Glycerol resulted in low viabilities in all cases, indicating that it
is inappropriate for the preservation of lactic acid bacteria during
freeze-drying, as was also demonstrated in a previous study (Font
de Valdez et al., 1983 ).
Table 1
Effect of lyoprotectant and storage on viability of freeze dried immobilized L. casei ATCC 393 cells on apple pieces.
Lyoprotectant Storage at 4 C
Viability (log cfu/g) % Viability Survival factor
AF 6 months 12 months AF 6 months 12 months AF 6 months 12 months
Before freeze drying 9.5 ± 0.1 100 1.00
Glucose 9.2 ± 0.1 8.8 ± 0.1 8.1 ± 0.1 43.9 ± 7.1 16.3 ± 1.5 3.7 ± 0.5 0.96 ± 0.01 0.92 ± 0.01 0.85 ± 0.01
Fructose 8.5 ± 0.1 8.3 ± 0.1 7.9 ± 0.1 8.8 ± 1.7 6.0 ± 0.8 2.5 ± 0.6 0.89 ± 0.01 0.87 ± 0.01 0.83 ± 0.01
Galactose 9.0 ± 0.1 8.8 ± 0.1 8.3 ± 0.1 29.6 ± 3.8 17.1 ± 2.3 5.9 ± 1.2 0.94 ± 0.01 0.92 ± 0.01 0.87 ± 0.01
Sucrose 8.8 ± 0.1 8.6 ± 0.1 8.1 ± 0.1 19.8 ± 4.5 10.1 ± 0.9 3.7 ± 0.5 0.93 ± 0.01 0.90 ± 0.01 0.85 ± 0.01
Maltose 8.7 ± 0.1 8.5 ± 0.1 8.0 ± 0.1 13.6 ± 2.6 8.4 ± 1.2 3.2 ± 0.3 0.91 ± 0.01 0.89 ± 0.01 0.84 ± 0.01
Lactose 9.2 ± 0.1 9.1 ± 0.1 8.7 ± 0.1 45.9 ± 6.0 33.2 ± 3.2 13.8 ± 0.9 0.96 ± 0.01 0.95 ± 0.01 0.91 ± 0.01
Trehalose 9.1 ± 0.1 8.8 ± 0.1 8.2 ± 0.1 34.8 ± 3.4 16.0 ± 2.1 4.5 ± 1.0 0.95 ± 0.01 0.92 ± 0.01 0.86 ± 0.01
Raffinose 9.1 ± 0.1 8.8 þ 0.1 8.2 ± 0.1 37.2 ± 2.4 17.4 ± 2.5 4.9 ± 0.3 0.95 ± 0.01 0.92 ± 0.01 0.86 ± 0.01
Starch 8.5 ± 0.1 8.3 ± 0.1 7.8 ± 0.1 9.2 ± 2.1 5.1 ± 0.6 1.8 ± 0.3 0.89 ± 0.01 0.86 ± 0.01 0.82 ± 0.01
Glycerol 8.5 ± 0.1 8.1 ± 0.1 7.6 ± 0.1 8.7 ± 0.9 4.0 ± 1.1 1.2 ± 0.2 0.89 ± 0.01 0.85 ± 0.01 0.80 ± 0.01
Sorbitol 9.0 ± 0.1 8.7 ± 0.1 8.1 ± 0.1 27.2 ± 5.3 12.9 ± 1.6 3.7 ± 0.2 0.94 ± 0.01 0.91 ± 0.01 0.85 ± 0.01
Monosodium glutamate 8.8 ± 0.1 8.5 ± 0.1 8.0 ± 0.1 18.7 ± 3.0 9.4 ± 0.6 2.9 ± 0.3 0.92 ± 0.01 0.89 ± 0.01 0.84 ± 0.01
Peptone 9.0 ± 0.1 8.9 ± 0.1 8.6 ± 0.1 28.9 ± 1.9 22.9 ± 2.3 10.5 ± 0.7 0.94 ± 0.01 0.93 ± 0.01 0.90 ± 0.01
Skim milk 8.6 ± 0.1 8.3 ± 0.1 7.9 ± 0.1 12.1 ± 1.2 6.3 ± 0.7 2.0 ± 0.2 0.90 ± 0.01 0.87 ± 0.01 0.82 ± 0.01
Whey 9.1 ± 0.1 9.0 ± 0.1 8.7 ± 0.1 37.2 ± 2.4 28.9 ± 3.6 13.0 ± 2.1 0.95 ± 0.01 0.94 ± 0.01 0.91 ± 0.01
Control (no lyoprotectant) 8.5 ± 0.1 7.8 ± 0.1 7.0 ± 0.1 8.9 ± 0.9 2.0 ± 0.5 0.3 ± 0.1 0.89 ± 0.01 0.82 ± 0.01 0.73 ± 0.01
(AF: After Freeze-drying) Data are presented as the mean values of triplications ± SD.
Table 2
Effect of lyoprotectant and storage on viability of freeze dried immobilized L. casei ATCC 393 cells on casein.
