Chronological development of element concentrations in grapes during growth and ripeness and during fermentation of must determined by instrumental neutron-activation analyses

Abstract

The chronological development of element concentrations during growth and ripeness of grapes described in the literature has only been concerned with the macro elements Mg, K, and Ca. Concentrations of trace elements in must are only described as a snapshot at the end of the ripeness. Therefore, the motivation for the present work was to accompany the growth and the ripening process of grapes successively by systematically determining element concentrations in grapes of Riesling and Cabernet Sauvignon by neutron-activation analyses. While for a number of elements, the concentrations in the grapes increased as a function of grape development (e.g., Na, K, Rb, Al), other concentrations decreased (e.g., Mg, Ca, Mn). These decreases are not only to be attributed to a dilution by an increasing uptake of water during growth, but also by an active transport of the cations out of the berries. Furthermore, the interest focused on the influence of mineral substances on the process of fermentation and on the uptake of trace elements by the yeasts.

Biomass estimation and characterization of the nutrient components of thinned unripe grapes in China and the global grape industries

“…Only the RGF of SM did not detect the presence of zinc, and the zinc content of other samples ranged from 0.14 to 1.35 mg/100 g. Compared with RGF, the zinc content of TUR was more uniform. Except for ZX, the content of K in RGF of other table grape varieties is significantly higher than that of TUR ( p < 0.05), and with the ripening of fruit, the Ca and Mg contents of most varieties decrease, with similar results also observed in the studies of Feige et al, 2014 , Mahmood et al, 2012 . The Cu content of all TUR varieties was higher than that of RGF, and all varieties demonstrated significance except for KH ( p < 0.01).…”

“… Feige et al (2014) also mentioned that K, Ca and Mg are the most abundant mineral elements in grape fruits. Mg and Ca participate in cell development and are components of cell walls.…”