Pre-peeled potatoes, treated with heated ascorbic/citric acid solutions to control browning, undergo firming and separation of superficial tissues that affect texture after mashing and slicing following cooking. Examination of superficial parenchyma cells in cooked potatoes by scanning and transmission electron microscopy indicated greater cell wall rigidity and middle lamella retention in samples treated with browning inhibitors than in untreated controls. Lumps in mashed potatoes prepared from treated samples showed similar characteristics. Treated samples sometimes displayed a discontinuity beneath the superficial tissue, corresponding to site of tissue separation during slicing. These observations are consistent with treatment-induced changes in cell wall and/or middle lamella pectins as the cause of such textural defects.