Single-layer drying characteristics and colour kinetics of red chilli

Single‐layer drying experiments were conducted under controlled conditions of temperature, relative humidity (RH) and air velocity to find out the effects of drying conditions and blanching on the drying rate and colour of Thai red chilli. Drying rate increased with an increase of drying air temperature and a decrease of RH. Air temperatures above 65 °C affected the colour of red chilli. Red chilli should be dried at an air velocity equal to or just above 0.50 m s^?1. Above this value, the drying rate becomes independent of air velocity. RH and air velocity have no effect on the colour of red chilli. Faster drying rate and higher colour value was found for the blanched sample rather than the unblanched sample. The Newton and the Page equations were fitted to the experimental data. The Newton equation was found to describe the single‐layer drying of red chilli better than the Page equation.     

Time course of the colour of young red wines from Vitis vinifera L. during ageing in bottle

The colour characteristics of red wines from Vitis vinifera L. cv Tempranillo, Graciano and Cabernet Sauvignon (vintage 2000) from Navarra (Spain), was studied during 26 months of ageing in bottle through the evaluation of the wine visible spectrum and of several colorimetric indices (colour intensity, %red, %yellow, %blue, %dA and tint) and CIELAB variables (L*, C*, h, a* and b*). During ageing in bottle, the spectrum of Tempranillo wine (pH 4.3) mainly changed in the absorbance range between 420 and 500 nm, whereas Graciano (pH 3.5) and Cabernet Sauvignon (pH 3.6) wines registered a decrease in absorbance in the interval between 500 and 560 nm. The time course of the different wine colour parameters was found to fit either a second‐order polynomium or a linear model, depending on the grape variety employed. CIELAB variables could be described in terms of their colorimetric index counterparts, showing b* and h relative greater errors. Although the wine total chromatic changes in CIELAB units registered after 26 months of ageing in bottle indicated changes perceivable by the human eye (ΔE* ≥ 2.7) for the three varieties studied, Graciano and Cabernet Sauvignon wines showed a more balanced colour evolution than Tempranillo wine.     

萝卜红色素的提取与性质研究

本文报道了从红心萝卜中提取花青素类天然食用色素、用大孔吸附树脂精制花青素类天然食用色素的工艺方法,以及萝卜红色素的理化性质,包括光谱特征和溶液pH及其它理化因素对萝卜红色素颜色稳定性、呈色强度和色调等的影响。研究表明,与其它来源的花青素一样,随pH增大,最大吸收波长向长波方向移动。当溶液中Cl-浓度增加时,最大吸收峰处吸光强度增加。     

皂化-硅胶柱层析法纯化辣椒红色素

探讨了辣椒红色素的纯化工艺,首先采用碱性乙醇皂化法去除辣椒油树脂中的脂肪酸,然后经过硅胶柱层析脱除辣椒红色素中的辣椒碱。实验结果表明,最佳的皂化条件为:NaOH溶液浓度0.8mol/L,固液比1∶15(g/mL),皂化温度50℃,皂化时间2h,乙醇浓度70%(V/V),最佳的硅胶柱层析条件为:上样量1∶40(m样品∶m硅胶),径高比1∶10,洗脱流速1BV/h,得到的辣椒红色素的色价为672。      

Participation of cysteine protease cathepsin L in the gel disintegration of red bulleye (Priacanthus macracanthus) surimi gel paste

BACKGROUND: Endogenous proteases, among them cysteine‐type proteases, are reported to contribute to gel disintegration, resulting in kamaboko of poor quality. Severe gel disintegration occurs in red bulleye surimi gel paste. The objective of this study was to clarify the participation of cysteine protease cathepsin L in the gel disintegration of red bulleye surimi. The surimi was made into kamaboko with and without cathepsin L inhibitors. To confirm its hydrolysis action, crude cathepsin L was also extracted and added to the surimi to make kamaboko. RESULTS: The gel strength of kamaboko obtained by both one‐step (50 °C, 2 h) and two‐step (50 °C, 2 h + 80 °C, 20 min) heating was very low in the absence of inhibitors. Protease inhibitors E‐64 and leupeptin were found to enhance the gel strength considerably. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that the hydrolysis of kamaboko was promoted by crude cathepsin L and inhibited by E‐64 and leupeptin. The gel strength of two‐step heated kamaboko was increased from 12 to 110 and 130 g cm^?2 by E‐64 and leupeptin respectively at a concentration of 0.2 g kg^?1 surimi. CONCLUSION: Endogenous cathepsin L of red bulleye surimi participates in gel disintegration during kamaboko processing. It does so by degrading the myosin heavy chain of actomyosin and consequently hindering the gelation of red bulleye surimi. Copyright © 2009 Society of Chemical Industry     

