Abstract:
The objectives of this study were to investigate protective agents with various glass transition temperature (Tg) affecting the survival of L. plantarum FT35 during spray drying and storage. The protective agents used in this study were glucose, sucrose, lactose, maltodextrin DE 10, and soluble starch. The Tg of these protective agents were 35.33 oC , 75.13 oC, 119.34 oC, 160 oC and 243 oC, respectively. The 20 hours cultured L. plantarum FT35 were mixed with solution of protective agent which was adjusted to have 1.6-1.7 Cp. The mixtures were spray dried with inlet temperature at 185 oC, feed rate of 20 ml/min and outlet temperature of 85+5 oC. It was found that protective agents with high Tg provided the protective bacterial cell property greater than protective agents with low Tg. Amoung these protective agents, soluble starch gave the highest of cell survival at 93.4%. The powder-products were vacuum packed in laminate aluminum foil bags (PP/PE/AluPE/PP) and stored at room temperature (30-35oC) for 4 week. The stored products contained viable cells of L. plantarum FT35 at 85.6% of the initial amount. To find the proper concentration of soluble starch, the concentration of 1.5% 2.5% 3.5% 4.5% and 10% were varied. It was found that 2.5% soluble starch provided the cell highest survival of L.plantarum FT35 at 93.4%. The powder-products of L. plantarum FT35 with 2.5% soluble starch were stored at room temperature (30-35oC) and 4oC for 8 weeks, it was found that 6.28+0.55 log CFU/g and 2.43+0.63 log CFU/g reduced respectively. The powder product stored 4oC for 8 weeks for starter culture of fish fermentation and comparison efficacy with fresh starter culture, this study did not find a significant difference.