Determination of glassy state by cryo-SEM and DSC in cryopreservation of mint shoot tips by encapsulation–dehydration

Cryopreservation of mint shoot tips grown in vitro (Mentha 9 piperita) was performed after encapsulation in alginate beads. Encapsulated shoot tips were first precultured in sucrose enriched medium (0.75 M) and then dried under a sterile air flow (0–6 h). After cooling in liquid nitrogen and warming in a warm water bath, alginate beads were transferred to solid culture medium for 4 weeks. The effect of dehydration time of the encapsulated shoots was evaluated for water content, cooling and warming rates, ice crystal formation and cellular vitrification, by using low temperature scanning electron microscopy and differential scanning calorimetry. Viability of the recovered material showed a close relation between the dehydration time, cooling and warming rates, ice formation avoidance and tissue vitrification. At short drying periods (up to 3 h), ice crystals were formed and the viability was low or absent. After longer drying periods (5 and 6 h), both beads and specimens became vitrified.Fil: Schneider Teixeira, Aline. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigaciones En Criotecnología de Alimentos (i); Argentina. Consejo Superior de Investigaciones Científicas. Instituto de Ciencia y Tecnologia de Alimentos y Nutrición; EspañaFil: González Benito, M. Elena. Universidad Politécnica de Madrid. Escuela Técnica Superior de Ingenieros Agrónomos de Madrid; EspañaFil: Molina García, Antonio D.. Consejo Superior de Investigaciones Científicas. Instituto de Ciencia y Tecnologia de Alimentos y Nutrición; Españ