The presentation described the fatty acids and amino acids composition of Spirulina supplements available on Slovenian market. Forty-seven samples of Spirulina food supplements from the Slovenian market were collected for this research. The analyzed samples were fresh or dry in capsule, powder or tablet form, produced in Japan, China, India, Hawaii, Italy, Portugal and Taiwan. Total fatty acid content in the samples was determined after esterification by GC-MS. The amino acid derivatives were prepared using the Phenomenex EZ:faast Amino Acid Hydrolysate kit for GC-MS. In the commercial Spirulina samples fatty acids distribution was in the following order, according to their falling concentrations: palmitic acid ) linoleic acid (omega-6) ) gamma-linolenic acid (omega-6) ) stearic acid ) oleic acid (omega-9) ) palmitoleic acid (omega-7) ) elaidic acid (omega-9). Alpha-linolenic acid (omega-3) was also found in some samples, but only in small concentrations. Great deviations in fatty acid compositions were found in some samples indicating possible adulterations. Amino acid analysis showed a diverse amino acid composition of commercial Spirulina samples. In our samples we managed to determine all the essential amino acids: valine, leucine, isoleucine, threonine, methionine, phenylalanine, lysine, histidine and tryptophan and also most of the non-essential amino acids. A great proportion of determined fatty acids and amino acids are essential for human consumption, therefore Spirulina food supplements could contribute to daily essential and non-essential amino acid and fatty acid intake.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 32775207Arthrospira platensis (spirulina) belongs to microalgae and has been consumed by humans for millennia mainly because of its high content of high quality proteins, vitamins, minerals and other bioactive compounds. Due to the known beneficial effects of lactic acid fermentation on the shelf life, functionality and sensory properties, fresh biomass of A. platensis microalgae was subjected to lactic acid fermentation by two lactic acid bacteria species - Lactobacillus plantarum and Lactobacillus brevis. By varying inoculum size (1 %, 5 % (v / v)), nutrients added (dH2O, solution of glucose and yeast extract, 0.9 and 3 % (w/v) NaCl) and fermentation time (24, 48, 72 h) the optimal fermentation conditions according to the measured parameters (pH, lactic acid bacteria concentration and lactic acid concentration) were selected. Lactic acid fermentation proceeded optimal with 1 % inoculum and addition of 0,9 % (w/v) NaCl as a liquid. Due to the constant values between 24 and 72 h, 24 h was selected as the optimal fermentation time. We also found that native lactic acid bacteria are already present in the microalgal biomass, which independently perform the fermentation to some extent, but they do not make a major contribution when using starter culture. Furthermore, the antioxidant activity of water and ethanol extracts of non-fermented and fermented microalgae paste using yeast Saccharomyces cerevisiae was tested. Compared to non-fermented paste, the antioxidant activity of ethanol paste extracts increased after fermentation, but decreased or did not change in water extracts, depending on the concentration of the extract and the starter culture used. The A. platensis microalgae proved to be a good sole substrate for lactic acid fermentation where their antioxidative properties tested on the cell model also changed.
D.10 Educational activities
COBISS.SI-ID: 5107832The aim of our study was to optimize the extraction of unfermented and fermented paste of cyanobacteria species A. platensis and to compare the content of total phenolic compounds (TPC) and antioxidant capacity (AOC) of aqueous and ethanolic extracts of unfermented paste extracts with fermented paste extracts. The paste underwent lactic acid fermentation with two different lactic acid bacteria (Lb. plantarum and Lb. brevis) for 24, 48 and 72 hours. The most effective was two-phase extraction (twice for 30 minutes) in water bath at 40 °C using distilled water or 96 % ethanol as extraction solvents. TPC was determined by the Folin-Ciocalteu method and the results were expressed as gallic acid equivalent. AOC was determined by DPPH· radical scavenging method and the results were expressed the as trolox equivalent. The highest TPC and AOC content were determined in aqueous extracts of unfermented paste (4.38 mM TPC and 1.40 mM AOC). The lowest TPC and AOC content was obtained in ethanolic extracts of unfermented paste (0.66 mM TPC and 0.46 mM AOC). In the case of aqueous extracts, the content of TPC and AOC was reduced by fermentation, while the content of TPC and AOC increased in the ethanolic extracts of fermented A. platensis paste. Subsequently, the extracts were dried and re-dissolved in a smaller amount of solvent (aqueous extracts with distilled water to obtain 50 mg dry matter/mL, ethanol extracts with dimethyl sulfoxide to obtain 100 mg dry matter/mL). With this procedure we have managed to preserve most of the antioxidants.
D.10 Educational activities
COBISS.SI-ID: 5026424