Spinach contains a lot of oxalic acid. If oxalic acid is not removed, spinach will feel astringent, and after eating, it will form calcium oxalate with calcium, which is not conducive to human absorption and utilization. Therefore, it is necessary to blanch to remove oxalic acid from spinach.
Toona sinensis is a special food in spring, which contains a lot of nitrate and nitrite. If blanched, nitrite in Toona sinensis can be removed and Toona sinensis can be made greener and more fragrant.
Broccoli needs blanching, because its flowers are dense, directly exposed, easily exposed to insects and dirt, and difficult to clean. Blanching water can remove oxalic acid and astringency, which is healthier.
Green beans need to be blanched because they contain saponins and lectins. Blanching can destroy growth and maintain color and taste.