Spray Dryer Parameters for Fruit Juice Drying
2 Abstract: Spray drying is one of the most complex methods for fruit juice drying. Fruit juice is very sensitive and affected the different drying parameters. These parameters should be tested and determined before the design of the dryers. With laboratory spray dryer the basic parameters for drying of orange juice with 65% concentration was studied. The investigated parameters include: drying agent material, feed flow rate inlet and outlet air temperature and sticky point temperature. Tests were performed without and with agent materials and studied the different operating condition of spray drying and the sticky point temperature for orange juice powder. The results of statistical analysis of experimental data show that the parameters of inlet air temperature and feed flow rate have significant effect on the dryer yield and wall deposit of spray dryer individually and jointly. Also with the addition of liquid glucose, the optimum conditions have been obtained with feed flow rate of 15 ml min , inlet air temperature of 130°C and outlet air temperature of 85°C. For the orange powder 1 containing 2% moisture, the sticky point temperature was 44°C.
HIGH-TEMPERATURE SPRAY DRYING
This paper summarizes the results of long-term studies on high-temperature spray drying performed at the Institute of Engineering Thermophysics in Kiev. Two-stage processing involving evaporation followed by drying is proposed to dewater very dilute and temperature-sensitive materials. A new calculation procedure, which accounts for the gas-particle flow pattern and process kinetics, is given along with the performance data for selected drying plants designed according to the procedure developed.
Calcium as an Adjuvant for Spray-Drying Acid Whey
Cottage cheese whey was treated with calcium compounds to reduce sticking in dryer box and cyclone while spray drying (inlet air of 178 to 180 C; exit air of 70 to 74 C). Concentrated whey (22 to 24% solids) neutralized to pH 6.0 with an aqueous suspension of 4% calcium oxide (wt/vol), dried easily, but it was chalky, bitter, and stringent with a high solubility index. The neutralized whey was clarified with desludging centrifuge to remove insoluble calcium salts. This greatly improved flavor, decreased solubility index, increased product clarity upon reconstitution, decreased ash content, and reduced wear on drying equipment. The precipitate formed from calcium addition occupied up to 20% of the bowl volume and reduced yield of protein during clarification. In addition, the protein content of the powder also was reduced. Samples neutralized to pH 5.5 with calcium oxide plus .05% calcium chloride and samples containing only .3% calcium chloride dried more easily than control, but some caking occurred in cyclone. Although clarification of these latter samples improved the solubility index and flavor, they were unacceptable due to bitter and astringent flavors.