Effect of organic acids on the growth of Leuconostoc oenos and Lactobacillus hilgardii strains isolated from red wines

OENO One ◽  
1991 ◽  
Vol 25 (2) ◽  
pp. 99
Author(s):  
María Cristina Manca de Nadra ◽  
Ana María Strasser de Saad

<p style="text-align: justify;">The effect of organic acids on the growth of <em>Leuconostoc oenos</em> and <em>Lactobacillus hilgardii</em> strains was investigated, and the interaction between organic acids, ethanol and inoculum level was determined. The four selected strains of <em>Leuconostoc oenos</em> : X<sub>2</sub>L, E<sub>2</sub>, ST<sub>2</sub> and L<sub>2</sub> and the two selected strains of <em>Lactobacillus hilgardii</em> : 7<sub>j</sub> and X<sub>1</sub>B are resistent to 10 p. cent ethanol, a typical concentration for a table wine.</p><p style="text-align: justify;">The effect of the additives depends on the strain, except for dodecanoic acid which produces a growth inhibition in the six strains. Dodecanoic acid is an effective inhibitor when added to grape juice and might be used as a substitute of SO<sub>2</sub>, or rather in association with SO<sub>2</sub>.</p>

OENO One ◽  
1993 ◽  
Vol 27 (2) ◽  
pp. 135 ◽  
Author(s):  
María Julia Amoroso ◽  
Fabiana María Saguir ◽  
María Cristina Manca de Nadra

<p style="text-align: justify;"><em>Leuconostoc oenos</em> strains: m, L<sub>2</sub> ST, X<sub>2</sub>L, have been isolated from different Argentinian red wines. Amino acids, vitamins and base requirements were determined in a synthetic medium containing L-malic acid, citric acid or both organic acids. The organisms differed in their requirements. The growth of the four <em>L. oenos</em> strains studied was greater in the synthetic medium with L-malic acid plus citric acid. In this medium, <em>L. oenos</em> m, L<sub>2</sub>, and ST eliminated their amino acid requirements, however X<sub>2</sub>L in the same medium increased these requirements. In respect of the vitamin and base requirements, <em>L. oenos</em> m and L<sub>2</sub> showed no significant difference by the addition of L-malic acid, citric acid or both organic acids to the synthetic medium. <em>L. oenos</em> ST needed L-malic acid plus citric acid to avoid these requirements, while the X<sub>2</sub>L strain increased its requirements with both organic acids.</p>


