Maria Małecka

Antioxidant activity of ethanolic extracts of amaranth seeds

Antioxidant activity of ethanolic extracts obtained from two amaranth species was evaluated in a beta-carotene-linoleic acid model system. The addition of amaranth extracts in the range of 0.01-0.1% inhibited degradation of a beta-carotene in a model emulsion during incubation at 60 degrees C; 0.05% addition of amaranth seeds extract was proposed as practically applicable. The total content of phenolic compounds was estimated by the Folin-Ciocalteu method and ranged from 39.17 mg/100 g of Amaranthus caudatus to 56.22 mg/100 g of A. paniculatus seeds. Free phenolic acids contained in ethanolic extracts of amaranth seeds were purified and isolated by solid-phase extraction (SPE) and identified by reversed-phase high-performance liquid chromatography (RP-HPLC). The technique involved gave a good separation of the free phenolic acids in the amaranth seeds. Significant differences in phenolic acids profiles of both amaranth species were observed.

The Effect of Rosemary Extract on the Sensory Quality of Flaxseed Oil During Storage

Th e aim of the study was to evaluate the eff ect of rosemary extract on the sensory quality of fl axseed oil during storage in practical storage conditions (at room and refrigerator temperature). Th e fl axseed oil with 0.05% rosemary extract, 0.02% BHT and control sample were subjected to a regular sensory analysis. Th e intensity of bitter taste, nutty, oxidized and grassy fl avours was evaluated with the use of a quantitative descriptive analysis (QDA) by a trained sensory panel. Th e addition of rosemary extract and BHT in the amount of 0.05% and 0.02%, respectively, to the fresh fl axseed oil did not cause a statistically signifi cant change in its taste perception. Storage in practical conditions revealed benefi cial eff ects of these substances on the sensory quality of the oil as compared to the control samples. Th e addition of rosemary extract periodically lowered the intensity of a bitter taste. Th e addition of BHT delayed the appearance of an unacceptable level of bitterness, and thus extended the shelf-life of fl axseed oil by 14 days at room temperature and 28 days under refrigerator storage.