Assessment of Chemical Composition and In Vitro Antioxidant, Antidiabetic, Anticholinesterase and Microbial Virulence-Quenching Effects of Salad Burnet (Sanguisorba minor L.) Harvested from Algeria.

Sanguisorba minor is a medicinal vegetable used in seasoning desserts, juices, and beverages. An evaluation of the total flavonoid, phenolic, tannin and anthocyanin contents indicated that these classes of compounds are distributed variably in the different fractions. In summary, the HPLC-DAD analyses enabled the identification and quantification of thirteen phenolic compounds in an ethyl acetate extract (EAE), nine in a dichloromethane extract (DCME), seven in an aqueous extract (AQE) and four in a butanol extract (BE). Rutin was the most abundant phenolic compound in the BE (278.4 ± 1.20 µg/g) and AQE (32.87 ± 0.23 µg/g) fractions, while apigenin was the most abundant in the DCME (84.75 ± 0.60 µg/g) and EAE (156.8 ± 0.95 µg/g) fractions. The presence of phenolic compounds in the fractions conferred good antioxidant capacity, especially the EAE and DCME fractions, which both exhibited higher antioxidant effects than BHA and α-tocopherol in DPPH• and CUPRAC assays. Additionally, in the ABTS•+ assay, EAE (IC50 = 9.27 ± 0.33 µg/mL) was more active than α-tocopherol (IC50 = 35.50 ± 0.55 µg/mL), and BHA (IC50 = 12.70 ± 0.10 µg/mL). At 200 µg/mL, the fractions inhibited acetylcholinesterase and butyrylcholinesterase as well as α-amylase and α-glucosidase, indicating that they can slow neurodegeneration and hyperglycemia. Minimal inhibitory concentration (MIC) values ranged from 0.312 mg/mL to 1.25 mg/mL, and fractions showed good biofilm inhibition against Staphylococcus aureus and Escherichia coli. The extracts exhibited good violacein inhibition in Chromobacterium violaceum CV12472 and Chromobacterium violaceum CV026, despite the supply of external acyl-homoserine lactone to CV026. The antioxidant, quorum-sensing, antibiofilm and enzyme inhibition attributes indicate the potential for the application of S. minor as a food preservative.

Synthesis and characterization of novel chitosan derivatives (containing dipyridinium quaternary salts) with antimicrobial potential.

Chitosan derivatives are versatile materials, biocompatible and biodegradable, that can be tailor-made to suit specific biomedical applications. In this study, two N-heterocyclic salts (N,N'-diphenacyl-[4,4'-dipyridinium] dibromide (DP) and N,N'-diphenacyl-1,2-bis-(4-pyridinium)ethane dibromide (DPE)) were used for chitosan functionalization to enhance its antimicrobial potential. Physico-chemical characterization of the newly synthesized derivatives (Ch-DP and Ch-DPE) was performed by elemental analysis, spectrometry (UV-Vis, FTIR), electrochemistry (OCP, CV), and electron microscopy (SEM) proving that the highest degree of functionalization was obtained for Ch-DP. The antimicrobial effect of chitosan functionalization was further tested in terms of its interaction with Listeria monocytogenes Scott A, and Staphylococcus aureus ATCC 25923, as Gram-positive bacteria and Escherichia coli ATCC 25922, as Gram-negative bacterium, respectively, showing that the Ch-DP had a good inhibitory activity compared with Ch-DPE.

Phytochemical Characterization and In Vitro Evaluation of the Anti-Sickle Cell Activity of Aqueous and Ethanolic Extracts of Two Medicinal Plants from Niger: Flueggea virosa (Roxb. ex Willd.) Royle and Kigelia africana (Lam.) Benth.

