Impact of cryogenic grinding on phenolic compounds, sterols and antioxidant activity of flaxseed cake

Cilj ovog rada bio je utvrditi utjecaj vremena i načina mljevenja (s i bez primjene kriohlađenja) na sastav i udio sterola, fenolnih spojeva te antioksidacijsku aktivnost lanene pogače. Preliminarnim istraživanjima odabrani su uvjeti mljevenja pogače s i bez hlađenja tekućim dušikom, u trajanju od 8 i 16 minuta. U samljevenim pogačama steroli i fenolni spojevi određeni su kromatografskim metodama, a antioksidacijska aktivnost određena je spektrofotometrijskim metodama. Rezultati su pokazali kako način i vrijeme mljevenja imaju statistički značajan utjecaj (p ≤ 0,05) na udio β-sitosterola, β-sitostanola, cikloartenola i Δ7- avenasterola, dok se udio ostalih sterola nije značajno promijenio u odnosu na kontrolni uzorak pogače. Način i vrijeme mljevenja značajno su utjecali na povećanje koncentracije fenolnih spojeva. Predtretman kriomljevenja u trajanju od 16 minuta utjecao je na povećanje koncentracije ukupnih fenolnih spojeva za 81,93 % u odnosu na kontrolni uzorak. Udio sekoizolarikirezinol-diglukozida (SDG) pokazao je statistički značajnu korelaciju s antioksidacijskom aktivnošću.The aim of this study was to determine impact of time and milling type (with or without cryocooling) on composition and content of flaxseed cake sterols, phenols and antioxidant activity of flaxseed cake. Preliminary studies were undertaken to optimise grinding parameters of cake, with and without using liquid nitrogen cooling for 8 and 16 minutes. In milled cake samples sterols and phenolic compounds were determined using chromatographic methods. Antioxidant activity of produced cakes was investigated using spectrophotometric methods. The results showed significant impact (p ≤ 0,05) of time and milling type on β-sitosterol, β-sitostanol, cycloartenol and Δ7- avenasterol content while the impact on other sterols content was not determined. Time and milling type had significant impact on the increase in phenolic concentration. Phenolic concentration was increased by 81,93 % in the sample treated for 16 minutes using cryocooling compared to the control sample. Content of secoisolariciresinol-diglucoside (SDG) showed statistically significant correlation with antioxidant activity