Microstructural and chemical investigation of subsurface hardened potatoes (Solanum tuberosum L.)

Summary Microstructural changes related to subsurface hardening of pre-peeled potatoes were investigated using cv. Sava potatoes peeled using an industrial peeler, a laboratory knife peeler or a hand knife peeler. The pre-peeled potatoes were packed in polymer bags and stored at 18°C for six days until cooking. Potato hardness and microstructure of the tissue was investigated. Cellulose and suberin in hard potato tissue increased linearly with increase in mechanical impact in a damage barrel. The area of cell walls and especially cell corners of mechanically damaged potatoes showed white autofluorescence in blue light. The number of layers of bricklike and autofluorescent parenchyma increased significantly with increasing hardness. Subsurface hardening was related to percentage cells with fluorescent gelatinised cell mass and curly cell walls in a depth of the potato tissue corresponding to the depth of maximum hardness.