Abstract: In order to investigate the difference in the storage stability of freeze-dried Lactobacillus plantarum KLDS 1.0328 under different nutritional conditions, the effects of glucose and/or Tween-80 stress on the growth, acid production, morphology and cell membrane fatty acid composition of this strain, the antibacterial activity of bacteriocin produced by it, and the survival rate of its freeze-dried cells during frozen storage were analyzed. It was found that both glucose and Tween-80 stress had different impacts on the growth, acid production and bacteriocin antibacterial activity. Scanning electron microscopic (SEM) results indicated that the bacterial cell shape changed from short rod-like to long rod-like or oval-shaped and that the size also changed when exposed to Tween-80 stress or glucose-Tween-80 stress. The ratio of unsaturated fatty acids to saturated fatty acids in the cell membrane increased under all nutrient stress conditions. In addition, the stability and survival rate of freeze-dried cells stored at ?18 ℃ for up to 42 days were significantly improved by glucose stress.

Key words: Lactobacillus plantarum; nutrient stress; glucose; Tween-80; freeze-drying; storage stability