栗子壳色素的分级与稳定性研究

根据溶解性不同,将栗子壳色素分级得到3种色素组分Fr.1、Fr.2和Fr.3。Fr.1只溶于碱性水溶液;Fr.2溶于碱性水溶液和亲水性有机溶剂;Fr.3在任何pH值的水溶液中都能溶解,在亲水性有机溶剂中也能溶解。对栗子壳色素各分级组分进行了化学定性分析和紫外-可见光光谱分析,并研究了它们的稳定性。各分级组分均具有酚类物质的性质,但不具有黄酮类化合物的典型性质,也不具有鞣性。3种栗子壳色素组分的紫外-可见光光谱都是随着波长增大而吸光度逐渐减小的曲线,在可见光区没有明显的吸收峰,仅在270 nm左右有一肩峰。3种色素组分的溶液颜色均随着pH值的增大而逐渐加深,Fr.1对加热和紫外线相对稳定,而Fr.3最为敏感。氧化剂可使栗子壳色素褪色,且Fr.1褪色幅度最大,Fr.2最小。各色素组分均对还原剂、蔗糖、Na+、Mg2+稳定而对Al3+、Ca2+、Fe2+、Fe3+、Cu2+和Zn2+的稳定性较差。     

板栗壳棕色素的提取、纯化及应用研究进展

板栗壳作为食品加工废弃物,来源丰富,成本低廉,可用于提取板栗壳棕色素。板栗壳棕色素是一种性质稳定且具有一定保健功能的天然色素,近年来得到了广泛的研究和应用。本文综述了板栗壳棕色素的提取方法,包括溶剂浸提法、超声波提取法、微波提取法、超临界流体萃取法、酶法提取法等,以及板栗壳棕色素在食品、纺织品中的应用,讨论了目前存在的问题,并展望了板栗色素的应用前景。     

Quantitative separation of antioxidant pigments in purple sea urchin shells using a reversed-phase high performance liquid chromatography

Sea urchin shells are generally discarded as food waste after removal of edible gonads, although they possess significant amount of polyhydroxylated naphtoquinone pigments having potent antioxidant property. In this study, separation and quantification of the pigment mixtures from purple sea urchin shells were performed using a C18 reversed-phase HPLC with isocratic elution of 50% mixture of solvent (A) formic acid: water (0.1: 100, v/v) and solvent (B) MeOH: acetonitrile (5: 9, v/v) at a flow rate of 0.5 mL/min. The pigment mixtures were separated into four major peaks in 30 min, which assumed to be spinochromes A, B and C and echinochrome A on the basis of UV-Vis absorption spectra obtained by a diode array detector. LC-MS analysis also supported these results by producing the predominant base peaks at m/z 221.1, 279.1, 265.1, and 263.1 corresponding to the pseudomolecular ions [M-H]⁻ of the respective compounds. The HPLC method also showed good correlations (r² > 0.98) between injected amounts of these pigments and peak areas recorded at 340 and 520 nm. These results indicated that the HPLC method developed in this study would be applicable for the separation and quantification of these major pigments in sea urchin shells.     

酶解和碱处理对半乳糖醛酸-木素脱氢聚合物复合体结构的影响

以果胶结构单元D-半乳糖醛酸和木素前驱物松柏醇-β-D-葡萄糖苷为原料,在多种生物酶的协同作用下合成了半乳糖醛酸-木素脱氢聚合物复合体(GDHPC),并分别用酶解(果胶酶)和碱法(1 mol/L的NaOH)对GDHPC进行处理。FT-IR和13C-NMR分析表明,D-半乳糖醛酸和木素脱氢聚合物之间形成了以苯甲醚键和酯键2种形式连接的木素-碳水化合物连接键;酶解和碱法处理都能在一定程度上削弱D-半乳糖醛酸的特征峰;碱法处理能降解酯键,但对苯甲醚键的降解作用并不明显;酶解对酯键和苯甲醚键的降解效果均较差。     

Electron spin resonance (ESR) spectroscopy study of dry-cured ham treated with electron-beam

