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The improvement of a surface plasmon resonance (SPR)-based immunoassay for the detection of traces of egg-based fining agents in red wines is herein described. The latter represents an extension of a previously developed direct assay targeted to the detection of ovalbumin (OVA) as marker of the presence of egg white powder residues, a typical fining agent utilized by the winery industry. In this paper, a suitable pre-treatment procedure was optimized for the sensitive detection of OVA at sub-ppm levels in red wines fortified with egg-white powder, by using an immunoassay proved to be reliable for both white and rosee wines. A red wine from Chianti grapes selected as reference matrix was artificially contaminated with egg-white powder before undergoing different sample purification. Several purification strategies were investigated and tested in order to challenge the limit of detection (LOD) obtained with the methods currently in use for egg allergen detection. Finally, the optimized two-step pre-treatment, combining polyvinylpolypyrrolidone-based purification and size exclusion chromatography, enabled to achieve an LOD in red wine as low as 0.2 μg/mL. The optimized SPR-based method met the method performance criteria issued by the International Organization of Vine and Wine (OIV) concerning the minimum sensitivity required for the analyses of potentially allergenic fining agent proteins in wines, confirming the biosensor as promising tool to monitor the residual contamination level of fined red wines.

A polyvinylpolypyrrolidone (PVPP) supported Brønsted acidic catalyst ([PVPP-BS]HSO4) was prepared by coupling SO3H-functionalized polyvinylpolypyrrolidone with H2SO4in this work. After the characterization through FT-IR, FESEM, TG, BET, and elemental analysis, it was found that 1,4-butane sultone (BS) and sulfuric acid reacted with PVPP and were immobilized on PVPP surface. The prepared[PVPP-BS]HSO4catalyst shows high catalytic activity for a series of esterification reactions and could be separated from the reacted mixture easily. Moreover, this catalyst could be recycled and reused for six times without significant loss of catalytic performance.

This work deals with the screening of seven lignocellulosic residues: chestnut and pistachio shells, grass, leaf fruit, vine leaf, and, red and white grape stems as feedstocks for the release of ferulic acid by sequential pre-treatment with dilute sulfuric acid and alkaline hydrolysis with NaOH. Grass showed the highest concentration of both ferulic acid (312.0 mg/L) and p-coumaric acid (542.7 mg/L). Ferulic acid was further purified from the brown liquor by ethanol extraction, or adsorption with activated charcoal or polyvinylpolypyrrolidone (PVPP). Finally, streams coming from these treatments were fermented by Streptomyces setonii after nutrients supplementation in solid state fermentation. Ferulic acid treated with PVPP presented the best results, achieving 92.1 mg/L 4-vinyl guaiacol (3-methoxy 4-hydroxystyrene) after 30 h of fermentation (QP = 3.071 mg/L h; YP/S = 0.44 g/g), thus confirming the efficacy of the materials as renewable feedstocks, and the treatments for producing natural food additives with high add value.

A variety of fining agents are commercially available to the wine industry, including proteins and inorganic ion exchangers. These fining agents are essentially used to control the levels of phenolics in wine, but they also have the potential to interact with other wine components, most often as a side effect. They are therefore expected to influence, at least in part, the potential for wine protein haze formation. Six common fining agents—casein, egg albumin, isinglass, chitosan, chitin, and polyvinylpolypyrrolidone (PVPP)—were analyzed to assess their effects on wine protein haze-forming potential and on the levels of proteins and phenolic compounds in a Muscat of Alexandria wine. Bentonite was selected as the positive control, whereas nonfined wine was used as the negative control. Differential results were detected among the selected fining agents when compared to the controls. Egg albumin and chitosan, although incapable of stabilizing the wine, originated a small but significant decrease in the protein haze formed, whereas chitosan and PVPP were second to bentonite in removing the most polyphenols from the wine. Thus, while chitosan fining removes a fraction of polyphenols from the wine and seems to induce a small decrease in its haze-forming potential, PVPP eliminates more polyphenols while leaving its haze-forming potential unaltered. The fining agents analyzed did not significantly affect wine protein content but did remove considerable levels of polyphenols and presented no apparent effect on protein stabilization of the fined wines. Results show that these fining agents do not contribute significantly to protein stabilization in white wines, confirming that bentonite was the most effective agent in wine protein stabilization.

A highly efficient method for the acylation of alcohols, phenols and trimethylsilyl ethers with acetic anhydride is described using polyvinylpolypyrrolidone-bound boron trifluoride (PVPP-BF 3 ) under mild and heterogeneous conditions at room temperature in good to excellent yields. The polyvinylpolypyrrolidone-boron trifluoride complex shows more water tolerant, non-corrosive and stable solid catalyst elevated Lewis acid properties.

A highly efficient method for the oxidation of sulfides to sulfones using polyvinylpolypyrrolidone-supported boron trifluoride (PVPP-BF3) in the presence of (35%) hydrogen peroxide has been developed. This procedure cleanly oxidizes dialkyl and alkyl aryl sulfides to the corresponding sulfones in excellent yields at room temperature.

The anti-allergic effects of the edible brown alga, Ecklonia stolonifera, are known to affect both degranulation in KU812 cells and anti-inflammatory properties of RAW 264.7 cells. Additional anti-allergic effects of E. stolonifera extracts were therefore investigated by examining the inhibitory effects of algal extracts on enzymes associated with eicosanoid synthesis, the inflammation reaction, and anti-degranulation activity in rat basophilic leukemia (RBL) -2H3 cells. A methanol: chloroform (1: 2, v/v) extract of the alga inhibited the enzyme activities and degranulation in stimulated RBL cells in a dose-dependent manner. When phenolic compounds were removed from the M/C extract by treatment with polyvinylpolypyrrolidone resin, the obtained residue did not exhibit the same inhibitory activities. These results imply that the active compounds present in the M/C extract may be phenolic compounds, such as phlorotannins. In addition, the novel anti-allergic effects of E. stolonifera that contributed to inhibiting the enzymatic activities were also clarified.

