Abstract: Two color measurement methods, NCS (Natural Color System) color card and color difference meter, were used to collect color difference data of broccoli steamed by 0.20, 0.45, and 0.80 g/(min·L) steam. The obtained color difference data were processed to obtain Yellowness difference (ΔG) of the NCS color card, yellowness value of the color difference meter (b value), yellowness difference of the color difference meter (Δb value), and total difference of the color difference meter (ΔE value) and other indicators. Finally, through comparative analysis ΔE, the highest probability of correctly distinguishing the three kinds of steam is 87.5%, and the coefficient of variation is the lowest, which is more suitable as an evaluation index. It was also found that with the increase of ΔE, the amount of steam decreased gradually, the cooking time of broccoli increased gradually, and the vitamin content decreased gradually.

Key words: Broccoli, Color difference, Steam capacity