35 research outputs found
Influence of de-hulled rapeseed roasting on the physicochemical composition and oxidative state of oil
The effect of roasting time on the contents of bioactive compounds (tocopherols, phytosterols, phenolic compounds), antioxidant capacity and physicochemical properties of rapeseed oil pressed from de-hulled seeds was investigated. The de-hulled seeds were roasted at a temperature of 165 °C for 20, 40, 60, 80, and 100 min. The results of this study show that a roasting pre-treatment led to a gradual increase in canolol content (from 1.34 to 117.33 mg/100 g), total phytosterols (from 573.51 to 609.86 mg/100 g) and total carotenoids (0.82 to 2.41 mg/100 g), while only slight changes in the contents of tocopherols were noted. With the increase in roasting time a gradual increase in oxidative stability (from 4.27 to 6.85 h), and antioxidant capacity, seen mainly in the hydrophilic fraction of oil (from 0.32 to 2.30 mmol TEAC/l) was found. Although roasting resulted in the formation of primary and secondary oxidation products, the quality parameters of oils were within Codex Alimentarius limits
Value-Added Potential of Expeller-Pressed Canola Oil Refining: Characterization of Sinapic Acid Derivatives and Tocopherols from Byproducts
Valuable phenolic antioxidants are
lost during oil refining, but
evaluation of their occurrence in refining byproducts is lacking.
Rapeseed and canola oil are both rich sources of sinapic acid derivatives
and tocopherols. The retention and loss of sinapic acid derivatives
and tocopherols in commercially produced expeller-pressed canola oils
subjected to various refining steps and the respective byproducts
were investigated. Loss of canolol (<b>3</b>) and tocopherols
were observed during bleaching (84.9%) and deodorization (37.6%),
respectively. Sinapic acid (<b>2</b>) (42.9 ÎŒg/g), sinapine
(<b>1</b>) (199 ÎŒg/g), and canolol (344 ÎŒg/g) were
found in the refining byproducts, namely, soap stock, spent bleaching
clay, and wash water, for the first time. Tocopherols (3.75 mg/g)
and other nonidentified phenolic compounds (2.7 mg sinapic acid equivalent/g)
were found in deodistillates, a byproduct of deodorization. DPPH radical
scavenging confirmed the antioxidant potential of the byproducts.
This study confirms the value<b>-</b>added potential of byproducts
of refining as sources of endogenous phenolics