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Primary Amino Nitrogen Assay Kit (PANOPA)

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0:05 Introduction
0:50 Principle
1:24  Reagent Preparation
2:34 Procedure
4:52 Calculation

Primary Amino Nitrogen Assay Kit K-PANOPA Scheme
   
Product code: K-PANOPA
€127.00

100 assays (manual) / 1000 assays (microplate) / 1100 assays (auto-analyser)

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Content: 100 assays (manual) / 1000 assays (microplate) / 1100 assays (auto-analyser)
Shipping Temperature: Ambient
Storage Temperature: Short term stability: 2-8oC,
Long term stability: See individual component labels
Stability: > 2 years under recommended storage conditions
Analyte: Nitrogen, Primary Amino Nitrogen, YAN
Assay Format: Spectrophotometer, Microplate, Auto-analyser
Detection Method: Absorbance
Wavelength (nm): 340
Signal Response: Increase
Linear Range: 0.2 to 10 µg of amino nitrogen per assay
Limit of Detection: 2.59 mg N/L
Reaction Time (min): ~ 15 min
Application examples: Grape juice, must, wine and other materials.
Method recognition: Novel method

The Primary Amino Nitrogen (PANOPA) Assay Kit is suitable for the measurement and analysis of primary amino nitrogen in grape juice/must and wine.

Note for Content: The number of manual tests per kit can be doubled if all volumes are halved.  This can be readily accommodated using the MegaQuantTM  Wave Spectrophotometer (D-MQWAVE).

Display our complete list of nitrogen test kits.

View White paper - Free Amino Nitrogen.

Scheme-K-PANOPA PANOPA Megazyme

Advantages
  • Simple format (absorbances read at 340 nm) 
  • Very competitive price (cost per test) 
  • All reagents stable for > 2 years after preparation 
  • Mega-Calc™ software tool is available from our website for hassle-free raw data processing 
  • Standard included 
  • Suitable for manual, microplate and auto-analyser formats
Publications
Megazyme publication

Megazyme “advanced” wine test kits general characteristics and validation.

Charnock, S. J., McCleary, B. V., Daverede, C. & Gallant, P. (2006). Reveue des Oenologues, 120, 1-5.

Many of the enzymatic test kits are official methods of prestigious organisations such as the Association of Official Analytical Chemicals (AOAC) and the American Association of Cereal Chemists (AACC) in response to the interest from oenologists. Megazyme decided to use its long history of enzymatic bio-analysis to make a significant contribution to the wine industry, by the development of a range of advanced enzymatic test kits. This task has now been successfully completed through the strategic and comprehensive process of identifying limitations of existing enzymatic bio-analysis test kits where they occurred, and then using advanced techniques, such as molecular biology (photo 1), to rapidly overcome them. Novel test kits have also been developed for analytes of emerging interest to the oenologist, such as yeast available nitrogen (YAN; see pages 2-3 of issue 117 article), or where previously enzymes were simply either not available, or were too expensive to employ, such as for D-mannitol analysis.

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Megazyme publication

Grape and wine analysis: Oenologists to exploit advanced test kits.

Charnock, S. C. & McCleary, B. V. (2005). Revue des Enology, 117, 1-5.

It is without doubt that testing plays a pivotal role throughout the whole of the vinification process. To produce the best possible quality wine and to minimise process problems such as “stuck” fermentation or troublesome infections, it is now recognised that if possible testing should begin prior to harvesting of the grapes and continue through to bottling. Traditional methods of wine analysis are often expensive, time consuming, require either elaborate equipment or specialist expertise and frequently lack accuracy. However, enzymatic bio-analysis enables the accurate measurement of the vast majority of analytes of interest to the wine maker, using just one piece of apparatus, the spectrophotometer (see previous issue No. 116 for a detailed technical review). Grape juice and wine are amenable to enzymatic testing as being liquids they are homogenous, easy to manipulate, and can generally be analysed without any sample preparation.

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Publication

In Vitro Protective Effect of Paste and Sauce Extract Made with Protaetia brevitarsis Larvae on HepG2 Cells Damaged by Ethanol.

Hwang, D., Goo, T. W. & Yun, E. Y. (2020). Insects, 11(8), 494.