Effects of fining with different bentonite labels and doses on colloidal stability and colour of a Valpolicella red wine

This study addressed four different labels of activated sodium bentonite during the fining of a young Valpolicella red wine. Preliminary tests determined the bentonite dose (0.15, 0.30 or 0.50 g L^?1) that would achieve colloidal stability, and this dose was further applied during laboratory‐scale trials. The bentonites were characterised by physico‐chemical parameters, and the effects of the label and dose on the wine colloidal stability, proteins, colour indices and phenolic compounds were measured. The results demonstrated that 0.50 g L^?1 for every bentonite label provided colloidal stabilisation without harshly affecting the colour. Unlike to what happens in white wines the least charged bentonite labels were effective at stabilising the red wine colloidal state by partially reducing its protein content. Simultaneously, the most negatively charged clay samples determined the largest depletions on the total polyphenols, anthocyanins, tannins and polymeric pigments. The differentiated action of clays with different surface charge density among white and red wines may be explained by the interaction mediated by positively charged anthocyanins towards either protein or tannin depletion. Although pioneering, these results may move towards the definition of a safe, allergen‐free, and effective adjuvant for colloidal stabilisation targeted to wine type.     

Enzymatic vegetable extract with bio‐ active components: Influence of fertiliser on the colour and anthocyanins of red grapes

BACKGROUND: The obtention and physicochemical characterization of an enzymatic vegetable extract (EVE) from agroindustrial wastes by a proteolytic extraction is described. The main components of EVE are nitrogen (peptides and free amino acids) and phytohormones (auxins, gibberellins, cytokinins), as functional components. The effect of EVE as fertilizer/biostimulant on several parameters of red grapes, such as colour and anthocyanins, was also evaluated. RESULTS: Its application induced high anthocyanin content with the specific induction of petunidin. Tristimulus colorimetry was applied in order to study the colour of musts. Grape juice with significant and perceptible differences in colour characteristics was obtained using EVE. The colour points were located around redder hues (h_ab) on the (a*b*)‐plane and lightness (L*) was lower. CONCLUSION: The fertilization with biostimulant shows a promising future in the functional plant nutrition linked with an increase in the organoleptic and quality food parameters. Copyright © 2007 Society of Chemical Industry     

An ethanol spray at veraison enhances colour in red wines

Aqueous ethanol (5% v/v) was sprayed onto bunches of Vitis vinifera L. cv. Cabernet Sauvignon 8–9 weeks following full flowering (controls were sprayed with water). Internal ethylene concentration in treated berries increased to a maximum within 6 hours, and berry colour subsequently increased substantially (maximum attained 2–3 weeks after spraying). Berry fresh weight at harvest was unaffected by ethanol treatment, but wine made from treated grapes showed greater colour intensity compared with control grapes.     

十二烷基硫酸钠-聚丙烯酰胺凝胶电泳法测定饮料中红豆含量

目的 建立十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate-polyacrylamide gel electrophoresis,SDS-PAGE)法定量分析植物蛋白饮料中红豆成分含量的方法.方法 从8个主要蛋白条带中选取一个蛋白条带作为定量标记蛋白,配制红豆标准品进行SDS-PAGE实...     

