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.
Development of a small scale processing system for concentrated ginger powders.
Mature ginger rhizomes with the age of 10-12 months was used in the study. Ginger juice was extracted using a hydraulic press and evaporated in traditional pan, natural circulation and agitated vacuum evaporators. The evaporators had no significant difference on a , solubility, water solubility index, water w absorption index and bulk density of concentrated ginger powders (p>0.05). The natural circulation and agitated vacuum evaporators provided higher lightness of concentrated ginger powders than traditional pan evaporator (p 0.05). However, the evaporators had no significant difference on yellowness (a*/b*) of concentrated ginger powders and L* and a*/b* of reconstituted ginger powders. The agitated vacuum evaporator provided the highest 6-gingerol remaining (p 0.05).
Plasticizing Effect of Water on Thermal Behavior and Crystallization of Amorphous Food Models
Dehydrated sugar solutions were used as models of thermal behavior of amorphous foods, and of the effect of temperature, moisture content and time on physical state of such foods. The transition temperatures determined were glass transition (Tg), crystallization (Tcr) and melting (Tm) which all decreased with increasing moisture. Tg of a sucrose/ fructose model had a slightly lower value than the empirical “sticky point,” at all moisture contents studied. Crystallization of sucrose was delayed by addition of fructose or starch. Crystallization above Tg was time-dependent, and the relaxation time of this process followed the WLF equation.