Sickle cell anaemia is a hereditary blood disorder that attacks the red blood cells and deforms them, giving them a sickle shape. Sickle cell anaemia is a serious health problem in the West African country of Niger. Moreover, the cost associated with medical care is very high. The main objective of this study is to contribute to the valorisation of Flueggea virosa (Roxb. ex Willd.) Royle (aerial part), Kigelia africana (lam), and Benth (leaves) from Niger were used to treat sickle cell disease using aqueous and ethanolic extracts of phytochemical compounds. To achieve this objective, the evaluation of anti-sickle cell activity was carried out in vitro using the Emmel technique through the normalisation rate. The analyses showed that the aqueous and ethanolic extracts contained various classes of bioactive substances known for their valuable biological activities. The chemical composition rich in bioactive compounds led to very good results in biological assays. Thus, from a dose of 0.05 mg/mL, the ethanolic extracts of the two plants normalised up to 75% of the sickle cells. As the rate of normalisation was shown to be dose-dependent, at a dose of 10 mg/mL, the ethanolic extracts showed the best rates of sickle cell normalisation, with 95% for F. virosa and 93% for K. africana. Phytochemical screening was used to correlate the secondary metabolite and anti-sickle cell activities of the extracts from the two plants. These results may justify the use of these two species in traditional medicine for the treatment of sickle cell disease in Niger. The inclusion of these plants in phytomedicines could provide significant relief to people suffering from sickle cell disease.

Uncorking Haloanisoles in Wine.

Haloanisoles in wine have devastating effects on the aroma and quality of the wine. 2,4,6-trichloroanisole (TCA) was discovered and coined as "cork taint" in 1982. However, we now understand that there are many more haloanisoles that contribute to these musty odors, including 2,4,6-Tribromoanisiole (TBA), 2,3,4,6-tetrachloroanisole (TeCA), and pentachloroanisole (PCA). While TCA, TeCA, and PCA can all be traced back to the cork, TBA's phenol precursor is ubiquitous in building material as a fire retardant, making it a much larger vector. All haloanisoles have the ability to aerosolize and resettle onto surfaces in the winery, making this a very difficult problem to eliminate. This literature review will cover the multiple haloanisoles found in wine, their sensory impacts, their effect on wine quality, and current methodologies with regard to their analysis.

Bridging the Chemical Profile and Biological Activities of a New Variety of Agastache foeniculum (Pursh) Kuntze Extracts and Essential Oil.

This study investigated the phytochemical content of alcoholic extracts and essential oil of a new variety of medicinal plants, Agastache foeniculum (Pursh), which Kuntze adapted for cultivation in Romania, namely "Aromat de Buzau". The essential oil was investigated by GC-MS, while the identification and quantification of various compounds from alcoholic extracts were performed by HPLC-DAD. The total phenol and flavonoid contents of the extracts were evaluated by using standard phytochemical methods. The antioxidant activities of ethanol, methanol extracts, and essential oil of the plant were also assessed against 2,2'-diphenyl-1-picrylhydrazyl (DPPH•), 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS•+), and by ferric reducing power (FRAP) using spectroscopic methods. Cyclic voltammetry was used to evaluate the antioxidant capacity of the essential oil. The concentrations of phenolic compounds were higher in methanolic extract compared to ethanolic extract. A significant correlation was found between total phenol and total flavonoid contents (r = 0.9087). Significant high correlations were also found between the total phenolic compounds and the antioxidant activities of the extracts (r ≥ 0.8600, p < 0.05). In addition, the extracts and essential oil showed good antioxidant and xanthine oxidase inhibitory activities. Estragole was detected as the major constituent of the essential oil (94.89%). The cytotoxic activity of the essential oil was evaluated by the MTT assay. At lower concentrations (1 µg/mL) high cytotoxicity against MCF-7 breast cancer cells was observed but not on the non-tumoral dermal fibroblasts (HDF) which indicated selectivity for cancer cells and suggests the presence of biologically active components that contribute to the observed high cytotoxic effect. Findings from the present study offer new perspectives on the use of A. foeniculum as a potential source of bioactive compounds and a good candidate for pharmaceutical plant-based products.

Exploration of the Antioxidant and Anti-inflammatory Potential of Cassia sieberiana DC and Piliostigma thonningii (Schumach.) Milne-Redh, Traditionally Used in the Treatment of Hepatitis in the Hauts-Bassins Region of Burkina Faso.

