The effects of cold stress on stevosides induction and protein electrophoretic pattern of Stevia rebaudiana Bertoni

Stevia rebaudiana Bertoni, (Asteraceae) is a well-known plant with its natural sweetening compounds named as steviosides. In the present work, Stevia plants was treated with 2 and 4 days of cold stress at 4 °C and then total stevioside level, content of  certain steviosides and electrophotetic pattern of proteins were evaluated using spectrophotometry, HPLC and SDS-PAGE methods, respectively. The results indicated that cold treatment (4 days) caused a 40% increase in total sativoside content of Stevia rebaudiana. The results of HPLC analysis showed that the amount of Rebaudioside A, a known stevioside, increased significantly after 2 days of cold treatment as 70% more than control. The SDS- PAGE analysis of the plant proteins revealed that some protein bands density were increased in the cold treated groups of Stevia compared with control group. These bands might be related to heat chock proteins. From a practical point of view, cold treatment can elevate Rebaudioside A in Stevia cultivation. This compound has large applications in heart-healthy foods and debating cookies as food additive.