A study focusing on the distinct fine structure of starch in mealy and waxy potatoes

In this research, we examined the fine structure of starch in three mealy and three waxy potato varieties to understand their impact on potato texture. This research revealed significant variations in starch granule morphology, particle size, crystalline structure, molecular structure, and pasting properties between the different textures. Mealy potato starch granules appeared as rounded ovoid with inconsistent particle sizes (ranging from 35.9 to 41.8 μm), whereas waxy potato starch granules exhibited sharp polygonal shapes with consistent larger sizes (42.1-49.7 μm). While both types displayed a B-type crystalline morphology, the relative crystallinity of mealy potato starch (31.28%, 38.00% and 29.07%) is higher than that of waxy potato starch (27.38% 26.68% and 26.12%) as determined by X-ray diffraction. Additionally, the mealy potato starches had lower amylopectin content, degree of branching, short-chain amylopectin content, and molecular weight, but higher trough viscosity, final viscosity, and setback value than waxy potato starches. These differences in fine structure contributed significantly to the variations in texture between mealy and waxy potato starches, highlighting potential implications for breeding programs aimed at improving specific textural attributes for targeted application in the food industry.