Inflammation is the supreme biological response to illness. In the Hauts-Bassins region, in traditional medicine, all parts of Cassia sieberiana and Piliostigma thonningii are used to treat hepatitis and inflammation. The aim of this study was to evaluate the in vitro antioxidant and anti-inflammatory activities of their aqueous extracts. High performance liquid chromatography with photodiode array (HPLC-DAD) and ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-MS/MS) analyses highlighted the presence of polyphenols and flavonoids. Antioxidant and anti-inflammatory activities were measured by various methods such as DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), TAC (total antioxidant capacity), anti-protease, anti-lipoxygenase, and membrane stabilization. The best antioxidant activity was observed in the bark (DPPH: IC50 = 13.45 ± 0.10 µg/mL) and roots (TAC = 29.68 ± 1.48 mg AAE/g DW) of Piliostigma thonningii and in the roots (ABTS: IC50 = 1.83 ± 0.34 µg/mL) of Cassia sieberiana. The best anti-inflammatory activity was observed in the bark (anti-lipoxygenase: IC50 = 13.04 ± 1.99 µg/mL) and leaves (anti-proteases: IC50 = 75.74 ± 1.07 µg/mL, membrane stabilization: IC50 = 48.32 ± 6.39 µg/mL) of Cassia sieberiana. Total polyphenols (ABTS: r = -0.679, TAC: r = 0.960) and condensed tannins (ABTS: r = -0.702, TAC: r = 0.701) were strongly correlated with antioxidant activity. Total flavonoids (anti-proteases: r = -0.729), condensed tannins (anti-proteases: r = 0.698), and vitamin C (anti-proteases: r = -0.953) were strongly correlated with anti-inflammatory activity. Total polyphenols, flavonoids, condensed tannins, and vitamin C could contribute to the antioxidant and anti-inflammatory activities of the two studied plants. These results could validate the traditional use of these plants to treat various inflammatory diseases.

Biosorptive Removal of Ethacridine Lactate from Aqueous Solutions by Saccharomyces pastorianus Residual Biomass/Calcium Alginate Composite Beads: Fixed-Bed Column Study.

In this study, ethacridine lactate removal from aqueous solution using a biosorbent material based on residual microbial biomass and natural polymers in fixed-bed continuous column was investigated. Composite beads of Saccharomyces pastorianus residual biomass and calcium alginate were obtained by immobilization technique. The prepared biosorbent was characterized by Fourier transformed infrared spectroscopy, scanning electron microscopy, and analysis of point of zero charge value. Then, laboratory-scale experiments by fixed-bed column biosorption were conducted in continuous system. To this purpose, the column bed high (5 cm; 7.5 cm), initial pollutant concentration (20 mg/L; 40 mg/L), and solution flow through the column (0.6 mL/min; 1.5 mL/min) were considered the main parameters. Recorded breakthrough curves suggest that lower flow rates, greater bed heights, and a lower concentration of ethacridine lactate led to an increased biosorption of the target compound. The biosorption dynamic was investigated by nonlinear regression analysis using the Adams-Bohart, Yoon-Nelson, Clark, and Yan mathematical models. Conclusively, our research highlights, firstly, that the obtained biosorbent material has the required properties for retaining the ethacridine lactate from aqueous solution in continuous system. Secondly, it emphasizes that the modeling approach reveals an acceptable fitting with the experimental data for the Yoon-Nelson, Clark, and Yan models.

Prevalence and Management of Alkyl-Methoxypyrazines in a Changing Climate: Viticultural and Oenological Considerations.

Alkyl-methoxypyrazines are an important class of odor-active molecules that contribute green, 'unripe' characters to wine and are considered undesirable in most wine styles. They are naturally occurring grape metabolites in many cultivars, but can also be derived from some Coccinellidae species when these 'ladybugs' are inadvertently introduced into the must during harvesting operations. The projected impacts of climate change are discussed, and we conclude that these include an altered alkyl-methoxypyrazine composition in grapes and wines in many wine regions. Thus, a careful consideration of how to manage them in both the vineyard and winery is important and timely. This review brings together the relevant literatures on viticultural and oenological interventions aimed at mitigating alkyl-methoxypyrazine loads, and makes recommendations on their management with an aim to maintaining wine quality under a changing and challenging climate.

