紫番薯色素和紫洋葱色素的稳定性比较研究

文章研究了温度、pH值、金属离子、氧化剂和还原剂等对紫番薯色素和紫洋葱色素两种色素稳定性的影响。实验结果表明,紫番薯色素和紫洋葱色素的热稳定性好;紫洋葱色素在酸性环境下具有更好的稳定性,而紫番薯色素则在碱性环境下具有更好的稳定性;金属离子K+、Na+、Mg2+对两种色素的影响均不大,但Fe3+、Cu2+对色素的影响较大。紫番薯色素受氧化剂和还原剂的影响较大,而紫洋葱色素耐受氧化剂和还原剂的能力较强。总之,两种色素均具有较好的化学物理稳定性,具有良好的开发利用前景。     

亚临界水法提取新鲜紫薯中花色苷

以花色苷提取率为考察指标,采用亚临界水提取新鲜紫薯中天然色素花色苷。通过单因素实验和正交实验确定最优提取条件为：提取温度115℃、提取时间13min、液料比8∶1（mL∶g）、pH值3.0,在此条件下,新鲜紫薯中花色苷的提取率最高可以达到0.139mg·g^-1,与水提法相比,提取时间缩短了近5倍,产品色价提高了6.2%。     

Binding of metal cations to chemically modified wool and antimicrobial properties of the wool–metal complexes

Wool was modified by treatment with tannic acid (TA) or by acylation with ethylenediaminetetraacetic (EDTA) dianhydride. Kinetics of modification with TA and acylation with EDTA–dianhydride was investigated as a function of the reaction time. Wool displayed a higher breaking load and lower elongation at break as the degree of acylation increased. The absorption of metal cations (Ag⁺, Cu²⁺) by untreated and chemically modified wool was studied as a function of the kind of modifying agent, weight gain, and pH of the metal solution. Absorption of Ag⁺ and Cu²⁺ at alkaline pH increased with increasing weight gain of both TA and EDTA–dianhydride. The absorption of metal cations by untreated and TA‐treated wool below pH 7 was negligible. Acylation with EDTA–dianhydride enabled wool to absorb and bind significant amounts of metal cations at acidic and neutral pHs. The wool–Ag complexes exhibited low levels of metal desorption at acidic pH, irrespective of chemical modification. Higher levels of metal desorption were shown by wool–Cu and wool–EDTA–Cu complexes. Wool–Ag complexes exhibited prominent antimicrobial activity against Cornebacterium and E. coli. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3513–3519, 2001     

微波辅助提取紫薯花青素的研究

文章以紫薯为原料,在微波条件下萃取其花青素,探讨了微波的辐射时间,温度,液固比,提取剂浓度对紫薯花青素萃取的影响,并采用大孔树脂AB-8纯化提取液,将纯化后的提取液进行反相高效液相色谱分析其成分。实验结果表明,紫薯花青素微波最佳提取条件为:辐射时间60 s,温度50℃,液固比40∶1,提取剂为1%HCl-95%乙醇溶液,最佳酸醇比为50∶50。     

Effects of pretreatments on properties of microwave-vacuum drying of sweet potato slices

Abstract

Pretreatments of blanching (BL); osmotic dehydration at 35°Brix of sucrose (OD); ultrasound in distilled water (UD), and ultrasound-assisted osmotic dehydration (UO) were carried out for microwave-vacuum drying (MVD) orange- and purple-flesh sweet potato slices, and effects on their properties were investigated in this study. UO had improvements effects on water loss, solid gain, and relaxation time of the samples compared to other pretreatments. Low-field nuclear magnetic resonance results offered a view of water state concerning the effects of different pretreatments on sweet potato. UD treatment following by BL showed a long relaxation time corresponding to the weaker degree of bound hydrogen proton or the greater freedom degree of hydrogen comparing to other pretreated samples. Differential scanning calorimetry parameters appeared to be sensitive to pretreatments by increased Tg value compared to blanched sample. The value of Tg shows that it does not depend only of the water content but also on the experimental conditions (pretreatments). The dried sweet potato exhibited amorphous structures as evidenced by the X-ray diffractograms due to the BL treatment and MVD. Concentration of total phenolics and anthocyanins were high in purple sweet potatoes, whereas content of vitamin C and total carotenoid were high in orange ones. Application of UO is suitable for retention of bioactive compound and stability of MVD sweet potato slices.     

