@article{
author = "Žilić, Slađana and Šobajić, Slađana and Mladenović-Drinić, Snežana D. and Kresović, Branka J. and Vasić, Marko G.",
year = "2010",
abstract = "Effects of increased temperatures on the lipoxygenase activity and changes of soya bean fatty acids were observed in the present study. The kernels of soya bean cultivars Bosa and ZPS 015 were subjected to the treatments of extrusion, autoclaving, micronisation and microwave roasting. Depending on the technological processing procedure, the kernels were exposed to temperatures ranging from 60 to 150°C for 25 to 30 seconds during extrusion and for 30 minutes during autoclaving. The temperature that developed in the course of the microwave radiation and autoclaving did not cause statistically significant differences between oil content in heat treated and fresh kernels of soya bean. However, the oil content was higher in soya bean flakes (micronized kernels) and lower in grits than in fresh kernels. The heat treatments resulted in the significant decrease of the linolenic fatty acid content. Depending on the temperature and applied heat treatments, the content of linoleic and oleic fatty acid oscillated. High temperatures caused changes in unsaturated fatty acids with 18 carbon atoms resulting in relative increase of the stearic acid content. The lipoxygenase activity decreased in correlation with increased temperatures and the time of heating. The maximum drop of the activity was observed after kernel exposure to the extrusion and micronisation processes at the temperature of 100oC. However, a significant lipoxygenase activity increase was recorded in both studied cultivars after one-minute microwave heating, i.e. at the temperature about 60°C. A further temperature increase led to a gradual denaturation of the enzyme and therefore to its decreased activity., U ovom radu prikazani su rezultati promene aktivnosti lipoksigenaze 1 i sadržaja masnih kiselina u sojinom zrnu pod uticajem povišene temperature. Zrno soje sorte Bosa i ZPS 015 bilo je podvrgnuto tretmanima suve i vlažne ekstruzije, autoklaviranju, mikronizaciji i prženju u mikrotalasnoj peći. U zavisnosti od tehnološkog tretmana prerade zrno je bilo izloženo dejstvu povišene temperature od 60 do 150°C u trajanju od svega 25 do 30 sekundi pri ekstruziji do 30 minuta pri autoklaviranju. Povišena temperatura tokom mikrotalasnog prženja i autoklaviranja nije uticala na sadržaj ulja u sojinom zrnu. Međutim, u sojinim flekicama sadržaj ulja bio je viši, a u grizu niži od sadržaja u sirovom sojinom zrnu. Primenjeni termički tretmani prerade uticali su na značajno smanjenje sadržaja linolenske kiseline u ulju sojinog zrna. U zavisnosti od temperature, kao i vrste termičkog tretmana sadržaj linolne i oleinske kiseline u prerađenom sojinom zrnu je varirao. Povišena temperatura uslovila je promene nezasićenih masnih kiselina sa 18 ugljenikovih atoma rezultirajući povećanje sadržaja stearinske kiseline. Prema našim rezultatima aktivnost lipoksiganaze je opadala sa povećanjem temperature i produženjem tretmana prerade. Maksimalan pad aktivnosti lipoksigenaze utvrđen je već nakon izlaganja zrna temperaturi od 100oC tokom ekstruzije i mikronizacije. Međutim, nakom jednog minuta prženja zrna u mikrotalasnoj peći (60°C) aktivnost lipoksigenaze je bila viša u odnosu na aktivnost u sirovom zrnu. Daljim produženjem tretmana, a time i povećanjem temperature došlo je do postepene denaturacije enzima i smanjenja aktivnosti.",
publisher = "Univerzitet u Beogradu - Poljoprivredni fakultet, Beograd",
journal = "Journal of Agricultural Sciences, Belgrade",
title = "Effects of heat processing on soya bean fatty acids content and the lipoxygenase activity, Uticaj termičkih tretmana prerade na sadržaj masnih kiselina sojinog zrna i aktivnost lipoksigenaze",
volume = "55",
number = "1",
pages = "55-64",
doi = "10.2298/JAS1001055Z"
}
