Resumen

CALLISAYA A, Juan Carlos  y  ALVARADO K, Juan Antonio. Oxidative stability in almonds of bertholletia excelsa; accelerated deterioration of the dry fruits under thermal conditions. Rev. Bol. Quim [online]. 2016, vol.33, n.2, pp.62-71. ISSN 0250-5460.

Bertholletia excelsa (Lecythidaceae), amazonian almonds from Bolivia or Brazil nuts is an economically important plant in the Bolivian Amazonian region . It has a significant content of bioactive compounds with antioxidant properties such as vitamin C, E, (3-carotenes and a complex mixture of phenolic compounds. It is very susceptible to oxidative deterioration, which is the biggest problem in this type of food, with the altering of the texture, appearance, flavor and aroma. However, the high content of phenolic compounds inhibits lipid oxidation of these nuts, depending on the variation of the characteristic physical and chemical parameters.. The aim of this work is to determine the oxidative stability of lipids in of Bertholletia excelsa. According to the experimental design (Diagram 1) we proceed to take 3 to 4 nuts for each one of the four heat treatments, each forty days. Determining the peroxidation is carried out with the TBARS technique. It occurs the formation of a coloured complex MDA-TBARS when the sample is treated with trichloroacetic acid (TCA). The extract obtained from the samples under acidic conditions is distilled, the solution of TB A is added to portions of the distillate under thermal conditions, the solution takes a pinkish coloration that can be spectrophotometrically quantified at a wavelength of 538 nm. The oxidative process of the dry fruit comports thermal conditions at four temperatures showing a zero-order kinetics. The concentration of MDA increases with the induced peroxidation accelerated process The useful life activation energy was 19,89 kcal/mol, a value according to the literature. Also, the lifetime estimated in the oxidative stability study concludes that at a storage temperature below -80°C, almonds have a duration of 7 years and at temperatures of 20, 25 and 45 ° C, the lifetime diminishes to 2.5; 2.4; and 2.1 years, respectively. The variation of the storage temperature at -80, 20, 25 and 40 ° C evidence a dependence between the rate constant of reaction "k" and temperature, wherein the variation in the degradation rate of lipids is increased at higher temperature.

Palabras clave : Antioxidant activity; Phenolic compounds; Bertholletia excelsa; Lecythidaceae.

        · resumen en Español     · texto en Español     · Español ( pdf )