Highly efficient method for the preparation ofN-tert-butyl amides by reaction of nitriles withtert-butyl acetate is described using polyvinylpolypyrrolidone-supported boron trifluoride (PVPP-BF3) at 70°C in good to excellent yields. Selective amidation of benzonitrile in the presence of acetonitrile was also achieved. polyvinylpolypyrrolidone-boron trifluoride complex shows non-corrosive and stable solid catalyst elevated Lewis acid property.

Effects of highly hygroscopic sorbitol, citric acid, sodium carboxymethyl cellulose or polyvinylpolypyrrolidone, on the hydrolysis of simvastatin in tablets at 25°/90% RH were studied. The simvastatin tablets were prepared by direct powder compression. Simvastatin and its hydrolyte, simvastatin acid, were quantitatively analysed by high performance liquid chromotography. The hygroscopicity, water swelling ratio, water solubility and pH of the four hygroscopic excipients were investigated. During the investigation period, the weight gain of sorbitol or citric acid increased faster than that of polyvinylpolypyrrolidone or sodium carboxymethyl cellulose at 25°/90% RH, accordingly, the moisture sorption of the tablets containing citric acid or sorbitol (T-3 or T-6) were more than that of the tablets containing sodium carboxymethyl cellulose or polyvinylpolypyrrolidone (T-4 or T-5). The increase of simvastatin acid content with time at 25°/90% RH for the tablets was in the following order: T-6 < T-4 < T-3 < T-5. The effects of the four excipients on the hydrolysis of simvastatin in tablet were related to not only their hygroscopicity but also their other properties, such as moisture retention capacity and pH. Sorbitol as hygroscopic excipient in tablet can most effectively prevent the hydrolysis of simvastatin in tablet.

A new method to determine the iodothyronines, 3,3′,5-triiodo-L-thyronine (T3), 3,3′,5,5′-tetraiodo-L-thyronine (L-thyroxine, T4), and 3,3′,5′-triiodo-L-thyronine (reverse-T3, rT3), in dietary supplements containing dried thyroid by high-performance liquid chromatography was developed using a pre-column derivative with 4-fluoro-7-nitrobenzofurazan (NBD-F) without using LC/MS. T3, T4, and rT3 were released from dried thyroid in dietary supplements by using protease. The protease reaction was finished in 18 h at 37 °C. Iodothyronines released from dried thyroid were treated on a polyvinylpolypyrrolidone (PVPP) column. Iodothyronines adsorbed on PVPP were eluted with 60% acetonitorile. Iodothyronines present in the eluate from the PVPP column were then derivatized with NBD-F. The reaction of iodothyronines with NBD-F was completed in 30 min at 60 °C. These derivatives were measured by HPLC using an octadecylsilane column with a fluorescence detector. Phosphoric acid (0.1%) was added to 630 ml of acetonitrile to a final volume of 1,000 ml, and the mixture was used as the mobile phase. The excitation wavelength on the fluorescence detector was 470 nm, and the emission wavelength was 530 nm. The linearity of iodothyronines as a coefficient of the correlation value was 0.999, and the quantitation limit of iodothyronines was 0.001 μg/ml. The results confirmed that dried thyroid was added to seven dietary supplements. The recovery rate was in the range of 80.8–104.6%, 81.4–103.7%, and 82.2–104.5% for T3, T4, and rT3, respectively. Previously, dried thyroid in dietary supplements was examined by the combination of measuring T3 and T4 by LC/MS and confirmation of epithelial nuclei forming follicles by a microscope. However, microscopic confirmation of epithelial nuclei forming follicles can be complicated by physical alteration during dietary supplement processing. We suggest that the present of dried thyroid in dietary supplements can be confirmed by detecting rT3 without a microscope.

Polyvinylpolypyrrolidone-supported hydrogen peroxide (PVP-H2O2), silica sulfuric acid (SiO2OSO3H) and catalytic amounts of ammonium bromide (NH4Br) are introduced as green media for the in situ generation of bromoniume ion (Br+), which was applied for the selective oxidation of sulfides and alcohols into sulfoxides and carbonyl compounds, respectively. The oxidation reactions were carried out heterogeneously in acetonitrile, as solvent, at room temperature (oxidation of sulfides) and/or 60 °C (oxidation of alcohols).

In this study, the content of soluble, free forms of phenolic compounds (total phenolics, flavonoids, PVPP (polyvinylpolypyrrolidone) bound phenolics, proanthocyanidins and phenolic acids), as well as the content of carotenoids and tocopherols, were determined in whole grains of bread and durum wheat, rye, hull-less barley and hull-less oat, each represented with four genotypes. Antioxidant activity was evaluated as radical scavenging activity with DPPH (2,2-diphenyl-1-picrylhydrazyl) reagent, as well as by hydrogen transfer reaction (reduction power) based on the reduction of Fe 3+ . Generally, a considerable variation in antioxidant activities and phytochemical contents was observed between the cereals. Remarkably higher DPPH radical scavenging ability and reducing power were detected in hull-less barley, followed by rye and hull-less oat and durum and bread wheat, indicating that small grain species have different major antioxidants with different properties. Hull-less barley had the highest content of total free phenols, flavonoids, PVPP bound phenolics and contained flavan-3-ols, not found in other species. Hull-less oat had the highest content of tocopherols, very high content of yellow pigments and PVPP bound phenolics. Ferulic acid was the major free phenolic acid in small grain cereals tested. The relationship between the content of soluble phenols, as well as reducing power and DPPH • scavenging activity are also considered.

North American ginseng (NAG) (Panax quinquefolius L.) is a medicinally important plant with multiple uses in the natural health product industry. As seed propagation is time-consuming because of the slow growth cycle of the plant, in vitro propagation using a bioreactor system was evaluated as an effective approach to accelerate plant production. An efficient method was developed to multiply nodal explants of NAG using liquid-culture medium and a simple temporary immersion culture vessel. The effects of plant growth regulators, phenolics, and chemical additives (activated charcoal, melatonin, polyvinylpolypyrrolidone, and ascorbic acid) were evaluated on in vitro-grown NAG plants. The highest number (12) of shoots per single node was induced in half-strength Schenk and Hildebrandt basal medium containing 2.5 mg/l kinetin, in which 81% of the cultured nodes responded. In a culture medium with 0.5 mg/l α-naphthalene acetic acid (NAA), roots were induced in 78% of the explants compared to 50% with a medium containing indole-3-acetic acid. All of the resulting plants appeared phenotypically normal, and 93% of the rooted plants were established in the greenhouse. Phenolic production increased significantly (P < 0.05) over a 4-wk culture period with a negative impact on growth and proliferation. Activated charcoal (AC; 50 mg/l) significantly reduced total phenolic content and was the most effective treatment for increasing shoot proliferation. Shoot production increased as the phenolic content of the cultures decreased. The most effective treatment for NAG development from cultured nodal explants in the bioreactor was 2.5 mg/l kinetin, 0.5 mg/l NAA, and 50 mg/l AC in liquid culture medium. This protocol may be useful in providing NAG tissues or plants for a range of ginseng-based natural health products.

