Influence of the Season on the Total Lipids and Fatty Acid Composition of Grasses at the Different Altitudes in the Region of the Middle Rhodopes


Institute of Cryobiology and Food Technologies, BG – 1407 Sofia, Bulgaria


TSVETKOVA, V. and L. ANGELOW, 2010. Influence of the season on the total lipids and fatty acid composition of grasses at the different altitudes in the region of the Middle Rhodopes. Bulg. J. Agric. Sci., 16: 748-753

The investigation is related to a study of the lipid content and fatty acid profile of the grass associations containing mainly Gramineae species and Fabaceae species from the region of Middle Rhodopes. Plant samples are taken from the meadows at 800 m, 1000 m and 1200 m altitudes and results show a low lipid content in the grasses during the spring period April - June.
The established differences in the concentrations of saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids as well as the changed proportions of the main fatty acids (palmitic, oleic, linoleic and linolenic) are supposed to have influence on the milk fatty acid profile. The content of saturated fatty acids increases from April to June and reaches 22.5 mol%, 27.5 mol% and 26.3 mol%, respectively at 800 m, 1000 m and 1200 m, predominantly due to the molar concentration of the palmitic acid which varies between 16 and 20 mol%, while the level of monounsaturated fatty acids doesn’t change during the experiments. The higher concentrations of polyunsaturated fatty acids (64-72 mol %) at three altitudes are due to 18:3 (48-61 mol%; 48-56 mol% and 50-57 mol %) and 18:2 (from 13 to 18 mol%). It has to be noted that the high polyunsaturated fatty acids levels during the whole vegetation period are favorable for providing an optimal supply of essential fatty acids to grazing animals as well as for the increased synthesis and secretion of conjugated linoleic acid in milk lipids, which prevent human beings from atherosclerosis, obesity, diabetes and stimulate the immune system.

Key words: grasses, fat, fatty acids, altitude, season

Abbreviations: SFA-saturated fatty acids; MUFA - monounsaturated fatty acids; PUFA - polyunsaturated fatty acids; CLA - conjugated linoleic acid, FAME - fatty acid methyl esters

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