Determination Of Volatile Fatty Acids Research Articles

Determination of volatile fatty acids C1–C6, and lactic acid in silage juice

AbstractA method for the determination of volatile fatty acids, C1–C6, and lactic acid in silage juice is described. The procedure is simple and capable of application to large numbers of samples. It involves separation of the free acids by ion exchange, formation of their benzyl esters by the addition of benzyl bromide to a solution of the tetrabutylammonium salts in acetone and ultimate determination by gas liquid chromatography.

Štúdium prchavých mastných kyselín v melase kapilárnou plynovou chromatografiou.

Štúdium prchavých mastných kyselín v melase kapilárnou plynovou chromatografiou.

The determination of volatile fatty acids in the caecum of the conscious rabbit

1. A method of obtaining dialysed samples from the caecum of the conscious rabbit is described. 2. Values for total volatile fatty acid content and for molar proportions of individual volatile fatty acids in dialysate samples were in good agreement with those obtained from caecal material. 3. The volatile fatty acid level in the caecum throughout the day was determined using two groups of animals, one group fed ad lib. and the other group on a restricted food intake. These results indicated a marked diurnal fluctuation in volatile fatty acid level in the caecum of rabbits fed once/d which was not evident in those fed ad lib.

Utilization of Micronized Sorghum Grain by Dairy Calves

Forty-two heifers (24 Holsteins and 18 Ayrshires) were used to compare utilization of rations containing 60% dry rolled and micronized sorghum grain. Calves within each breed were assigned to three groups: (a) control (dry rolled), (b) micronized (380 g/liter), and (c) micronized (230 g/liter). During an 8-wk trial, weights were recorded weekly and rumen samples for volatile fatty acid determination were taken 4 to 5h after feeding during the 4th wk. Nine bull calves (six Holsteins and three Ayrshires) were in a 3×3 Latin square design to determine digestibility of rations in the heifer trial. Mean weight gains were 46.9, 46.0, and 43.8kg for heifers fed dry rolled, micronized (380 g/liter), and micronized (230 g/liter) sorghum grain. Average feed intake was higher in the group of heifers fed the dry rolled grain ration, i.e., 164.7kg compared to 150.0 and 142.4kg for the above groups fed micronized grain. There was a trend for greater feed efficiency by calves fed micronized grain which was consistent with slightly higher digestibility of dry matter and organic matter in the micronized rations. Micronized sorghum grain was accepted readily by young dairy calves.

Determination of volatile fatty acids in plasma after ethanolic extraction.

1. A new rapid micro-method for measuring plasma volatile fatty acids is described. The volatile fatty acids are extracted from plasma with ethanol in the presence of a known quantity of internal standard (sodium isobutyrate). After evaporation of the ethanolic solution of the sodium salts, the residue is dissolved in a dilute solution of orthophosphoric acid to permit analysis by g.l.c. 2. A technique of g.l.c. analysis is described which permits the separation of all the volatile fatty acids from the other plasma constituents at temperatures below 100 degrees C in 5 min. 3. Steam-distillation techniques are unsatisfactory when the acetic acid concentrations in the plasma are below 0.2mm. Heating of a number of plasma constituents in acid conditions gives rise to acetic acid. 4. The binding of volatile fatty acids to plasma proteins was studied; this binding is negligible for acetic acid, but increases with the length of the fatty acid carbon chain. 5. The limits of use of the method and the physiological implications are discussed.

A method for the determination of volatile fatty acids in the blood plasma of ruminant animals.

An improved method for the determination of volatile fatty acids in the blood plasma of ruminant animals is described. The acids are extracted as their sodium salts with isopropyl alcohol and then dissolved in 9 + 1 diethyl ether-formic acid for determination by gas-liquid chromatography.

Improved Method for the Determination of Volatile Fatty Acids in Ruminant Blood Plasma

A method is described for blood plasma volatile fatty acids using direct steam distillation with an anti-foaming agent. Free fatty acids are collected on a microcondenser prior to gas liquid chromatographic analysis. The method is accurate through a wide range for acetate (.05 to 2.50 μmoles per liter), propionate, isobutyrate, butyrate, and valerate (5.0 to 220.0μmoles per liter). However, with increasing concentration there is decreasing precision. The low precision at high concentrations is not serious, since precision is good within the physiologic range. Volatile fatty acids from aqueous solutions and those added to sheep and cattle blood plasma were quantitatively recovered. A comparison was made of the volatile fatty acid in the jugular blood of sheep under conditions of fasting and refeeding.

Rapid method for the gas-chromatographic determination of volatile fatty acids in rumen fluid

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRapid method for the gas-chromatographic determination of volatile fatty acids in rumen fluidBernard G. Cottyn and Charles V. BoucqueCite this: J. Agric. Food Chem. 1968, 16, 1, 105–107Publication Date (Print):January 1, 1968Publication History Published online1 May 2002Published inissue 1 January 1968https://doi.org/10.1021/jf60155a002RIGHTS & PERMISSIONSArticle Views1651Altmetric-Citations234LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (296 KB) Get e-Alerts Get e-Alerts

Volatile fatty acid determination by automatic analysis

The method for volatile fatty acid determinations, as developed by Montgomery et al. (1962) for sewage sludge examination, has been modified and adapted for automatic analysis. The precision and accuracy obtained have been found to be suitable for the purpose of digester sludge control.

Collaborative Study on the Quantitative Determination of Volatile Fatty Acids by Gas Chromatography and by Column Partition Chromatography

Collaborative Study on the Quantitative Determination of Volatile Fatty Acids by Gas Chromatography and by Column Partition Chromatography

Gas Chromatographic Determination of Volatile Fatty Acids in Aqueous Media its use in Bovine Rumen Fluid and in Silage

A rapid quantitative method for the gas chromatographic determination of volatile fatty acids in aqueous media is described. It includes the use of formic acid for the elimination of “ghost peaks” and of iso-valeric acid as an internal standard. The method has been used for the examination of bovine rumen fluid and of silage. Statistical treatment of the result shows that the fluid from lactating cows has a significantly higher content of butyric acid than has the fluid from dry cows; such a difference could not be demonstrated as to acetic, propionic and valeric acid. Some experience from the determination of the volatile fatty acids in silage is also reported.

Determination of Volatile Fatty Acids in Bovine Blood by Isotope Dilution1,2

Summary The levels of acetate, butyrate, and valerate in venous cow blood were determined by an isotope dilution technique involving an acidified acetone-ethanol extraction procedure. It was found that acetate accounts for most of the total volatile fatty acids (VFA) in venous bovine blood and probably is present in greater amounts than heretofore reported. The isotope dilution technique is a valuable tool for the determination of the level of the VFA in blood, but maximum precision and accuracy probably will not be possible until the mode of transport of VFA in blood is understood.

Determination of volatile fatty acids in silage by distillation and by chromatographic methods

Determination of volatile fatty acids in silage by distillation and by chromatographic methods

Determination of Volatile Fatty Acids in Natural Rubber Latex

Abstract The want of a chemical method to determine incipient decomposition in preserved latex has been long felt by producers and consumers of latex. A method often used is to neutralize the ammonia in latex with boric acid or sulfuric acid, and to judge the extent of decomposition from the intensity of putrefactive odors. This method, besides having limitations common to all subjective tests, is insufficiently sensitive to detect the early stages of putrefaction. Another way of assessing deterioration in latex is to determine the total concentration of acidic substances by KOH titration. Though it is widely used in industry, the method has several disadvantages, both as a test for decomposition and as an index of processing behavior. First, acids are estimated which titrate up to pH 11.2, thus failing to discriminate between stabilizing (i.e. soap forming) and destabilizing (e.g. formic, acetic) acids. Second, conjugate acids of bases, basic groups of zwitterions from amino acids, etc., are included. Third, it fails with latexes to which soaps or fixed alkalies have been added. Following observations made in 1941 by the late W. S. Davey at the Rubber Research Institute of Malaya, we have now shown that a substantial proportion of the acids formed in latex as a result of natural degradation processes can be distilled in steam, and that these volatile acids consist mainly of acetic acid, with some formic and propionic acids. It is considered that a test of spoilage based on the estimation of these acids would be free from the disadvantages that are inherent in the KOH titration, and methods of determining quantitatively the volatile fatty acids in latex have accordingly been worked out.

