Assessment of oxidative deterioration of soybean oil at ambient and sunlight storage

• Published in: Grasas y aceites (Sevilla) Vol. 58; no. 4; pp. 390 - 395
• Main Authors: Chatha, S.A.S, Anwar, F, Hussain, A.I
• Format: Journal Article
• Language: English
• Published: Consejo Superior de Investigaciones Científicas 01.10.2007
• Subjects: ACEITE DE SOJA; ALMACENAMIENTO; APTITUD PARA LA CONSERVACION; APTITUDE A LA CONSERVATION; conjugated oxidation products; DAYLIGHT; DETERIORATION; DETERIORO; ENVIRONMENTAL TEMPERATURE; http://www.fao.org/aos/agrovoc#c_10350; http://www.fao.org/aos/agrovoc#c_16508; http://www.fao.org/aos/agrovoc#c_2135; http://www.fao.org/aos/agrovoc#c_2598; http://www.fao.org/aos/agrovoc#c_4082; http://www.fao.org/aos/agrovoc#c_5472; http://www.fao.org/aos/agrovoc#c_5721; http://www.fao.org/aos/agrovoc#c_7427; HUILE DE SOJA; KEEPING QUALITY; LUMIERE DU JOUR; LUZ DEL DIA; OXIDACION; OXIDATION; oxidation parameters; OXYDATION; peroxide value; PEROXIDES; PEROXIDOS; PEROXYDE; SOYBEAN OIL; STOCKAGE; STORAGE; TEMPERATURA AMBIENTAL; TEMPERATURE AMBIANTE
• ISSN: 0017-3495; 1988-4214
• DOI: 10.3989/gya.2007.v58.i4.451

Se lleva a cabo un estudio para conocer las diferencias en la oxidación del aceite de soja conservado a temperatura ambiente y a la luz solar durante un periodo de 180 días. Los cambios en la oxidación fueron evaluados mediante medidas periódicas del índice de peróxidos, color, acidez libre, índice de refracción (RI), índice de p-anisidina, dienos conjugados e índice de yodo. Al final del periodo de almacenamiento, los niveles de acidez e índice de peróxidos fueron 1,77 y 2,90% y 20.52, 41.89 meq/kg de aceite, respectivamente para los aceites a temperatura ambiente y a la luz solar. Los valores iniciales de RI (40 grados C), p-anisidina, dienos conjugados y trienos conjugados a los 180 días fueron 1.4647 y 1.4659; 36.13 y 50.40; 23.97 y 41.49; y 13.81 y 19.35, respectivamente. Por el contrario, el índice de iodo (g I/100 g aceite) disminuyó desde 138.0 a 126.18 y 118.04, respectivamente. Los resultados de los distintos parámetros analizados demostraron que la magnitud de la degradación oxidativa de las muestras de aceite de soja expuestas a la luz solar fue en todos los casos, significativamente superior (P<0.05) a la que ocurre a temperatura ambiente. This study was carried out in order to probe the extent of oxidative alterations in soybean oil (SBO), subjected to ambient and sunlight storage, over a period of 180 days. The magnitude of oxidative changes was monitored by the periodical measurement of peroxide value (PV), color, free fatty acid (FFA) contents, refractive index (RI), p-anisidine-, conjugated dienes-, conjugated trienes-, and iodine- values. At the end of storage period (180 days), the initial contents of FFA (0.02% as oleic acid) and PV (0.02 meq/kg of oil) of the SBO samples subjected to ambient and sunlight storage reached the level of 1.77, 2.90% and 20.52, 41.89 meq/kg of oil, respectively. The initial values of RI (40 deg C) (1.4630), panisidine (1.10), conjugated dienes (0.08) and conjugated trienes (0.04) rose to the point of 1.4647, 1.4659; 36.13, 50.40; 23.97, 41.49 and 13.81, 19.35, respectively. Whereas, the iodine value (g of I/100 g of oil) decreased from 138.00 to 126.18 and 118.04, respectively. At the end of storage period, the overall order, indicative of the oxidative changes in RI, FFA, IV, color (red + yellow), PV, P-anisidine, conjugated dienes and conjugated trienes of the SBO subjected to ambient and sunlight storage was as follows: 1.001:1.002, 1.00:1.65, 0.91:0.86, 0.80:0.60 + 0.75:0.50, 1.00:2.04, 1.00:1.39, 1.00:1.73 and 1.00:1.40, respectively. The results of various parameters investigated in the present study demonstrated the magnitude of oxidative deterioration of the SBO samples exposed to sunlight to be significantly (P<0.05) pronounced as compared with that of ambient.