Abstract:
This research aimed to study the utilization of Jerusalem artichoke (Helianthus tuberosus L.) powder as a carbon source for the growth of Lactobacillus casei TISTR 1463 and optimize drying conditions for production of fermented milk powder by Spray dryer. Results showed that L. casei could use Jerusalem artichoke powder for growing and producing lactic acid in similar way as growing in MRS broth, which glucose was used as a carbon source. The addition of 0 2 4 and 6% Jerusalem artichoke powder in fermented milk was significantly affected pH, cell density and lactic acid production (p<0.05). The addition of Jerusalem artichoke powder resulted in higher probiotic number, lactic acid content and rate of pH reduction. Therefore, the fermentation time was decreased. Two samples with 4 and 6% Jerusalem artichoke powder fermented for 13 hour 54 minutes and 11 hour 37 minutes, respectively were selected to spray dry at 2 different inlet temperatures (150 and 170 degrees Celsius). It was found that the higher inlet temperature significantly decreased moisture content, Aw, bulk density, cell density and lactic acid content but increased pH value of fermented milk powder (p <0.05). The sensory evaluation of fermented milk tablet supplemented with 6% Jerusalem artichoke powdered and dried at 150 inlet temperature was the most satisfied for the smell (7.68 ± 0.91) and overall liking (6.39 ± 1.05).