Eco-Friendly Biosorbents Based on Microbial Biomass and Natural Polymers: Synthesis, Characterization and Application for the Removal of Drugs and Dyes from Aqueous Solutions.

Pharmaceuticals and dyes are a very important part of the nonbiodegradable or hard biodegradable substances present in wastewater. Microorganisms are already known to be effective biosorbents, but the use of free microbial cells involves difficulties in their separation from effluents and limits their application in wastewater treatment. Thus, this study aimed to develop biosorbents by immobilizing Saccharomyces cerevisiae, Saccharomyces pastorianus and Saccharomyces pastorianus residual biomass on natural polymers (alginate and chitosan) and to evaluate the biosorptive potential for removal of pharmaceuticals and dyes from water. Six types of biosorbents were synthesized and characterized by Scanning Electron Microscopy and Fourier Transform Infrared Spectroscopy techniques and their biosorptive capacities for three drugs (cephalexin, rifampicin, ethacridine lactate) and two dyes (orange II and indigo carmine) were evaluated. The obtained results show that the removal efficiency depends on the polymer type used for the immobilization. In case of alginate the removal efficiency is between 40.05% and 96.41% for drugs and between 27.83% and 58.29% for dyes, while in the case of chitosan it is between 40.83% and 77.92% for drugs and between 17.17% and 44.77% for dyes. In general, the synthesized biosorbents proved to be promising for the removal of drugs and dyes from aqueous solutions.

A Review of Ladybug Taint in Wine: Origins, Prevention, and Remediation.

Ladybug taint (also known as ladybird taint) is a relatively recently recognized fault that has been identified in wines from a wide range of terroirs. Alkyl-methoxypyrazines-particularly 2-isopropyl-3-methoxypyrazine-have been determined as the causal compounds, and these are introduced into grape must during processing, when specific species of vineyard-dwelling Coccinellidae are incorporated into the harvested fruit. Coccinella septempunctata, and especially the invasive Harmonia axyridis, are the beetles implicated, and climate change is facilitating wider dispersal and survivability of H. axyridis in viticultural regions worldwide. Affected wines are typically characterized as possessing excessively green, bell pepper-, and peanut-like aroma and flavor. In this paper, we review a range of vineyard practices that seek to reduce Coccinellidae densities, as well as both "standard" and novel wine treatments aimed at reducing alkyl-methoxypyrazine load. We conclude that while prevention of ladybug taint is preferable, there are several winery interventions that can remediate the quality of wine affected by this taint, although they vary in their relative efficacy and specificity.

Enzymatic Management of pH in White Wines.

This paper investigates the potential of the enzymatic management of high pH in white juice and wine using a combination of enzymes-glucose oxidase coupled with catalase. Catazyme® 25 L, a commercially available blend of the two enzymes, was added at different doses (0.2 g/L, 0.6 g/L, and 1g/L) to white grape juice and various parameters (glucose, gluconic acid, pH) were monitored over 24 h of treatment. Treated wines were fermented to dryness without any difficulty and the wines were chemically and sensorially evaluated. At the highest dose (1 g/L), pH was reduced from 3.9 to 3.2, with 20.5 g of gluconic acid produced, while at the lowest dose (0.2 g/L), pH decreased from 4.0 to 3.5 and 8.8 g of gluconic acid was produced. Flash profiling indicated that treated wines were lighter in color than the control and were described using terms such as floral, fruit, citrus, and sour while the control wine was described as being fermented, medicinal, pungent, and oxidized. In conclusion, glucose oxidase coupled with catalase was shown to be effective at significantly reducing juice and wine pH in a short amount of time and with a positive impact on the organoleptic profiles of the treated wines.

Comparative Study of the Chemical Compositions and Antioxidant Activities of Fresh Juices from Romanian Cucurbitaceae Varieties.

