Linders L J, Wolkers W F, Hoekstra F A, van 't Riet K
Department of Food Science, Wageningen Agricultural University, The Netherlands.
Cryobiology. 1997 Aug;35(1):31-40. doi: 10.1006/cryo.1997.2021.
The relation between the protective effect of externally added carbohydrates on Lactobacillus plantarum cells during air-drying and the phase behavior of cell membranes was studied. The residual activity after drying could be improved from 44% in the control to 79 and 66% after the addition of sorbitol and maltose, respectively, whereas trehalose addition resulted in a residual activity of 30%. Membrane phase transition temperatures (Tm) were determined in intact hydrated and dry cells, using Fourier transform infrared spectroscopy. The Tm of hydrated cells was 4 degrees C, increasing to only 20 degrees C after drying. Because endogenous soluble sugars were absent, this phase behavior is attributed to the structure of the predominant phospholipids, PG and lysyl-PG. The restricted increase of Tm is held responsible for the survival of part of the cells. The added maltose, trehalose, and sorbitol did not influence Tm in vivo. We suggest that the effective carbohydrates act through their free radical scavenging activity and not by direct interaction with the polar lipid headgroups.
研究了外加碳水化合物在空气干燥过程中对植物乳杆菌细胞的保护作用与细胞膜相行为之间的关系。干燥后的残留活性可从对照中的44%分别提高到添加山梨醇和麦芽糖后的79%和66%，而添加海藻糖后的残留活性为30%。使用傅里叶变换红外光谱法测定完整水合细胞和干燥细胞中的膜相变温度（Tm）。水合细胞的Tm为4℃，干燥后仅升至20℃。由于不存在内源性可溶性糖，这种相行为归因于主要磷脂PG和赖氨酰-PG的结构。Tm的有限升高是部分细胞存活的原因。添加的麦芽糖、海藻糖和山梨醇在体内不影响Tm。我们认为，有效的碳水化合物通过其自由基清除活性起作用，而不是通过与极性脂质头基团直接相互作用。