The generation, accumulation and decay of free radicals in muscle and fat fractions from three varieties of Spanish dry-cured ham treated (0–4 kGy) in an electron accelerator have been studied by electron spin resonance (ESR) spectroscopy. In the ESR spectra from fat fractions, a well-resolved triplet signal corresponding to an alkyl radical was found only in treated samples. Linear regression models (P < 0.05) were obtained for ESR signal intensity estimation using the absorbed dose and storage time at 4 °C (from 0 to 28 days). Several ESR signals were observed in the spectra from muscle fractions related to the presence of metalloprotein complexes. However, no significant (P > 0.05) differences were found between ESR spectra from untreated (0 kGy) and treated (0–4 kGy) samples. Results suggest that the analysis of ESR spectrum in fat samples can be used to evaluate the E-beam treatment of dry-cured ham.     

光谱技术在木素结构分析中的应用

介绍了紫外光谱、红外光谱、核磁共振谱(~1H-NMR、I~3C-NMR、2D~1H~(13)C-NMR、~(31)P-NMR)、电子自旋共振谱等光谱技术的原理、特点及其在木素结构分析中的作用和优缺点,为选择适宜的检测方法进一步研究木素结构提供了一定的依据。     

Improved analysis of Monascus pigments based on their pH-sensitive UV-Vis absorption and reactivity properties

Monascus pigments, a mixture of azaphilones mainly composed of red, orange and yellow pigments, are usually prepared in aqueous ethanol and analysed by ultraviolet-visible (UV-Vis) spectroscopy. The pH of aqueous ethanol used during sample preparation and analysis has never been considered a key parameter to control; however, this study shows that the UV-Vis spectra and colour characteristics of the six major pigments are strongly influenced by the pH of the solvent employed. In addition, the increase of solvent pH results in a remarkable increase of the amination reaction of orange pigments with amino compounds, and at higher pH (≥ 6.0) a significant amount of orange pigment derivatives rapidly form. The consequent impact of these pH-sensitive properties on pigment analysis is further discussed. Based on the presented results, we propose that the sample preparation and analysis of Monascus pigments should be uniformly performed at low pH (≤ 2.5) to avoid variations of UV-Vis spectra and the creation of artefacts due to the occurrence of amination reactions, and ensure an accurate analysis that truly reflects pigment characteristics in the samples.     

Melanization of flavonoids by fungal and bacterial laccases

Laccase activity in plants results in the formation of a number of brown pigments, often referred to as tannins. Laccase-dependent pigment production is also catalogued in numerous fungal and bacterial species. The laccase of the haploid yeast Cryptococcus neoformans forms melanin-like pigmentation outside the cell wall in the presence of exogenous substrates. While this process is a contributing factor to its virulence in humans, the evolutionary intent for the laccase function remains a mystery. We show here that C. neoformans and Bacillus subtilis have the ability to create melanin-like pigments from a variety of flavonoid molecules across a range of conformations, preferring those with 3',4'-dihydroxylations. Since flavonoids are ubiquitous plant molecules and often-considered antimicrobial agents, we postulate that they are the intended natural targets of laccase activity and result in the formation of a defensive melanin-like coat. These results suggests a new mechanism by which flavonoid-melanin formation may occur, using not only A- and C-ring linkages, but also monomer links through the B-ring of the flavonoid structure. We also show that resveratrol and other non- and mono-hydroxylated polyphenol substrates have the ability to restrict pigment formation and may be potent inhibitors of laccase activity.     

Environmentally friendly wood adhesives based on chestnut (<Emphasis Type="Italic">Castanea sativa</Emphasis>) shell tannins

The aim of this work was the formulation of adhesives for particleboards based on tannins extracted from industrial lignocellulosic wastes, namely chestnut shell, chestnut bur and eucalyptus bark. The interest was centred on the possibility of completely removing formaldehyde from adhesive formulations. For this, hardener alternatives to formaldehyde were used: tris(hydroxymethyl)nitromethane (TRIS), glyoxal (GLY) and hexametilentetramine (HEX). The influence of the type and concentration of the hardener and pH on adhesive gel time and pot-life were studied. A comparative structural characterization of the adhesives was performed by 13C-NMR spectroscopy. Thermomechanical analyses (TMA) tests were carried out as an indication of the final strength of the adhesive systems. Particleboards type 2 of interior use (EN 312) were manufactured with adhesives based on chestnut shell tannins alone or mixed with chestnut bur/or eucalyptus bark tannins. Free-formaldehyde was determined, and boards were prepared with TRIS, GLY and HEX tannin adhesives were classified as E0.     

