2% (v/v) L. acidophilus was inoculated in the ripe banana medium which was obtained by the banana puree with the addition of three-times of aseptic water. The lactic acid bacteria inoculated were in the states of free cell and immobilized cell, respectively, and then cultivated at 37.degree.C for 48 hr after inoculation. The matrices used for cell immobilization were calcium alginate and k-carrageenan, and the diameters of the bacteria-containing gel beads of calcium alginate andκ-carrageenan were 2.6 mm and 3.0 mm respectively. The fermented products obtained were then freeze-dried, and the dried samples were stored at 25.degree.C and RH 60% for storage test. Results indicated that immobilization had protection effects to cells during freeze-drying. After freeze-drying, the survival of immobilized cell was better than free cell (9.31 Log CFU/mL), and that of calcium alginate immobilization (10.48 Log CFU/mL-gel) was better thanκ-carrageenan immobilization (10.22 Log CFU/mL-gel). For the hygroscopicity of the dried products during storage, the hygroscopicity of free cell products was higher than immobilized cell products, and that ofκ-carrageenan immobilized products was higher than that of calcium alginate immobilized products.
