Browsing by Subject "Hydrate"

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Production of CO₂ gas hydrates with its application in wheat bread making process
(2023) Srivastava, Shubhangi; Hitzmann, Bernd
The basic requirements necessary for gas hydrate (GH) formation are low temperature, high pressure, the presence of guest molecules, and the desired amounts of water molecules. The most common guest molecules used for the GH are ethane, methane, butane, propane, nitrogen, and carbon dioxide. Hydrate based technological applications almost always require rapid hydrate formation along with high gas uptake to be economically viable. One possible approach to achieving the same is the introduction of particular additives into the system. These additives are known as hydrate promoters. In recent times, amino acids have emerged as a highly effective class of promoters, and unlike surfactants, they promise a clean mode of kinetic action, i.e., no foam formation. Hence, the first part of the thesis dealt with the optimisation of GH formation with the application of amino acid promoters. The optimisation of the GH production was performed with different combinations of promoter ingredients namely cysteine, valine, leucine, and methionine. The amino acids leucine and methionine gave some positive results with the application of promoters for the production of GH therefore, these two amino acids were carried further for the experimentation purpose in the production of GH. Also, a combinational use of these amino acids (leucine and methionine) was studied to investigate the effect on percentage CO₂ retention in comparison to the normal water GH. The conventional baker’s yeast, Saccharomyces cerevisiae, remains the popular leavening agent in the bread baking industry. Carbon dioxide required for the rising of dough is produced by the metabolism of yeast with the consumption of sugars in the dough, which is a time and energy-consuming process. This research attempts to utilize carbon dioxide gas hydrate as a leavening agent in bread. Despite plentiful experiments on CO₂ gas hydrates in other fields, there is still an urge to carry out more analysis to elucidate various applications of GH in baking and positively validate its sustainability. The temperature stability of GH is important while baking due to the exposure to high temperatures during the various steps involved. In order to effectively use CO₂ GH as a leavening agent in the baking industry, a concise evaluation of the formation of CO₂ GH and its gas containment capacity should be adequately analysed and documented. Also, the effect of CO₂ GH properties by the addition of promoters should be taken into consideration as baking involves higher temperatures, and stabilising the GH at higher temperatures is an important criterion in the context of baking different products. Hence, the effect of a higher temperature of 90 ℃; on the CO₂ gas entrapment of the produced GH with promoters was studied. It was observed that the stability of GH decreases with an increase in temperature, but the addition of promoters, especially leucine + methionine + lecithin increased the CO₂ uptake during GH formation. Another part of the thesis was the application of GH in the baking bread with/without promoters and the study of physio chemical properties of bread. By varying the percentage of gas hydrates from 10-60 %, analysis of the performance of CO₂ GH as a leavening agent during baking was done. The effectiveness of GH bread was evaluated by comparing its characteristics to those of standard bread made with yeast. Also, a comparative evaluation was made for bread with and without promoters GH as leavening agents in terms of different physio chemical characteristics of the bread, such as moisture analysis, volume analysis, pore analysis, texture profile analysis, and baking loss. The results show that the bread with 20 % and 40 % GH obtained the best results in terms of volume and pore size. The next part of the thesis dealt with a comparative analysis of the partial replacement of yeast with CO₂ GH as leavening agents in bread baking. By partially eliminating the yeast, variations of bread dough were produced by the addition of GH in different percentages (20-70 %). The effectiveness of GH on bread manufacture was evaluated by comparing its characteristics to that of standard bread made with yeast. Once the bread was baked, the texture profile, volume, moisture content, and pore size were recorded to compare the leavening effect of GH with the standard recipe when partial addition of yeast was done. The best results combinations with respect to specific volume, pore analysis and hardness were obtained with 70 % GH + 50 % yeast and 70 % GH + 75 % yeast, respectively. As the final part of the thesis, the influence of additives on wheat bread baked with promoter induced CO₂ GH as leavening agents was studied. The additives used for the study were ascorbic acid (AC), egg white (EW), and rice flour (RF). These additives were added to the GH bread containing different amounts of GH (40, 60, and 70 % GH). Also, a combination of these additives in a wheat GH bread recipe was studied for each respective percentage of GH. Based on the results of the study, it was found that 70 % GH+ AC+EW+RF wheat bread was found to be the best in terms of textural analysis, pore size analysis, and other physiochemical parameters. Therefore, this research study will help us in understanding the application of GH in the bread baking process with replacement of conventional baking agents such as yeast.