Biopreservative activity of bacteriocin-producing lactic acid bacteria

Biopreservative efficiency of bacterioicn in apple colonies morphologically appeared as smooth round

juice and coconut water

colonies, circular, 2 mm in size, creamish white in

Apple juice and coconut water were obtained

color on MRS agar medium (Sablon et al ., 2000). The

aseptically in the laboratory.

strains G1 and G2 were identified as Lactobacillus

casie , G3 and G4 were identified as Streptococcus

Group A: Testing the efficacy of bacteriocin in apple species based on their physiological and biochemical

juice: Four tubes were taken and 5 ml of apple juice

characteristics as per the data is presented in Table 1.

was added to each tube. The bacteriocin was not

added to the tube 1, but 25 ul , 50 ul and 100 ul were

Table 1. Identification of isolated LAB

added to the tube 2, tube 3 and tube 4, respectively.

Group B: Testing the efficiency of bacteriocin in

Abbre-

S.

viation

General

Identified

coconut water: Four tubes were taken and 5 ml

Sample

No

of

properties

organism

of coconut water was added to each tube. The

isolates

bacteriocin was not added to the tube 1, but 100 ul,

1

Green

G1

Gram

positive Lactobacillus

200 ul and 400 ul were added to the tube 2, tube 3 and

gram

rods,

catalase casie

tube 4 respectively.

negative,

no

hemolysis, acid

All the above mentioned eight tubes of group A and

p r o d u c t i o n

B were incubated at room temperature. .

in

glucose

and

mannitol

Processing of tubes containing apple juice

fermentation

withbacteriocin

2

Green

G2

Gram

positive Lactobacillus

At zero time (immediately after the addition of

gram

rods,

catalase casie

negative,

no

bacteriocin to the apple juice) and at 24 hrs of

hemolysis, acid

incubation, 100 ul of sample from all the four tubes

p r o d u c t i o n

was plated (spread plate method) on nutrient agar

in

glucose

(NA) and incubated over night at temperature of

and

mannitol

37°C. The plates were observed for microbial colonies.

fermentation

3

Greeen

G3

Gram

positive Streptococcus

Processing of tubes containing coconut water with

gram

cocci,

catalase species

bacteriocin

negative,

no

hemolysis

At zero minute and at 72 hrs of incubation, 100 ul of

4

Green

G4

Gram

positive Streptococcus

sample from all the four tubes was plated on nutrient

gram

cocci,

catalase species

agar (NA) and incubated over night at a temperature

negative,

no

of 37°C. The plates were observed for microbial

hemolysis

colonies.

Sharpe (2009) reported 8.7% bacteriocinogenic

strains among 92 LAB isolated from fresh-cut

Results and Discussion

vegetable products, whereas Sezer and Guven (2009)

Characterization of isolated strains

screened 12,700 LAB isolates from milk and meat

products and found only 35 exhibited bacteriocin

A total of four isolates were isolated and named

production. Therefore, the choice of food source and

as G1, G2, G3, and G4. The isolates G1 and G2

media are important for the successfully isolation

were gram-positive rods, catalase negative, acid

of bacteriocinogenic LAB. The strains were isolated

production in glucose showed fermentation of

from fermented green gram batter (Table 1).

mannitol, no haemolysis on blood agar, Isolated

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