| Abstract [eng] |
Hemp Seeds are a perfect and natural blend of easily digested proteins, essential fats (Omega 3 and 6), Gamma Linolenic Acid (GLA), antioxidants, amino acids, fiber, iron, zinc, carotene, phospholipids, phytosterols, vitamin B1, vitamin B2, vitamin B6, vitamin D, vitamin E, chlorophyll, calcium, magnesium, sulfur, copper, potassium, phosphorus, and enzymes [13]. The aim of this work is extraction of lipids, proteins and antioxidants from hemp seeds, evaluation and improvement of oxidative stability of obtained oil. Evaluation of antioxidant activity of extracts. Analyzation of protein composition and their functional properties. Determination of amino acids. Extracts from hemp seeds were obtained by choosing needed parameters and different solvents in different type of extractions. It was used supercritical CO2, Soxhlet extractions and cold pressing of hemp seeds to obtain lipids. Accelerated solvent extraction with different solvents (water, acetone, ethanol, water and ethanol solution) were used to obtain extracts from residue after supercritical CO2 extraction to evaluate their antioxidant activity. Protein extraction was done by Osborn. To obtain different protein fractions it was used different type of solvents: albumins – water, globulins – NaCl solution, prolamins – solution of water and ethanol, glutenins – NaOH solution. Antioxidant activity of extracts was evaluated by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical cation (ABTS•+) scavenging, oxygen radical absorbance capacity (ORAC) assays, and DPPH radical scavenging assay. The total content of phenolic compounds in the extracts was determined using the Folin-Ciocalteu method. It was also measured tocopherol content. The stability of hemp seed oil and its solutions with antioxidants, expressed by induction period (IP) of their oxidation was determined using Oxipress and Rancimat methods. Induction period (IP) showed that that hemp oil with antioxidant DURALOX BLEND AN-110 XT (0,4 % concentration) has the best oxidative stability. It was evaluated, that the lowest peroxide concentration was in oil with antioxidant DURALOX OXIDATION MANAGEMENT (DOM), which was kept in fridge (4-5°C). The entire time of experiment (18 months), oil have not reached the critical value of peroxides at this conditions. The electrophoresis showed that the extracts contains proteins, whose molecular weight is between 20000 and 45000 Da. Comparing these results with the literature referred to, it was found that in these limits is protein Edestin molecular weight. |