Antioxidant property of polyhydroxylated naphthoquinone pigments from shells of purple sea urchin Anthocidaris crassispina

Sea urchin gonads are highly priced sushi foodstuff “Uni” in Japanese traditional food, but after removal of them the residual shells with spines are dumped as waste. However, sea urchin shells contain naphthoquinone pigments with several phenolic hydroxyl groups, which were expected to act as potent antioxidant substances by donating hydrogens. Our previous study has evaluated their antioxidant ability to depress lipid peroxidation. This study examined other antioxidant property of the pigments from purple sea urchin shells, which possess larger amount of pigments than those of red and green sea urchins. The pigments as well as known antioxidant, α-tocopherol, exhibited 1,1-diphenyl 2-picryhydrazyl (DPPH) radical scavenging ability. Superoxide anion radical and hydrogen peroxide were also scavenged while hydroxyl radical, one of the most reactive oxygen species, was not significantly inhibited. However, because the pigments had significant activity to scavenge hydrogen peroxide and superoxide anion radical that could be in vivo precursors of hydroxyl radical, sea urchin pigments would be able to depress the generation of its related active oxygen radical species. These results suggested that sea urchin shells, which are still regarded as food waste, would be a new bio-resource for obtaining natural antioxidant.     

Electron Spin Resonance Analysis of Radiation-Induced Free Radicals in Shells and Membranes of Different Poultry Eggs

Radiation-induced free radicals were investigated in the shells and membranes of ostrich, duck, hen, and quail eggs using electron spin resonance (ESR) spectroscopy. The non-irradiated egg shells and membranes showed a single resonance signal centered at g?=?2.0048?±?0.0001 and 2.0072?±?0.0002, respectively. Upon irradiation (1–3 kGy), a dose-dependent asymmetric ESR signal centered at g?=?1.9998?±?0.0002 was also determined in all eggshell samples, whereas the membranes were found silent for radiation-specific ESR signals. An X-ray diffraction spectrometric study showed the abundance of calcite minerals in the all egg shells. Radiation-induced and trapped CO ₃ ^3? , CO ₃ ^? , and CO ₂ ^? paramagnetic entities in the calcite matrix of egg shells might be responsible for a typical ESR signal. The ESR-based identification of all irradiated eggshells was easily possible in practical dose range (1–3 kGy).     

漆酶/天然介体体系漂白硫酸盐竹浆的机理研究

对硫酸盐竹浆包含漆酶/天然介体漂白段的全无氯(TCF)漂白各段的残余木素进行了GPC、TGA、FT-IR、1H-NMR和t3C-NMR分析,主要探讨漆酶/天然介体体系(LMS)漂白的机理.分析表明,随漂白的进行,竹浆残余木素的总体变化趋势为分子质量降低;经LMS处理后,竹浆残余木素的热稳定性变差,更易在较低温度下热解;竹浆木素为GSH型,结构单元以G为主,苯丙烷单元之间的连接以β-O-4′为主,此外还有β-1′和β-5′连接.原浆木素中的羟基以酚羟基为主,苯丙烷单元中S的含量(以物质的量计,下同)少于1/3;O段残余木素中,脂肪族羟基比酚羟基多,且有少量-COOH、-OCH3被脱除,苯丙烷单元中G＞H＞S;LMS段残余木素中的羟基以脂肪族羟基为主,S单元含量增加,H单元含量减少,争1′连接增加,β-5′连接很少.     

