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The Chemistry of Hazardous Materials
Published in Armen S. Casparian, Gergely Sirokman, Ann O. Omollo, Rapid Review of Chemistry for the Life Sciences and Engineering, 2021
Armen S. Casparian, Gergely Sirokman, Ann O. Omollo
Acetic acid is found in many food products in the concentration range of 3%–6% by mass and is responsible for the sour taste. Vinegar is about 5% acetic acid by mass. Concentrated acetic acid, 80%–99% by mass, is known as glacial acetic acid. It is produced through the reaction of methanol and carbon monoxide. It releases a vapor, which, if inhaled, produces a choking and suffocating sensation and can readily damage the bronchial tract and eyes. It is highly corrosive. It is an OSHA category 3 flammable liquid and an NFPA class II combustible liquid (see Section 4.4 for clarification). OSHA’s PEL for the vapor concentration is 10 ppm averaged over an 8-hour workday.
Environmental Effects of Energy Production and Utilization
Published in Efstathios E. Michaelides, Energy, the Environment, and Sustainability, 2018
The pH of pure water is 7. Acids have lower pH and bases have higher pH: the pH of vinegar is 2.5 and the pH of (the much stronger) sulfuric acid is less than 1. The normal pH level of natural freshwater is in the range of 6.8–7.4. Most fish and several other aquatic organisms do not thrive outside this natural range of pH. The addition of the acids in lakes and rivers by the acid precipitation process significantly lowers the pH in rivers and lakes, with the result that several species languish or disappear. Some of the more dramatic acid precipitation observations of the 1970s in North America and Europe are [1] as follows:
Production of Vinegar
Published in Nduka Okafor, Benedict C. Okeke, Modern Industrial Microbiology and Biotechnology, 2017
Nduka Okafor, Benedict C. Okeke
Vinegar is normally a product of two fermentations: alcoholic fermentation with a yeast and the production of acetic acid from the alcohol by acetic acid bacteria. There is no distillation between the two fermentations, except in the production of spirit vinegar. The vinegar may or may not be flavored. The substrate for the alcoholic fermentation for vinegar productions varies between different locations. Thus, while wine vinegar made from grapes is common in continental Europe and other vine growing countries, malt vinegar is common in the United Kingdom; the United States on account of its great variety of climatic regions uses both malt and wine vinegars. Rice vinegar is common in the far Eastern countries of Japan and China, and pineapple vinegar is used in Malaysia. In some tropical countries, vinegar has been manufactured from palm wine derived from oil or raffia palm.
Biorefining process of agricultural onions to functional vinegar
Published in Preparative Biochemistry & Biotechnology, 2023
Xinhua Liu, Liangliang Zhang, Chunxin Cao, Jianfeng Wang, Xiaoming Sun, Jianfeng Yuan
Now vinegar manufacture usually occurs in two successive fermentation, i.e., the facultative anaerobic conversion of sugars to ethanol by yeast (alcoholic fermentation), and the aerobic oxidation of ethanol to acetic acid with acetic bacteria as the protagonist (acetic fermentation).[7,8] The molecular mechanism of oxidation of ethanol to acetic acid by acetic bacteria has been thoroughly studied, and it has been confirmed that this process is the result of joint action of membrane binding alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH) and ubiquinone oxidase, linked to the respiratory chain.[9,10] However, there is called peroxidation in this process, resulting in reducing the accumulation of acetic acid. This is mainly because acetic acid bacteria assimilate acetate and CO2via the TCA cycle to resist the acetic acid.[11]
Vinegar from Bael (Aegle marmelos): A Mixed Culture Approach
Published in Indian Chemical Engineer, 2018
Kaustav Chakraborty, Suman Kumar Saha, Utpal Raychaudhuri, Runu Chakraborty
Industrial vinegar production is carried out by sequential fermentation of ethanol and acetic acid independently catalysed by cultures of yeast and bacteria. Using a mixed culture can provide viable alternative to it [10]. Previous studies indicated the capability of mixed culture in improving productivity over the pure culture, specifically in case of a multi-stage process, while, acknowledging the need for further analysis and optimization. According to the European Union regulations, the minimum legal limit of acetic acid is 6% (w/v) for wine vinegar and 5% for other types while residual alcohol must remain below 1.5%. Approximately 40% (w/w) of fermented sugar converts to acetic acid, which practically limits the acetic acid production potential of any ingredients [11]. Therefore, acetous fermentation should be completed in terms of alcohol utilization, which itself indicates low-residual alcohol content.