This study investigated the dynamic changes in legume starches (common vetch, mung bean, and pea) during gelatinization. All three starches displayed a similar pattern: water absorption and swelling at lower temperatures (50-65 °C), structural rupture at medium temperatures (65-75 °C), and melting/reorganization at higher temperatures (75-90 °C). Gelatinization likely starts with internal structural dissociation, as evidenced by the weakening of the double helix structure and decreasing order observed throughout the process. Lamellar analysis further revealed that the amorphous region swelled first, followed by swelling and melting of the crystalline region. Interestingly, the resulting mutual melting system exhibited varying density, with mung bean starch showing the highest density, followed by pea starch and common vetch starch being the least dense. These findings contribute to a deeper understanding of morphological and structural transformations occurring within legume starches during gelatinization.