sythetic pesticide

ORGANOCHLORINE, ORGANOPHOSPHORUS

AND SYNTHETIC PYRETHROID PESTICIDES

AFFECTING AMINO ACIDS IN COTTON SEEDS

AND WHEAT GRAIN DURING STORAGE

I. A. K. AFRIDI*

Z. PARVEEN*

S. Z. MASUD*

ABSTRACT

This paper presents results of the effects of studied pesticides on amino acids in cotton seeds

and wheat grains stored at the room temperature (30 ± 3°C) after pesticide treatment for one month. Each sample was analyzed in triplicate along with a control sample. The influence on amino acids, was found to be variable and significant. The analytical data, obtained by employing amino acid analyzer, showed significant quantitative variations in amino acids of both the food commodities.

Key Words: Pesticide effects, amino acids.

Chemistry

INTRODUCTION

Many scientists have studied the effects of different pesticides on total protein in cotton seeds, wheat grains and in other crops such as maize and soybeans and found quantitative variations (1-8). The nutritive value of protein and proteinaceous foods and food products depends on their amino acids composition and essential amino acids balance. Effects of some herbicides on amino acids in soybeans have been studied and it was reported that lysine increased without reducing the amount of total protein (9). In another study, the action of different herbicides on quantitative

and qualitative changes in soils was compared (10). