Formic and acetic acids in archaeological wood. A comparison between the Vasa Warship, the Bremen Cog, the Oberländer Boat and the Danish Viking Ships

Holzforschung ◽  
2006 ◽  
Vol 60 (3) ◽  
pp. 259-264 ◽  
Author(s):  
Jens Glastrup ◽  
Yvonne Shashoua ◽  
Helge Egsgaard ◽  
Martin Nordvig Mortensen
Keyword(s):  
Acetic Acid ◽  
Formic Acid ◽  
Gas Phase ◽  
Acid Content ◽  
Solid Phase ◽  
Gas Chromatography Mass Spectrometry ◽  
Archaeological Wood ◽  
Acetic Acid Content ◽  
Age Dependent ◽  
Acetic Acids

Abstract A method has been developed to analyse and quantify formic and acetic acids in archaeological and fresh wood. The method takes advantage of the fact that, in equilibrium, the gas-phase concentrations of formic and acetic acids over pulverised archaeological wood in a sulfuric acid solution are proportional to their absolute concentrations in wood. The method is based on automated solid-phase micro extraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS). Good linearity of the calibration curves was observed. The content of formic and acetic acids in archaeological wood from ships conserved with polyethylene glycol (PEG) was determined. The content of formic acid is related to the intensity of conservation and, hence, the PEG content in wood. Accordingly, formic acid found in the hull of the ships may partly be a result of PEG degradation. The formic acid content in the Vasa warship is, on average, not higher than in the other ships analysed. In contrast, the acetic acid content in PEG-preserved archaeological wood is lower than in fresh wood. The acetic acid content is age-dependent and is lowest in 1000-year-old wood. The acetic acid probably originates from the wood.

scholarly journals Effect of Co-Inoculation with Saccharomyces cerevisiae and Lactic Acid Bacteria on the Content of Propan-2-ol, Acetaldehyde and Weak Acids in Fermented Distillery Mashes

2019 ◽  
Vol 20 (7) ◽  
pp. 1659
Author(s):  
Katarzyna Pielech-Przybylska ◽  
Maria Balcerek ◽  
Grzegorz Ciepielowski ◽  
Barbara Pacholczyk-Sienicka ◽  
Łukasz Albrecht ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Acid Content ◽  
Isopropyl Alcohol ◽  
Quantitative Composition ◽  
Acetic Acid Content ◽  
Initial Ph

The qualitative and quantitative composition of volatile compounds in fermented distillery mash determines the quality of the obtained distillate of agricultural origin (i.e., raw spirit) and the effectiveness of further purification steps. Propan-2-ol (syn. isopropyl alcohol), due to its low boiling point, is difficult to remove by rectification. Therefore, its synthesis needs to be limited during fermentation by Saccharomyces cerevisiae yeast, while at the same time controlling the levels of acetaldehyde and acetic acid, which are likewise known to determine the quality of raw spirit. Lactic acid bacteria (LAB) are a common but undesirable contaminant in distillery mashes. They are responsible for the production of undesirable compounds, which can affect synthesis of propan-2-ol. Some bacteria strains are able to synthesize isopropyl alcohol. This study therefore set out to investigate whether LAB with S. cerevisiae yeast are responsible for conversion of acetone to propan-2-ol, as well as the effects of the amount of LAB inoculum and fermentation parameters (pH and temperature) on the content of isopropyl alcohol, acetaldehyde, lactic acid and acetic acid in fermented mashes. The results of NMR and comprehensive two-dimensional gas chromatography coupled with time of flight mass spectrometry (GC × GC-TOF MS) analysis confirmed the ability of the yeast and LAB strains to metabolize acetone via its reduction to isopropyl alcohol. Efficient fermentation of distillery mashes was observed in all tested mashes with an initial LAB count of 3.34–6.34 log cfu/mL, which had no significant effect on the ethanol content. However, changes were observed in the contents of by-products. Lowering the initial pH of the mashes to 4.5, without and with LAB (3.34–4.34 log cfu/mL), resulted in a decrease in propan-2-ol and a concomitant increase in acetaldehyde content, while a higher pH (5.0 and 5.5) increased the content of propan-2-ol and decreased acetaldehyde content. Higher temperature (35 °C) promoted propan-2-ol synthesis and also resulted in increased acetic acid content in the fermented mashes compared to the controls. Moreover, the acetic acid content rose with increases in the initial pH and the initial LAB count.

Preparation and Properties of Acidified Prevulcanized Natural Rubber Latex

2014 ◽  
Vol 997 ◽  
pp. 239-242
Author(s):  
Guang Lu ◽  
He Ping Yu ◽  
Yong Zhou Wang ◽  
Yong Yue Luo ◽  
Zong Qiang Zeng
Keyword(s):  
Tensile Strength ◽  
Acetic Acid ◽  
Natural Rubber ◽  
Acid Content ◽  
Natural Rubber Latex ◽  
Rubber Latex ◽  
Elongation At Break ◽  
Acetic Acid Content ◽  
Hot Air ◽  
Aging Resistance

After a maturation of three days at ambient temperature, the sulfur-prevulcanized natural rubber latex (SNRL) was stabilized by 20wt% Peregal O, and then acidified with the 36wt% acetic acid by a ratio of 5, 15, 25, 35 and 45 g of 36wt% acetic acid to 100g SNRL, to obtain acidified prevulcanized NR latex (ASNRL) with different acidity, respectively. The viscosity of ASNRL increased, while the nitrogen content decreased, with the increment of acetic acid content and the decrease in pH; for unaged samples, the tensile strength, elongation at break, 300% and 500% moduli of the ASNRL films were only slightly lower than those of SNRL film; however the hot-air aging resistance decreased with the increment of acetic acid content.

scholarly journals Dynamics of Volatile Compounds in Triticale Bread with Sourdough: From Flour to Bread

Foods ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1837
Author(s):  
Ruta Galoburda ◽  
Evita Straumite ◽  
Martins Sabovics ◽  
Zanda Kruma
Keyword(s):  
Acetic Acid ◽  
Volatile Compounds ◽  
Solid Phase ◽  
Nutritional Composition ◽  
Gas Chromatography Mass Spectrometry ◽  
Human Consumption ◽  
Bread Making ◽  
Two Stage ◽  
Peak Areas ◽  
Flour Blend

Triticale has been suggested for human consumption due to its valuable nutritional composition. The aim of this study was to evaluate volatile compound dynamics in the technological processes of triticale bread and triticale bread with sourdough prepared using Lactobacillus sanfranciscensis based cultures. Two types of sourdough ready-to-use sourdough and two-stage sourdough were used for bread making. Triticale bread without sourdough was used as a control. Volatile compounds from a headspace of flour blend, sourdough, as well as mixed dough, fermented dough, bread crumb and crust were extracted using solid-phase microextraction (SPME) in combination with gas chromatography/mass spectrometry. Alcohols, mainly 1-hexanol, were the main volatiles in the triticale flour blend, whereas in the headspace of sourdough samples ethyl-acetate, ethanol and acetic acid dominated. Two-stage sourdough after 30 min fermentation showed the highest sum of peak areas formed by 14 volatile compounds, resulting in substrates for further aroma development in bread. A total of 29 compounds were identified in the bread: in the crumb the dominant volatile compounds were alcohols, ketones, acids, but in the crust—alcohols, aldehydes, furans dominated. The use of two-stage sourdough provided a more diverse spectrum of volatile compounds. Such volatile compounds as ethanol, 3-methyl-1-butanol, 2-methyl-1-propanol, 2-hydroxy-2-butanone, 2-methylpropanoic acid, and acetic acid were identified in all the analysed samples in all stages of bread making.

Formic acid as a silage additive

1973 ◽  
Vol 81 (1) ◽  
pp. 117-124 ◽  
Author(s):  
R. F. Wilson ◽  
R. J. Wilkins
Keyword(s):  
Lactic Acid ◽  
Formic Acid ◽  
Perennial Ryegrass ◽  
Acid Content ◽  
Test Tube ◽  
Fresh Weight ◽  
Ammonia Content ◽  
A Value ◽  
Lactic Acid Content ◽  
Acetic Acids

SummaryPure swards of cocksfoot and perennial ryegrass cut on three occasions and of lucerne cut on two occasions were ensiled in test-tube silos after three treatments: (i) unwilted without additive, (ii) unwilted after the addition of formic acid at 0-23 % of fresh weight, and (iii) wilted to a water content of about 70 %, with no additive. Replicate silos were opened at intervals up to 105 days in order to follow the course of fermentation.Silages from the final sampling could be divided into two clearly defined groups. Those where the lactic acid content, expressed as a percentage of total fermentation acids (L %T), was over 60 (19 silages) were considered stable while those with a value less than 20 (5 silages) were considered unstable.The addition of formic acid resulted in a reduction in pH of the ensiled material from 5–86 + 0–12 to 4–60 ±0–11. This value changed little during the first 6 days after ensiling but then fell as lactic and acetic acids were formed. Stable silages made from unwilted crops without additive contained more lactic acid than those made with formic acid, but the converse was true for unstable silages. The ammonia content of silages made from unwilted material was always lower when formic acid had been applied. Wilting before ensiling gave stable silages from all crops.

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