Processing fresh tomatoes into tomato powder can greatly increase its added value, and it is also a good way to solve the problem of low price and perishable tomato season.
First, choose raw materials
Fresh, mature, bright red, pest-free tomatoes are used as raw materials.
Second, crushing and heating.
The tomatoes are crushed and then immediately heated to 85 °C.
In order to remove the skin and seeds of the tomatoes, a double-channel pulping machine is used for beating. The screen size of the first beater is 0.8 to 1 cm, and the screen diameter of the second beater is generally 0.4 to 0.6 cm. The speed of the beater is generally 800 to 1200 rpm. The amount of skin residue obtained after beating should generally be controlled at 4% to 5%.
Fourth, vacuum concentration
Concentration methods are vacuum concentration and atmospheric concentration. Concentration at atmospheric pressure, due to the high concentration of the concentration, causes the color and flavor of the tomato slurry to decrease, and the product quality is poor, so vacuum concentration is generally used. The temperature used for vacuum concentration is only about 50 ° C, and the vacuum is above 670 mm Hg.
Generally, tomato concentrates are spray dried and foam dried.
1. Spray drying method
Prior to spray drying, the tomato concentrated slurry is homogenized. The homogenization pressure is 150 to 200 kg/cm 2 . Drying is generally carried out using a centrifugal or two-fluid or spray dryer with a cooling jacket on the tower wall. If the heating medium is pre-dehumidified dry air, the inlet air temperature during drying is generally about 150 ° C to 160 ° C, the outlet air temperature is 77 ° C to 85 ° C, and the feed concentration is generally 20% to 30%.
2. Foam Drying Method
The key to this drying method is to form a stable foam in a tomato concentrate by adding a foaming substance such as soy protein, globulin, fatty acid ester, sugar ester, and glyceryl monostearate. The gas passing through the dryer was at a temperature of about 93 ° C and a velocity of about 100 to 130 m / sec, which was added in a countercurrent manner. Generally dry for 15 to 18 minutes.