We made paste and sauce using protein-rich Protaetia brevitarsis larvae (PBL) and evaluated their fermentation levels. After pretreatment with the paste and sauce extracts, HepG2 cells were damaged with ethanol (EtOH), and then the effects of the paste and sauce were evaluated. As a result, we confirmed that the PBL paste and sauce extracts reduced the aspartate aminotransferase (AST) and alanine aminotransaminase (ALT) content in the medium as compared to soybean (Glycine max) sauce and paste extracts. In addition, the PBL paste and sauce extracts significantly lowered the level of tumor necrosis factor (TNF)-α and interleukin (IL)-6, which are biomarkers of inflammation, and significantly increased the inhibition rate of superoxide dismutase (SOD) and reduced glutathione (GSH), which are antioxidative indicators, in proportion to the amount of PBL added to the paste and sauce. These results suggest that an intake of PBL paste and sauce, a novel type of fermented food made from insects, may be effective for liver protection through anti-inflammatory and antioxidative effects against hepatocyte injury caused by EtOH.

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Publication

Soil Nitrogen Fertilization Increases Yeast Assimilable Nitrogen Concentrations in ‘Golden Russet’and ‘Medaille d’Or’Apples Used for Cider Production.

Karl, A. D., Brown, M. G., Ma, S., Sandbrook, A., Stewart, A. C., Cheng, L., Mansfield, A. K. & Peck, G. M. (2020). Hort. Science, 55(8), 1345-1355.

The recent growth in the U.S. hard-cider industry has increased the demand for cider apples (Malus×domestica Borkh.), but little is known about how to manage orchard soil fertility best to optimize horticultural performance and juice characteristics for these cultivars. To assess whether nitrogen fertilizer applied to the soil can improve apple juice and cider quality, calcium nitrate (CaNO3) fertilizer was applied at different rates to the soil beneath ‘Golden Russet’ and ‘Medaille d’Or’ trees over the course of three growing seasons. The experiment started when the trees were in their second leaf. The trees were cropped in their third and fourth leaf. At the end of the first growing season of the experiment, the greatest fertilizer rate increased tree trunk cross-sectional area (TCSA) by 82% relative to the control, but this difference did not persist through to the end of the study. Yield and crop load were unaffected by the nitrogen fertilization treatments. Increasing the nitrogen fertilizer rate correlated positively with more advanced harvest maturity in ‘Golden Russet’ fruit, which resulted in greater soluble solid concentration (SSC). Fruit from the greatest fertilizer rate treatment had an average starch pattern index (SPI) that was 1 U greater than in the control, and an SSC that was 3% greater than the control. The fertilizer treatments did not affect juice pH, titratable acidity (TA), or total polyphenol concentrations. Yeast assimilable nitrogen (YAN) concentrations were increased by nitrogen fertilization for both cultivars in both harvest years. The greatest fertilizer treatment increased juice primary amino nitrogen by 103% relative to the control. Greater nitrogen fertilization rates correlated positively with less hydrogen sulfide production during the fermentation of ‘Golden Russet’ juice from the first, but not the second, harvest. During the first year, cumulative hydrogen sulfide production for the ‘Golden Russet’ control treatment was 29.6 μg·L-1 compared with the ‘Golden Russet’ high treatment, which cumulatively produced 0.1 μg·L-1. Greater maximum fermentation rates and shorter fermentation durations correlated positively with increased fertilization rate for both cultivars after the second harvest. High treatment fermentations had maximum fermentation rates 110% greater, and fermentation durations 30% shorter than the control. Other horticultural and juice-quality parameters were not affected negatively by the CaNOtreatments. In orchards producing apples specifically for the hard-cider industry, nitrogen fertilizer could increase juice YAN, thus reducing the need for exogenous additions during cider production.

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Publication

Modelling of S. cerevisiae and T. delbrueckii pure culture fermentation in synthetic media using a compartmental nitrogen model.

Brou, P., Patricia, T., Beaufort, S. & Brandam, C. (2020). OENO One, 54(2), 299-311.

Aim: The objective of the present work is to propose a model describing the evolution of the pure culture fermentation of two oenological yeasts: S. cerevisiae and T. delbrueckii. Methods and results: For both yeasts, pure culture fermentation was performed in a synthetic medium with different initial concentrations of yeast available nitrogen. The datasets obtained from those experiments were used to identify the parameters of the proposed model. Conclusions: The developed comprehensive model of wine-making fermentation is based on the partition of assimilated nitrogen between the constitutive and the storage compartments. It efficiently describes the evolution of S. cerevisiae and T. delbrueckii pure cultures. This mass-balance model provides a stoichiometric approach in biomass production, unlike nitrogen backboned models used in winemaking. Moreover, it gives an estimation of non-accessed data such as nitrogen partition between vacuole and cytosol during T. delbrueckii fermentation. Significance and impact of the study: The developed model is robust enough to precisely describe the fermentation evolution of two pure culture yeasts and therefore has future potential for modelling mixed culture fermentations of S. cerevisiae and T. delbrueckii.

