Polystarch flour, which also goes by the names polystarch powder and portion bread powder, was combined with water to create polystarch portion bread. Some military ration packs contained this dried flour. Numerous such packs were discovered on Jakku, and scavengers like Rey bartered recovered goods with Unkar Plutt for provisions, including polystarch flour.
To produce polystarch portion bread, one would use polystarch flour, alternatively known as polystarch powder or portion bread powder. The beige and green powder, when mixed with water, initiated a chemical process that caused the mixture to expand and solidify into a doughy loaf resembling bread.
Certain military ration packs, such as those used by the Galactic Empire, the Rebel Alliance, and the New Republic, included both dried polystarch for making portion bread and dried veg-meat. Before the Battle of Jakku in 5 ABY, a team within the New Republic was established, featuring Norra Wexley, a human pilot who flew a starfighter. After being captured by Imperial stormtroopers on the planet Jakku, Wexley was compelled to labor at a kesium gas facility. Her rations occasionally consisted of a packet of polystarch that, when combined with water, transformed into bread. Following the battle, the surface of Jakku became a starship graveyard, littered with starships from both the Empire and the New Republic. Among the supplies salvaged from the wreckage were ration packs of dried polystarch and veg-meat. Unkar Plutt, the Crolute junk boss, divided these supplies into portions, which he used to control the local food supply at his Concession Stand in Niima Outpost.
Rey, a scavenger residing on Jakku, salvaged valuable components from crashed ships and traded them with Unkar Plutt for portions that included dried polystarch. On one occasion, she competed with Sarco Plank, a Melitto scavenger, to salvage the wreckage of a star destroyer known locally as the "Ghost Ship." However, they encountered K-8Z8, a still-active security droid. Rey prompted Plank to abandon a fortune in polystarch and veg-meat rations to escape the droid. Subsequently, Plank provided her with several portions, and they shared a meal of polystarch portion bread.
In 34 ABY, the First Order attacked the village of Tuanul on Jakku. Although they captured Poe Dameron, a pilot from the Resistance, he managed to instruct his droid, BB-8, to continue his mission. While traversing the Kelvin Ravine, BB-8 encountered an Aleena mother who pleaded for assistance in feeding her starving children. Recalling the presence of polystarch and veg-meat packets in a starship, BB-8 guided the family to the rations before resuming his journey. Shortly after, he met Rey, who had just finished a dinner of veg-meat and polystarch portion bread.
Some time after the passing of the renowned smuggler Han Solo, his Wookiee companion Chewbacca found himself in possession of Solo's vessel, the Millennium Falcon. When the ship required replacement parts and repairs, Chewbacca reached an agreement with Hondo Ohnaka, a Weequay and former pirate who was contemplating a new business venture, to lend him the ship in exchange for assistance with the repairs. During his journey to Batuu, Ohnaka discovered packets of dried polystarch ration packs in the ship's galley, but he dismissed them as something he wouldn't even offer to his worst adversary.