复合益生菌发酵南瓜浆菌株筛选及发酵工艺优化

为了获得发酵南瓜浆复合益生菌株，以南瓜浆为原料，分别选择8株乳酸菌对其进行发酵，以活菌数、可滴定酸和pH值为考察指标，筛选出活菌数最高、发酵能力最强的植物乳杆菌（Lactobacillus plantarum）CICC21824和降酸速度最快、适应性最强的嗜热链球菌（Streptococcus thermophilus）CICC20373，并将这2株乳酸菌以1∶1比例复配发酵南瓜浆，以活菌数为评价指标，通过Box-Benhnken试验设计，优化复合益生菌发酵南瓜浆的工艺条件。结果表明，最佳发酵工艺条件为料液比1∶1（g∶mL），接种量7.8%（V/V），发酵温度33 ℃，发酵时间24 h。在此优化条件下，乳酸菌发酵南瓜浆的活菌数为9.89 lg（CFU/mL）。

Screening of strains and optimization of fermentation technology for pumpkin pulp fermentation by compound probiotics

To obtain the suitable probiotics for pumpkin pulp fermentation, the pumpkin pulp was fermented by 8 lactic acid bacteria. Using viable count, titratable acid and pH value as evaluation indexes, the Lactobacillus plantarum CICC21824 with high viable count and fermentability and the Streptococcus thermophilus CICC20373 with fastest acid reduction rate and greatest adaptability were selected. The pumpkin pulp was fermented by the 2 lactic acid bacteria with ratio 1∶1, and using viable account as evaluation index, the process conditions of the pumpkin pulp fermentation by the complex probiotics were optimized by Box-Benhnken experimental design. The results showed that the optimal fermentation process conditions were solid-liquid ratio 1∶1 (g∶ml), inoculum 7.8% (V/V), fermentation temperature 33 ℃, and time 24 h. Under these optimal conditions, the viable count in pumpkin pulp fermented by lactic acid bacteria was 9.89 lg(CFU/ml).