The objective of the study was to determine changes in pectic substances contained in potato tubers, at several stages of the production of French fries, as well as texture-forming effects of these compounds. The samples studied in the laboratory were: potato tubers, strips, and French fries. French fries were obtained from nine posts within one production line. An Instron apparatus was applied to determine contents of pectic substances in the samples of potato tubers, strips, and French fries, as well as their textures. After blanching, the content of water–soluble pectins in potatoes was by 30% lower, whereas the content of protopectins – by 50% higher than in the raw material. The content of protopectins in French fries was three times as high as in potatoes processed. At the most stages of the potato processing, their texture depended on the content of pectins The texture of semi-fried and ready-made French fries was positively and statistically significantly correlated with the content of protopectin (r = 0.71) and total proteins (r = 0.63).