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Publication

Factors influencing the production of the antioxidant hydroxytyrosol during alcoholic fermentation: Yeast strain, initial tyrosine concentration and initial must.

Rebollo-Romero, I., Fernández-Cruz, E., Carrasco-Galán, F., Valero, E., Cantos-Villar, E., Cerezo, A. B., Troncosso, A. M. & Garcia-Parrilla, M. C. (2020). LWT, 130, 109631.

Hydroxytyrosol is well known for its potent antioxidant activity and anticarcinogenic, antimicrobial, cardioprotective and neuroprotective properties. Main food sources are olive oil (formed from the hydrolysis of oleuropein) and wine. One possible explanation to its origin in wines is the synthesis from tyrosol, which in turn is produced from the Ehrlich pathway by yeasts. This work aims to explore the factors that could increase the content as the strain of yeast, the initial tyrosine concentrations as precursor and the effect of synthetic and sterilized natural grape musts. Alcoholic fermentations in synthetic must showed that hydroxytyrosol is produced by all the yeast strains under study. Commercial Saccharomyces cerevisiae yeasts were those which produced higher concentrations, being the Red Fruit strain the biggest producer (6.12 ng/mL). Once the strain was selected, alcoholic fermentations were performed in synthetic must, with different tyrosine concentrations. The amount of hydroxytyrosol did not increase in a proportional way as tyrosine does. On the other hand, higher concentrations of hydroxytyrosol were obtained in natural grape musts (10.46 ng/mL) than in synthetic must (4.03 ng/mL). This work confirms the capacity of winemaking yeasts to produce the bioactive hydroxytyrosol.

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Publication

Assessing the oenological potential of Nakazawaea ishiwadae, Candida railenensis and Debaryomyces hansenii strains in mixed-culture grape must fermentation with Saccharomyces cerevisiae.

van Wyk, N., Pretorius, I. S. & von Wallbrunn, C. (2020). Fermentation, 6(2), 49.

Recently, there has been a growing interest in the role of non-Saccharomyces yeast (NSY) as a coculturing partner with Saccharomyces cerevisiae during grape must fermentation. We investigated three new strains, namely Nakazawaea ishiwadae, Candida railenensis and Debaryomyces hansenii, for their oenological potential in mixed-culture micro-vinifications with S. cerevisiae Vin13 using Muscaris grape must. None of the NSY strains impeded the fermentation performance as all the mixed-culture experiments finished at the same time. Coculturing with N. ishiwadae yielded significantly higher concentrations of ethyl and acetate esters in the final wine product. Apart from higher acetic acid levels, wines produced with C. railenensis and D. hansenii yielded much lower esters concentrations. The concentrations of certain terpenes and norisoprenoids were also significantly modulated in the mixed-culture fermentations. This study reveals the rarely reported species of N. ishiwadae as a promising coculturing partner for increasing aroma-active compounds in a wine.

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Publication

Saccharomyces uvarum yeast isolate consumes acetic acid during fermentation of high sugar juice and juice with high starting volatile acidity.

Inglis, D., Kelly, J., van Dyk, S., Dowling, L., Pickering, G. & Kemp, B. (2020). OENO One, 54(2).

