Determination of fatty acid composition,lipase activity and thermal properties of oat breeding samples

Oat is relatively new culture plant compared to wheat and barley. Inspite of having an important role in animal feeding in the past, oat has been gaining importance for human consumption as well as industrial raw materials. In this study, 60 lines and 4 standard varieties (Kırklar, Kahraman, Sebat and Yeniçeri) developed as a result of winter oat breeding studies by Thrace Agricultural Research Institute and 45 lines and 5 standard varieties (Sarı, Fetih, Sebat, Haskara and Checota) developed as a result of summer oat breeding studies by the Eagean Agricultural Research Institute were evaluated in terms of human consumption, storage stability and some properties of starch. In this study, fat content, fatty acid composition, lipase activity and differential scanning calorimetry (DSC ) parameters were determined for total 452 oat samples which are 256 line/variety (winter 64x2 locationx2 year) grown by TTAE in Kırklareli and Edirne locations; and 196 line/variety (summer 49x2 locationx2 year) grown by ETAE in Karacabey and Menemen locations in 2014-2015 and 2015-2016 crop years. The oil content (in dry basis) of oat lines/varieties obtained both two crop years (n=452) ranged between 5,7-13,7% (mean value 8,9±1,31%). Oleic (34,2-48,2%), linoleic acid (29,9- 43,5%) and palmitic (12,8-21,2%) acid are three major fatty acids of oats and they comprised pproximately 90-95% of the total fatty acids of the samples. In addition to these three major fatty acids, it was determined that oats contain stearic (1,1-3,6%), linolenic (0,6-1,4%) and cis-11-eicosenoic acid (0,6-1,5%) besides myristic, palmitoleic, arachidic, behenic,lignoceric and nervonic acid (below 1%). The results of lipase activity analysis having a great importance in evaulation of storage stability of the oats varied between 0,5-9,4 U/g (average 3,7±1,81 U/g). As a result of the correlation analysis, there was no significant correlation between oil content and lipase activity (p> 0,05, r = 0,065). Three endothermic transitions were observed in the thermograms, obtained as a result of analysis of oat lines/varieties by differential scanning calorimetry. The first transition process, corresponds to the loss of starch crystallinity, the second corresponds to the transition of the amylose-lipid complex and the third was associated with the transition of protein (globulins) denaturation. The gelatinization temperatures of the samples were from 60,5 to 67,5°C (average 64,0±1,45°C) and the enthalpy values were 4,0-9,1 J/g (average 5,8±0,62 J/g); the transition temperatures of the amylose-lipid complex were 91,0-97,9°C (average 93,7±0,79°C); the enthalpy values were 0,4-2,0 J/g (average 1,2±0,25 J/g) and the transition temperatures of the protein denaturation were 108,2-114,8°C (average 111,4±0,99°C); and the enthalpy values varied between 0,2-1,9 J/g (average of 0,9±0,31 J/g ) in this study. Among the oat samples, the lines of 43, 14, 34, 18, 4 and Checota, Fetih, Kahraman(standart varieties) from summer breeding materials and the lines of 3, 12, 13, 23, 29, 44 and 64 from winter breeding materials are suitable in terms of either human consumption and storage stability.