Preparation of metal‐containing protein fibers and their antimicrobial properties

Bombyx mori silk, Antheraea pernyi silk, and wool fibers were chemically modified by treatment with tannic acid (TA) or by acylation with ethylenediaminetetraacetic (EDTA) dianhydride. Kinetics of TA loading or acylation with EDTA‐dianhydride varied from fiber to fiber. B. mori silk and wool displayed the highest weight gains with TA and EDTA‐dianhydride, respectively. The uptake of different metal ions (Ag⁺, Cu²⁺, Co²⁺) by protein fibers, either untreated or chemically modified, was studied as a function of weight gain and pH of the aqueous metal solution. Below pH 7, absorption of metal ions by untreated and TA‐treated fibers was negligible. Acylation with EDTA‐dianhydride enabled protein fibers to absorb and bind significant amounts of metal ions in the acidic and neutral pH range. The levels of metal desorption at acidic pH depended on the fiber‐metal combination. Untreated protein fibers usually displayed the lowest stability of the metal complex. Metal complexes with protein fibers exhibited prominent antimicrobial activity against the plant pathogen Cornebacterium. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 638–644, 2003     

Absorption of metal cations by modified B. mori silk and preparation of fabrics with antimicrobial activity

Silk fabrics were modified by treatment with tannic acid (TA) solution or by acylation with ethylenediaminetetraacetic (EDTA) dianhydride. Kinetics of modification with TA and acylation with EDTA–dianhydride was investigated. The physico‐mechanical properties of silk fabrics acylated with EDTA–dianhydride remained unchanged regardless of chemical modification. The absorption of metal cations (Ag⁺, Cu²⁺) by untreated and modified silk fabrics was studied as a function of the kind of modifying agent, weight gain, and pH of the metal solution. The absorption of Cu²⁺ at alkaline pH was not significantly influenced by chemical modification of the silk substrate. The absorption of Ag⁺ by acylated silk remained at a level as low as untreated silk, while was enhanced by TA. The higher the content of TA, the higher the absorption of Ag⁺. With respect to the pH of the metal solution, the acylation with EDTA–dianhydride enabled silk to absorb and bind metal cations even in the acidic and neutral pH range, where tannic acid had no effect. Medium to high levels of metal desorption were exhibited by untreated and modified silk fabrics towards the metal cations, with the only exception of the silk–tannic acid–Ag complex, which displayed an extraordinary stability. All metal‐containing silks exhibited significant antibacterial activity. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 297–303, 2001     

紫甘薯花青素的功能特性研究

采用抗坏血酸和BHT作为对照,测定了紫甘薯花青素的还原能力、对食用油脂的抗氧化能力及对.OH自由基和O2-.自由基的清除能力。结果表明,当浓度大到0.5mg/mL时,其还原能力接近抗坏血酸;在豆油基质中紫甘薯花青素的抗氧化活性高于BHT;在试验质量浓度范围内,紫甘薯花青素对.OH自由基的清除率为81.2%,活性略低于抗坏血酸;对O2-.自由基的清除率可达91.3%,活性强于BHT。     

Anthocyanins/chitosan films doped by nano zinc oxide for active and intelligent packaging: comparison of anthocyanins source from purple tomato or black wolfberry

The multifunctional films was prepared by blending chitosan and nano-ZnO with purple tomato anthocyanins or black wolfberry anthocyanins. The properties of films functioned by anthocyanins source and nano-ZnO content were studied. It was found purple tomato anthocyanins showed more significant color change against pH than black wolfberry anthocyanins. The nano-ZnO were widely dispersed in matrix and enhanced the compatibility of anthocyanins with chitosan. However, the anthocyanins source influenced the properties of the films more slightly than nano-ZnO addition. The tensile strength, antioxidant and antibacterial effects of the chitosan films dramatically increased after cooperated by nano-ZnO and anthocyanins, which also enhanced with increase of nano-ZnO content, whereas the elongation at break of the composite films decreased. Especially, the anthocyanin and nano-ZnO promoted the antibacterial activity of films synergistically. Composite films made from black wolfberry anthocyanins exhibited higher mechanical performance than those made from purple tomato anthocyanins but weaker antibacterial effects. The purple tomato anthocyanins/chitosan and nano-ZnO/purple tomato anthocyanins/chitosan films effectively reflected pork spoilage, changing their colors from dark green to brown, indicating the potential for applications in active and intelligent food packaging.     