An improved single-step protocol has been developed for extracting pure community humic substance-free DNA from alkaline soils and sediments. The method is based on direct cell lysis in the presence of powdered activated charcoal and polyvinylpolypyrrolidone followed by precipitation with polyethyleneglycol and isopropanol. The strategy allows simultaneous isolation and purification of DNA while minimizing the loss of DNA with respect to other available protocols for metagenomic DNA extraction. Moreover, the purity levels are significant, which are difficult to attain with any of the methods reported in the literature for DNA extraction from soils. The DNA thus extracted was free from humic substances and, therefore, could be processed for restriction digestion, PCR amplification as well as for the construction of metagenomic libraries.

Adsorbent is one of the most important factors for separation efficiency in fixed-bed purification techniques. The adsorption behavior of catechins and caffeine onto polyvinylpolypyrrolidone (PVPP) was investigated by static adsorption tests. The results showed that catechins rather than caffeine were preferred to adsorb onto PVPP since the adsorption selectivity coefficient of total catechins vs caffeine was around 22.5, and that adsorption of catechins could be described by the pseudo-second-order model. Adsorption amount of caffeine onto PVPP in green tea extracts solution was much higher than that in purified caffeine solution although the initial concentration of caffeine was similar in the two solutions, indicating the caffeine might be attached with catechins which were adsorbed by PVPP instead of being adsorbed by PVPP directly. The results also showed that the adsorption capacity of catechins and caffeine decreased with an increase in temperature, and that Freundlich and Langmuir models were both suitable for describing the isothermal adsorption of catechins, but not suitable for caffeine. The predicted maximum monolayer adsorption capacity of total catechins by PVPP was 671.77 mg g(-1) at 20 °C, which was significantly higher than that by other reported adsorbents. The thermodynamics analyses indicated that the adsorption of catechins onto PVPP was a spontaneous and exothermic physisorption process, revealing lower temperature was favorable for the adsorption of catechins. Elution tests showed that the desorption rates of catechins and caffeine were higher than 91% and 99% after two elution stages; in detail, almost all of the caffeine could be washed down at the water eluting stage, while catechins could be recovered at the dimethyl sulfoxide/ethanol solution eluting stage. Thus, the PVPP could be used as an excellent alternative adsorbent candidate for separating catechins from crude tea extracts, although some investigations, such as exploring the new eluants with low boiling point and high desorption efficiency, should be conducted furthermore.

Mild and efficient method for bromination of electron-rich aromatic compounds is described using polyvinylpolypyrrolidone–bromine complex (PVPP–Br 2 ). The reaction proceeded smoothly with phenols and N , N -alkylated amines to afford the corresponding monobrominated product in good yields at ambient temperature.

J. Inst. Brew. 117(3), 329–334, 2011 The tannoid content test, introduced by Chapon, is accepted as a recommended MEBAK analytical method for the detection of haze-forming polyphenols in beer and other intermediates. Un-der certain conditions, the results can be used directly for pre-dicting the colloidal stability of beer. Its disadvantage is that it does not provide detectable results for beers stabilized by high doses of polyvinylpolypyrrolidone (PVPP). A test modification is proposed that increases the test sensitivity and gives non-zero results, even for highly stabilized samples that are not measur-able by the standard test. The modification is based on adding saturated ammonium sulphate solution (SASS) to the sample to reach 9% saturation (0.5 mL of SASS to 5 mL sample volume) before the actual test performance. The results of the modified test can simply be converted to results obtained by the standard method. Tannoid content correlates linearly with the content of haze-forming polyphenols and with chill haze produced after defined accelerated aging. In a set of beer samples of one brand having different degrees of stabilization, a high correlation was determined between test results and long-term colloidal stability. The modified test can be used as a rapid and simple test for checking the stabilization process. It is particularly suitable for Pilsner type beer of long (more than 6 months) colloidal stability controlled by stabilization on the side of polyphenols.

Boar taint, an off-odor and an off-flavor in the meat from some uncastrated male pigs, is due to high levels of the testicular steroid hormone, androstenone, and the indole, skatole. Thus far, there are no known methods for controlling both androstenone and skatole through dietary means. We tested the adsorbent agents, cholestyramine (CH), activated carbon (AC), tween-60 (Tween), bentonite (BNT) and polyvinylpolypyrrolidone (PVPP) for binding androstenone, estrone (E(1)), estrone sulfate (E(1)S) and skatole from buffer solutions in an in vitro system. The goal was to determine the potential utility of these binding agents as feed additives to control boar taint. Michaelis-Menten analysis was utilized to determine the effectiveness of the adsorbents. At pH 7.4, E(1)S was bound to AC and CH with the highest B(max) (maximum binding), whereas Tween and AC had the greatest B(max) for E(1). The B(max) for skatole at pH 7.4 was highest for AC, CH and PVPP. AC had a higher B(max) for androstenone than CH and Tween. The B(max) values at pH 3.0 with E(1)S for AC and CH were essentially 100%, whereas the binding of Tween to E(1)S at pH 3.0 decreased by 49.5% from binding at pH 7.4 (P < 0.05). The Ad(int) values, which represent efficiency of binding, illustrated that AC bound E(1), androstenone and skatole with greater efficiency than the other binding agents at pH 7.4, whereas AC bound E(1)S as efficiently as CH. We conclude that AC was the most effective adsorbent agent for binding E(1), E(1)S, androstenone and skatole in vitro, followed by CH, Tween, PVPP and lastly BNT. These adsorbent agents may be useful for binding boar taint compounds in in vivo studies to decrease the risk of boar taint.