固体辣椒红色素稳定性研究

本文研究了固体辣椒红色素在贮存过程中的光稳定性、热稳定性、耐氧化还原性等。结果表明，固体辣椒红色素宜于低温、避光、充氮下保存。     

Effects of high hydrostatic pressure on structure and colour of red ginseng (Panax ginseng)

BACKGROUND: The conventional method of processing ginseng (Panax ginseng) roots into red ginseng involves mainly heating and drying processes. In the present study, this method was modified by using high hydrostatic pressure (HHP) to improve the physicochemical characteristics of red ginseng. RESULTS: The HHP process (600 MPa for 1 min) significantly improved the histological properties of red ginseng by increasing cellular disruption and release of cell contents. The total reducing sugar content was significantly (P < 0.05) higher (increased from 10.67 to 15.25 mg g^?1) in red ginseng processed at 600 MPa for 1 min. Similarly, the total free amino acid content also increased significantly (from 2.81 to 7.77 mg g^?1). The HHP process resulted in superior and more even colouration and gave an attractive visual appearance to red ginseng. The optical density at 420 nm and Hunter's colour a value (redness) of extracts prepared from red ginseng increased significantly (P < 0.05) with the application of HHP. CONCLUSION: HHP‐processed red ginseng has significantly higher reducing sugar and free amino acid contents together with a more compact cell structure and superior visual quality (brighter red colour). Hence the application of HHP in red ginseng processing can result in ginseng products of improved quality compared with those obtained by the conventional method. Copyright © 2012 Society of Chemical Industry     

HPLC法同时检测辣椒制品中8种非食用红色色素

建立了凝胶柱净化-高效液相色谱法同时检测辣椒制品中苏丹红Ⅰ、苏丹红Ⅱ、苏丹红Ⅲ、苏丹红Ⅳ、对位红、苏丹红G、苏丹红7B和苏丹红B等8种红色色素的方法。样品用正己烷或正己烷/丙酮提取,提取液经BioBeadsS-X3凝胶柱净化。净化后的样品采用ZorbaxSBC18柱分离,以0.1%甲酸水溶液(A)和含0.1%甲酸的甲醇丙酮(9∶1,V/V)溶液(B)为流动相,流速1mL/min,检测波长505nm。上述8种色素组分在其质量浓度为0.16～2.56mg/L时有良好的线性关系,方法的检测限为15～46μg/kg;平均加标回收率为89.9%～118.2%,相对标准偏差为2.3%～4.8%。该方法灵敏可靠,适合于辣椒制品中多种脂溶性红色色素的同时检测。     

The effect of Saccharomyces cerevisiae and Saccharomyces bayanus yeast on colour properties and pigment profiles of a Cabernet Sauvignon red wine

Red wine was made from the same batch of Cabernet Sauvignon grapes but with two different yeasts, Saccharomyces cerevisiae (SC) or Saccharomyces bayanus (SB). The colour properties and pigment profiles of SC and SB wines were compared at 8 days and 387 days after yeast inoculation. Grape anthocyanin concentration was found to be lower in SB wines than in SC wines at day 8 and 387, but SB wine exhibited greater wine colour density, a* and b*. The anthocyanin concentration did not correlate with wine colour density. The levels of pigmented polymers and SO₂ non-bleachable pigments were found to be higher in SB wine at day 387, demonstrating that the formation of stable pyranoanthocyanins and pigmented polymers was enhanced by SB yeast. Electrospray mass spectrometry was used for the compositional analysis of pyranoanthocyanins, and direct and ethyl-bridged linked condensation dimers of malvidin 3- O -glucoside (MvG) with flavanols (catechin or epicatechin). The data demonstrated that the formation of acetaldehyde-mediated pigments was enhanced by the use of the SB yeast. The compositional analysis suggested that the differences in colour properties and pigment profiles of SC and SB wines were largely due to the greater production of acetaldehyde-mediated pigments by the use of SB yeast.     

