Effect of physicochemical properties of starch on the tendency of potato tuber flesh to darkening and the processed product quality

摘要

The aim of the present research was to determine whether, and to what extent, the selected potato starch quality parameters affect the tendency of potato tuber flesh to darkening and the value of thermal processing products. The research was carried out after harvest and after 6 months of tuber storage at the temperature of +8deg C and relative air humidity of 95%. The research material was made up of three mid-early potato cultivars: two Polish cultivars, 'Lena' and 'Mors', and 'Agria', a German cultivar. The research was carried out in three vegetation periods in Poland (the Kujawy and Pomorze region) and in Germany (Lower Saxony). The starch grain size, gel stability after defrosting and raw and cooked tuber flesh tendencies to darkening were significantly modified by the genetic factor, while neither the site nor the year of cultivation affected these characters significantly As a result of tuber storage, genetic conditions affected the share of large grains (>60 jxm) more considerably than thestorage conditions and time; unlike the starch gel stability since a high variation in this character depended on the site of cultivation and place of storage. The potato tuber storage time increases the degree of darkening and the tendency leads to theFrench fries and chips quality deterioration. The results of the present research clearly show that the fraction of starch grains >60 |xm was significantly positively correlated with raw and cooked tuber flesh darkening, whereas fraction <40 |xm was significantly negatively correlated with these potato tuber characters.