Antioxidant Capacity of Phenolics from Canola Hulls as Affected by Different Solvents

Abstract

Potential use of canola hulls as a source of natural antioxidants was explored. The antioxidant activity of 80-100% (v/v) methanol and 70-80% (v/v) acetone extracts of canola hulls in a β-carotene-linoleate model system was comparable to that displayed by butylated hydroxyanisole (BHA). The scavenging effect of the above extracts, at 40 μg/assay on (DPPH) radical, was over 95%.Rapeseed species include Brassica napus, Brassica campestris, and Brassica junce, commonly known as rape, turnip rape, and leaf mustard, respectively. In Canada and Europe the seeds of rape and turnip rape are known as rapeseed. Traditional rapeseed varieties contained from 22 to 66% erucic acid in their oil. In 1979, the name canola was adopted in Canada for genetically modified rapeseed varieties containing less than 2% erucic acid in their oil and no more than 30 μηοΐββ^ of one or any combination of the four aliphatic glucosinolates (gluconapin, progoitrin, glucobrassicanapin, and napoleiferin) in its defatted meal. In 1997, this definition was revised to less than 1% of erucic acid in the oil and 18 μηιοΐββ/^ of one or any combination of the above four aliphatic glucosinolates. The US Food and Drug Administration recognized rapeseed and canola as different species in 1985 (i).

Antioxidant Activity of Hazelnut Skin Phenolics

“…Although a range of solvents (acetone, ethanol, methanol, and water) have been used for the extraction of various groups of phenolic compounds from plant materials , 80% (v/v) acetone is the most effective solvent for extraction of condensed tannins from hazelnut kernel and hazelnut green leafy cover , a majority of leguminous seeds , pulses, and tree nuts , as well as other plant materials . The reason why acetone is more effective than other solvent extracts is that condensed tannins are relatively high-molecular-weight compounds and hence better extracted into acetone with an appropriate polarity.…”

Techniques for Analysis of Plant Phenolic Compounds

“…Normally, increasing time and temperature promote analyte solubility; however, plant phenolics are generally degraded or undergo undesirable reactions such as enzymatic oxidation by extended extraction times and high temperatures [ 38 , 39 ]. Naczk et al [ 40 ] demonstrated that the optimum extraction time and temperature to extract phenolics from canola meal is 2 min (2 × 1 min) at room temperature. The solvent-to-sample ratio and the number of replicate extractions performed for each sample also affect the recovery of phenolics.…”

Endogenous Phenolics in Hulls and Cotyledons of Mustard and Canola: A Comparative Study on Its Sinapates and Antioxidant Capacity

“…A significant reduction (>90%) in the oxidation of LDL particles by rapeseed phenolics was reported [ 14 ]. The antioxidant effectiveness of canola hulls extracts in methanol and acetone was comparable to butylated hydroxyanisole in model systems of β-carotene-linoleate [ 15 ]. The rapeseed phenolics were better antioxidants towards liposomes membrane oxidation and the radical scavenging activities of such phenolics from rapeseed oil were significantly high [ 16 ].…”