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Production of Fermented Foods
Published in Nduka Okafor, Benedict C. Okeke, Modern Industrial Microbiology and Biotechnology, 2017
Nduka Okafor, Benedict C. Okeke
The aroma of fermented materials such as beer, wine, fruit wines, and dough exhibit some resemblance. However, the aroma of bread is distinct from those of the substances mentioned earlier because of the baking process. During baking, the lower boiling point materialsescapewiththeovengases. Furthermore, newcompoundsresultfromthechemical reactions taking place at the high temperature. The flavor compounds found in bread are organic acids, esters, alcohols, aldehydes, ketones, and other carbonyl compounds. The organic acids include formic, acetic, propionic, n-butyric, isobutyric, isocapric, heptanoic, caprylic, pelargonic, capric, lactic, and pyruvic acids. The esters include the ethyl esters of most of these acids as would be expected in their reaction with ethanol. Beside ethanol, amyl alcohols and isobutanol are the most abundant alcohols. In oven vapor condensates, ethanol constitutes 11–12% while other alcohols collectively make up only about 0.04%. Besides the three earlier-mentioned alcohols, others are n-propanol, 2-3-butanediol, and β-phenyl ethyl alcohol. At least one study has found a correlation between the concentration of amyl alcohols and the aroma of bread. Of the aldehydes and ketones, acetaldehyde appears to be the major component of pre-fermentation. Formaldehyde, acetone, propionaldehyde, isobutyraldehyde, methylethyl ketone, 2-methyl butanol, and isovaleraldehyde are others. A good proportion of many of these is lost during baking.
Influence of puff topographies on e-liquid heating temperature, emission characteristics and modeled lung deposition of Puff Bar™
Published in Aerosol Science and Technology, 2023
Anand Ranpara, Aleksandr B. Stefaniak, Elizabeth Fernandez, Lauren N. Bowers, Elizabeth D. Arnold, Ryan F. LeBouf
The top five VCCs emitted by mass from Puff Bar™ e-liquids (µg/puff) are presented in Figure 4. These five VCCs are carcinogens (formaldehyde [0.61 ± 0.35] and acetaldehyde [0.46 ± 0.47]) and respiratory irritants (acetone [0.42 ± 0.14], isovaleraldehyde [0.22 ± 0.05], and acrolein [0.18 ± 0.25]). Figure 5 shows the proportion of specific VCCs out of the total mass of VCCs. The largest to smallest proportion of VCCs for all flavors and puff volumes were formaldehyde (29.6% ± 0.12), acetone (23.9% ± 0.09), acetaldehyde (16.4% ± 0.09), isovaleraldehyde (14.5% ± 0.08), and acrolein (5.0% ± 0.05). We also noticed trace amounts (less than 5.0% of the total) of other respiratory irritants such as propionaldehyde (4.7% ± 0.04), 2-butanone (3.1% ± 0.04), and total tolualdehyde (2.3% ± 0.02) (SI Figures S1A and B).