Cucurbitaceae is a family of health-promoting plants due to their compounds with beneficial effects. The aim of this study was to analyze, for the first time, the chemical composition, the antioxidant activity and the metal chelating properties of fruit juices obtained from four different species of the Cucurbitaceae family cultivated in Romania, namely Momordica charantia, Cucumis metuliferus, Benincasa hispida and Trichosanthes cucumerina. The samples of juice were analyzed by high-performance liquid chromatography (HPLC) and all the four species displayed high levels of the two triterpenes, oleanolic and ursolic acids, and also in phenolic compounds, including catechin, (-)-epicatechin and gallic acid. The juices demonstrated significant antioxidant activity against the free radical 2,2-diphenyl-1-picrylhydrazyl (ranging from 20 to 95%,), a good iron binding ability (ranging from 7.45 ± 0.28% to 86.95 ± 0.97%) and also promising antioxidant potential against the ABTS radical (ranging from 4.97 to 32.60 µETx/mL juice). Our findings raise interesting questions for further research on Cucurbitaceae fruit juices and, consequently, their very good antioxidant potential suggests these fruits should be further explored for their protective effect against oxidative damage. This is the first time the chemical composition and antioxidant activities of fruit juices from these four Romanian Cucurbitaceae varieties have been investigated.

Green Accelerated Synthesis, Antimicrobial Activity and Seed Germination Test of Quaternary Ammonium Salts of 1,2-bis(4-pyridyl)ethane.

A family of fifteen quaternary ammonium salts (QAs), bearing the 1,2-bis(4-pyridyl)ethane core, were obtained using for the first time two different green methods, such as microwave (MW) and ultrasounds (US) irradiation, with very good yields and in much shorter times compared to the classical method, and an assay on their antimicrobial action against Escherichia coli (E. coli) was carried out. While 12 to 24 hours were required for complete alkylation of 1,2-bis(4-pyridyl)ethane by reactive halogenated derivatives in anhydrous solvent under reflux conditions, MW and US irradiation reduced the reaction time and the desired products were achieved in a few min. One of the aims of this study was to evaluate the antibacterial potential of the synthesized QAs against pathogenic bacteria, along with their impact on germination activity of wheat seeds (Triticum aestivum L.). The antibacterial activity of the QAs against Escherichia coli was explored by determining the minimum inhibitory concentration (MIC). The MIC values varied from 0.312 to 2.5 mg/mL, highlighting the lowest values attained for the derivatives containing methoxy, chlorine and benzofurane functional groups. The viability of aerobic bacteria was determined with the Tetrazolium/Formazan Test, a method that was found to be the best alternative approach with respect to the difuzimetric method. Seeds of Triticum aestivum L. were used for the evaluation of the germination indicators, such as seed germination (SG), the relative seed germination (RSG), the relative radicle growth (RRG), and the seed germination index (GI). The toxicity studies of QAs 1, 4 and 7, at two different concentrations, showed no inhibitory effect on seed germination.

Chemical and Sensory Evaluation of Silicone and Polylactic Acid-Based Remedial Treatments for Elevated Methoxypyrazine Levels in Wine.

Alkylmethoxypyrazines (MPs) are a class of compounds that can elicit undesirable aroma and flavor characteristics in wine, and resist remediation using traditional wine making approaches. MPs are grape-derived constituents as well as contaminants from Coccinellidae beetles present during wine processing; the latter eliciting an off-flavor referred to as 'ladybug taint'. In this study we investigated the capacity of two plastic polymers-one silicone-based, the other polylactic acid-based-applied with varying surface areas to reduce concentrations of isopropylmethoxypyrazine (IPMP), sec-butylmethoxypyrazine (SBMP) and isobutylmethoxypyrazine (IBMP) in a Merlot wine using multi-dimensional gas chromatography coupled with mass spectrometry and headspace solid phase microextraction (SPME-MDGCMS). The impact of treatments on the sensory characteristics of the wine (descriptive analysis) and volatile aroma compounds (VOCs) (SPME-MDGCMS) was also investigated. Results showed substantial reductions for all of the target odorants: up to 38%, 44% and 39% for IPMP, SBMP and IBMP, respectively, for the silicone polymer, and up to 75%, 78% and 77% for IPMP, SBMP and IBMP, respectively, for the polylactic acid polymer. These polymers had no or minimal effect on VOCs at applications of 200 cm²/L for silicone or for all polylactic acid treatments. Sensory impacts were less clear, but generally showed minimal effect from the treatments. Taken overall, the data confirm the utility of both polylactic acid and silicone polymers in reducing elevated levels of grape-derived MPs, as well as potentially improving wine contaminated by ladybug taint.

