French‐fried Potatoes: Palatability as Related to Microscopic Structure of Frozen Par‐fries

Abstract

SUMMARY When tissue was taken from finish‐fried or par‐fried potatoes not subjected to fixing or embedding, potato cells were found to be plump, and the surfaces were comparatively smooth, faintly showing the outlines of the gelatinized starch granules within. Cells from tissue that had been frozen showed reticulation, especially those from tissue frozen at ‐18°C as contrasted with tissue frozen at ‐78°C. When tissue was observed during freezing, cell separation was pronounced, as well as pushing together or shrinking of gelled starch granules, and cell distortion. When thawed, the potato cells partially recovered their original plumpness although breaks between the cells remained. Recovery of gelation was incomplete in starch granules from cells from potato tissue that had been par‐fried, frozen, and finish‐fried. A taste‐test panel preferred French‐fried potatoes frozen as an intermediate step in preparation, especially noting less cohesiveness of texture and greater tenderness of crust.

Relationships of Histological Structure to Texture of Fresh and Processed Fruits and Vegetables

“…diminished by a subsequent heat treatment. Freezing produces a similar textural effect in French-cut, frozen par-fries intended for finish frying (Reeve et al, 1968;Spiruta and Mackey, 1961). Further changes take place when frozen par-fries are thawed and held before finish frying.…”

Oil Absorption During Frying of Frozen Parfried Potatoes

“…Interestingly, formation of a crust (thickness ca. 1 mm) during frying of potato pieces does not lead to the rupture of cells in the crust (size approximately 150 m),which remain largely intact but shrunken and dehydrated, with swollen starch granules pushing against the cell walls (Spiruta and Mackey 1961). Recently, Pedreshi and others (1999) using confocal laser scanning microscopy demonstrated that oil in the crust is arranged as an "egg-box" surrounding intact shrunken cells but does not penetrate into them.…”

Observations on Strawberry Texture a Three‐pronged Approach

“…Potatoes have received considerable attention, with textural attributes such as softness of cooked (Personius and Sharp, 1937), 'cottoniness' of frozen (Longree, 1950), stickiness of dehydrated (Reeve, 1963), mealiness of cooked (Reeve, 1967) and cohesiveness of par-fried (Spiruta and Mackey, 1961) having been relatedat least partiallyto histology. An excellent review of interrelationships between structure and textural qualities of processed potatoes has been published recently by Reeve (1967).…”