Chemical composition of shells from red (Strongylocentrotus franciscanus) and green (Strongylocentrotus droebachiensis) sea urchin

The shells from red and green sea urchins accounted for 47.9 and 40.7% of their body weights, respectively. The red and green sea urchin shells contained 91.08 and 90.77% minerals and 4.06 and 4.99% proteins, respectively. The shells did not contain any chitin. Sea urchin shells had a relatively large amount of naphthoquinone pigments, 121 mg per 100 g in red and 163 mg per 100 g in green species. The small quantities of glucosamine detected (20 mg/g in red and 25 mg/g in green sea urchins) originated from mucopolysaccharides present in a layer of connective tissues attached to the shells. Using EI–MS spinochromes A, B, C, and D were found in fractions of naphthoquinone pigments separated from shells of green sea urchin by Sephadex LH-20 column chromatography. The presence of the molecular ion of spinochrome D in its mass spectrum of well separated fractions V–VII may suggest that this compound can appear as a complex with organic compounds and could be a derivative of benzene dicarboxylic acid.     

纤维素酶法提取板栗壳色素的工艺条件优化

以板栗壳为原料,通过单因素试验,考察提取剂乙醇体积分数、提取时间、提取温度、纤维素酶添加量、料液比和提取液pH值对板栗壳色素提取效果的影响。在单因素试验的基础上,根据中心组合(Box-Behnken)试验设计原理,采用四因素三水平的响应面分析法,确定提取板栗壳色素的最佳工艺条件为pH6、纤维素酶添加量0.6%、提取温度94℃、提取时间120min。     

板栗壳多酚的超声波辅助低共熔溶剂提取工艺优化及其成分分析

采用低共熔溶剂（Deep eutectic solvents,DESs）-超声波辅助提取法对废弃板栗壳中的多酚进行提取并进行成分鉴定。本实验成功合成8种不同的DESs,并用傅里叶红外变换光谱表征氢键供体和氢键受体之间氢键的形成。基于单因素实验,采用响应面法优化超声波功率、液固比、低共熔溶剂水分含量三个因素对总酚得率的影响,经大孔吸附树脂纯化后进行多酚成分鉴定。结果表明,8种DESs中,氯化胆碱-草酸（摩尔比1:1）合成的DES-1总酚得率最高,且明显高于传统溶剂（水和40%乙醇）;最佳提取工艺参数为:超声波功率348 W、液固比42:1 mL/g、水分含量32%,总酚得率为（99.66±2.63） mg/g,与理论总酚得率99.44 mg/g接近,采用AB-8大孔树脂从DESs提取物中回收多酚,回收率高达97.92%±1.78%。UHPLC-ESI-Q-TOF-MS/MS从粗提物中初步鉴定出13种酚类物质。本研究提供了一种绿色、高效的从板栗壳中提取多酚的方法,可为板栗壳废弃物的开发利用提供技术支撑。     

Antioxidative activity of the crude extract of lignan glycosides from unroasted Burma black sesame meal

Sesame seed contains lignans and lignan glycosides. The antioxidative activity of the crude extract of lignan glycosides obtained from unroasted defatted black sesame seeds was investigated in this study. The components responsible for the antioxidative activity were also studied. The unroasted black sesame seeds, after defatted with n-hexane, were extracted with 80% methanolic solution to prepare for the crude extract of lignan glycosides. After chromatographic separation of this crude extract with octadecylsilane (ODS) column (2.5 cm i.d.×100 cm), four fractions (Fr1, Fr2, Fr3, Fr4) of the crude extract were obtained from the eluents of 25, 50, 75% aqueous methanolic solution and 100% methanol, respectively. Among them, Fr2 and Fr3 showed better antioxidative activity by 2,2-Diphenyl-1-picrylhydrazyl hydrate (DPPH) antioxidative assay. These two fractions were further purified by preparative HPLC (Hyperprep 100 C18 column; 20 mm i.d.×250 mm) and the main constituents were found to be lignan glycosides and some unknown brown materials. It was interesting to find that the brown materials (in Fr2) exhibited exceptional DPPH free radical scavenging effect, whereas the identified sesaminol triglucoside in Fr2 and sesaminol diglucoside in Fr3 possess no such activity. Using Cu⁺²-induced oxidation of human low-density lipoprotein (LDL) for the antioxidative assay, similar results were observed. Seaminol triglucoside and sesaminol diglucoside showed no effect on the extension of lag phase, while the brown materials had excellent inhibitory effect on the oxidation of LDL. Furthermore, natural antioxidants such as γ-tocopherol, sesamol and sesaminol were not detected in the crude extract of lignan glycosides. Our findings suggest that the brown materials present in Fr2 had a significant contribution to the antioxidative activity of the crude extract of lignan glycosides. Identification of the responsible components is underway.     

