Biophenols and Antioxidant Properties of Australian Canola Meal

Abstract

During the extraction of canola oil, large quantities of meal are produced. Extracting biophenols from Australian canola meal (ACM) adds value to an otherwise low-value agro-industrial byproduct. This study examined the biophenol content and the antioxidant activity of ACM, the impact of extraction conditions, and varietal differences. Sinapine was the principal biophenol in ACM. In crude and hydrolyzed extracts, 31 compounds were identified: 2 dihexosides, 2 organic acids, 4 glucosinolates, 17 sinapic acid derivatives, 2 cyclic spermidine alkaloids, caffeic acid and its dihexoside, kaempferol, and its C-glucoside. ACM showed significant free radical scavenging activity in DPPH(•) and ABTS(•+) assays. Sinapine was the chief contributor to ACM antioxidant activity, whereas kaempferol sinapoyl triglucoside isomer was the most potent antioxidant. Biophenol content ranged between 12.8 and 15.4 mg GAE/g DW. Differences among studied cultivars were generally quantitative. The Tarcoola cultivar showed the highest biophenol content and antioxidant activity.

Phenolic Compounds with Antioxidant Properties from Canola Meal Extracts Inhibit Adipogenesis

“…However, water extracts appeared to have higher recovery. The data gathered from UV-vis spectra, ABTS scavenging activity, and relative retention times were compared with reference standards and literature data to characterize the chemical composition of CMEs as described previously [2]. The online-ABTS HPLC analysis showed that, generally, most detected compounds demonstrate good ABTS radical scavenging activity.…”

“…The TPC of various extracts in decreasing order was as follows: AE > BE > ME > EE > WE > CE > HE ( Figure 1). Various extracts were chemically characterized by HPLC-DAD-MS/MS using commercially available reference standards and spectral data from previous literature [2]. Different extracts showed different phenolic profile [35] that reflects the relative polarity of various extracting solvents.…”

“…We employed various solvents with a wide range of polarities in order to comprehensively explore canola meal bioactive constituents. While hydro-alcoholic solvents are the most commonly used extraction solvent for plant phenols [47,48], hydro-acetone solvents showed superior quantitative properties [2,35]. Chloroform and hexane are immiscible with water, while n-butanol has limited water miscibility.…”

“…Total phenolic content (TPC) was determined using the Folin-Ciocalteu reagent, as previously described [2]. A calibration curve was produced using a range of gallic acid concentrations (0.1, 0.2, 0.3, 0.4, 0.5, and 0.6 mg/mL) in 50% aqueous methanol.…”

“…On the other hand, plant phenols are attracting increasing attention as multipotent antioxidant molecules that can be used to generate high-value nutraceutical products. The extraction of canola meal phenols is an appealing high-tech solution to generate antioxidant-rich extracts for the food and pharmaceutical industries while enhancing the value of the remaining meal by increasing its digestibility [2].…”