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In this study the main proteolytic modification indicators of wheat seed were monitored during the germination in order to establish the minimal time needed to achieve their optimal ratio. The indicators monitored were total nitrogen, soluble nitrogen, Kolbach number, relative extract VZ 45 °C (Hartong index), free amino nitrogen (FAN), colour, colour after boiling and pH of laboratory wort. Regarding steeping and kilning, standard micromalting procedures for wheat were followed, while germination was prolonged to 7 days. Sampling during germination was performed daily. Domestic bread wheat variety “Golubica” (AI, Osijek) which is characterized by increased total nitrogen content was chosen for investigation on basis of available multiannual data for micromalting quality indicators. The obtained results indicate the necessity of germination time prolongation (up to 12-24 h) for wheat varieties characterized by increased total nitrogen, in order to achieve sufficient protein degradation, as well as adequate ration between different nitrogen fractions. Furthermore, the comparison of the obtained results with the available quality indicators data for middle European wheat varieties have shown retarded proteolytic degradation of “Golubica” variety during micromalting. This can be the result of forced seed maturation at the end of vegetation period, which is characteristic for Croatian agro climatic area, and cannot be avoided. Indicators of seed’s proteolytic degradation can be mainly influenced by optimising the micromalting procedures. |