Aim: A Saccharomyces uvarum isolate was assessed for its ability to metabolize acetic acid present in juice and during the fermentation of partially dehydrated grapes. The impact on other yeast metabolites was also compared using an S. uvarum isolate and an S. cerevisiae wine yeast. The upper limit of fruit concentration that allowed the S. uvarum isolate to ferment wines to < 5 g/L residual sugar was defined. Methods and results: Cabernet franc grapes were partially dehydrated to three different post-harvest sugar targets (24.5 °Brix, 26.0 °Brix, and 27.5 °Brix) along with non-dehydrated grapes (21.5 °Brix control). Musts from all treatments were vinified with either the S. uvarum isolate CN1, formerly identified as S. bayanus, or S. cerevisiae EC1118. All wines were successfully vinified to less than 5 g/L residual sugar. Fermentation kinetics between the two yeasts were similar for all wines other than 27.5 °Brix, where CN1 took three days longer. During fermentation with CN1, acetic acid peaked on day two, then decreased in concentration, resulting in final wine acetic acid lower than that measured on day two. Wines fermented with EC1118 showed an increase in acetic acid over the time-course of fermentation. Significantly lower wine oxidative compounds (acetic acid, acetaldehyde and ethyl acetate) and higher glycerol resulted in wine produced with CN1 in comparison to EC1118. Both yeasts produced comparable ethanol at each Brix level tested. Further studies showed that CN1 lowered acetic acid seven-fold from 0.48 g/L in juice to 0.07 g/L in wine whereas EC1118 reduced acetic acid to 0.18 g/L. Conclusions: The autochthonous S. uvarum yeast isolate successfully fermented partially dehydrated grapes to < 5 g/L sugar up to 27.5 ºBrix. The consumption rate of acetic acid was faster than its production during fermentation, resulting in low acetic acid, acetaldehyde and ethyl acetate in wine in comparison to a commercial S. cerevisiae yeast while consistently producing higher glycerol. Significance and impact of the study: The S. uvarum yeast isolate can metabolize acetic acid during fermentation to significantly lower acetic acid, ethyl acetate and acetaldehyde in wine. It can also reduce acetic acid by seven-fold from the starting juice to the finished wine, which could have potential application for managing sour rot arising in the vineyard or during the dehydration process in making appassimento-style wines.

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Publication

Influence of Nutrient Supplementation on Torulaspora Delbrueckii Wine Fermentation Aroma.

Mecca, D., Benito, S., Beisert, B., Brezina, S., Fritsch, S., Semmler, H. & Rauhut, D. (2020). Fermentation, 6(1), 35.

This study was performed with the aim of characterizing the fermentative performance of three commercial strains of Torulaspora delbrueckii and their impact on the production of volatile and non-volatile compounds. Laboratory-scale single culture fermentations were performed using a commercial white grape juice. The addition of commercial nutrient products enabled us to test the yeasts under two different nutrient conditions. The addition of nutrients promoted fermentation intensity from 9% to 20 % with significant differences (p < 0.05) among the strains tested. The strain diversity together with the nutrient availability influenced the production of volatile compounds.

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Publication

Nutrient Addition to Low pH Base Wines (L. cv. Riesling) during Yeast Acclimatization for Sparkling Wine: Its Influence on Yeast Cell Growth, Sugar Consumption and Nitrogen Usage.

Kemp, B., Plante, J. & Inglis, D. L. (2020). Beverages, 6(1), 10.

In traditional method sparkling wine production, to carry out a successful second alcoholic fermentation, yeast are acclimatized to stressful base wine conditions. Base wines typically have low pH, low nutrient concentrations, high acid concentrations, contain sulfur dioxide (SO2), and high ethanol concentrations. Supplementing yeast during the acclimatization stages prior to second alcoholic fermentation with different nutrient sources was assessed to determine the impact on yeast growth, sugar consumption and nitrogen usage. Four treatments were tested with Saccharomyces cerevisiae strain EC1118: the control (T1) with no additives; addition of diammonium phosphate (DAP) during acclimatization, (T2); Go-Ferm® inclusion during yeast rehydration (GF), (T3); and DAP + GF (T4). Results (n = 4) indicated that supplementing with DAP, GF or DAP + GF increased both the rate of sugar consumption and the concentration of viable cells during the yeast acclimatization phase in comparison to the control. Treatments supplemented with DAP + GF or DAP alone resulted in yeast consuming 228 and 220 mg N/L during the acclimatization phase, respectively. Yeast treated only with GF consumed 94 mg N/L in comparison to the control, which consumed 23 mg N/L. The time required to reach the target specific gravity (1.010) during acclimatization was significantly reduced to 57 h for yeast treated with DAP and GF, 69 h for yeast treated with DAP only and 81 h for yeast rehydrated with GF in comparison to 105 h for the control. Our results suggest that nutrients used during yeast acclimatization could have an important impact on the kinetics of second alcoholic fermentation.

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Publication

Viability of IR spectroscopy for the accurate measurement of yeast assimilable nitrogen content of grape juice.

Petrovic, G., Aleixandre-Tudo, J. L. & Buica, A. (2020). Talanta, 206, 120241.

