| Abstract [eng] |
In recent years, quinoa and hemp seeds gain more and more interest, because of the content of fiber, macro and micro compounds, protein, lipids, folic acid, iodine, vitamin B. Lactic acid bacteria are associated with health care and are the main microorganisms used in food industry. During this study, quinoa and hemp seeds were fermented using Lactobacillus bacteria strains. Technological and functional properties were evaluated of fermented quinoa and hemp seeds, and protein fractions extracted from these seeds. Bread was made using fermented and unfermented quinoa and hemp seeds. The highest antioxidant activity was determined in quinoa seeds fermented with Lactobacillus plantarum MR24 (169.4 trolox equivalent in mg per 100 g of fermented seeds). The highest antimicrobial activity was obtained in quinoa seeds fermented with Lactobacillus acidophilus DSM 20079 against Bacillus cereus, hemp seeds fermented with Lactobacillus plantarum MR24 against Staphylococcus aureus and Bacillus cereus and hemp seeds fermented with Lactobacillus acidophilus DSM 20079 against Bacillus subtilis, Bacillus cereus, Escherichia coli, and Salmonella typhimurium. The highest total phenolic content was obtained in quinoa and hemp seeds fermented with Lactobacillus brevis R26 (61.4 and 65.6 galic acid equivalent in mg per 100 g of fermented seeds). The highest L-lactic acid concentration was obtained in quinoa seeds fermented with Lactobacillus acidophilus DSM 20079 (42.5 g per kg of fermented seeds). Quinoa seeds fermentation with Lactobacillus brevis R26 and Lactobacillus acidophilus DSM 20079 decreased lipid peroxidation during storage in freezer at –18 °C temperature. After hydrolysis with pepsin >45 kDa molecular weight proteins were hydrolysed. The main fractions after hydrolysis was from 6,5 kDa to 24 kDa. It was observed that fermentation using Lactobacillus bacteria strains and hydrolysis with pepsin has an influence on the size of proteins. The highest antioxidant activity and total phenolic content were obtained in proteins fraction soluble in 70 % ethanol. Antioxidant activity was lower after enzymatic hydrolysis. Protein fraction soluble in 70 % ethanol obtained from quinoa seeds fermented with Lactobacillus acidophilus DSM 20079 showed the highest DPPH and ABTS radical scavenging activity (7716 and 3261 trolox equivalent in mg per 100 g of protein) and total phenolic content (186 galic acid equivalent in mg per 100 g of protein). In all cases, higher antimicrobial activity was obtained after hydrolysis with pepsin. The highest antimicrobial activity was obtained in protein fraction soluble in 70 % ethanol from hemp seeds fermented with Lactobacillus acidophilus DSM 20079 and quinoa seeds fermented with Lactobacillus plantarum MR24. Bread was made using fermented and unfermented quinoa and hemp seeds. Texture properties (total titratable acidity, porosity, specific volume, shape retention) and sensory properties were determined. Specific volume and porosity (in almost all cases) were lower in bread with fermented seeds compared with control bread (without seed). Shape retention in bread with 5 % of unfermented quinoa flour was the highest (0.57). Total titratable acidity was the highest in bread with 10 % of fermented hemp seed (2.4 oN). |