N-Hydroxy-N,N'-diarylbenzamidine as a New Extraction System for Vanadium(V) in the Presence of Carboxylic Acids,Phenols, Aldehydes,Thiocyanate, and Azide

Abstract

N- Hydroxy- N -m-tolyl-N'-(2-methyl-5-chloro) phenyl-p-toluamidine hydrochloride (HTMCPTH) has been used as a new and convenient extraction system for vanadium(V) in the presence of all organic compounds containing -COOH, -CHO, -OH (phenolic) groups, and also in SCN^? and N₃ ^? media. HTMCPTH reacts with vanadium(V) to give a 1:2 complex (having a flat peak in the region 550–590 nm with 750 l/mole/cm). In the presence of various adduct-forming substances, a quantitative recovery of metal and marked absorbance enhancement into chloroform have been observed on the basis of formation and hyper- and bathochromic shift of the hydrophobic species formed. The extracting species is found to be 1:2:1 (V: HTMCPTH: RCOOH/ ArCOOH/ArOH/ArCHO) and 1:2:2 (V: HTMCPTH: SCN^?/N₃ ^?) mixed complexes. The nature of adduct-forming substances has a large effect on absorbance and the λ_max of mixed complexes. The effective molar absorbances lie between 3500 to 8000 l/mole/cm. Fe^{3 +}, Cu^{2 +}, Zn^{2 +}, Ni^{2 +}, Co^{2 +}, Mn^{2 +}, Al^{3 +}, Cr^{3 +}, Ti^{4 +}, Zr^{4 +}, Mo^{6 +}, etc. do not interfere. The method is accurately applied for determination of vanadium content in BCS steels.     

Extraction of anthocyanins from Aronia melanocarpa skin waste as a sustainable source of natural colorants

Aronia melanocarpa (Michx.) Elliott (black chokeberry) skin wastes from the production of Aronia fruit juice were extracted using a batch extraction method and a novel integrated extraction‐adsorption process. Optimum conditions for batch extraction were as follows: 60 °C, 3 h, acid (0.1% v/v hydrochloric acid), biomass‐to‐solvent ratio of 1:16, and biomass‐to‐solid phase extraction resin ratio of 1:1. The integrated extraction‐adsorption process gave improved anthocyanin yields of higher quality when the process was performed for 3 h without cooling of the circulating liquid, and with a flow rate of 1.3 ml s^?1. Overall, the new method showed better anthocyanin yield and purity compared with the batch method, increasing the extraction yield by ca. 20% (5.25→6.34 mg g^?1 dry weight of pomace) and increasing anthocyanin content by ca. 40% (19.9%→28.4% w/w dry weight of extract). This method also simplified the process as three steps were eliminated saving time and energy. Furthermore, the integrated extraction‐adsorption method is industrially scalable to produce large quantities of anthocyanins. In the batch method, anthocyanins present in A. melanocarpa skins were identified as cyanidin‐3‐O‐galactoside (38.8%), cyanidin‐3‐O‐arabinoside (6.4%), cyanidin‐3‐O‐glucoside (3.6%), cyanidin‐3‐O‐xyloside (0.5%), and the cyanidin aglycon (50.7%); in the continuous method, anthocyanin content was cyanidin‐3‐O‐galactoside (45.7%), cyanidin‐3‐O‐arabinoside (16%), cyanidin‐3‐O‐glucoside (3.6%), cyanidin‐3‐O‐xyloside (2.7%), and the cyanidin aglycon (32%). The integrated extraction‐adsorption method was shown to be substantially less susceptible to acid‐catalysed anthocyanin decomposition processes. All anthocyanins were derived from only one anthocyanidin parent structure (cyanidin), and only monosaccharide glycosides were identified, which is unusual when compared with other berries that typically have more anthocyanidins and/or greater glycosylation diversity.     