Up to date, there have been only a few reports on the measurement of YAN and/or its components using IR spectroscopy, suffering from various limitations (number of samples, validation strategies, etc.). In this work, three IR spectral instruments measuring in different modes and ranges of the IR spectrum (FT-IR, FT-NIR, and ATR-MIR), were compared and evaluated for their accuracy to measure both total YAN as well as the components, FAN and ammonia separately, using over 900 grape juice samples from 28 cultivars over three seasons. The global and vintage-based models were evaluated using R2CAL/VAL, RMSEC/P, and RPDCAL/VAL. Randomization tests were used for pair-wise comparison of models. FT-IR and FT-NIR instruments gave the best results, while ATR-MIR can be used for screening purposes. Considering the accuracy, robustness, high throughput, and cost-effective nature, the models produced by both FT-IR and FT-NIR spectroscopy can provide winemakers with the opportunity to make timelier and more informed nutrient supplementation decisions, facilitating the achievement of their desired wine style and quality.

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Publication

The Use of CRISPR-Cas9 Genome Editing to Determine the Importance of Glycerol Uptake in Wine Yeast During Icewine Fermentation.

Muysson, J., Miller, L., Allie, R. & Inglis, D. L. (2019). Fermentation, 5(4), 93.

The high concentration of sugars in Icewine juice causes formidable stress for the fermenting Saccharomyces cerevisiae, causing cells to lose water and shrink in size. Yeast can combat this stress by increasing the internal concentration of glycerol by activating the high osmolarity glycerol response to synthesize glycerol and by actively transporting glycerol into the cell from the environment. The H+/glycerol symporter, Stl1p, has been previously characterized as being glucose repressed and inactivated, despite osmotic stress induction. To further investigate the role of Stl1p in Icewine fermentations, we developed a rapid single plasmid CRISPR-Cas9-based genome editing method to construct a strain of the common Icewine yeast, S. cerevisiae K1-V1116, that lacks STL1. In an Icewine fermentation, the ∆STL1 strain had reduced fermentation performance, and elevated glycerol and acetic acid production compared to the parent. These results demonstrate that glycerol uptake by Stl1p has a significant role during osmotically challenging Icewine fermentations in K1-V1116 despite potential glucose downregulation.

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Publication

A 2-year multisite study of viticultural and environmental factors affecting rotundone concentration in Duras red wine.

Geffroy, O., Descôtes, J., Levasseur-Garcia, C., Debord, C., Denux, J. P. & Dufourcq, T. (2019). OENO One, 53(3).

Aim: A study was carried out in 2013 and 2014 to determine the key environmental and viticultural variables affecting the concentration of rotundone, the black pepper aroma compound, in Vitis vinifera L. cv. Duras red wines at 10 different vineyard blocks. Methods and Results: For each block, data for fruit quality attributes, as well as climatic and agronomical variables, were collected. Rotundone was quantified in wines prepared by microvinification techniques (in a 1-L Erlenmeyer flask). Rotundone concentration varied across blocks from 63 ng/L to 239 ng/L in 2013 and from 25 ng/L to 115 ng/L in 2014. Three separate partial least squares regression models were constructed to predict rotundone concentration in wines in 2013, in 2014, and in both vintages. Gluconic acid, a secondary metabolite of Botrytis cinerea, had a substantial contribution to the 2013 and multivintage models, with a negative regression coefficient with rotundone concentration. Other predictors were associated with abiotic factors such as cumulative rainfall, thermal index, hours of sunshine and mean daily irradiation. Conclusions: Our results indicate that mesoscale climatic variables are the key factors determining rotundone concentration, and also suggest that Botrytis cinerea may be involved in rotundone degradation. Significance and impact of the study: Our findings may assist grape growers producing Duras red wines to select specific vineyard blocks with the aim of producing wines with a desired rotundone concentration. They also open up new fields of investigation into mechanisms involved in possible rotundone degradation by Botrytis cinerea.

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Publication

Saccharomyces cerevisiae and Torulaspora delbrueckii intra-and extra-cellular aromatic amino acids metabolism.

Álvarez-Fernández, M. A., Fernández-Cruz, E., Garcia-Parrilla, M. C., Troncoso, A. M., Mattivi, F., Vrhovsek, U. & Arapitsas, P. (2019). Journal of Agricultural and Food Chemistry, 67(28), 7942-7953.