Previous studies on biological pretreatment of switchgrass by solid-state fermentation with Acidothermus cellulolyticus 11B have shown that inhibitory compounds prevent growth on untreated switchgrass. A. cellulolyticus was grown in liquid medium containing cellobiose with phenolic monomers added to determine if the phenolic compounds are one possible source of inhibition. Cinnamic acid derivatives (trans-p-coumaric, trans-ferulic, and hydrocinnamic acids), hydroxybenzoic acids (p-hydroxybenzoic, syringic, and vanillic acids), benzaldehydes (vanillin and p-hydroxybenzaldehyde), and condensed tannin monomers (catechin and epicatechin) were tested at levels up to 20 mM. All compounds exhibited a dose-response relationship and strongly inhibited growth at 20 mM. trans-p-Coumaric acid was found to be the strongest inhibitor of A. cellulolyticus growth, with a specific growth rate of 0.004 h−1 at 1 mM (0.18 h−1 without phenolic monomer). GC-MS and HPLC methods were used to confirm the presence of these phenolic compounds in switchgrass and measure the amounts extracted using different conditions. The amounts of phenolic compounds measured were found to be higher than the threshold for growth inhibition. Leaching with water at 55°C was inefficient at removing bound phenolics, whereas NaOH treatment improved efficiency. Phenolic compounds spiked into alkaline pretreated switchgrass were also found to inhibit growth of A. cellulolyticus in solid-state fermentation. However, addition of insoluble polyvinylpolypyrrolidone (PVPP) to switchgrass improved growth of A. cellulolyticus in liquid cultures, providing a possible approach for alleviating microbial inhibition due to phenolic compounds in lignocellulose. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2011

The purpose of this study was to evaluate the effects of various clarification treatments on organic acid compositions, phenolic compounds and on some other quality parameters including color and turbidity of pomegranate juice. All the clarification treatments resulted in an acceptable final clarity which is greater than 90% as light transmittance at 650 nm. The treatments significantly differed in their effects on the phenolic compounds and organic acid compositions of raw pomegranate juice. The ultrafiltration process had no observable effect on the phenolic compounds and organic acid compositions of raw pomegranate juice. Conventional clarification was more effective than others on the reduction of organic acids. The phenolic composition of pomegranate juice was significantly affected by polyvinylpolypyrrolidone together with conventional clarification treatment. PRACTICAL APPLICATIONS In the present study, the effects of various clarification treatments that are being increasingly adopted by the juice industry on total phenolic compounds, organic acid compositions, phenolic compounds, soluble solid content (°Brix), color and turbidity of pomegranate juice have been investigated. This study would allow for the assessment of the different clarification treatments on quality of pomegranate juice. Thereby, a compositional database for pomegranate juice consisting of phenolics and organic acids can be formed, which can provide useful information for evaluating the authenticity and human health benefits of the pomegranate juice.

The impact of juice press fractions upon the content of varietal thiols in Sauvignon blanc has been examined for wines fermented at the laboratory scale (750 mL). Wines made from pressed juices (taken at 0.25 and 1.0 bar) contained less than half the concentration of 3-mercaptohexan-1-ol (3MH) and 3-mercaptohexyl acetate (3MHA), important contributors to the tropical and passion fruit character of Sauvignon blanc wines, compared to wines made from free run juices. The pressed juices and wines exhibited lower acidity values, more rapid decline in glutathione content, and more advanced polyphenol oxidation. Supplementation of the juices with glutathione (at 67 mg/L) prior to fermentation led to lower varietal thiol concentrations in the finished wines, typically by several percent, whereas treatment with polyvinylpolypyrrolidone (PVPP) made no impact on wine parameters. Pasteurization of pressed juices increased 3MHA content in the finished wines, but also led to a decline in 3MH concentrations.

The aim of the present work was the development of a suitable methodology for the separation and determination of phenolic compounds in the hop plant. The developed methodology was based on the sample purification by adsorption of phenolic compounds from the matrix to polyvinylpolypyrrolidone (PVPP) and subsequent desorption of the adsorbed polyphenols with acetone/water (70:30, v/v). At last, the extract was analyzed by HPLC-DAD and HPLC-ESI-MS/MS. The first phase of this work consisted of the study of the adsorption behavior of several classes of phenolic compounds (e.g. phenolic acids, flavonols, and flavanols) by PVPP in model solutions. It has been observed that the process of adsorption of the different phenolic compounds to PVPP (at low concentrations) is differentiated, depending on the structure of the compound (number of OH groups, aromatic rings, and stereochemistry hindrance). For example, within the phenolic acids class (benzoic, p-hydroxybenzoic, protocatechuic and gallic acids) the PVPP adsorption increases with the number of OH groups of the phenolic compound. On the other hand, the derivatization of OH groups (methylation and glycosylation) resulted in a greatly diminished binding. The use of PVPP revealed to be very efficient for adsorption of several phenolic compounds such as catechin, epicatechin, xanthohumol and quercetin, since high adsorption and recovery values were obtained. The methodology was further applied for the extraction and isolation of phenolic compounds from hops. With this methodology, it was possible to obtain high adsorption values (>or=80%) and recovery yield values (>or=70%) for the most important phenolic compounds from hops such as xanthohumol, catechin, epicatechin, quercetin and kaempferol glycosides, and in addition it allows the identification of about 30 phenolic compounds by HPLC-DAD and HPLC-ESI-MS/MS.

We examined the antibacterial effects of cocoa on periodontal pathogenic bacteria, including Porphyromonas gingivalis, Fusobacterium nucleatum and Prevotella intermedia, compared with its effects on indigenous oral streptococci. A colony-forming unit (CFU) assay in the presence and absence of 1.0% and 3.0% (w/v) cocoa revealed that the growth of periodontal pathogenic bacteria was significantly suppressed by cocoa in concentration- and incubation time-dependent manners, although cocoa had no effect on the growth of indigenous streptococci. Methanol- and ethanol-extractable fractions from cocoa were also subjected to the CFU assay to determine and characterize the component (s) responsible for these effects. Fractions containing mainly cocoa polyphenols showed antibacterial effects. After treatment with polyvinylpolypyrrolidone, an absorbent of polyphenols, the methanol-extractable fraction lost its effect. These results suggest that cocoa has significant antibacterial effects against periodontal pathogenic bacteria and that polyphenols are responsible.

