Table 2.
Changes in physico-chemical characteristics and microbiological parameters of probiotic control yogurt (PCY) and probiotic Spirulina yogurt (PSY, 7% w/w) during storage at 6–8 °C
| Day of storage | Physico-chemical characteristics | Microbiological parameters | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| pH | Acidity (%) | L. acidophilus count (log CFU mL−1) | Increase/decrease in viability of L. acidophilus (%)# | Total plate count (log CFU mL−1) | ||||||
| PCY | PSY (7% w/w) | PCY | PSY (7% w/w) | PCY | PSY (7% w/w) | PCY | PSY (7% w/w) | PCY | PSY (7% w/w) | |
| 0 | 4.55 ± 0.05 | 4.43 ± 0.02** | 0.76 ± 0.02 | 0.84 ± 0.02*** | 8.12 ± 0.11 | 8.57 ± 0.13* | 100.00 | 100.00 | 8.81 ± 0.16 | 8.93 ± 0.14 n.s. |
| 3 | 4.53 ± 0.03 | 4.34 ± 0.03*** | 0.78 ± 0.01 | 0.88 ± 0.03*** | 8.23 ± 0.14 | 8.83 ± 0.11*** | 101.35 | 103.03 | 8.96 ± 0.07 | 8.84 ± 0.09 n.s. |
| 6 | 4.50 ± 0.10 | 4.30 ± 0.01*** | 0.79 ± 0.02 | 0.90 ± 0.02*** | 8.11 ± 0.22 | 8.66 ± 0.16** | 99.88 | 101.05 | 9.09 ± 0.09 | 8.73 ± 0.16* |
| 9 | 4.48 ± 0.02 | 4.25 ± 0.01*** | 0.81 ± 0.01 | 1.07 ± 0.00*** | 7.86 ± 0.08 | 8.12 ± 0.21 n.s. | 96.80 | 94.75 | 9.02 ± 0.13 | 8.66 ± 0.18* |
| 12 | 4.45 ± 0.01 | 4.23 ± 0.01*** | 0.82 ± 0.00 | 1.12 ± 0.01*** | 7.71 ± 0.15 | 7.84 ± 0.24 n.s. | 94.95 | 91.48 | 8.92 ± 0.17 | 8.58 ± 0.14 n.s. |
| 15 | 4.43 ± 0.02 | 4.19 ± 0.02*** | 0.83 ± 0.01 | 1.17 ± 0.01*** | 7.43 ± 0.12 | 7.58 ± 0.16 n.s. | 91.50 | 88.45 | 8.83 ± 0.09 | 8.43 ± 0.21* |
| 18 | 4.41 ± 0.03 | 4.17 ± 0.01*** | 0.84 ± 0.02 | 1.22 ± 0.00*** | 6.98 ± 0.15 | 7.08 ± 0.19 n.s. | 85.96 | 82.61 | 8.65 ± 0.18 | 8.30 ± 0.16* |
Data represents mean ± S.D. of three independent experiments (except #). The mean values of PSY were compared against PCY by two way ANOVA, Bonferroni’s multiple comparison test; ***P < 0.001, **P < 0.01, *P < 0.05, n.s. (not significant) P > 0.05