If I buy a freshly squeezed juice of vegetables and fruit from the shuk in jerusalem and am unsure about the massrot can i remove 1% plus from th juice and maaser it?

ב"ה Shalom If the juice was bought from a place with a proper kosher certificate, there is no reason to assume that Terumot and Masserot were not taken. The kosher certificate covers all aspects of Kashrut. However, if the juice was bought from a place where there is no kosher certificate, then Terumot and Masserot are not the only problem. There is also the issue of "Orlah". Were the fruits for the juice from trees which have already passed the years which are required for Orlah? Were the fruits examined for insects before juicing? What was cut with the knife before cutting the fruit? Meat? Cheese? something totally not kosher? However, in a case where you are only unsure just of the taking of Terumot and Masserot, then they may be taken even after having them juiced if one forgot.. But since you are in doubt, a Bracha should not be said when taking Terumot and Masserot. Also, a person must know the proper order of taking Terumot and Masserot and should say the proper text as appears in the siddurim while doing it. All the best