Abstract
French fries made from low specific gravity potatoes are poor in texture and soggy in appearance. High specific gravity potatoes, on the other hand, produce mealy, firm and good-textured french fries.
A comparison of raw potatoes of high and low specific gravity for protopectin, the degree of esterification, water-soluble pectins and divalent cations revealed no significant differences. Low specific gravity potatoes, however, were found to contain significantly higher levels of free calcium and lower degree of esterification of water-soluble pectins.
Similar comparisons of french fries made from these potatoes showed that low specific gravity fries had a higher degree of protopectin de-esterification, greater breakdown of protopectin and higher levels of free calcium. It was concluded that protopectin of low specific gravity potatoes possesses fewer and/or weaker cross linkages, is poorly polymerized, and a substantial percentage of it breaks down on frying. This weakens the cell wall and results in a french fry of poor texture.
Resumen
Papas fritas a la francesa hechas de papas con baja gravedad específica son deficientes en estructura y se muestran blandas. Al contrario, papas de alta gravedad específica producen papas fritas que son harinosas y tienen una textura buena.
Una comparación de papas crudas de alta y baja gravedad específica para protopectina, el grado de esterificación, pectinas solubles en agua, y cationes divalentes, no reveló diferencias significantes. Sinembargo, se encontró que las papas de baja gravedad específica contenían significativamente niveles mucho más altos de calcio libre y un grado más bajo de esterificación de pectinas solubles en agua.
Comparaciones similares de papas fritas a la francesa hechas de esas papas demostraron que fritos de baja gravedad específica tenían más alto grado de protopectina de de-esterificación, mayor desintegración de protopectina y más altos niveles de calcio libre. Se concluye que la protopectina de las papas de baja gravedad específica posee menos y/o más débil cruce genético, está pobremente polimerizada, y un porcenteje substancial de esta protopectina se desintegra al freir. Este proceso debilita la pared celular y da como resultado fritos de textura pobre.
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Jaswal, A.S. Pectic substances and the texture of french fried potatoes. American Potato Journal 46, 168–173 (1969). https://doi.org/10.1007/BF02872359
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DOI: https://doi.org/10.1007/BF02872359