Determination of Sinapic Acid Derivatives in Canola Extracts Using High-Performance Liquid Chromatography

A high-performance liquid chromatographic (HPLC) method with diode array detection (DAD) was used to determine the total phenolics, including sinapic acid derivatives in canola. Ten Western Canadian canola seeds, six other commodity canola seeds, their corresponding press cakes and meals were analyzed. Seeds of European 00 rapeseed and Brassica Juncea (Indian mustard) were included for comparison. Phenolic compounds were separated using a gradient elution system of water–methanol-ο-phosphoric acid solution with a flow rate of 0.8 ml/min. In addition to sinapine (SP) and sinapic acid (SA), sinapoyl glucose (SG) is reported in the methanolic extracts. The detection and quantification limits of these compounds were 0.20–0.40 and 0.50–0.80 μg/ml, respectively with recovery values over 98.0%. The content of total phenolics, SP, SA and SG in canola extracts ranged from 9.16 to 16.13, 6.39 to 12.28, 0.11 to 0.59 and 1.36 to 7.50 mg/g, respectively with significant differences among varieties

Effect of Spray-Dried Flavonoid Microparticles on Oxidative Stability of Methyl Linoleate as Lipid Model System

© 2016, AOCS. Microencapsulated quercetin (Q) and epicatechin (E) were prepared by spray-drying using inulin (IN) as encapsulating agent (Q–IN and E–IN) as well as with Capsul (C) as channelizing agent (Q–IN–C and E–IN–C). Microparticles were added to methyl linoleate (ML) and results showed that Q microparticles markedly improved its oxidative stability by increasing the induction period values and delaying the formation of oxidation compounds, as determined by high-performance size-exclusion chromatography, with respect to E microparticles, thus suggesting the importance of flavonoid C-ring substitution. Remaining levels of Q in the lipid system throughout oxidation of ML added with Q microparticles seemed to show two releasing zones: the first one corresponds to the equilibrium zone, when Q released from microparticles replaces Q that is being degraded; the second zone corresponds to the degradation of Q, when the release rate of the encapsulated Q is slower than its degradation ra

Antioxidant activity and kinetics studies of quercetin, epicatechin and naringenin in bulk methyl linoleate

The objective of this work was to evaluate the antioxidant action of flavonoids with specific differences in chemical structure, namely, quercetin (Q), epicatechin (E) and naringenin (N), in bulk methyl linoleate (ML) under different oxidation conditions at 60 A degrees C, in an oven and in a Rancimat apparatus. The oxidation kinetics were studied by direct and concomitant analysis of primary and secondary oxidation compounds. Addition of 200 mg/kg of E or Q to ML increased about tenfold the oxidative stability of ML. The protective effect was significantly higher for E, independent of the oxidation conditions used. However, N showed no effect. Results obtained were attributed to differences in structural features and polarity. Thus, the presence of the ortho-dihydroxy structure in the B ring and the 3-hydroxyl group in the C ring of E and Q seemed to be determinant and the comparatively higher polarity of E may have enhanced its antioxidant efficiency.Fondecyt Project Grant (Conicyt, Chile) 1120308 ACT Project Grant (Conicyt, Chile) 1105 Spanish Ministry of Economy and Competitiveness AGL2013-45110-