engleski

Falling number changes during wheat seeds ageing under different storage conditions

Free radical generation/oxidation and nonenzymatic glycosylation within seeds that occur during seed storage/ageing cause molecular damage and subsequently lead to protein denaturation and loss of enzyme activities. Synergistic effect of these molecular impairments could manifest through physicochemical changes of wheat seeds milling products, and among them, the Falling number (FN). Since the Falling number represents an indirect measure of α -amylase activity, it could be expected that molecular damages of proteins/enzymes during seed ageing will lead to changes in α -amylase activity, and subsequently FN. Thus, the aim of this study was to investigate changes of the Falling number of three wheat varieties aged one year under different storage conditions. Wheat seeds of varieties Divana, Žitarka and Srpanjka, were aged during one year under four different storage conditions: (1) 4 ± ; 0.5 °C ; 45 ± ; 4% RH ; (2) 25 ± ; 0.7 °C ; 45 ± ; 7% ; (3) 40 ± ; 0.6 °C ; 45 ± ; 2% RH ; and (4) warehouse conditions fluctuating from 2 - 25 °C and 60 - 74% RH due to environmental climate changes. The Falling number in wheat seeds flours was determined monthly. During one-year ageing all three wheat varieties showed an increase in the Falling number. The increase was dependent on the variety (Divana > Žitarka > Srpanjka) as well as applied ageing conditions as follows: 40 ± ; 0.6 °C ; 45 ± ; 2% RH > 25 ± ; 0.7 °C ; 45 ± ; 7% RH > 2 – 25 °C ; 60-74% RH > 4 ± ; 0.5 °C ; 45 ± ; 4% RH. Comparison of FN changes under various storage conditions indicate the significant increase in FN starting from the storage temperature rise above +15 °C. High correlation between FN and accumulation of advanced glycosylation end products indicates that FN increase could be attributed to molecular impairments of proteins and α amylase activity due to non-enzymatic glycosylation and subsequent Maillard reactions.

ageing; wheat; Falling number

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