鹿茸水提物模拟胃肠消化物对小鼠脾细胞增殖的影响

研究鹿茸水提取物模拟胃肠消化物(AEVA-SGD)的分离组分对小鼠脾淋巴细胞增殖的影响。AEVA-SGD的分离采用凝胶层析法和RP-HPLC法。应用WST-8法检测各分离组分对小鼠脾淋巴细胞增殖的影响,采用高分辨质谱对有效分离组分进行初步鉴定。结果显示,AEVA-SGD经Sephadex LH-20分离后得到6个组分(A～F)。其中,组分F对小鼠脾细胞增殖的影响最为显著,可单独促进小鼠脾细胞增殖,但对ConA诱导的T淋巴细胞增殖有抑制作用。经RP-HPLC将组分F分为3个部分,初步鉴定组分F1为鸟嘌呤,F2为1-甲基鸟嘌呤和黄嘌呤,F3为多种小肽的混合物。组分F3对小鼠脾细胞增殖的影响最大,组分F对小鼠脾细胞增殖的影响是其各分离组分协同作用的结果。     

Cell wall proteins of Kluyveromyces fragilis: Surface and emulsifying properties

Yeast cell wall proteins were extracted from homogenized suspensions with 0.75 mol/l NaOH, yielding after precipitation at isoelectric pH a pale-brown sediment. Lyophilized sample was fractionated on Sephadex G-50 to yield three fractions (Fr 1, Fr 2 and Fr 3). Fr 1, which had the highest yields and protein content, showed the highest molecular weight and best surface properties. Fr 2 and Fr 3 were mainly composed by polysaccharide-protein complexes. Fr 1 was further subfractionated on Sephacryl S-300 to produce three fractions (Fr A, Fr B and Fr C). All subfractions, turned out to be highly foamy during evaporation. The highest yields were obtained for Fr A, which also showed the highest molecular weight. Fractions Fr 1 and their subfractions Fr B and Fr C exhibited good surface activity and high emulsifying activity. Emulsions prepared with these fractions were the most stable against creaming and coalescence. Fr 2 cream phase presented a gel-like behavior as a consequence of polysaccharides acting as thickening agents.     

板栗壳黄酮结构分析及其对胰脂肪酶活力的抑制作用

在分析板栗壳黄酮结构的基础上，研究其对胰脂肪酶的抑制作用及类型。采用醇提法提取板栗壳中的黄酮，并用AB-8大孔吸附树脂进行纯化，冻干后得到的黄酮含量为（107.50±1.00）mg/g，提取得率为（5.66±0.05）%。利用超高效液相色谱-四极杆/静电场轨道阱质谱联用技术对板栗壳黄酮进行结构分析，鉴定出8 种黄酮类化合物。采用对硝基苯酚法测定胰脂肪酶活力，分别考察板栗壳黄酮对胰脂肪酶的抑制效果及不同反应条件下板栗壳黄酮对胰脂肪酶活性的影响，结果表明，板栗壳黄酮对胰脂肪酶有较好的抑制作用，半抑制浓度（half maximal inhibitory concentration，IC50）为0.074 mg/mL，且使胰脂肪酶最适pH值向碱性偏移。通过Lineweaver-Burk双倒数作图法确定其抑制类型为非竞争性抑制，抑制常数Ki＝53.19 mg/mL。由此可见，板栗壳黄酮是一种效果良好的胰脂肪酶抑制剂。     

壳聚糖镍配合物对尿素吸附性能研究

合成了壳聚糖和金属元素Ni的配合物,通过红外光谱(IR)和紫外吸收光谱做了表征,并研究了壳聚糖-Ni对尿素的吸附性能,探讨了尿素初始质量浓度、反应pH、温度及时间对吸附量的影响。结果发现,壳聚糖-Ni配合物对尿素具有很好的吸附能力,当尿素溶液的初始浓度为3.5mg/mL,反应温度为20℃,pH为6.0,反应时间为10h时,壳聚糖-Ni对尿素的吸附性能最好。