Extending the flavor stability of beer with modern day constraints of temperature exposure and time to retail is essential in insuring fresh beer flavor to the customer. Pilot brewing trials produced five packaged beers from a single American light brew. The control light beer (CW) was stored at 22.2°C and was compared against the four remaining beers which were: control light beer held at 4.4°C (CC), Divergan HM (DHM) treated light beer (T1), 5.1 ppm iso-α-acids (IAA) (T2) and 0.5 ppm iso-α-acids (T3) treated light beer, all held at 22.2°C for 13 weeks. DHM is an insoluble copolymer of polyvinyl-imidazole (PVI) and polyvinylpolypyrrolidone (PVPP) (9:1) with good trace metal chelating strength. EPR and sensory profiles were developed over the 13 weeks of treatment at 22.2°C at fresh, 2-, 4-, 6-, 8-, 10-, and 13-week intervals to ascertain and compare sensory flavor stability and EPR metrics data. In addition, three other stabilities were measured, namely physical, foam, and microbiological along with other chemical profiles measuring trace metals, fatty acids, sulfur compounds, and polyphenols. The control light beer (CC) held at 4.4°C showed the best flavor stability via EPR and sensory profiles followed by the DHM treated beer (T1) which showed improved flavor stability because transition metals such as copper, iron, and manganese were effectively chelated by DHM and removed during filtration. The IAA dosed light beers T2 and T3 showed the opposite results with decreased flavor stability via EPR metrics and sensory profiles. The transition metals were not removed but actually increased in packaged beer probably because the IAA tests were dosed after filtration. IAA bound or chelated transition metals need to be removed in the beer filtration process in order to improve flavor stability by mitigation of the transition metals, which catalyze the Haber-Weiss and Fenton free radical oxidation reactions. Also, after 13 weeks of storage at 22.2°C, the non-pasteurized light warm treated control (CW), cold treated control (CC), and DHM treated (T1) showed microbiological instability from Lactobacillus brevis infection, whereas both the IAA dosed light beers, T2 and T3, showed no beer spoiling organism breakdown.

Polyphenols from the ethanol extracts of Sargassum tenerrimum (ST) with potent antiallergic effects were studied to optimize separation process through column chromatography. The adsorption and desorption characteristics of three widely used adsorbents: macroporous resin, silica gel, and polyvinylpolypyrrolidone (PVPP), were critically evaluated respectively and studied for the optimization of preparative separation of polyphenols. Static operations on these adsorbents showed that macroporous resin had the best adsorption and desorption capability among the three adsorbents. Dynamic adsorption and desorption with macroporous resin packed column were also conducted to optimize the parameters such as: with the optimal values shown in brackets, the concentration of extract solution (4 times diluted), pH value (6–7), adsorption speed (3 BV h−1, bed volumes/per hour), concentration of ethanol (80%), elution speed (3 BV h−1) and elution volume (7 BV). The chromatographic process so optimized gave a purity of 62.43% from the crude polyphenols, providing a promising basis for large scale preparation of bioactive polyphenols upon further scaling up tests.

Adsorptivity of polyvinylpolypyrrolidone (PVPP), a candidate resin with selectivity to U(VI) in HNO3 media, to various metal ions was examined. It was found that PVPP has a strong adsorptivity to U(VI) in wide concentration range of HNO3. The Scatchard plot analysis revealed that the adsorption of U(VI) by PVPP occurs at plural binding sites. The infrared spectroscopic analysis suggested that the strong binding site is due to the coordination of the carbonyl oxygen atom and the nitrogen atom in the pyrrolidone ring to UO2 2+. It was also found that fission product ions except Re(VII) as the simulant of Tc(VII) and Pd(II) are not adsorbed onto PVPP. The adsorptivities to Tc(VII) and Pd(II) species are weak, indicating that U(VI) can be separated from other metal ions by PVPP.

The inhibitory effect of green tea extract on apple polyphenol oxidase (PPO) and on apple browning was investigated. PPO has been isolated from apples (cv. Golden Delicious), and extraction with polyvinylpolypyrrolidone and Triton X100 yielded a 6.45-fold increase in the specific enzyme activity. The optimum pH and temperature of the enzyme was found as 5.5 and 25C, respectively. The kinetics of enzyme-catalyzed reactions followed the Michaelis-Menten model, and the PPO exhibited a Km value of 4.76 mM. Apple PPO activity was inhibited by green tea extract, and the inhibitory effect toward apple PPO increased with increasing extract concentration. Addition of 30 mg/mL green tea extract resulted in approximately 42% inhibition on apple PPO activity. To support the inhibition behavior of PPO, apple browning was also investigated by immersing apple slices into green tea extract, and it was revealed that the browning of apple slices was effectively retarded by the green tea extract. PRACTICAL APPLICATIONS The quality of fruits, especially apples, depends on controlling the enzymatic browning that affects its organoleptic and nutritional qualities. Addition of chemicals, pH adjustment, refrigeration, thermal treatments and exclusion of oxygen are among the most effective methods for the inhibition of polyphenol oxidases (PPO). Consumer demand for minimally processed and fresh-like food products has undergone a continuous rise in recent years. Several authors have stated the necessity to evaluate the inhibitory effect of natural and nontoxic compounds on PPO activity and its potential applicability to the food industry. Experiments showed that green tea has an inhibitory effect on the activity of apple PPO and its browning. Our results suggest that green tea extract could potentially be used as a natural inhibitor of PPO, and its utilization is possible due to its wide occurrence, low cost and nontoxicity, but further feasibility studies are needed to increase its effect as an anti-browning agent in its application in the food industry.

