Hilchos Shemittah v’Yoveil 5:21

The sanctity of the shemittah produce doesn’t apply to the kinds of shells and seeds that non-kohanim may use from terumah. Rather, such things are considered like wood unless they can be used for dyeing. Shemittah sanctity does apply to hearts of palm.

Hilchos Shemittah v’Yoveil 5:22

Let’s say that someone wraps up shemittah spices and puts them into cooked food. If the spices lose their flavor, they become permitted; if they retain their flavor, they are still imbued with shemittah sanctity.