The invention discloses a preparation method of a black tomato freeze-dried
powder. The method adopting black tomatoes as a
raw material comprises the following steps: choosing black tomatoes, removing impurities, disinfecting by using an
aqueous solution of
chlorine dioxide,
cutting, pre-cooling, carrying out vacuum freeze-
drying until the
water content of the obtained material is 3.0-5.0%, and taking out the black tomatoes, wherein computer
automatic control temperature
programming is adopted in the vacuum freeze-
drying process, the heating process is carried out according to a function of F=F1+(t / t1)3*(F2-F1), F is the heating medium temperature at the t moment after heating, t is 0 ~ t1, the unit of t is min, the total time t1 = 1020~1200min, an initial temperature F1 is 30~35DEG C, and a final temperature F2 is 50~55DEG C; and carrying out
refrigeration crushing at a low temperature being smaller than -50DEG C to obtain the black tomato freeze-dried
powder with the
granularity being greater than 200 meshes. The black tomato freeze-dried
powder is packaged by a silver paper bag, so the
shelf life at normal temperature exceeds 1.5 years. The black tomato powder reserves nutritional substances and taste of fresh black tomatoes, and the above whole process is suitable for industrial production.