The influence of cooking on the antioxidant properties and polyphenol content in buckwheat, barley and millet groats and the transfer of the compounds to the water

The research subject was the influence of the cooking process on the polyphenol content and antioxidant properties of groats (buckwheat groats, barley groats, millet groats) and on the colour parameters of the products. After groats cooking, also the water was tested for the polyphenol content and antioxidant properties that permeated into the decoction of the cooked raw material. The evaluation of the antioxidant properties of groats was conducted with the DPPH radical assay, the polyphenol content was determined with the Folin-Ciocalteu reagent, and the colour was determined with the trichromatic colorimetry method using the Konica Minolta CM-5 colorimeter (Osaka, Japan). The cooking process significantly lowered the content of polyphenolic compounds and antioxidant properties of the ready products. The best antioxidant properties after cooking were found in buckwheat groats and the weakest in millet groats. The polyphenol content in cooked products depended on the type of groats. Cooking significantly decreased the polyphenol content, but only in buckwheat and barley groats, as well as causing a change of groats colour as compared to uncooked samples. The most antioxidant properties were found in the water from cooking barley groats, and the least - from cooking millet groats. The most polyphenols permeated into the water from cooking buckwheat groats, and the least from cooking millet groats. All groats, except millet groats, darkened after cooking. In all types of groats, the correlation coefficients between colour parameter and general polyphenol content and the ability to scavenge DPPH radicals showed very strong negative dependences. The conducted research can help in designing the technological process of cooking buckwheat, barley and millet groats, and a way of using the water from cooked groats for consumption.

Alteration of biochemical parameters and microstructure of Fagopyrum esculentum Moench grain in process of germination

Biochemical parameters alteration of Fagopyrum esculentum Moench grain in process of germination was studied. It was found that during germination of Fagopyrum esculentum Moench grain within 24 hours the content of ascorbic acid, thiamine, nicotinic acids, pantothenic acids and routine was increased. The peptide composition of Fagopyrum esculentum Moench grain was studied by gel electrophoresis. The most significant alteration of reserve globulins structure are observed during germination phase from 20 till 24 hours. New low-molecular polypeptides appear during above mentioned period, that indicates embryonic awakening and synthesis of new protein compounds, mainly hydrolases. The process of proteolysis during germination of Fagopyrum esculentum Moench grain promotes a content increase of soluble fractions and sum of albumins and globulins. There is a significant decrease of insoluble protein residue during germination phase change. Chromatographic method was used to determine the change of carbohydrate composition of Fagopyrum esculentum Moench grains during germination. It was established that the content of total carbohydrates amount in grain extracts increases. Electron scanning microscopy revealed that after 12 hours germination of Fagopyrum esculentum Moench grain, swelling of starch grains and minor damage of their packaging in endosperm are observed. After 24 hours, endosperm of germinated grain significantly changed microstructure: starch grains and components of protein matrix had a vague outline, grain disintegration was observed. Evaluation of antioxidant activity of alcohol extract from Fagopyrum esculentum Moench grain germinated during 24 hours showed that percentage of DPPG free radicals inhibition increases with process prolongation. Thus, Fagopyrum esculentum Moench grain germinated within 24 hours is characterized by a high content of biologically active substances and can be used in food technologies for functional products development.