Application of plastic polymers in remediating wine with elevated alkyl-methoxypyrazine levels.

3-Alkyl-2-methoxypyrazines (MPs) are odour-active compounds that elicit atypical green aromas and flavours in some wines, and are resilient to removal using traditional wine-making approaches. They originate either as contaminants from Coccinellidae beetles inadvertently introduced during wine processing ("ladybug taint") or as grape-derived constituents that are undesirable at elevated levels. In this study we investigated the capacity of a selection of plastic polymers to reduce concentrations of three MPs: isopropyl methoxypyrazine (IPMP), secbutyl methoxypyrazine (SBMP) and isobutyl methoxypyrazine (IBMP). In Trial 1, red wine was spiked with IPMP (20 ng/l), SBMP (20 ng/l) and IBMP (20 ng/l), then separately treated with 13 plastic polymers (surface area 350 cm(2)/l). Three polymers were then identified for further testing based on the results from Trial 1: silicone, ethylene and vinyl acetate (EVA) and a poly-lactic acid-based biodegradable polymer. In Trial 2, the efficacy of these selected polymers to reduce MP levels in red wine was tested as a function of contact time. Solid-phase micro-extraction multi-dimensional GC-MS was used to measure MP levels before and after treatment with the polymers. Results showed significant reductions in all target odorants after 24 h treatment: silicone reduced IPMP and IBMP by 96% and 100%, respectively, while the biodegradable polymer decreased IPMP and IBMP concentrations by 52% and 36%, respectively. EVA was less effective in lowering MP levels (7% IPMP and 23% IBMP after 24 h). Taken overall, the data suggest the potential for the use of poly-lactic acid and silicone in treating wines contaminated by ladybug taint, as well as in reducing high levels of grape-derived MPs.

Methoxypyrazine composition of Coccinellidae-tainted Riesling and Pinot noir wine from Germany.

BACKGROUND: Harmonia axyridis (multicolored Asian ladybeetle) and Coccinella septempunctata (seven-spot ladybeetle) (Coccinellidae) are found in many wine regions in Europe and the Americas, where they are responsible for a pronounced wine fault known as 'ladybug taint' when incorporated with grapes during harvest operations. Methoxypyrazines have been proposed in the literature as the compounds responsible for the taint. This study sought to expand on this identification and also determine the effectiveness of heating Coccinellidae-affected grape must prior to fermentation as a possible remedial intervention. Riesling and Pinot noir grapes were infested with H. axyridis or C. septempunctata at different densities and fermented to dryness. The Pinot noir was either must heated prior to fermentation or processed without heating (control). All wines were analyzed for 2-isopropyl-, 2-sec-butyl-, 2-isobutyl- and 2,5-dimethyl-3-methoxypyrazine using headspace solid phase microextraction/multidimensional gas chromatography/mass spectrometry. RESULTS: Concentrations of 2-isopropyl-3-methoxypyrazine increased with beetle density for both Coccinellidae species, while other methoxypyrazines showed inconsistent or no variation with infestations levels. Heating of Pinot noir grapes prior to fermentation resulted in a moderate decrease in all methoxypyrazines. CONCLUSION: These results provide direction for more targeted treatments aimed at remediating musts/wines affected by Coccinellidae and indicate that winegrowers do not need to differentiate between H. axyridis and C. septempunctata when making action threshold decisions in the vineyard or winery.

Development of a rapid method for the quantitative analysis of four methoxypyrazines in white and red wine using multi-dimensional Gas Chromatography-Mass Spectrometry.

