Relationships between composition, microstructure and cooking performances of six potato varieties.

Potatoes tubers are the raw materials of many processed food, such as cooked potatoes in hot water, baked potatoes and the most popular fried potatoes. The objective of this work was to study the impact of boiling, baking and frying on microstructure and properties of six potato varieties (Agata, Agria, Innovator, Lady Rosetta, Musica and Spunta) with different origin. Scanning Electron Microscopy revealed significant differences between varieties and tuber microstructure changes following all cooking processes. Differential Scanning Calorimeter analysis showed that the transition temperatures (ranging between 60 °C and 85 °C) and enthalpies of gelatinization (2.1 J/g-3.9 J/g) of tubers were also variety dependent. In addition, the elasticity modulus of cooked samples depended on process type and followed the order: baked potatoes > boiled > fried potatoes. In particular, baked Lady Rosetta (224.3 kPa) showed the least decrease in rigidity between thermal processes. Fried Agria and Spunta, (56.3 and 61 kPa, respectively) had the smallest value of Young's modulus. Molecular marker analyses provided a genetic fingerprinting of our varieties, allowing the identification of diagnostic markers. Innovator revealed an important genetic distance from the other varieties. Such distance corresponded to its exclusive phenotypic traits, that are known to affect thermochemical properties. The information obtained in this work may be useful to further study and associate genetic sequences with appreciable food technological traits.