remove categories from product

I have found the solution, actually it is very simple:

$terms = get_the_terms($product_id, 'product_cat');
foreach($terms as $term){
    wp_remove_object_terms($product_id, $term->term_id, 'product_cat');
}

This code get all the therms with the ‘product_cat’ taxonomy, with a foreach loop I remove all the items.