Photobleaching,light‐induced discolouration in red peppers

Red peppers dried in sunlight experience surface bleaching, centred near the calyx, on the face exposed to the light. In this study, bleaching mechanisms were studied under simulated irradiation conditions by placing pericarp discs in 2‐(N‐morpholino) ethane sulfonic acid (MES) and sucrose solution. The moisture content near the calyx of the pepper decreased more slowly than that on the apex side. In addition, pericarp discs incubated without MES/sucrose solution retained more carotenoids than those incubated with solution after 27 h of light treatment. Carotenoids in pericarp discs exposed to the light decreased rapidly over the incubation time, whereas in the dark they decreased slowly and remained higher in content. Changes in malondialdehyde (MDA) level and electrolyte leakage were not observed for pericarp incubation in the dark. A sharp increase in the level of MDA and a change in electrolyte leakage from discs exposed to the light occurred when carotenoids were exhausted. Carotenoid degradation was markedly suppressed by the addition of ascorbic acid. These results demonstrate that carotenoids in red pepper pericarp played a role in protecting cells and were subsequently degraded under intense light conditions. Copyright © 2006 Society of Chemical Industry     

提高计算机测色配色系统应用精确性的途径和方法

对提高测色系统应用精确性的途径和方法,以及利用测试结果进行色光调整作了探讨,结果表明应用测色配色系统减少了人为因素的干扰,提高了染色过程中颜色的精确度。     

Effect of protein additives, sodium ascorbate, and microbial transglutaminase on the texture and colour of red tilapia surimi gel

Beef plasma protein (BPP) and egg white, at levels of 10, 20 and 30 g kg⁻¹, and sodium ascorbate (SA) and microbial transglutaminase (MTGase), at levels of 1, 2 and 3 g kg⁻¹, were individually added into red tilapia surimi. This gel was set at 40 °C for 90 min followed by heating at 90 °C for 30 min. Gel qualities were analysed and compared with those of non-supplemented red tilapia control gel. Compared with the control, each additive significantly affected gel strength due to an increase in breaking force. Although BPP could improve texture characteristics, higher addition levels of BPP significantly affected gel whiteness. The addition of SA and MTGase were found to increase surimi gel strength and improve whiteness. Amongst all treatments, the addition of 2 g kg⁻¹ MTGase was found to provide the best gel qualities.     

凝胶渗透色谱-高效液相色谱法测定糟蛋中4种 苏丹红的残留量

目的建立一种凝胶渗透色谱-高效液相色谱法(gel permeation chromatography-high performance liquid chromatography,GPC-HPLC)同时测定糟蛋中4种苏丹红(苏丹红Ⅰ、Ⅱ、Ⅲ和Ⅳ)的方法。方法糟蛋样品经环己烷-乙酸乙酯提取,经Bio-Beads S-X3凝胶柱净化;采用Agilent Zorbax SB C_(18)色谱柱对糟蛋中4种苏丹红进行分离,以97%乙腈水溶液为流动相,流速为1.0 m L/min,用配有紫外检测器的液相色谱仪检测,检测波长为478 nm和520 nm。结果 4种苏丹红样品在0.1~25.0 mg/L浓度范围内线性良好(r~20.999),该方法的检测限为6.3~11.9μg/kg,加标回收率为86.0%~101.2%,相对标准偏差(RSD)在1.68%~4.58%之间。结论本方法操作简便、准确可靠,可应用于糟蛋中苏丹红的检测。     

Some challenges in modern hair colour formulations

Formulation of hair coloring product involves two stages, first a development of product base followed by formulation of desired shade. During that process a special consideration needs to be given to a whole range of product characteristics such as dye stability in the product medium, colour wearability on hair, light fading and finally rheology of the product. This paper reviews improvement in permanent coloring products as it relates to dye and base composition. Examples are shown where a reduction or elimination of certain dyes, m-phenylenediamine or sodium picramate, improves long term stability and product performance on hair. In cases when only reduction of the dyes was carried out, improvement in stability was achieved through their use as secondary colour contributors and not as primary ones. There are also other composition aspects that impact colour performance of the final product. For example, pH of the coloring mixture has a pronounced effect on the final colour developed in hair. It is shown that a shift in tonality caused by pH change can be predicted for finished product using a simple system composed of the main coupler-intermediate pair employed in the product. The colour response to pH change of this simple system was found to mirror that of the product. This predictability can be used as a formulation tool to develop more efficient dye systems. Effects of some functional materials on colour result such as propylene glycol, ascorbic acid or silicone are also shown.