EJPAU, 2000, Volume 3, Issue 2
Agricultural Engineering

The state of knowledge about eggplant and the methods of its storage is the subject of the paper. In the experimental part, the effect of freezing treatment on eggplant fruits was investigated and the range of its cryoscopic temperature was determined.

The paper presents the results of studies on ultrasound processing of meat after slaughter on the changes of texture properties after freezing and thawing. The studies were carried out on M.semimembranosus of young slaughter cattle with a liveweight of 450-500 kg. The samples were processed with ultrasounds of the frequency of 25 kHz and intensity of 2 W/cm². After slaughter they were chilled, frozen and thawed. The parameters of texture (hardness, cohesiveness, elasticity) of thermally treated meat were measured by TPA test (50% deformation, 10 mm/min). Texture tests were conducted with the use of Instron device model 4302.

The reconstitutional properties of mushroom fruitbodies dried convectionally and sublimatically were analysed. The fruitbodies of nameko (Pholiota nameko) and shiitake (Lentinus edodes) which differ in the structure, chemical composition and growth rate were examined. It was found that the most important influence on the rehydration rapidity (time of rehydration) was exterted by the method of drying. The differences between these two species of mushrooms were also distinctive and dependent on individual features of raw substrate and was closely connected with the examinated mushroom species.

The qualitative and quantitative evaluation of the content of volatile aroma compounds in the fruit bodies of two species of edible mushrooms: oyster (Pleurotus ostreatus) and nameko (Pholiota nameko) was performed by gas chromatography coupled with mass spectrophotometry. Both examined species of fungi differed from each other in the amounts of the main volatile substances. The most important components determining the aroma of these mushrooms were octen-1,3-ol and octanal. It was also shown that the retention of these substances was effected by the method of sample preparation for the analyses and the method of liophilization. The sublimatic drying enabled the retention of 50% of aroma compounds in oyster fruit bodies and 39.2% in nameko fruitbodies. Freezing of fruit bodies after harvesting enabled the retention of 63.5% of aroma compounds in oyster fruit bodies and 75% in nameko fruitbodies.