| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4563770 | LWT - Food Science and Technology | 2016 | 6 Pages |
•The optimum conditions for freeze-drying of probiotic cells were assessed.•Cell counts up to 10.9 log cfu/g were observed applying 5 °C/min cooling rate.•Lactose was the most efficient lyoprotectant for immobilized cells on apples pieces.•Monosodium glutamate proved the best lyoprotectant for immobilized cells on casein.•After storage for 1 year at 4 °C, cell counts were higher than 6 log cfu/g.
The optimum conditions for freeze-drying of free or immobilized Lactobacillus casei ATCC 393 on apple pieces and casein were investigated. Initially, the effect of cooling rate on cell viability of free cells was assessed. Application of 5 °C/min resulted in significant higher levels (10.8 log cfu/g) after 15 days of storage at 4 °C, compared to other rates tested. In a second step, the effect of lyoprotectants (solutions of sugars, starch, polyols, nitrogenous compounds and whey) on viable cell counts of both free and immobilized cells was evaluated. Lactose and monosodium glutamate were the most efficient agents for immobilized cells on apple pieces and casein, accounting for 9.2 log cfu/g and 9.7 log cfu/g, respectively. In all cases, concentrations above 6 log cfu/g (minimum required levels for conferring a probiotic effect) were monitored after storage at 4 °C for up to 12 months, suggesting the suitability of the technology for the production of probiotic foods.
