Effect of ultrasonic treatment on the polyphenol content and antioxidant capacity of extract from defatted hemp, flax and canola seed cakes

Abstract

The effectiveness of ultrasonic extraction of phenolics and flavonoids from defatted hemp, flax and canola seed cakes was compared to the conventional extraction method. Ultrasonic treatment at room temperature showed increased polyphenol extraction yield and antioxidant capacity by two-fold over the conventional extraction method. Different combinations of ultrasonic treatment parameters consisting of solvent volume (25, 50, 75 and 100 mL), extraction time (20, 30 and 40 min) and temperature (40, 50, 60 and 70 °C) were selected for polyphenol extractions from the seed cakes. The chosen parameters had a significant effect (p<0.05) on the polyphenol extraction yield and subsequent antioxidant capacity from the seed cakes. Application of heat during ultrasonic extraction yielded higher polyphenol content in extracts compared to the non-heated extraction. From an orthogonal design test, the best combination of parameters was 50 mL of solvent volume, 20 min of extraction time and 70 °C of ultrasonic temperature.

Antioxidant Properties of Camelina sativa Oil and Press-Cakes

“…It should be pointed out that defatting of the press-cake was crucial, when extracts were prepared at room temperature: total amount of polyphenols increased more than 50% in comparison to extracts obtained from crude, non-defatted camelina meal. Total amount of polyphenols in camelina meal extracts was comparable or even about two times higher than in similar extracts of rapeseed (about 700 mg GAE/100 g (Barba et al, 2015) up to 1000 mg GAE/100 g (Teh and Birch, 2014)), flax or hempseed meal (for both last, about 400 mg GAE/100 g (Teh and Birch, 2014)). Thus, false flax press-cake is a potential source of polyphenols in comparison with other oil seed meals.…”

Sinapinic and protocatechuic acids found in rapeseed: isolation, characterisation and potential benefits for human health as functional food ingredients

“…walls and release of the bioactive contents (Khoddami et al, 2013). Teh and Birch (2014) previously determined the optimal parameters to extract phenolics from defatted canola seed cakes to comprise a 200 W ultrasound extraction with a solvent volume of 50 mL, extraction time of 20 min, and temperature of 70°C. This method was found to be advantageous over traditional methods in that it involves low cost, has low solvent consumption and increases the antioxidant activity of the extracts (Teh and Birch, 2014).…”

“…Efficient, simpler and more economic methods of isolation allow for the utilisation of rapeseed by-products and ensure total utilisation of the crop, with no or limited waste generation (Chemat et al, 2012). Various novel methods to extract phenolic acids from various natural product sources have been carried out to date, including UAE, MAE, HVED and PEF extractions (Teh and Birch, 2014;Barba et al, 2015;Teh et al, 2015).…”

“…Traditional methods of isolating phenolics from rapeseed meal include organic solvent and enzymatic extraction; however, this can require large volumes of solvent, while the associated toxicity of certain organic solvents such as methanol makes them unsuitable for use in final food applications. This has encouraged the development of novel isolation methods such as ultrasound-assisted (UAE), microwave-assisted (MAE), high-voltage electrical discharge (HVED) and pulsed electric field (PEF) extraction processes (Teh and Birch, 2014;Barba et al, 2015;Teh et al, 2015). In the first part of this review, existing and novel methods of isolating these phenolic compounds from rapeseed meal are examined.…”

Analysis of Bioactive Components of Oilseed Cakes by High-Performance Thin-Layer Chromatography-(Bio)assay Combined with Mass Spectrometry

“…There are only few reports on the quantity of these phytochemicals in the oilseed cake extracts (total phenolics content and total flavonoids content) and their total antioxidative activities (via 2,2-diphenyl-1-picrylhydrazyl (DPPH˙) scavenging activity, oxygen radical absorbance capacity (ORAC), ferric reducing antioxidant power (FRAP), iron chelating capacity and β-carotene bleaching test) [7,8]. As the polyphenol extracts of seed cakes of hemp (Cannabis sativa), flax (Linum usitatissimum) and canola (Brassica napus) have not been studied in detail yet, information on single effective compounds would be of interest, since the polyphenols that exhibit functional and nutraceutical properties could also be used in functional food, additionally to its use in feed.…”