Journal of Environmental Biology

Effect of varying pH on protein composition and yield

of amaranth seed (Amaranthus blitum)

Author Details

Reema Srivastava (Corresponding author)

Laboratory of Cytogenetics, Center of Advanced Study in Botany, Banaras Hindu University,

Varanasi - 221005, India

e-mail: reemasri.bhu@gmail.com

Bijoy K. Roy

Laboratory of Cytogenetics, Center of Advanced Study in Botany, Banaras Hindu University,

Varanasi - 221 005,India

Publication Data

Paper received:

07 April 2010

Revised received:

13 December 2010

Accepted:

18 December 2010

Abstract

The isolation procedure of the seed proteins of Amaranthus blitum have been analyzed at different pH conditions. Qualitative studies were carried out by using electrophoretic technique sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Mainly four protein fractions i.e. albumin, globulin, prolamin and glutelin were obtained. Protein isolates were prepared by (a) extraction at different alkaline pH (9, 10, 11 and 12) and precipitation at pH 5 and (b) extraction at pH 9 and precipitation at different pH (4, 5, 6 and 7). The composition of isolates, prepared by method (a), depended on extraction pH. The isolate extracted at pH 8 was mainly composed of albumin and globulin, whereas at pH 9, 10 and 11 showed the presence of prolamin and glutelin. Electrophoretic pattern of different isolates had five major bands with molecular weight of 30, 45, 72, 84 and 90 kDt respectively. The increase of the extraction pH led to the increase in protein yield. With method (b) isolates obtained were variable in composition. At pH 7 albumin and prolamine were present, whereas at pH 4, 5 and 6 all 4 protein fractions were precipitated. According to the quantitative estimation of the albumin, globulin, prolamin and glutelin in the seed flour the contents were 26.4, 25, 5.81 and 42.7%, respectively. The results suggest that composition of protein isolates could be controlled by different extraction and precipitation pH.

Key words

Amaranthus blitum, Albumin, Globulin, Prolamin,Glutelin, Protein isolates

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