Qualidade física, química e antimicrobiana de sabões líquidos elaborados com óleo residual de fritura e diferentes agentes saponificantes
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2013-03-04
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Universidade Federal de Goiás
Resumo
The residual oils obtained from the process of frying food are considered hazardous waste by the ministry of environment, due to their degradative nature when improperly discarded in soil and groundwater. Thousands of tons of this waste are produced daily across the country, and more than half are discarded improperly, because no public policies that encourage proper disposal and even recycling of these oils. Soaps are carboxylic salts can be made from these wastes, becoming an alternative to the recycling of frying oils, promoting sustainable development. Liquid soaps are widely used either as cleaning products or toiletries, however the use of frying oils in these products, delimits the knowledge still popular, with little initiative industries in marketing these products. Therefore, this work was developed with the aim to formulate liquid soaps with residual oil in a frying food industry, different pHs (8, 10, 12 and 14) and saponified by different bases (KOH / NaOH). The soaps were evaluated for their technological qualities, divided into physical (foaming ability, solubility, viscosity and cleaning), chemical properties (acidity and alkalinity free) and microbiological (minimal inhibitory concentration for E. coli and S. aureus). The two tests with liquid soaps KOH or NaOH, were processed under mechanical stirring and soaps obtained at pH 8, 10, 12 and 14 using KOH or HCL / NaOH to correct pH. Liquid soaps with KOH showed characteristics less viscous than treatments with NaOH (propensity for solidification) confirming the better employment of this base in the production of liquid soaps. The cleaning power of soaps with KOH and NaOH was similar (yield around 93% of the ability to clean greasy surfaces to soiling 87% with low levels of fats), increasing with an increase in pH of the formulations. Liquid soaps with KOH and NaOH, showed good ability of foaming, however the best solubilization capacity (water, ethanol, methanol, acetone and petroleum ether), was acquired with soaps with KOH (pH 10, 12 and 14), soaps pH 8 were sparingly soluble in both assays (KOH / NaOH). The antibacterial analysis, through minimum inhibitory concentration showed that soaps with NaOH able to inhibit the cultivation of S. aureus and E. coli, a smaller amount (6.25 and 25%, respectively) than the soap with KOH (at least 50% of soap and 100). The kinetic model that best fit the values obtained for pH was processing the first order. Both trials evaluated had technological characteristics favorable for their marketing, with soaps with more alkaline pH may be intended for industrial use, since its high pH does not allow it to be handled by untrained people. Soaps with lower pHs (8, 10), may be destined for domestic or commercial, allowing a good efficiency of their application.
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HERRANZ, A. P. Qualidade física, química e antimicrobiana de sabões líquidos elaborados com óleo residual de fritura e diferentes agentes saponificantes. 2013. 180 f. Dissertação (Mestrado em Ciência e Tecnologia de Alimentos) - Universidade Federal de Goiás, Goiânia, 2013.