Quantity not stored when inserting products

[António Sousa i9]

$product = new Product();
		$product->ean13 = $row['CODBARRAS'];
		$product->reference = $row['REF']; 
		$product->name = array((int)Configuration::get('PS_LANG_DEFAULT') => $row['PRODUTO']);
		$product->link_rewrite = array((int)Configuration::get('PS_LANG_DEFAULT') =>  $link_rewrite);
		$product->id_manufacturer = $row['MARCA']; 
		$product->id_category = $row['SECCAO'];
		$product->id_tax_rules_group = $tax_rule; 
		$product->id_category_default = $row['SECCAO'];
		$product->quantity = $row['STOCK']; 
 		$product->redirect_type = '404';
 		$product->quantity = 200; 
		$product->price = $price;
		$product->delivery_in_stock = '1-2 dias úteis após confirmação da encomenda';
		$product->delivery_out_stock = 'Entre em contacto connosco!';
		$product->out_of_stock = 2;
		$product->description =  $row['DESCRICAO'];
		$product->description_short = $row['RESUMO']; 
		$product->show_price = 1;
		$product->on_sale = 0;
		$product->online_only = 0;
		$product->meta_keywords = $row['PALAVRAS_CHAVE'];
		$product->date_upd = $data_tratada;
		$product->is_virtual=0;
		$product->add();
		$

I'm using this code and the quantity is not been stored into the platform. 

Does anyone know what is wrong ? 

thahk you