The oil of Alpinia galanga (L.) Willd in Phu Tho was obtained by steam distillation and dried with Na 2 SO 4. By Gas chromatography-mass spectrometry (GC-MS) method, 29 components in the oil were predicted by comparing their retention times and molecular weights with the standards'. In particular, there were 10 hydrocarbons such as monoterpenes: 29.15%, sesquiterpenes: 21.06%, and 19 oxygenated components like aldehydes (7.29%), alcohols (32.43%), ketones (1.09%), and esters (7.57%). Physico-chemical properties, antioxidant activities as well as antimicrobial activities of the oils were also analyzed. The density (at 20°C), acid index and ester index of the oil were 0.812 g/ml; 0.653 mg KOH/g and 0.728 mg KOH/g, respectively. The antioxidant activity was determined by using 1,1diphenyl-2-picrylhydrazol (DPPH) radical percentage inhibition and it was 47.15±0.34%. Antimicrobial activity against Salmonella typhi, Bacillus cereus, Staphylococcus aureus and Escherichia coli of the oil was identified by agar diffusion method.

Lactic Acid Bacteria in general and Lactobacillus plantarum in particular have broad applications, especially in the food industry, pharmacy and medicine. Bacteriocins synthesized by LAB are safe as they do not cause allergy and harm to health. In this study, the optimal temperature and time for the growing of the strain L. plantarum UL487 to obtain its maximal bacteriocin activity were30oC and 1 day, respectively. Besides, some properties of the bacteriocin such as its activity units on 5 indicator strains and the effects of pH and temperature on the bacteriocin’s activity were evaluated. Furthermore, bacteriocin synthesized by the strain L. plantarum UL487 was primarily purified by using a cation exchange column. After purification, the bacteriocin’s purity increased 2.069 times.