Tryptophan, phenylalanine, and tyrosine play an important role as nitrogen sources in yeast metabolism. They regulate biomass production and fermentation rate, and their catabolites contribute to wine health benefits and sensorial character through the yeast biotransformation of grape juice constitutes into biologically active and flavor-impacting components. A UHPLC-MS/MS method was applied to monitor 37 tryptophan/phenylalanine/tyrosine yeast metabolites both in extra- and intracellular extracts produced by the fermentation of two Saccharomyces cerevisiae strains and one Torulaspora delbrueckii. The results shed light on the intra- and extra-cellular metabolomic dynamics, by combining metabolic needs, stimuli, and signals. Among others, the results indicated (a) the production of 2-aminoacetophenone by yeasts, mainly by the two Saccharomyces cerevisiae; (b) the deactivation and/or detoxification of tryptophol via sulfonation reaction; and (c) the deacetylation of N-acetyl tryptophan ethyl ester and N-acetyl tyrosine ethyl ester by producing the corresponding ethyl esters.

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Publication

Screening for oily yeasts able to convert hydrolysates from biomass to biofuels while maintaining industrial process relevance.

Slininger, P. J., Dien, B. S., Quarterman, J. C., Thompson, S. R. & Kurtzman, C. P. (2019). “Microbial Lipid Production”, Humana, New York, NY, 249-283.

Research has recently intensified to discover new oleaginous yeast strains able to function quickly and efficiently in low-cost lignocellulosic hydrolysates to produce high-quality lipids for use in biodiesel and chemicals. Detailed techniques are given here for ranking candidate yeast strains based on conversion of hydrolysate sugars to lipids and then optimizing cultivation conditions for best performers in a 96-well aerobic microcultivation format. A full battery of assays applicable to high throughput of small-volume samples are described for efficiently evaluating cell biomass production, lipid accumulation, fatty acid composition, and sugar utilization. Original data is additionally presented on the validation of the microtechnique for GC analysis of lipid composition in yeast since this application involved modification of a previously published assay for microalgae.

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Publication

Saccharomyces cerevisiae-Starmerella bacillaris strains interaction modulates chemical and volatile profile in red wine mixed fermentations.

Englezos, V., Pollon, M., Rantsiou, K., Ortiz-Julien, A., Botto, R., Segade, S. R., Giacossa, S., Rolle, L. & Cocolin, L. (2019). Food Research International, 122, 392-401.

The use of Starmerella bacillaris in combination with Saccharomyces cerevisiae is considered as a state-of-the-art biological application to modulate wine composition. This application implies a detailed understanding of yeast-yeast interactions during mixed fermentations and their effect on the composition of the resulting wines. In this context, ten commercial S. cerevisiae strains were used as partners of an indigenous, previously characterized Starm. bacillaris strain in order to get a better insight into the impact of S. cerevisiae strain employed. The different combinations of strains tested influenced the growth dynamics, the fermentation behavior and, as a consequence, wine composition in a couple-dependent manner. In addition, wines produced from mixed fermentations had significantly lower levels of ethanol, acetic acid and ethyl acetate, and showed higher amounts of glycerol, higher alcohols and esters compared to pure S. cerevisiae control fermentations. This study reveals the importance of S. cerevisiae strain choice on the chemical composition of the wines produced from mixed culture fermentations with Starm. bacillaris.

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Magnetic resonance imaging of the human ferritin heavy chain reporter gene carried by dendrimer-entrapped gold nanoparticles.

Zhuo, Y., Chen, F., Kong, L., Li, T., Lu, L., Yang, J., Tao, Y., Xiangyang, S. & Li, K. (2019). Journal of Biomedical Nanotechnology, 15(3), 518-530.

This paper aimed to find an effective method to destroy cancer cells by targeting breast cancer cells with natural killer (NK) cells transfected with the human ferritin heavy chain (hFTH1) gene by polyethylene glycol (PEG)-modified dendrimerentrapped gold nanoparticles (Au DENPs). In this study, fifth-generation polyamidoamine (G5 PAMAM) dendrimers modified with PEG were used as templates to entrap gold nanoparticles to transfect hFTH1 into NK cells. Our results revealed that the prepared Au DENPs/FTH1 provided high-quality imaging performance (hypointensity on T2-weighted MR imaging) and efficient transfection efficiency (reaching 80.2%) at a N/P ratio (ratio of the number of surface primary amines on {(Au0)25-G5 NH2-mPEG17} to the number of phosphate groups in the hFTH1 backbone) of 5:1. Interestingly, the results showed that Au DENPs/FTH1 effectively guided NK-92 cells to concentrate around tumor cells for effective gene therapy without severely impacting their activity. This work will provide a new research platform for immunotherapy based on NK cells and lead to the optimization and even individualization of breast cancer immunotherapy through nanomolecular visualization research, which has a broad scope for future clinical applications.

