Antimicrobials from Lactobacillus plantarum isolated from turmeric (Curcuma longa linn.) and their applications as biopreservative and in edible film Melada Supakijnoraset Food Engineering and Bioprocess Technology, School of Environment, Resources and Development, Asian Institute of Technology

Probiotic The probiotics are most commonly defined as live microbial feed supplements that beneficially affect the host by improving its intestinal microbial balance. LactobacillusBifidobacterium

Probiotic Antimicrobial substances

User-friendly and eco-friendly The films can be consumed with the packaged product Replace the polyehtylene packages and reduce the environmental pollution The films can function as carriers for antimicrobial and antioxidant agents

Compare the efficiency of bacteriocin production between Lactobacillus plantarum and Lactobacillus casei. Extraction and purification of the bacteriocin from probiotic bacteria from tumeric rhizome and study the effect of temperature and pH to activity of bacteriocin and determination of molecular mass of bacteriocin. To study the application of bacteriocin as a food biopreservative. Preparation, characterization and application of bacteriocin-cassava starch film.

Bacterial culture and media MRS medium 37°C Nutrient medium 37°C Probiotic strains Lactobacillus plantarum Lactobacillus casei TISTR 1463 Pathogen strains Escherichia coli TISTR 780 Salmonella typhimurium TISTR 292 Staphylococcus aureus TISTR 029

Antimicrobial and bacteriocin activity assay L. plantarum and L. casei were cultured in MRS broth The culture of both strain were taken every 2 h (from 16 to 26 h) Bacteriocin activity test adjust pH to 6.5 and add catalase enzyme

Bacteriocin activity assay Table 1 show the inhibition zones by Agar well diffusion assay strain Diameter of inhibition zone of L. plantarum (mm) (18 h) Diameter of inhibition zone of L. casei (mm) (24 h) E. coli Salmonella typhimurium 10- Staphylococcus aureus 10

Purification of bacteriocin 1 L of Lactobacillus plantarum culture in MRS medium at 37°C, 18 h Protein precipitation by ammonium sulphate Dialyze bacteriocin overnight through 1000 Da MWCO membrane Agar well diffusion assay Indicator : L. casei Fig 1. Dialyze bacteriocin through dialysis membrane

Fig. 2 Bacteriocin activity of L. plantarum against L. casei

the effect of temperature and pH on bacteriocin activity Sensitivity of bacteriocin to heat and pH pHHeat 40°C60°C80°C95°C 10 min20 min30 min60 min Agar well diffusion test pH 3pH 5pH 7pH 9 Agar well diffusion test 2 h

The effect of temperature on bacteriocin activity Bacteriocin activity stable at 95 ° C for 10 min. The activity decreases with the increasing time in 95 ° C.

The effect of pH on bacteriocin activity Bacteriocin activity stable at pH 5 and 7. At pH 3 and pH 9, bacteriocin activity decrease 50%.

Determination of molecular mass of bacteriocin Sodium dodecyl sulfate polyacrylamide gel electrophoresis SDS-PAGE is a technique widely used to separate proteins according to their electrophoretic mobility

Determination of molecular mass of bacteriocin Molecular weight (Daltons) 14,437 6,512 3,496 1, kDa 1-2 kDa Inhibition zone

Shelf-life of pasteurized milk First treatment : without partially purified bacteriocin (Control) Second treatment: 0.5% partially purified bacteriocin Third treatment: 1% partially purified bacteriocin Forth treatment: 2.5% partially purified bacteriocin

pH of pasteurized milk during storage

Preparation of cassava starch based films Control film Mixture of cassava starch, glycerol and water at ratio of 5.0: 2.0: 93.0 to obtain film forming solution Partially purified bacteriocin film Mixture of cassava starch, glycerol, bacteriocin and water at ratio of 5.0: 2.0: 1.0: 92.0 to obtain film forming solution The whole extracts film Mixture of cassava starch, glycerol, supernatant of L. plantarum culure at 18 h and water at ratio of 5.0: 2.0: 46.5: 46.5 to obtain film forming solution

Physical properties of cassava starch based film Scanning Electron Microscope (SEM)

Shelf-life of fermented pork Microbial testing Plastic bag (control) Cassava starch film incorporated with the whole extract Cassava starch film incorporated with bacteriocin

Bacteriocin activity of both L. plantarum and L. casei showed significant antibacterial activities against indicator strains which were Escherichia coli, Salmonella typhimurium and Staphylococcus aureus. L. plantarum can produce more efficient of bacteriocin than L. casei TISTR The activity of partially purified bacteriocin from L. plantarum is 5,120 AU/ml. The bacteriocin activity of L. plantarum was not affected when treated at 95°C for 10 min, and stable at pH 5 and pH 7.

The molecular weight of bacteriocin extracted from L. plantarum isolated from turmeric rhizome is approximately 1-2 kDa and kDa. The partially purified bacteriocin from L. plantarum has ability to prolong the shelf-life of product. The surface of all type of edible film based on cassava starch was wrinkled with small folding. The cassava starch incorporated with the whole extract has ability to prolong the shelf-life of product.