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.
SPRAY DRYING OF CONCENTRATED FRUIT JUICES
ABSTRACT Two spray dryers were tested to obtain powders from concentrated juices of blackcurrant, apricot, raspberry, with different maltodextrins as drying-aid agents. Composition of fruit juices and dextrose equivalent for maltodextrin are considered. Best results were obtained for a ratio juice to maltodextrin DE6 of 65/35 for blackcurrant, of 60/40 for apricot and 55/45 for raspberry, and low air temperatures (160–90°C). A compromise must be found between the ratio fruit juice to additives, the drying yield and the cost of raw materials.
Effect of Four Anticaking Agents on the Bulk Characteristics of Ground Sugar
Fine silicon oxide, sodium aluminum silcate, tricalcium phosphate and calcium stearate powders were admixed with dry ground sugar at four concentration levels between 0.1 to 2%. Appreciable increase in loose bulk density and decrease in compressibility were noticeable at 0.1% concentration in all four agents. The effect reached an apparent peak or a flat maximum at an agent concentration of about 0.5–1%. With the exception of silicon oxide treated powders, increase in density was accompanied by a corresponding decrease in compressibility. Bulk parameters (i.e., density and compressibility) were more sensitive indices to changes occurring in powders as compared to parameters determined in compacted specimens (i.e., yield in shear, internal friction and relaxation pattern). Results are explained in terms of possible bed arrays and their scatter by differences in particle size and shape distributions. Support for these explanations is presented in scanning electron micrographs of sugar treated and untreated particles.