. An adequate picture of phenolic compounds developed during maturation and ripening was determined using HPLC-DAD. Anthocyanins of all varieties increased during successive harvest stages; meanwhile flavonols and hydroxycinnamic acids decreased from unripe green to ripe blue stage of berry ripening. Blueberry antioxidant activity, as well as total phenolic content tended to decrease during ripening.