A cold-active ionically bound cell wall peroxidase was purified from a polyvinylpolypyrrolidone extract of mature vanilla beans by ultra filtration of 10 kDa and gel filtration chromatography on Sephacryl S-200. The Mr was 46.5 kDa determined by electrophoresis on SDS–PAGE, while native gel filtration confirmed tetramer enzyme form of approximately 186 kDa. The optimum pH and temperature were 3.8 and 16 °C, respectively, as determined with guaiacol as the substrate (Km 3.8 mmol/L). The pI was approximately 7.7. The POD was inhibited by 1,4-dithiothreitol, β-mercaptoethanol and sodium azide. The POD showed decreasing activity in the presence of ascorbic acid, NaEDTA and sodium dodecyl sulfate at 1 mmol/L. The enzyme lost 80% of its activity in the presence of 20% ethanol. These results will permit better understanding of POD role in vanilla curing process.

A Mild and efficient method for preparing amides by reaction of nitriles with benzhydrol and tertiary alcohols is described using polyvinylpolypyrrolidone-supported boron trifluoride. Selective amidation of benzhydrol in the presence of primary benzyl alcohols was also achieved.

At least two commercial instruments that perform automated turbidimetric titrations are available for determining haze-active (HA) constituents in beer. They have advantages over single-point measurements due to the interactions between beer HA polyphenols, HA proteins, and other beer constituents. Analysis of HA polyphenols is particularly difficult due to their low concentration in beer. Manual turbidimetric titrations with soluble polyvinylpyrrolidone (PVP) were carried out in model systems with a HA polyphenol (tannic acid [TA]), a non-HA polyphenol (epicatechin), a HA protein (gliadin), and a non-HA protein (lysozyme). Increasing concentrations of TA resulted in higher turbidity peaks at higher titrant volumes. Essentially no haze was seen with epicatechin or lysozyme. Gliadin solutions had an initial modest haze that decreased with increasing titrant. The effects of adding fixed amounts of epicatechin, lysozyme, or gliadin to TA were examined. In the presence of epicatechin or lysozyme, the titration endpoints were shifted higher. The endpoints with mixtures of gliadin and TA were similar to those found with TA alone. PVP titration also was applied to samples of unchillproofed beer treated with different amounts of silica or polyvinylpolypyrrolidone and showed responses of the expected magnitudes.

The sample pre-treatment method using a polyvinylpolypyrrolidone (PVPP) cartridge column combined with a quasi-flow injection analysis (quasi-FIA) system realized the rapid determination of caffeine in three types of tea, green, oolong and black tea. The measurement time for each tea sample pre-treated using a PVPP cartridge column was shortened to 20s. In the present system, the limits of detection and quantification were 0.3 microM (1.5 pmol injected) and 0.7 microM (3.5 pmol injected), respectively, and a linear calibration curve was afforded up to 800 microM (4 nmol injected). Within-run precision of analysis of standard solutions of 10 and 100 microM caffeine was 0.11 and 0.16% (n=6), respectively. Between-run precision of analysis of the same solutions over 6 days was 0.78 and 0.74% (n=6), respectively. Comparison with the conventional HPLC method indicated that the present quasi-FIA method using sample pre-treatment with a PVPP cartridge column was useful for the simple and precise determination of caffeine in green, oolong and black tea samples.

We have applied a sample pre-treatment method with a cartridge column filled with polyvinylpolypyrrolidone (PVPP) to the effective removal of polyphenols and simple UV spectrophotometry of caffeine in tea. The absorption maximum length (lambda(max)) for caffeine was close to those for tea catechins in aqueous 1% acetic acid; therefore, the UV spectrum of a non-treated green tea sample had a large absorption wave. In contrast, the absorbance of the green tea sample was gradually reduced by PVPP cartridge treatment using PVPP from 0 to 50 mg, and was nearly constant using a pre-treatment cartridge with more than 100 mg PVPP, because tea catechins were effectively removed and caffeine was mostly recovered from a green tea sample by means of PVPP cartridge treatment. The PVPP pre-treatment cartridge also removed polyphenols successfully from oolong and black tea samples. Comparison with conventional HPLC analysis indicated that the present pre-treatment method with a PVPP cartridge was useful for the simple and selective UV spectrophotometric determination of caffeine in green, oolong and black tea samples.

The regeneration of polyphenol oxidase (PPO) from leaves of Toona sinensis (A.Juss.) Roam (TS), denatured by boiling with 0.4% (w/v) sodium dodecyl sulfate (SDS) and 1% (v/v) β-mercaptoethanol, and was studied with SDS-polyacrylamide gel electrophoresis (PAGE) and the gel-activity-stained assay. The optimal regenerating conditions for the denatured TS-PPO were as follows: extracting with buffer of 150 mM Na-Pi, pH 7.2; regenerating with buffer of 50 mM Tris–HCl, pH 7.2, 2% Triton X-100 for 45 min. In addition, the PPO regeneration was promoted by the addition of Cu2+ in the recovery buffer. The regenerating activity of the denatured-PPO was reduced in samples extracted with buffers containing polyvinylpyrrolidone (PVP), polyvinylpolypyrrolidone (PVPP) or Triton X-100.

An enzymatic method for determining L-malic acid in wine based on an L-malate sensing layer with nicotinamide adenine dinucleotide (NAD+), L-malate dehydrogenase (L-MDH) and diaphorase (DI), immobilized by sol-gel technology, was constructed and evaluated. The sol-gel glass was prepared with tetramethoxysilane (TMOS), water and HCl. L-MDH catalyzes the reaction between L-malate and NAD+, producing NADH, whose fluorescence (λ exc = 340 nm, λ em = 430 nm) could be directly related to the amount of L-malate. NADH is converted to NAD+ by applying hexacyanoferrate(III) as oxidant in the presence of DI. Some parameters affecting sol-gel encapsulation and the pH of the enzymatic reaction were studied. The sensing layer has a dynamic range of 0.1–1.0 g/L of L-malate and a long-term storage stability of 25 days. It exhibits acceptable reproducibility [s r(%)≈10] and allows six regenerations. The content of L-malic acid was determined for different types of wine, and polyvinylpolypyrrolidone (PVPP) was used as a bleaching agent with red wine. The results obtained for the wine samples using the sensing layer are comparable to those obtained from a reference method based on UV-vis molecular absorption spectrometry, if the matrix effect is corrected for.