Lyoprotectant Storage at 4 C
Viability (log cfu/g) % Viability Survival factor
AF 6 months 12 months AF 6 months 12 months AF 6 months 12 months
Before freeze drying 9.8 ± 0.1 100 1.00
Glucose 9.7 ± 0.1 9.3 ± 0.1 9.2 ± 0.1 71.3 ± 11.6 35.1 ± 3.1 24.1 ± 3.1 0.98 ± 0.01 0.95 ± 0.01 0.94 ± 0.01
Fructose 9.5 ± 0.1 9.1 ± 0.1 8.8 ± 0.1 49.4 ± 9.6 19.8 ± 2.5 11.1 ± 2.5 0.97 ± 0.01 0.93 ± 0.01 0.90 ± 0.01
Galactose 9.2 ± 0.1 8.8 ± 0.1 8.6 ± 0.1 25.8 ± 3.4 10.8 ± 2.1 6.2 ± 1.2 0.94 ± 0.01 0.90 ± 0.01 0.88 ± 0.01
Sucrose 9.5 ± 0.1 9.2 ± 0.1 9.1 ± 0.1 54.4 ± 12.3 26.7 ± 3.2 18.3 ± 2.4 0.97 ± 0.01 0.94 ± 0.01 0.92 ± 0.01
Maltose 9.6 ± 0.1 9.3 ± 0.1 9.1 ± 0.1 60.8 ± 11.8 29.2 ± 3.4 19.5 ± 1.9 0.98 ± 0.01 0.95 ± 0.01 0.93 ± 0.01
Lactose 9.4 ± 0.1 9.1 ± 0.1 9.0 ± 0.1 40.0 ± 5.2 21.0 ± 2.6 15.2 ± 1.0 0.96 ± 0.01 0.93 ± 0.01 0.92 ± 0.01
Trehalose 9.7 ± 0.1 9.3 ± 0.1 9.0 ± 0.1 71.0 ± 6.9 29.8 ± 2.4 17.6 ± 4.0 0.98 ± 0.01 0.95 ± 0.01 0.92 ± 0.01
Raffinose 9.6 ± 0.1 9.1 ± 0.1 8.7 ± 0.1 58.9 ± 3.8 19.0 ± 1.7 8.5 ± 0.6 0.98 ± 0.01 0.93 ± 0.01 0.89 ± 0.01
Starch 9.4 ± 0.1 8.9 ± 0.1 8.6 ± 0.1 40.3 ± 9.1 13.6 ± 2.8 6.5 ± 1.3 0.96 ± 0.01 0.91 ± 0.01 0.88 ± 0.01
Glycerol 9.5 ± 0.1 9.0 ± 0.1 8.6 ± 0.1 50.2 ± 4.9 15.1 ± 0.9 6.4 ± 1.0 0.97 ± 0.01 0.92 ± 0.01 0.88 ± 0.01
Sorbitol 9.6 ± 0.1 9.4 ± 0.1 9.3 ± 0.1 69.8 ± 13.6 37.6 ± 2.9 28.2 ± 1.8 0.98 ± 0.01 0.96 ± 0.01 0.94 ± 0.01
Monosodium glutamate 9.7 ± 0.1 9.4 ± 0.1 9.3 ± 0.1 80.0 ± 13.0 42.7 ± 2.8 31.7 ± 3.1 0.99 ± 0.01 0.96 ± 0.01 0.95 ± 0.01
Peptone 9.5 ± 0.1 9.2 ± 0.1 8.9 ± 0.1 51.3 ± 3.3 22.4 ± 1.6 13.5 ± 0.9 0.97 ± 0.01 0.93 ± 0.01 0.91 ± 0.01
Skim milk 9.6 ± 0.1 9.3 ± 0.1 9.1 ± 0.1 63.2 ± 6.2 29.9 ± 3.2 19.5 ± 1.9 0.98 ± 0.01 0.95 ± 0.01 0.93 ± 0.01
Whey 9.4 ± 0.1 9.1 ± 0.1 8.9 ± 0.1 38.1 ± 2.5 18.7 ± 2.6 12.7 ± 2.1 0.96 ± 0.01 0.93 ± 0.01 0.91 ± 0.01
Control (no lyoprotectant) 8.7 ± 0.1 7.9 ± 0.1 7.7 ± 0.1 8.0 ± 0.8 1.3 ± 0.1 0.8 ± 0.2 0.89 ± 0.01 0.81 ± 0.01 0.79 ± 0.01
(AF: After Freeze-drying) Data are presented as the mean values of triplications ± SD.
D. Dimitrellou et al. / LWT - Food Science and Technology 69 (2016) 468e473 471
In all cases, the use of casein as immobilization support led to
higher cell viabilities compared to apple pieces. This may be
attributed to different nature of immobilization. In apple pieces,
L. casei cells were attached mainly on the surface, while in casein
the cells were entrapped inside the protein matrix. Moreover, the
protective role of milk proteins