Abstract: The effect of different concentrations of CaCl2 in the culture medium on the freeze-drying resistance and heat resistance of Lactobacillus plantarum LIP-1, a probiotic strain with hypolipidemic properties, was studied. The viable counts in different hot drinks were compared among freeze-dried cells of strain LIP-1 with or without added Ca2+ and a commercial probiotic. The results showed that the addition of 0.5 mmol/L Ca2+ to the medium not only significantly improved the freezedrying survival rate (P < 0.05) but also increased the heat resistance of the strain compared with the control group. When added to hot drinks, the survival rate of freeze-dried cells of strain LIP-1 with added Ca2+ was significantly higher that of a commercial probiotic. The intrinsic mechanism was investigated, showing that the damage degree of cell membrane and wall in LIP-1 were significantly lower than that in the other groups (P < 0.05). This was accompanied by a significant increase in the unsaturated fatty acid content of the cell membrane. The above results indicated that the addition of Ca2+ to the medium could significantly improve the cold and heat resistance of Lactobacillus plantarum LIP-1.

Key words: Ca2+; Lactobacillus plantarum LIP-1; freeze-drying survival rate; heat resistance; unsaturated fatty acids of the cell membrane

摘要： 以具有降血脂益生特性的植物乳杆菌LIP-1为研究对象，通过在培养基中添加不同浓度CaCl2，探究Ca2＋对菌株冷冻干燥抗性及耐热性的影响，并比较未加钙菌粉、加钙菌粉和未加钙市售菌粉在不同热饮中的活菌数。结果表明：与未添加Ca2＋对照组相比，培养基中添加0.5 mmol/L Ca2＋不仅可以显著提高菌株的冷冻干燥存活率（P＜0.05），并可以改善其耐热性；与市售菌粉相比，加钙菌粉在热饮中的植物乳杆菌LIP-1存活率显著提高，探究其内在机制发现，加钙菌粉的植物乳杆菌LIP-1细胞膜与细胞壁损伤程度显著低于其他组别（P＜0.05），同时细胞膜不饱和脂肪酸含量显著升高。上述结果表明，在培养基中添加Ca2＋能够显著提高植物乳杆菌LIP-1对冷热的抗性。

关键词: Ca2＋；植物乳杆菌LIP-1；冷冻干燥存活率；耐热性；细胞膜不饱和脂肪酸