Results of the instrumental colour measurement are shown in
Table 2. L⁄ expresses the white and black colour of tubers and
may be used as an indicator of discolouration of Jerusalem artichoke
tubers. The L⁄-value of raw tubers varied between 67.7 and 71.5 (Table 2). Draga and Rema had higher L⁄-values in the autumn
than in the spring, in both raw and boiled tubers. Raw tubers
were whiter than boiled tubers, as the L⁄-values were higher in raw
than in boiled tubers, regardless of variety and harvest time. As tubers
mainly had white-coloured flesh, a⁄ and b⁄-values were close
to 0. The b⁄-values were between 10.2 and 13.2 in raw and between
5.2 and 10.2 in boiled tubers (Table 2). Positive b⁄-values
indicates a slight yellow flesh colour. As the b⁄-values decreased,
tubers became slightly less yellow during boiling. Likewise the
b⁄-values, the hue gave yellow readings as values were around
90. The flesh of raw tubers was more intense in colour than the
flesh of boiled tubers, as chroma values were higher in raw than
in boiled tubers (Table 2).