This paper presents the results of measurements of stresses and critical deformations, as well as the energy in the critical point for carrot root samples. The measurements were conducted by applying different deformation speeds in the range of 0.083 to 3.333 mm/s. The carrot roots were stored in a dry room for four days in order to differentiate their moisture content and water potential level. Water potential proved to be the parameter that strongly influenced the level of critical deformation. The adequacy of using the criterion of critical deformation for carrot roots in the range of high water potential values was confirmed.
W artykule przedstawiono -wyniki badań dotyczące -wpływu działania fal ultradźwiękowych na przebieg procesu suszenia oraz na barwę suszu jabłkowego. Plastry jabłek odmiany „Idared" potraktowano ultradźwiękami o częstotliwości 21 kHz przez 10, 20 i 30 minut, a następnie poddano suszeniu. Materiał -wysuszono metodą konwekcyjną w temperaturze 70°C, przy przepływie powietrza z prędkością 2 m/s. W pracy -wykazano istotny -wpływ -wstępnej obróbki ultradźwiękami surowca na skrócenie czasu suszenia. 20 i 30-sto minutowe działanie ultradźwięków spowodowało znaczące zmniejszenie jasności suszy, zwiększenie wartości współrzędnych a*ib* oraz nasycenia barwy, w porównaniu z suszoną tkanką niepoddaną obróbce wstępnej.
The investigations were carried out on universal machine Instron 6022 in order to analyse phenomenon of creep in root of sugar beet. The experiment was performed in 3 measurement zones of roots of PN Mono 1 variety. The conducted investigations made it possible determining the pattern of deformation of root tissue in test of creep. The соmputer IBM PC/AT and programme Statgraphics of firm STSC were applied to analysis obtained results. On the basis of experiwental pattern of creep curves the theoretical curves were fitted using the least squares lethod. The high correlation coefficients between experimental ant theoretical curves of creep confirm right choice of mathematical model.
Due to the high cost of energy, and in order to obtain a product with the high nulritional value, the aim is to reduce the time of freezing. The study was focused on the impact of sonication on the process of freezing of apple tissue. Apples (ldared) slices was subjected to ultrasound at a frequency of 21 kHz and 35 through 10, 20 and 30 minutes, and then sub- jected to freezing. The material was frozen by air chilling to -25°C. The use of ultrasound pre-treatment shortened the freezing time, in comparison to untreated sample, however, these changes were significant in the case of ultrasound of frequency 35 kHz.
Cryopreservation (storage in liquid nitrogen, –196°C) is a technique that ensures safe, long−term conservation of plant species with recalcitrant seeds, vegetatively propagated species and biotechnology products such as somatic embryos, cell lines and genetically transformed material. The aim of cryostorage is to keep plant tissue in a safe way, which does not cause changes during storage at neither phenotypic, cytological and histological, biochemical, genetic nor epigenetic level. Therefore, before cryostorage will be applied for long−term preservation it should be thoroughly assess if it does not cause any injuries in plant material.