A review on the chemistry,coordination, structure and biological properties of 1-(acyl/aroyl)-3-(substituted) thioureas

This review provides an overview of the chemistry, structure and potential applications of 1-(acyl/aroyl)-3-(mono-substituted) and 1-(acyl/aroyl)-3,3-(di-substituted) thioureas, with general formula R¹C(O)N₍₁₎HC(S)N₍₃₎R²R³. In recent years, the title compounds have found extensive applications as ligands in coordination chemistry. The effect that nitrogen substituents exert on the intra- and intermolecular hydrogen-bonding interactions is discussed, including their role on the coordination properties displayed by these ligands. Novel applications of transition metal complexes bearing 1-(acyl/aroyl)-3-(mono- and di-substituted) thioureas are introduced. Biological aspects are also highlighted. As recently demonstrated, high-throughput screening assay and structure–activity analyses are feasible for this class of compounds. The chemical versatility of 1-(acyl)-3-(substituted) thiourea molecules and the derived metal complexes, together with the possibility of determining detailed structural properties, join biological applications in a promising interdisciplinary approach. The bibliography includes 382 references with emphasis on the literature appearing after 2007.     

Effect of high fat/high erucic acid diet on phosphatidate synthesis and phosphatidate phosphatase in the subcellular fractions of rat heart and liver

Rats of weaning age were fed for a period of 1,3 or 6 weeks either a control diet (laboratory stock diet) or a semisynthetic diet containing 20% by weight of either mustard seed oil (1/3 of the total fatty acids were comprised of erucic acid) or corn oil (2/3 of the total fatty acids consisted of linoleic acid). Mitochondrial and microsomal fractions were isolated from the hearts and livers of these rats, and the rate of acylation ofsn-[U-¹⁴C] glycerol 3-phosphate (P) was examined using palmitoyl-CoA or erucoyl-CoA as the acyl donor. In addition, activities of phosphatidate phosphatase of the mitochondrial, microsomal and soluble fractions were assayed. Studies on the acylation of glycerol 3-P with palmitoyl-CoA demonstrated that feeding of the high fat/high erucic acid diet for 1,3 or 6 weeks significantly increased the rate of formation of monoacylglycerol 3-P by the cardiac subcellular fractions as compared to the control. The rate of formation of diacylglycerol 3-P also increased but to a lesser degree. Feeding the high fat/high linoleic acid diet tended to increase acylation of glycerol 3-P by cardiac subcellular fractions. However, neither high fat diet influenced acyltransferase activities of the hepatic subcellular fractions or phosphatase activities of the cardiac and hepatic fractions. Studies on the acylation of glycerol 3-P with erucoyl-CoA demonstrated that the rate of acylation was ca. 1/10 that measured using palmitoyl-CoA in all experiments; in particular, the formation of diacylglycerol 3-P was extremely slow, suggesting that erucoyl-CoA is an unsuitable substrate for the position-2 of the monoacylglycerol 3-P. The rate of acylation by the cardiac and hepatic subcellular fractions was not influenced by the feeding of the high-fat diets. The rate of glycerol 3-P acylation by both cardiac and hepatic mitochondrial fraction was ca. 2/3 of the rate of acylation by the respective microsomal fraction. In addition, the ratio of monoacyl-to diacylglycerol 3-P synthesized by the mitochondrial fraction was smaller than that by the microsomal fraction. These results suggest that acylation of glycerol 3-P by the mitochondrial cannot be attributed to the action of the contaminating microsomal enzymes.     

Synthesis of chelating resins with iminodiacetic acid and its wastewater treatment application

