Effect of Ph and Temperature on Carotenoid Pigments produced

MATERIALS AND METHODS

Cultures and their maintenance

Characterized Rhodotorula minuta RAI ₃ obtained from air of dairy

environment was used in the present study for extraction of the pigment.

The yeast cultures were maintained as slant cultures on Malt Yeast Extract

Agar (MYEA) and working cultures in MYEB ( Kaur et al . , 2009 ) broth with

incubation at 30°C/3-5 days.

Production and extraction of pigment

R.minuta RAI ₃ , inoculated to broth media such as sterile MYEB as semi

synthetic medium, coconut water as natural medium and rice as natural

solid medium and incubated at 30°C for 3 rd , 6 th and 9 days respectively

(write the reference of your article about to publish ) .

pH adjustment and heat treatment of pigment

pH of the acetone extraction of extra and intracellular pigment of

Rhodotorula minuta was adjusted to pH 4, 5, 7, 8 and 9 using 0.1N

NaOH and HCl. and absorbance was measured at 520nm. Acetone

extracted pigment solution of Rhodotorula minuta was heated laboratory

pasteurization (63°C for 30 min), boiling (100°C/ 10 min) and sterilization

temperature (121°C/ 15 min) and change in absorbance was measured at

520 nm.

RESULTS AND DISCUSSION

Effect of different pH on extra and intracellular pigment of Rhodotorula

minuta RAI ₃ from sterile MYEB, coconut water and rice

The pigment solution showed its stability at pH 7 with no change in

absorbance (0.135 /ml) and (0.410 /ml) compared to control (pH 6). But

at acidic pH 4 and 5 absorbance of pigment decreased as shown in Tables

1 and 2. Maximum decrease in absorbance was observed at pH 4 (0.044 /

ml and 0.082 /ml for extra and intracellular respectively). Adjusting the

pH of extra and intracellular pigment to pH 8 and 9 found decrease in the

absorbance.ȱStatisticallyȱsignificantȱdifferenceȱwasȱnoticedȱwhenȱacetoneȱ

extracted pigment was of Rhodotorula minuta adjusted to pH 4, 5, 7, 8 and

9. Consistent pH changes were noticed in all the 3 media .Media has no

effectȱonȱstabilityȱonȱpigmentȱbutȱpHȱhasȱtheȱsignificantȱeffectȱonȱintensityȱ

of pigment. From the observations it can be concluded that the pigment

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