Author(s):  
О.Н. ШЕЛУДЬКО ◽  
Н.К. СТРИЖОВ ◽  
Е.С. КОСАРЕВ ◽  
Н.О. ШЕЛУДЬКО

Проведен сравнительный анализ вида кривых титрования, оптических спектров, содержания органических кислот и катионов щелочных и щелочноземельных металлов красных сортовых вин с нахождением критериальных маркеров. Объекты исследования – красные сортовые вина, произведенные по одной технологии из выращенного в центральной зоне Краснодарского края винограда сортов Каберне Совиньон, Мерло, Саперави, Изабелла. Установлено, что кривые титрования индивидуальны, позволяют дать качественную оценку подлинности винодельческой продукции по начальной величине рН (обусловлена содержанием калия), виду кривых титрования до начала скачка (обусловлен содержанием винной и яблочной кислот). Определено количественное содержание титруемых кислот, а также маркерные значения, подтверждающие подлинность вин: рНо, tk, dpH/dt. Оптические свойства вин не позволяют дать количественную оценку фенольных веществ, но расширяют возможности применения данного метода в качестве интегральной характеристики сортовых красных вин по виду оптического спектра и значению оптической плотности D и длине волны λ. Отношение катионов щелочных и щелочноземельных металлов между собой можно применять в качестве дополнительного маркера сортовых вин, произведенных из винограда вида Vitis vinifera или Vitis labrusca. Показано, что отличие форм кривых титрования разных вин, а также оптических спектров и различия содержания органических кислот и катионов щелочных и щелочноземельных металлов можно использовать как графические образы винодельческой продукции конкретного наименования в рамках национальной системы защиты вин, обладающих особыми качествами. A comparative analysis of the type of titration curves, optical spectra, the content of organic acids and cations of alkaline and alkaline earth metals of red varietal wines with the search for criteria markers was carried out. The objects of the study are red varietal wines produced using the same technology from grapes grown in the central zone of the Krasnodar Territory, the variety: Cabernet Sauvignon, Merlot, Saperavi, Isabella. It is established that the titration curves are individual, allowing us to give a qualitative assessment of the authenticity of wine products by the initial pH value (due to the potassium content), by the type of titration curves before the jump (due to the content of tartaric and malic acids). The quantitative content of titrated acids was determined, as well as marker values confirming the authenticity of the wines: pH, tk, dpH/dt. The optical properties of wines do not allow us to give a quantitative assessment of phenolic substances, but they expand the possibilities of using this method as an integral characteristic of varietal red wines by the type of optical spectrum and the value of the optical density D and the wavelength λ. The ratio of cations of alkali and alkaline earth metals to each other can be used as an additional marker of varietal wines produced from grapes of the Vitis vinifera or Vitis labrusca species. It is shown that the difference in the shapes of the titration curves of different wines, as well as the optical spectra and differences in the content of organic acids and cations of alkaline and alkaline earth metals can be used as graphic images of wine products of a specific denomination within the framework of the national system for the protection of wines with special qualities.


Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2007
Author(s):  
Lety del Pilar Fajardo Cabrera de Lima ◽  
Cristian David Chamorro Rodríguez ◽  
José Herminsul Mina Hernandez

In obtaining wood polymer composites (WPCs), a weak interfacial bonding can cause problems during the processing and affect the mechanical properties of the resulting composites. A coupling agent (CA) is commonly used to solving this limitation. To improve the interfacial bonding between bamboo fiber (BF) and a polypropylene matrix, the effect of three organic acids on the mechanical properties and interfacial morphology were investigated. The BF/PP composites were prepared in five families: the first without CA, the second using a maleic anhydride-grafted polypropylene coupling agent, and the third, fourth, and fifth families with the addition of organic acids (OA) tricarboxylic acid (TRIA), hexadecanoic acid (HEXA), and dodecanoic acid (DODA), respectively. The use of OA in BF/PP improved the interfacial adhesion with the PP matrix, and it results in better mechanical performance than composites without CA. Composites coupled with MAPP, TRIA, DODA, and HEXA showed an increase in Young’s modulus of about 26%, 23%, 15%, and 16% respectively compared to the composite without CA incorporation. In tensile strength, the increase in composites with CA was about 190%, while in the flexural modulus, the coupled composites showed higher values, and the increase was more in composites with TRIA: about 46%. The improvement caused by tricarboxylic acid was similar to that promoted by the addition of maleic anhydride-grafted polypropylene (MAPP).


2014 ◽  
Vol 38 (5) ◽  
pp. 480-486 ◽  
Author(s):  
Ana Carolina Vilas Boas ◽  
Paôla de Castro Henrique ◽  
Luiz Carlos de Oliveira Lima ◽  
Antônio Decarlos Neto

Phenolic compounds and anthocyanins content in grape juices varies in the cultivar, ripening and climate characteristics. The objective of this work was to characterize and evaluate antioxidant activity of grape juices produced in southwestern Minas Gerais. Grapes were harvested, sanitized and the juices from cultivars 'Bordô', 'Isabel Precoce', 'BRS Violeta' and 'BRS Rúbea' were produced in artisanal equipment by steam extraction and stored for 120 days. The following analyzes were performed during storage: color (L *), pH, soluble solids, titratable acidity, anthocyanins, antioxidant activity (DPPH and β-caroteno/linoleic acid), total phenolics, vitamin C and organic acids. Among the cultivars evaluated, the consumption of grape juice from cultivar 'BRS Violeta' is suggested due to its higher content of vitamin C, antioxidant activity, total phenolics, anthocyanins, and also due to a better physicochemical characteristic showed, when compared to the juices of the other cultivars.