Mild and convenient method for deprotection and direct oxidative deprotection of silyl ethers to the corresponding hydroxy and carbonyl compounds is described using polyvinylpolypyrrolidone-bromine complex (PVPP-Br2). Selective oxidative deprotection of benzylic silyl ethers in the presence of primary aliphatic alcohols was also achieved at room temperature.

The food additive polyvinylpolypyrrolidone is approved for use as a filter aid. The water-soluble substances test of polyvinylpolypyrrolidone often shows poor reproducibility. The instruction "boil gently while stirring using a stirrer" was considered critical, and so this issue was examined. The results showed that the use of a combination of both an oil bath and a stirrer provided good reproducibility without decomposition or other problems.

Supported TfOH appears to be a useful and recyclable heterogeneous catalyst for the rapid and efficient synthesis of guinoxaline derivatives via condensation of aromatic 1,2-diamines with 1,2-dicarbonyl compounds in water.

Polyvinylpolypyrrolidone-supported boron trifluoride has been studied for the synthesis of 1,8-dioxooctahydroxanthenes and 1,8-dioxodecahydroacridines. The reaction proceeded via condensation of: (1) aromatic aldehydes (1 eq.) and 5,5-dimethyl-1,3-cyclohexanedione (2 eq.) in acetonitrile at room temperature, (2) aromatic aldehydes (1 eq.), 5,5-dimethyl-1,3-cyclohexanedione (2 eq.), and aromatic amines (1 eq.) in acetonitrile at 80 °C in the presence of polyvinylpolypyrrolidone-supported boron trifluoride. This procedure cleanly converted a variety of aryl aldehydes with different substituent groups at ortho, meta, or para positions to the corresponding products. Convenience and efficiency, an easy work-up procedure, high yield, and simple preparation of the catalyst are some advantages of this method. In addition, the polyvinylpolypyrrolidone-supported boron trifluoride complex is a high loaded Lewis acid, which is stable, easy to handle, and retains effective activity after several months of storage.

The formation of callose in tree roots has been suggested as a physiological indicator of aluminum (Al) toxicity. Quantifying callose in the roots in forest soils, however, is hampered by the presence of autofluorescent materials in the roots that disturb the measurement of callose by fluorescence spectrophotometry. Tannins in the roots cause these measurement problems. Here we report on the measurement of callose in the root apices of European chestnut (Castanea sativa) seedlings collected in an acidified forest soil. The callose was quantified with a modified protocol which included three washing steps with polyvinylpolypyrrolidone (PVPP) before the callose was extracted. This procedure reduced the autofluorescence by about 50%. With the use of water or ethanol alone, callose could be measured in only about 15% of the root samples, whereas with the use of PVPP callose could be determined in 95% of the samples. This improved method could help to evaluate the effects of Al toxicity on tree roots grown in forest soils, where callose is detected as a physiological indicator.

Extracts of Jatoba, a South American herb, when injected i.p. into a mouse model of experimental autoimmune encephalomyelitis (EAE), inhibited the aggravation of clinical symptoms. At the same time, production of myelin oligodendrocyte glycoprotein Ag-specific IFN-γ and TNF-α by spleen cells was markedly suppressed. After administration of Jatoba there was minimal evidence of the demyelination that is characteristic of the EAE model. Decreases in clinical scores were observed when Jatoba extracts were injected just before Ag. The purified active compounds are likely to be polyphenols that are absorbable to polyvinylpolypyrrolidone. The active compounds were polymerized polyphenol polymers (procyanidins) and at least five degrees of polymerization were necessary for activity. In addition, extracts of other plant materials containing such procyanidins had similar activity. After administration of highly polymerized procyanidins, there was a decrease in both dendritic and CD4+ T cells. Although macrophages were increased in number, the expression of CD80 and MHC class II molecules was depressed indicating that the macrophages were immature. The results indicate that the suppression of development of EAE by the highly polymerized procyanidins resulted from an inhibition of Th1 and the effects might be associated with depression of Ag-presenting capability.

Microorganism DNA of rhizosphere soil from Pinus koraiensis and Pinus sylvestriformis were extracted by proteinase K based on SDS method, CTAB method, PVP (polyvinylpolypyrrolidone) method, and freezing and thawing method and the crude DNA from rhizosphere soil were purified by dialysis method, silver beads absorption method, and squeezing DNA gel method. The results of different extracting and purifying methods were compared and evaluated. Results indicated that the best method of extraction for microorganism DNA in rhizosphere soil was proteinse K based on SDS method with high salt concentration of 1.0% (w/v) NaCl, which could effectively eliminate humic acids and other impurities. The dialysis method was suitable to purify DNA from rhizosphere soil because of effectively removing brown matters and humic acids and the purified products were suited to PCR amplification. Squeezing DNA gel method was also a good purification method with the advantage of inexpensive in cost and efficient in use.

A method for indirect DNA extraction from various soils significantly differing in their physicochemical properties has been developed. The proposed method is based on cell desorption from soil particles using a Tris-EDTA (TE) buffer supplemented with polyvinylpolypyrrolydone (PVPP) and sodium dodecylsulfate (SDS). Methods for subsequent cell lysis and purification of DNA preparations based on alkaline lysis followed by chromatography on ion-exchange resins were described by us earlier. The purity of the DNA preparations obtained did not depend on the type of soil. It was shown that the DNA preparations can be used for the amplification of rather large fragments, e.g., sequences spanning the complete 16S rRNA gene.