The chelating resins have high potential applications for the selective removal and recovery of metal ions from industrial waste solutions. The hydrophilic acrylate monomer with the iminodiacetic acid chelating group was prepared from glycidyl methacrylate and iminodiacetic acid at 60°C. The microbeads, prepared from acrylate monomer with the iminodiacetic acid chelating group, were employed by inversion suspension polymerization. In the pH range of 2–6, a reasonably good equilibrium sorption capacity is maintained for Cr³⁺ (ca. 2.7 mmol/g) and Cu²⁺ (ca. 1.8 mmol/g) in the chelating resins. The adsorption of Cd²⁺ and Pb²⁺ on microbeads is clearly affected by the pH of the solution, such that these ions' adsorption capacity increased with the pH of the aqueous solution. The adsorption of Cd²⁺ (ca. 1.25–1.87 mmol/g) and Pb²⁺ (ca. 0.99–1.89 mmol/g) showed a maximum at approximately pH = 5 and 6, respectively. The adsorption isotherms of Cr³⁺ and Cu²⁺ adsorbed on microbeads were following the Langmuir isotherm, but the adsorption behavior of Cd²⁺ and Pb²⁺ were not. The concentration of alkaline earth–metal cations on the range of 0–200 ppm had no influence on metal ions adsorbed capacity of chelating resins. Additionally, NTA (nitrilotriacetic acid) had no significant influence on metal ion adsorption by chelating resins. Furthermore, phenol pollutant can be adsorbed effectively by metal ions chelated microbeads; therefore, the microbeads were useful not only in recovering metal ions but also in the treating phenol pollutants in wastewater. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1353–1362, 2002; DOI 10.1002/app.10243     

Formation of thermosensitive water‐soluble copolymers with phosphinic acid groups and the thermosensitivity of the copolymers and copolymer/metal complexes

Thermosensitive and water‐soluble copolymers were prepared through the copolymerization of acryloyloxypropyl phosphinic acid (APPA) and N‐isopropyl acrylamide (NIPAAm). The thermosensitivity of the copolymers and copolymer/metal complexes was studied. The APPA–NIPAAm copolymers with less than 11 mol % APPA moiety had a lower critical solution temperature (LCST) of approximately 45°C, but the APPA–NIPAAm copolymers with greater than 21 mol % APPA moiety had no LCST from 25 to 55°C. The APPA–NIPAAm copolymers had a higher adsorption capacity for Sm³⁺, Nd³⁺, and La³⁺ than for Cu²⁺, Ni²⁺ and Co²⁺. The APPA–NIPAAm (10:90) copolymer/metal (Sm³⁺, Nd³⁺, or La³⁺) complexes became water‐insoluble above 45°C at pH 6–7, but the APPA–NIPAAm (10:90) copolymer/metal (Cu²⁺,Ni²⁺, or Co²⁺) complexes were water‐soluble from 25 to 55°C at pH 6–7. The temperature at which both the APPA–NIPAAm copolymers and the copolymer/metal complexes became water‐insoluble increased as the pH values of the solutions increased. The APPA–NIPAAm copolymers were able to separate metal ions from their mixed solutions when the temperature of the solutions was changed; this was followed by centrifugation of the copolymer/metal complexes after the copolymers were added to the metal solutions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 116–125, 2004     

A study on microwave vacuum dried re-structured lychee (Litchi chinensis Sonn.) mixed with purple sweet potato (Ipomoea batatas) snacks

Lychee high sugar content is the biggest disadvantage in drying processes which limits the production of dried lychee for snacks. Purple sweet potato was blended with lychee to develop new snacks using microwave drying techniques. Optimal ingredients proportion and drying conditions were evaluated in terms of their influences on product's organoleptic properties (crispness and mouth feel) and quality attribute. The results showed that addition of 4% potato starch to paste mixture improved the crispness of dried chips. Also, the optimum ratio between purple sweet potato and lychee to produce desirable snacks was found to be 7:3 (W:W). In case of the drying parameters, the high power density resulted in shorter drying time and chips with improved nutrients. Generally speaking the method employed for the drying operation produced no browning throughout the experiments. Therefore, this research has a good future for industrial application.     

Novel Polymeric Metal Complexes of 2,7-Bis[2-(2′-Pyridyl) Benzimidazole]- 9,9′-Dioctylfluorene with Cu(II)and Zn(II): Synthesis and Luminescence Properties

