Extraction, purification and antioxidant activity of polysaccharide from cold pressed oil cake of 'Tengjiao' seed.

Tengjiao (Zanthoxylum armatum DC.) seed cold pressed oil cake (CPC), the main by-product of the cold-pressed oil process, is mainly used for animal feed or crop fertilizer, resulting in a great waste of resources. To improve the added value, the CPC polysaccharide (CPCP) was extracted and purified, and its antioxidant activity was studied. The extraction conditions by microwave assisted extraction, and purification conditions by trichloroacetic acid and polyamide column chromatography treatment were optimized. High performance liquid chromatography and Fourier transforms infrared were applied to characterize the primary structural features. And the antioxidant activity was analyzed by detecting the reducing power, and scavenging activity on radical of superoxide anion, DPPH and ABTS. The results showed that, under the optimal extraction conditions (liquid-to-solid ratio 44 mL/g, processing time 16 min, microwave power 500 W and extraction temperature 80 °C), and the optimal purification conditions, the extract rate of crude CPCP reached 4.76 ± 0.07%, and the purity increased from 48.52 ± 2.76% to 93.76 ± 2.06%. CPCP was mainly water-soluble pyranose with α-configuration, and composed of five kinds of monosaccharides including L-Rhamnose, D-Glucuronic acid, d-Glucose, D-Galactose and D-(-)-Arabinose. CPCP displayed certain degree of antioxidant activity, revealing the potential development and utilization value as antioxidants.

Proximate analysis of cold-press oil cakes after biological treatment with Trametes versicolor and Humicola grisea.

In order to increase the current knowledge on cold-press oil cakes composition, the present study aims to determine the chemical composition of oil cakes from hull-less pumpkin (Cucurbita pepo L.), flax (Linum usitatissimum L.), and hemp (Canabis sativa L.) before and after the biological treatment with Trametes versicolor and Humicola grisea using fungal-based solid-state technology. After 10 days of treatment, the content of ash, total nitrogen, total proteins, and total organic carbon increased in all the three oil cakes, while the content of ether extracts decreased. After treatment, the concentration of soluble carbohydrates decreased in pumpkin and hemp seed oil cakes, whereas it increased in flaxseed oil cake. During treatment with T. versicolor, the content of fructose significantly increased in hull-less pumpkin seed oil cake. Fiber content decreased in pumpkin and flaxseed oil cakes after treatment with both of the fungi, whereas it increased in flaxseed oil cake.