1989 ◽  
Vol 52 (4) ◽  
pp. 240-243 ◽  
Author(s):  
D. F. SPLITTSTOESSER ◽  
B. O. STOYLA

Various compounds were tested to determine whether they would substitute for SO2 as inhibitors of strains of Leuconostoc oenos when inoculated into a model fruit beverage containing 5°C Brix Concord grape and 0.1% yeast extract. The following additives and their maximal concentrations exhibited varying degrees of inhibitory activity: fumaric acid, 1.5 mg/ml; sorbic acid, 300 μg/ml; decanoic acid, 20 μg/ml; nisin, 100 IU/ml; and carbon dioxide, 2.8 volumes. Effectiveness of the inhibitors was enhanced by the presence of 8 to 10% ethanol, and was inversely related to the size of the inoculum.


1998 ◽  
Vol 61 (10) ◽  
pp. 1358-1362 ◽  
Author(s):  
E. RAJASHEKHARA ◽  
E. R. SURESH ◽  
S. ETHIRAJ

Heat-resistant molds, including Neosartorya fischeri, are known to spoil thermally processed fruit products. The control measures required for such problems must not cause an appreciable loss of the organoleptic qualities of the final products. In the present study we determined the thermal death rates of ascospores of N. fischeri ATCC 200957 in fruit juices containing organic acids and preservatives. The ascospores were able to survive for more than 6 h of heating at 75°C, 5 h at 80°C, and 3 to 4 h at 85°C in mango or grape juice. Of the four organic acids tested, citric acid exhibited the maximal destruction of ascospores in mango juice at 85°C (l/k = 27.22 min), and tartaric acid the least (1/k = 61.73 min). The effect of common preservatives on the thermal death rates of ascospores at 85°C in mango and grape juices was studied. Almost similar effects on thermal inactivation of ascospores were noted when potassium sorbate (l/k = 29.38 min) or sodium benzoate (l/k = 27.64 min) or the combination of both (l/k = 27.53 min) was used in mango juice. In grape juice, potassium sorbate (l/k = 25.07 min) was more effective than sodium benzoate (l/k = 50.08 min) or the combination of both (l/k = 40.79 min) in inactivation of ascospores of the mold. The thermal death rate (l/k) values in mango and grape juices in the absence of any preservative were 63.51 and 69.27 min respectively.


2012 ◽  
Vol 78 (23) ◽  
pp. 8377-8387 ◽  
Author(s):  
Azmat Ullah ◽  
Rick Orij ◽  
Stanley Brul ◽  
Gertien J. Smits

ABSTRACTWeak organic acids are naturally occurring compounds that are commercially used as preservatives in the food and beverage industries. They extend the shelf life of food products by inhibiting microbial growth. There are a number of theories that explain the antifungal properties of these weak acids, but the exact mechanism is still unknown. We set out to quantitatively determine the contributions of various mechanisms of antifungal activity of these weak acids, as well as the mechanisms that yeast uses to counteract their effects. We analyzed the effects of four weak organic acids differing in lipophilicity (sorbic, benzoic, propionic, and acetic acids) on growth and intracellular pH (pHi) inSaccharomyces cerevisiae. Although lipophilicity of the acids correlated with the rate of acidification of the cytosol, our data confirmed that not initial acidification, but rather the cell's ability to restore pHi, was a determinant for growth inhibition. This pHirecovery in turn depended on the nature of the organic anion. We identified long-term acidification as the major cause of growth inhibition under acetic acid stress. Restoration of pHi, and consequently growth rate, in the presence of this weak acid required the full activity of the plasma membrane ATPase Pma1p. Surprisingly, the proposed anion export pump Pdr12p was shown to play an important role in the ability of yeast cells to restore the pHiupon lipophilic (sorbic and benzoic) acid stress, probably through a charge interaction of anion and proton transport.


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