In the master thesis we evaluated the changes in the spectrum of phenolic compounds during the process of buckwheat malting. In the experiment we used the seeds of two varieties (Pyra and Darja) of common buckwheat (Fagopyrum esculentum Moench), which were soaked, germinated and dried. At different stages of the process, samples were taken for the analysis of water content and determination of various phenolic compounds (unmalted buckwheat, buckwheat soaked for 8 hours, germinated buckwheat after 16, 40, 64 and 88 hours, dried buckwheat for 22 hours at 60 °C and 18 hours at 80 °C). Water content was determined by drying and the content of phenolic compounds after extraction with methanol was determined by liquid chromatography with mass spectrometer detection (LC-MS). Twelve phenolic compounds (rutin, orientin, vitexin, isovitexin, quercetin, isoorientin, caffeic acid, luteolin, kaempferol, naringenin, apigenin and gallic acid) were determined in buckwheat samples. During germination, the content of all phenolic compounds increased significantly in both buckwheat cultivars. The most important phenolic compound in buckwheat is rutin, which was also the most abundand in germinated buckwheat (91.56 μg/g in unmalted buckwheat in Pyra cultivar and 103.07 μg/g in Darja cultivar; in 88 hours germinated buckwheat in Pyra cultivar 355.60 μg/g and 299.95 μg/g in Darja cultivar). The greatest increase in content during germination was found for orientin (factor 29.2 in Pyra and 21.3 in Darja), vitexin (factor 15.2 in Pyra and 14.0 in Darja) and isovitexin (factor 17.7 in Pyra and 15.7 in Darja). Under both drying regimes, the content of all phenolic compounds in both buckwheat cultivars decreased significantly, but the sum of phenolic compound content in the buckwheat malt was still a factor 2.2 to 3.4 (depending on cultivar and drying regime) higher than the sum of phenolic compound content in the unmalted buckwheat. After germination and drying, the buckwheat cultivar Pyra was found to have a slightly higher content of phenolic compounds than the buckwheat cultivar Darja. Germinated buckwheat and buckwheat malt are good sources of nutritionally important phenolic compounds.
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