The post-technological stability coefficient (PTSC) demonstrates that refrigeration results in greater day-to-day fluctuations in glycemic response compared to freezing, and that glycemic index alone does not fully capture the metabolic stability of stored rice.

When cooked rice is cooled or frozen, the starch molecules rearrange into a tightly packed, hard-to-digest structure. This makes it harder for digestive enzymes to break down the starch into sugar, so less sugar enters the bloodstream at once. Freezing creates a more stable version of this structure, so the amount of sugar released stays consistent from meal to meal. Refrigeration creates a less stable version that breaks down unevenly over time, causing unpredictable spikes in blood sugar between meals.