Penicillium roqueforiiによりチーズカードより生成される揮発性脂肪酸について

Changes of volatile fatty acids in whole milk curd, skim milk curd, goat's milk curd and cream inoculated with P. roqueforti and/or Str. lactis were experimented. Quantitative deter-mination of volatile fatty acids was done by modified DUCLAUX's method. Results obtained were as follows: (1) The total amount of volatile fatty acids in incubated whole milk curd was lower than that of commercial Roquefort cheese. (2) By addition of mercerated bread which was previously incubated with P. roqueforti before hooping, volatile fatty acids were produced more than usual inoculation. (3) Volatile fatty acids were produced more in goat's milk curd than in cow's milk curd. (4) By Sir. lactis, production of volatile fatty acids was slight and caproic, caprylic and capric acids were not produced. (5) Lower volatile fatty acids were produced from lactose in skim milk curd and the amount of fatty acids decreased after lactose were by P. roqueforti. (6) Higher volatile fatty acid, as well as lower acids, were produced from cream, but total amount of volatile fatty acids was lower than that of skim milk curd at the beginning of incubation period. (7) Most of the volatile fatty acids were in the form of salt and those in ester form were acetic and butyric.

A Rapid Direct-Distillation Method for Determining the Volatile Fatty Acids of Cheese

Summary A very short and rapid method for the determination of volatile fatty acids in cheese is presented. This new method required that a finely ground sulphuric acid-cheese mixture with a low pH be refluxed to drive off CO 2 and directly distilled in the presence of MgSO 4 . A specific quantity of water (250ml.) was added prior to distillation and the amount of distillate recovered was limited to 285ml. The insoluble volatile fatty acids were washed from the condenser tube by neutral alcohol. Distillates were titrated with N/20 NaOH, using phenolphthalein as indicator. The sum of the titrations of the water distillate and the alcohol rinse represented the total volatile acidity of cheese. The advantages of this method are that high recovery of the volatile fatty acids from cheese is accomplished in a very short time without the use of special glass-joined stills and with a minimum of apparatus and chemical reagents. This method is very adaptable to circumstances where large numbers of cheeses need to be tested in a short time. Direct distillation in the presence of MgSO 4 brought about a very effective recovery of pure lower-chain fatty acids when fresh fat and casein were in the mixture. Under these conditions, recovery was indirectly related to the number of carbon atoms present in each fatty acid.

Determination of Volatile Fatty Acids

Journal Article Determination of Volatile Fatty Acids Get access Fred Hillig, Fred Hillig Food Division, Food and Drug Administration, Federal Security Agency, Washington, D. C Search for other works by this author on: Oxford Academic Google Scholar Lila F Knudsen Lila F Knudsen Food Division, Food and Drug Administration, Federal Security Agency, Washington, D. C Search for other works by this author on: Oxford Academic Google Scholar Journal of Association of Official Agricultural Chemists, Volume 25, Issue 1, 1 February 1942, Pages 176–195, https://doi.org/10.1093/jaoac/25.1.176 Published: 14 February 2020

Determination of Volatile Fatty Acids as an Approach to the Evaluation of Spoilage in Canned Sardines

Determination of Volatile Fatty Acids as an Approach to the Evaluation of Spoilage in Canned Sardines

Determination of Volatile Fatty Acids as an Approach to the Evaluation of Spoilage in Canned Herring Roe

Determination of Volatile Fatty Acids as an Approach to the Evaluation of Spoilage in Canned Herring Roe

Concerning The Dyer Method for The Identification and Determination of Volatile Fatty Acids

Concerning The Dyer Method for The Identification and Determination of Volatile Fatty Acids