Alkyl-methoxypyrazines (MPs) are important odour-active constituents of many grape cultivars and their wines. Recently, a new MP - 2,5-dimethyl-3-methoxypyrazine (DMMP) - has been reported as a possible constituent of wine. This study sought to develop a rapid and reliable method for quantifying DMMP, isopropyl methoxypyrazine (IPMP), secbutyl methoxypyrazine (SBMP) and isobutyl methoxypyrazine (IBMP) in wine. The proposed method is able to rapidly and accurately resolve all 4 MPs in a range of wine styles, with limits of detection between 1 and 2 ng L(-1) for IPMP, SBMP and IBMP and 5 ng L(-1) for DMMP. Analysis of a set of 11 commercial wines agrees with previously published values for IPMP, SBMP and IBMP, and shows for the first time that DMMP may be an important and somewhat common odorant in red wines. To our knowledge, this is the first analytical method developed for the quantification of DMMP in wine.

Occurrence and contribution of alkyl methoxypyrazines in wine tainted by Harmonia axyridis and Coccinella septempunctata.

BACKGROUND: Ladybug taint (LBT) is a wine fault caused by the inadvertent incorporation of ladybeetles to the wine during the winemaking process. Harmonia axyridis, also known as the multicolored Asian lady-beetle (MALB), was the only species considered responsible for causing the taint. A second species, Coccinella septempunctata (7 Spot), has recently also been implicated. The main objectives of this study were to identify and quantify the compounds associated with ladybug taint of white and red wine from these two Coccinellidae species (Harmonia axyridis and Coccinella septempunctata), and determine the most odor-active compounds in LBT-affected wines. RESULTS: Results show that Coccinellidae can contribute dimethyl, isopropyl, secbutyl and isobutyl methoxypyrazine to wine when they are processed with grapes, and that the methoxypyrazine composition varies between MALB and 7 Spot. Isopropyl methoxypyrazine is the major contributor to LBT in wines produced with these ladybeetle species, although secbutyl and isobutyl methoxypyrazine may contribute in MALB- and 7 Spot-affected wines, respectively. Finally, dimethyl methoxypyrazine is reported for the first time in wines not affected by Coccinellidae; the global significance and prevalence of this compound in wine remains to be determined. CONCLUSION: Both Harmonia axyridis and Coccinella septempunctata can contribute alkyl methoxypyrazines, and particularly isopropyl methoxypyrazine, to wine at concentrations that can have a negative impact on wine quality. These findings will allow grape growers and winemakers to be more aware of the risks posed by 7 Spot beetles, and to take the appropriate preventative and remedial actions. Furthermore, this is the first time dimethyl methoxypyrazine is reported in wine, either as an endogenous or Coccinellidae-derived odorant.

Determination of ortho- and retronasal detection thresholds and odor impact of 2,5-dimethyl-3-methoxypyrazine in wine.

2,5-Dimethyl-3-methoxypyrazine (DMMP) has been recently identified in both Coccinellidae-tainted (by either Coccinella septempunctata or Harmonia axyridis beetles) and untainted wines; however, little is known regarding its impact on wine aroma and flavor. The aims of this study were to obtain an accurate estimate of both the ortho- and retronasal detection thresholds of DMMP in red wine and to understand how DMMP contributes to the aroma profile of red wine. In the first study, thresholds were determined for 21 individuals using the ASTM E679 ascending forced choice method of limits. The orthonasal group best estimate threshold (BET) was 31 ng/L and the retronasal group BET was 70 ng/L. A moderate variation in individual thresholds was observed for the orthonasal modality (standard deviation (SD) = 19.8) and a larger variation was noted for retronasal thresholds (SD = 111.8). In the second study, a panel of 8 assessors performed descriptive sensory analysis on 3 red wines containing various concentrations of added DMMP (0, 50, and 120 ng/L). Results show significant changes in aroma characteristics in the 120 ng/L wine and smaller effects at the 50 ng/L level. Overall, wines spiked with DMMP generated lower intensity ratings for cherry and red berry descriptors and higher ratings for earthy/musty and green/vegetal descriptors. When considered with other recent results on DMMP concentrations found in wine, DMMP can be considered a hitherto undescribed impact odorant in some wine styles.