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Representation of biologically active substances in the grape seeds (Vitis vinifera L.)
Horníčková, Štěpánka ; Hejtmánková, Alena (advisor) ; Vlastimil, Vlastimil (referee)
Seeds of 41 white and 22 blue vine varieties cultivated on six vine-growing areas were assessed as a by-product after winemaking on the contents of total polyphenols (TP) and phosphorus (P) spectrophotometrically, total tocols (TC) including individual tocols by HPLC-FLD, and metals (Ca, Mg, Na, K, Fe, Zn, Cu, and Mn) by FAAS. Remaining TP and TC levels were mainly affected by the variety, while levels of microelements (Cu, Mn, and Zn) and P or K by the vine-growing area. The highest TC and TP levels were found in the seeds of white varieties. Varieties of grape seeds have significant impact on the gamma-tocotrienol content. The color of grape varieties has significant impact on alpha-tocotrienol content. Grape seeds from grape cultivated on the Czech growing area contained higher levels of macroelements except P, however no significant differences between growing areas have been found. The crop year has significant influence on TP, Fe and Cu content. Results herein revealed the considerable potential of grape seeds, a by-product of the vinification process, as a valuable inexpensive source of high added value of nutritionally beneficial compounds - polyphenol and tocol antioxidants and macro- and microelements for use as feed additives in animal nutrition.
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Insect cold tolerance and seasonal changes in composition of sterols and tocopherols
URBAN, Tomáš
Presented work focused on researching cold resistance in insects (Pyrrhocoris apterus), especially in qualitative and quantitative composition and seasonal changes in the content of tocopherols and sterols in membranes. Collection of samples, tissue extraction, separation, sample preparation and the final analysis was included. There were detected three different sterols (animal cholesterol, plant sterols: campesterol and sitosterol). Also were detected ?-tocopherol and ?-tocopherol. Volume of cholesterol was in the range of 0.2 to 0.8 mol%, for phytosterols was the range from 1.2 to 15.2 mol%, and for tocopherols was the range from 0.1 to 31.3 mol%. Seasonal fluctuations of sterols and tocopherols were evaluated with a minimum in summer and maximum in winter.
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