Optimization of process parameters for the production of spray dried Ber (Ziziphus jujube L.) powder.

The study covers effect of operating variables of spray dryer i.e. inlet temperature (170, 180, 190, 200 and 210 °C,), aspirator blower capacity (40, 50, 60, 70 and 80 %) and feed pump capacity (9, 12, 15, 18, and 21 %) and processing parameters of feed i.e. total soluble solid (TSS) of feed (7.5 %) and encapsulating material, maltodextrin (4, 6, 8, 10, and 12 %), aerosil (1.0 %), citric acid (0.25 %) upon the physical properties (colour, packed density and hygroscopicity) of powder were observed. After complete evaluation and analysis of all the attributes for physical properties i.e. colour, packed density (0.45 g/cc) and hygroscopicity (0.17 g/g dry matter), it was concluded that best quality of Ber powder were obtained at inlet air temperature 190 °C, aspirator blower capacity 60 %, feed pump capacity 15 %, encapsulating material 8 %.

Effect of process and machine parameters on physical properties of extrudate during extrusion cooking of sorghum, horse gram and defatted soy flour blends.

Extrusion cooking of sorghum (Sorghum vulgaris), horse gram (Dolichos biflorus) and defatted soy (Glycine max) flour blends was done to prepare snacks by using a Brabender single-screw laboratory extruder. The combined effect of moisture content, blend ratio of feed, barrel temperature and screw speed of extruder on physical parameters of extrudate was studied. It was observed that 15% moisture content of feed, 80:10:10 (sorghum flour: horse gram flour: defatted soy flour) of blend ratio, 130 °C barrel temperature and 130 rpm of screw speed gave the highest sectional expansion index and longitudinal expansion index of extrudate, while 12% moisture content, 75:15:10 of blend ratio of feed, 135 °C of barrel temperature and 135 rpm of screw speed gave lowest bulk density of extrudate. A central composite rotable design (CCRD) of response surface methodology was used to develop prediction model. Second order quadratic regression model fitted adequately in the variation. The significance was established at p ≤ 0.05. It was also observed that increasing feed moisture content results in a higher density and lower expansion of extrudate. Increasing barrel temperature and screw speed reduced density but increased expansion of extrudate.