Lactic acid bacteria (LAB) that metabolize sugars to obtain energy and produce a large amount of lactate through the process are well known for their benefits. However, they can be used on a large scale only when good storage stability is guaranteed. The vitality and stability of several LAB strains were effectively protected in this investigation by L-theanine at 1% of the appropriate concentration (Lactiplantibacillus plantarum MG5023, Enterococcus faecium MG5232, Lactococcus lactis MG4668, Streptococcus thermophilus MG5140, and Bifidobacterium animalis subsp. lactis MG741). The inclusion of L-theanine as a protective agent significantly enhanced the viability of all strains throughout the freeze-drying process compared to that of the non-coated probiotics. The efficacy of L-theanine in improving bacterial stability and survivability was evaluated using accelerated stability tests, gastrointestinal (GI) tract survivability tests, and adhesion assays with intestinal epithelial cells. The cell surface was covered with substances including L-theanine, according to morphological findings, providing efficient defense against a variety of external stresses. Therefore, by exerting anti-freezing and anti-thawing properties, the adoption of L-theanine as a new and efficient protective agent may improve the stability and viability of a variety of probiotics.

乳酸菌（LAB）通过代谢糖来获取能量并在此过程中产生大量乳酸，其益处众所周知。但只有在保证良好的储存稳定性的情况下才能大规模使用。在本次研究中，1%适当浓度的L-茶氨酸有效保护了多种LAB菌株的活力和稳定性（植物乳杆菌MG5023、屎肠球菌MG5232、乳酸乳球菌MG4668、嗜热链球菌MG5140和动物双歧杆菌乳酸亚种MG741 ） 。与未包衣益生菌相比，L-茶氨酸作为保护剂显着增强了整个冷冻干燥过程中所有菌株的活力。使用加速稳定性测试、胃肠道 (GI) 道生存力测试和肠上皮细胞粘附测定来评估 L-茶氨酸在改善细菌稳定性和生存力方面的功效。根据形态学发现，细胞表面覆盖有包括L-茶氨酸在内的物质，可以有效防御各种外部应激。因此，通过发挥抗冻和抗解冻特性，采用L-茶氨酸作为新型高效保护剂可以提高多种益生菌的稳定性和活力。