Maestría en Química

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Subject: search.filters.subject.ESTABILIDAD OXIDATIVA

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    Extracción, caracterización e índice de estabilidad del aceite de ajonjolí (Sesamum indicum L.) a diferentes condiciones de inhibición oxidativa
    (Universidad Técnica de Ambato. Facultad de Ingeniería en Sistemas, Electrónica e Industrial. Maestría en Química, 2022) Ruiz Mora, Fátima Elizabeth; Córdova Suárez, Manolo Alexander
    Sesame (Sesamum indicum) (sesame) of the pedaliaceae family, has a high content of oleic acid (omega 9) and linoleic acid (omega 6), fatty acids considered essential, which are supplied by the diet and used as a substitute for olive oil. The present research evaluates the oxidative stability of sesame oil, using two antioxidants: one natural (alphatocopherol) and one synthetic butylated hydroxytoluene (BHT) at different concentrations: 0.01%, 0.03% and 0.05% for the first antioxidant and 0.01%, 0.02% for the BHT, proving that the best treatment using the alpha-tocopherol antioxidant was of concentration 0. 05% with a shelf life of 43.46 months and for the BHT at a concentration of 0.02% 38.13 months, also at an average temperature of 15 oC; After obtaining the best treatment, the physicochemical parameters were evaluated before and after 4 months, obtaining peroxide index values of 5.08±0.05 control, 11.7±0.025 control after 4 months, 4.59±0.015 with 0.05% alpha-tocopherol at 4 months and 4.57±0.03 with 0.02% BHT, demonstrating that the added antioxidants maintain the stability of the oil. The acidity, iodine, saponification and refraction indexes before and after the treatments are within the values established by the Ecuadorian Standard NTE INEN 8:2012. Finally, the fatty acid content was quantified, the main ones being Oleic Acid 33.37±0.01% and Linoleic Acid with 50.97±0.02%, obtaining a product suitable for human consumption.
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    Evaluación de la estabilidad oxidativa del aceite de chía (salvia hispanica l.) Obtenido por prensado a diferentes concentraciones de a-tocoferol como antioxidante
    (Universidad Técnica de Ambato. Facultad de Ingeniería en Sistemas, Electrónica e Industrial. Maestría en Química, 2021) Guayta Guaita, Irma Janeth; Briceño Carrasquel, Jorge Alexander
    Chia oil has a high content of polyunsaturated fatty acids, including linoleic acid (omega 6) and linolenic acid (omega 3); a characteristic highly valued for the prevention of cardiovascular diseases; the presence of these fatty acids causes a high chemical reactivity, so it is prone to oxidative transformations and isomerization; oxidative rancidity is one of the most important reactions of fatty acids, resulting in the loss of its nutritional value and shelf life of the oil. For this purpose, it was proposed to evaluate the oxidative stability of chia oil obtained by cold pressing at different concentrations of αtocopherol; to determine the oxidative stability of chia oil, 5 samples were prepared, TC 0% of Vitamin E and the T1, T2, T3, T4 with 0,025 %, 0,05%, 0,075 % and 0,10% of antioxidant respectively; demonstrating in the present study that T2 with 0,05% antioxidant is the best treatment to prolong the shelf life of chia oil, obtaining an estimated 264,395 days for its conservation and commercialization; Subsequently, the oil was stored at room temperature (15°C) for 15 months, after which time the fatty acids of the oil were quantified with 0,05% of alpha-tocopherol, obtaining as a result (17,71±0,07) % of linoleic acid and (65,03±0,19) % of linolenic acid and finally the physical-chemical tests were carried out, such as the percentage of humidity with (0,176±0,004) %, pH with (3,883±0,015) %, acidity indexes with (0,465±0,005) % and peroxide with (5,543±0,004) %; thus acquiring a product of excellent quality and suitable for human consumption.