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A statistical exploration of data to identify the role of cultivar and origin in the concentration and composition of yeast assimilable nitrogen.

Petrovic, G., Kidd, M. & Buica, A. (2019). Food Chemistry, 276, 528-537.

The study was undertaken to gain insight into the nitrogen status of grape juices currently used to make commercial wines in South Africa. This was done as yeast assimilable nitrogen (YAN) is most often suspected as the cause for problematic fermentations and has major implications for the organoleptic qualities of the final product. Using exploratory statistical methods, this study explored the possibility of identifying the role of cultivar and grape-growing district in the determination of the concentration and composition of YAN. However, as the dataset was found to be non-parametric and heteroscedastic, paired with unequal sample sizes, data analysis was approached with caution. Through the use of various suitable statistical analyses, cultivar was shown to play the more important role in determining the concentration and composition of YAN.

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Juice clarification with pectinase reduces yeast assimilable nitrogen in apple juice without affecting the polyphenol composition in cider.

Ma, S., Neilson, A., Lahne, J., Peck, G., O'Keefe, S., Hurley, E. K., Sandbrook, A. & Stewart, A. (2018). Journal of Food Science, 83(11), 2772-2781.

The term “cider” refers to the fermented beverage produced from apples. The rapid growth in the cider industry coupled with the prominence of traditional, or craft, approaches emphasizes the need for research on cider production. A common problem in ciders is the production of sulfur off‐aromas by yeast during fermentation. Prefermentation juice clarification has the potential to reduce the occurrence of unwanted sulfur off‐aromas. Concerns that prefermentation juice clarification will reduce the yeast assimilable nitrogen (YAN) and polyphenols in the juice have limited the application of this practice by cider makers. In this study, 3 clarification methods were applied to ‘York’ apple juice, that is, static settling, centrifugation, and pectinase. Raw (control) and clarified juice were fermented to cider, and the impact of clarification on the physicochemical parameters, amino acids and polyphenol content of the juice and cider was assessed. Juice clarification by pectinase decreased YAN by 50%, while static settling and centrifugation increased the concentration of most amino acids by 83%. All clarification treatments lowered the concentration of total polyphenols in the juice (from 60% to 30%, P < 0.05) and affected the individual polyphenols in the juice but these changes were not evident in the ciders. These findings demonstrate that prefermentation juice clarification results in changes in the chemistry profiles of apple juice. These changes were however not evident in the ciders. This approach therefore has the potential to limit the production of sulfur off‐aromas during cider production without adverse effects on quality.

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Augmentation of chemical and organoleptic properties in Syzygium cumini wine by incorporation of grape seeds during vinification.

VenuGopal, K. S., Cherita, C. & Anu-Appaiah, K. A. (2018). Food Chemistry, 242, 98-105.

The role of grape seed tannins on improving organoleptic properties and its involvement in color stabilization in red wine are well established. The addition of grape seeds as the source of condensed tannins in fruit wine may provide a solution for its color instability and improvement of sensory attributes. Syzgium cumini is traditionally known for its therapeutic properties. In the current study, the influence of yeasts and grape seed addition during fermentation on the chromatic, phenolic and sensory attributes of the wine was accessed. Grape seed addition improved the color characteristics of wine and increased overall phenolic composition. Analysis by HPLC revealed 6 major anthocyanins, among which 3, 5-diglucoside form of delphidin and petunidin was found to be the major components. Cluster and PLSR analysis explained the impact of seed addition on the yeasts, as well as on the perception of panelists, with bitterness and astringency as the dominating attributes.

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Safety Information
Symbol : GHS07, GHS08
Signal Word : Danger
Hazard Statements : H315, H317, H319, H360, H412
Precautionary Statements : P201, P202, P261, P264, P272, P273, P280, P302+P352, P305+P351+P338, P308+P313, P321, P333+P313, P362+P364, P501
Safety Data Sheet
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