No abstract

The thermooxidative behaviour of sunflower and rapeseed oils has been investigated by means of a derivatograph, using both dynamic and static (isothermal) temperature programs. The aim was to find the optimum experimental conditions for studying the oxidative stability of edible oils, in order to determine their storability. A novel method has been developed for the rapid indication of stability by modelling the oxidative changes under isothermal conditions.

The complex thermoanalytical investigation of oil stability has been made by means of the Derivato‐graph using dynamic and static programs. TG, DTG and DTA curves have been registered simultaneously. The aim of the experiments was to determine the optimum conditions for examination of oxidative stability and oxidation state of edible oils. Results show that the study of thermal decomposition under dynamic conditions allows the detection of thermal and oxidative degradation. Storability can be investigated under static (isothermal) conditions by modeling the oxidation processes. Oxidative changes can be followed quantitatively with thermogravi‐metry (TG) and derivative thermogravimetry (DTG) curves, while differential thermal analysis (DTA) measurements show exothermic enthalpy changes. A novel method has been developed for rapid indication of the oxidative stability using isothermal conditions.

The status and role of soil testing and plant analysis in the rather heterogeneous agricultural development of Central and Eastern Europe are summarized in the present paper, and an attempt is made to formulate the future tasks under the given changing political-economical circumstances. The paper is based, in the majority, on Hungarian facts, taking into consideration the experiences of the other "post block-countries," as well. Soil testing and plant analysis were in a relatively favourable position in the monolithic, centrallyorganized, quantity-oriented systems of Eastern Europe, where agricultural production was based -in most of the cases -on large-scale (sometimes "giant scale") state farms and collective farms. Relatively well equipped laboratories were established with high (sometimes oversized) analytical capacities and with highly qualified staff well trained in soil survey, laboratory analysis, data processing, interpretation, soil mapping, and advisory service. In the large state farms and collective farms, well educated agronomists represent the potential guaranty for the successful and efficient practical use of the provided data. Most of their activitieslarge-scale, 1:10,000 practical soil mapping; soil tests and plant analyses for quality control and for the planning and implementation of rational plant nutrition; irrigation, drainage and soil reclamation practices; the establishment of forests, orchards, vineyards and other plantations; etc., were frnanced from the central state budget and the information-advisory service was practically free of charge or given only for a "symbolic price" from the users. Similar systems were used in Hungary,