Acute high-temperature stress affects plant protein structure, leading to denaturation and aggregation. Although folding states of individual proteins have been extensively studied, little information is available on protein thermostability in complex mixtures. The objective of this study was to systematically examine protein stabilizing and destabilizing factors in pepper (Capsicum annuum L.) leaf extracts using light transmission measurements. Increasing turbidity and subsequent precipitation were monitored in heated extracts as changes in light scattering at 540 nm. Factors evaluated included leaf tissue concentration, buffer pH, compounds that can stabilize enzymatic activity (chelating agent, complexer of phenolics, and a compatible solute), and destabilizing agents (nonionic detergent and divalent cation). Leaf extract thermostability decreased with increasing tissue concentration from 6 to 60 g fresh weight per liter of buffer. Turbidity and precipitation occurred after exposure to higher temperatures as buffer pH increased from 6.0 to 7.0. Ethylenediaminetetraacetic acid (chelating agent) and polyvinylpolypyrrolidone (complexer of alkaloids and phenolics) had relatively small effects on extract thermostability. Nonionic detergent (Tween 20) destabilized extract thermostability, especially when incorporated in the extraction buffer. Calcium reduced thermostability by about 2 °C when added as CaCl2 at 1 mm. Calcium caused an increase in turbidity that was not directly associated with protein complexes and was not affected by treatment temperature. Mannitol, a compatible solute, increased the temperature at which turbidity and precipitation were induced, but only at high (500 mm) concentrations. Agents that stabilize or destabilize proteins at high temperatures can be assayed in plant extracts by measuring turbidity changes at 540 nm. These findings can be applied to functional studies determining the basis for differences in thermotolerance between genotypes and between control and acclimated tissues.

Leaf samples of Juglans regia (walnut), Rhus typhina (sumach), Aesculus hippocastanum (chestnut) and Salix alba (willow) were either freeze dried or oven dried and the amount of tannins was determined by two chemical assays (Folin Ciocalteau and ferric chloride method). In addition, the biological activity of these tannins was determined by their protein precipitation capacity and by a bioassay based on the incubation to the leaves in vitro in buffered rumen fluid with and without polyethylene glycol. Generally, oven drying is recognised to decrease the extractability and/or the biological activity of tannins. Our results however do not indicate a general decrease in extractability of tannins due to oven drying. The effects observed were plant specific with negative effects of oven drying in walnut and willow leafs, positive effects in chestnut leaves and no effects were observed for the sumach. No negative effects of oven drying were detected for the biological activity of the tannins. The specific protein precipitation capacity was nearly identical for the freeze dried and the oven dried tannins. Oven drying however decreased the solubility of the cell contents and the plant cell wall, which led to changes in fermentation end products, but the biological activity of the tannins was not negatively affected by the oven drying. Although some differences in the extractability and activity of the individual plant species were observed, we conclude from this work that the drying procedure has no negative effect on the biological activity of the tannins examined.

Red clover flowers are a rich source of isoflavones in the forms of biochanin A, formononetin, genistein, and genistin. A simple process was developed to recover isoflavones from red clover flowers as a nutraceutical product. Isoflavones were 1st extracted in alkaline water and insoluble polyvinylpolypyrrolidone (PVP) was then added to the extract for adsorbing isoflavones. The adsorbed isoflavones were subsequently eluted with ethanol and dried. The main steps of this process were optimized for the product yield and quality. The final product was an isoflavone concentrate, containing more than 20 wt% isoflavones, which represented a recovery of greater than 50% of the total isoflavone amount in red clover flowers.

In this study we assessed microconidia germination of the tomato pathogens F. oxysporum f. sp. lycopersici (Fol) and F. oxysporum f. sp. radicis-lycopersici (Forl) in the presence of root exudates. Tomato root exudates stimulated microconidia germination and the level of stimulation was affected by plant age. Treatment of root exudates with insoluble polyvinylpolypyrrolidone, which binds phenolic compounds, indicated that tomato root exudates contain phenolic compounds inhibitory to F. oxysporum microconidia germination. Our study indicates that tomato root exudates similarly stimulate microconidia germination of both Fol and Forl. However, individual F. oxysporum strains differ in the degree of germination response to the root exudates. Furthermore, root exudates from non-host plants also contain compounds that stimulate microconidia germination of Fol. In general, the effects of root exudates from non-host plants did not differ considerably from those of tomato. The ability of phenolic compound...

Proanthocyanidins have been characterized and levels compared in an ale and a lager using normal-phase liquid chromatography-mass spectroscopy (LC/MS) after a pre-concentration step employing Sephadex LH-20 chromatography. Twenty proanthocyanidins were identified including both non-galloylated and galloylated forms of the monomers, dimers and trimers. Oligomers greater than trimer were not detected. A proportion of all classes of proanthocyanidin adsorbed non-specifically to a silica xerogel product, but polyvinylpolypyrrolidone (PVPP) and a product that comprises polyvinylpyrrolidone (PVP) on a surface of amorphous silica displayed greater capability (i.e. specificity) for binding these materials. Of the two specific adsorbents, it was the PVPP that had the greater binding capability compared to the PVP-silica co-product.

Colloidal stabilisation of all malt and adjunct lager beers through selective removal of haze sensitive glycoproteins using silica gel and tannoid polyphenols using polyvinylpolypyrrolidone (PVPP) or a polyvinylpyrrolidone (PVP)-modified silica gel has been demonstrated during full brewery production. At this scale PVPP and the PVP-modified silica gel exhibited equivalent binding capability for tannoid polyphenols although PVPP removed additional polyphenolic species. Characterisation of proanthocyanidins following treatment at 4°C with PVPP and the PVP-modified silica gel silica co-product confirmed that PVPP removes a wider range of polyphenolics. Both products exhibited poorer polyphenolic binding capability at 4°C as would be expected for a physical adsorption process.

Filtration characteristics of apple juices pretreated with various filter-aids were studied to select an appropriate process for the clarification with higher permeate flux and lower membrane fouling, and for the production of high quality juice. Bentonite of 0.5% was superior filter-aid than 0.2% polyvinylpolypyrrolidone (PVPP), 0.1% activated carbon of 10–14 mesh, and the enzyme mixture of 0.03% pectinase and 0.003% amyalse in reducing juice turbidity, although PVPP was best in tannin rejection. Permeate fluxes during membrane filtration were effectively increased by filter-aids pretreatment, especially bentonite. From considering the recovery of permeate flux drop with time, ultrafiltration (MWCO 30,000) was presumed to be proper than microfiltration (0.01 μm pore size). In the quality change of apple juice, bentonite pretreatment and membrane filtrations improved color without the deteriorational changes of pH, total acidity, and the contents of total sugar, organic acid and Vitamin C, which are important quality index in fruit juice. Finally, ultrafiltration with bentonite pretreatment was optimal process for the effective clarification and the high quality of apple juice.