Summary
This study tries to combine the research on various effects important in stored product protection: Pest control with various fumigants against all developing stages of insects and storage of sensitive products at various temperatures and relative humidities and consequences for sensorial aspects of the quality of stored products. It presents new information on quality losses of dried figs after treatment under high or low atmospheric pressure of CO2. Apart from the investigation on the effects of the gas on the quality of stored figs, also the impact of different temperatures and relative humidities during storage of figs was subject of this study. The study included experiments on the efficiency of sulfuryl fluoride (SF), as an alternative fumigant to the ozone depleting and phased out methyl bromide on all developing stages of two important pest insects (Ephestia elutella and Oryzaephilus mercator).

The objects of the first chapter were the investigation of sugaring and browning of dried figs that appear during long term storage and cause significant economic losses. Therefore, dried figs treated one and two times with CO2 under high pressure (20 bar for 3 hours) together with untreated figs were stored for six months at 5°C and 15°C, respectively, at 65 % r.h. Representative dried fig samples were taken for the sensory tests and laboratory analysis every four weeks. The samples were analysed according to their optical and physiological characteristics. The investigations were separated in two groups as sensory tests and laboratory analyses. The sensory tests were carried out by untrained panellists. It was determined that the treatment with CO2 under high pressure - either one or two times – showed no significant differences in comparison with untreated dried figs.

The second chapter dealt with the effects of different storage conditions at various temperatures (5°C and 15°C) relative humidities (20 %, 65 %, 90 %) of dried figs on the two quality parameters dry matter and sugar content. Especially the possible reasons for the well known quality damages such as sugaring and browning on dried figs were investigated. The figs were stored for several months under different simulated storage conditions. The investigated figs had been previously treated with CO2 under high pressure. For the experiments, six different climatic conditions were installed for either four or eight weeks. The different target relative humidities were adjusted by use of saturated solutions of different salts in water. Pressurized air was continuously purged through gas washing bottles with these solutions and introduced into four experimental vessels with figs, connected with PVC tubing. Representative samples were taken every four weeks and analysed for their sensorial properties and same chemical contents. The results showed that the climatic storage conditions had a pronounced impact on the quality. Especially at the medium relative humidity of 65 % at 5°C as well as at 25°C the quality did not deteriorate whereas at lower as well as at higher relative humidities the figs lost their quality significantly.

In the third chapter, the efficacy of sulfuryl fluoride [SO2F2] against the eggs, larvae and pupae of the Warehouse Moth (Ephestia elutella HÜBNER), and the Merchant Grain Beetle (Oryzaephilus mercator FAUVEL), was investigated. The insects were cultivated in climatized chambers at 25°C and 28°C, respectively, and at 65 % relative humidity. In this study, the pre-mature life stages of the Warehouse Moth, especially one to four days old eggs, four weeks old larvae and five weeks old pupae were fumigated. The experiments were carried out at two different concentrations (11.6 g/m³, 21.3 g/m³) and three different temperatures (15°C, 20°C, 25°C) for three different exposure times (18 h, 24 h, 48 h), respectively. In addition, a third concentration of 30 g/m³ was applied for O. mercator. The exposure periods for this insect were slightly different (24 h, 48 h, 72 h). Each experiment was replicated three times. A Fourier Transmission Infrared Spectroscopy apparatus was used for determining the concentration. Subsequently, the results were statistically analysed by use of regression analysis. The investigations of the Warehouse Moth showed that the age of the eggs had a significant influence on the efficacy of the fumigation. The three and four day old eggs were more tolerant towards fumigation with low dosages of SO2F2 than one and two days old eggs. Also the investigated premature life stages of the Merchant Grain Beetle survived at low SO2F2 concentrations. All investigated developing stages of both species were controlled with ct products below the authorized German value of 1500 gh/m³.