Abstract  A novel ligand, 2,7-bis[2-(2′-Pyridyl)benzimidazole]- 9,9′-dioctylfluorene (BPDOF) and its polymeric complexes with copper(II) and zinc(II) were successfully synthesized and characterized by ¹H NMR, FT-IR, elemental analysis, UV-vis, conductivity measurements and gel permeation chromatography. The UV–vis absorption, fluorescence spectra, and thermal properties of these complexes were investigated at room temperature. The experimental results show that polymeric metal complexes BPDOF-Cu(II) and BPDOF-Zn(II) emit purple/green luminescence at 430 and 509 nm in DMF solution and emit green luminescence at 495 and 527 nm in the solid state. Thermal properties measurement and analysis show that they have good thermal stabilities. Graphical Abstract  Synthesis route: 2,7-bis[2-(2′-Pyridyl) benzimidazole]- 9,9′-dioctylfluorene (BPDOF) was synthesized using 2-(2′-Pyridyl)benzimidazole and 2,7-dibromo-9,9′-dioctylfluorene by Ullmann condensation. Polymeric metal complexes of the corresponding were synthesized with CuCl₂ · 2H₂O, ZnCl₂.      

Dietary Protection Against Free Radicals: A Case for Multiple Testing to Establish Structure-activity Relationships for Antioxidant Potential of Anthocyanic Plant Species

DNA damage by reactive species is associated with susceptibility to chronic human degenerative disorders. Anthocyanins are naturally occurring antioxidants, that may prevent or reverse such damage. There is considerable interest in anthocyanic food plants as good dietary sources, with the potential for reducing susceptibility to chronic disease. While structure-activity relationships have provided guidelines on molecular structure in relation to free hydroxyl-radical scavenging, this may not cover the situation in food plants where the anthocyanins are part of a complex mixture, and may be part of complex structures, including anthocyanic vacuolar inclusions (AVIs). Additionally, new analytical methods have revealed new structures in previously-studied materials. We have compared the antioxidant activities of extracts from six anthocyanin-rich edible plants (red cabbage, red lettuce, blueberries, pansies, purple sweetpotato skin, purple sweetpotato flesh and Maori potato flesh) using three chemical assays (DPPH, TRAP and ORAC), and the in vitro Comet assay. Extracts from the flowering plant, lisianthus, were used for comparison. The extracts showed differential effects in the chemical assays, suggesting that closely related structures have different affinities to scavenge different reactive species. Integration of anthocyanins to an AVI led to more sustained radical scavenging activity as compared with the free anthocyanin. All but the red lettuce extract could reduce endogenous DNA damage in HT-29 colon cancer cells. However, while extracts from purple sweetpotato skin and flesh, Maori potato and pansies, protected cells against subsequent challenge by hydrogen peroxide at 0°C, red cabbage extracts were pro-oxidant, while other extracts had no effect. When the peroxide challenge was at 37°C, all of the extracts appeared pro-oxidant. Maori potato extract, consistently the weakest antioxidant in all the chemical assays, was more effective in the Comet assays. These results highlight the dangers of generalising to potential health benefits, based solely on identification of high anthocyanic content in plants, results of a single antioxidant assay and traditional approaches to structure activity relationships. Subsequent studies might usefully consider complex mixtures and a battery of assays.     

Anthocyanin Extract from Purple Sweet Potato Exacerbate Mitophagy to Ameliorate Pyroptosis in Klebsiella pneumoniae Infection

Given the rise of morbidity and mortality caused by Klebsiella pneumoniae (KP), the increasing number of strains resistant to antibiotics, and the emergence of hypervirulent Klebsiella pneumonia, treatment of KP infection becomes difficult; thus, novel drugs are necessary for treatment. Anthocyanins, or natural flavonoids, have an extensive effect against bacterial infection. However, few studies on anti-KP are identified. Here, we evaluated the therapeutic effect of purple sweet potato anthocyanins (PSPAs) on KP, containing 98.7% delphinidin 3-sambubioside. Results showed that KP-infected mice after PSPAs treatment manifested decreased mortality, weakened lung injury, dampened inflammatory responses, and reduced bacterial systemic dissemination in vivo. In Vitro, PSPAs significantly suppressed pyroptosis and restricted NLRP3 inflammasome activation in alveolar macrophages infected with KP. As for the mechanism, PSPAs promote mitophagy by recruiting Parkin to the mitochondria. PSPAs-conferred mitophagy increased mitochondrial membrane potential and decreased mitochondrial reactive oxygen species and mitochondrial DNA, resulting in impaired NLRP3 inflammasome activation. In addition, the promotion of mitophagy by PSPAs required the Nrf2 signaling pathway. Collectively, these findings suggest that PSPAs are a potential option for the treatment of KP infection.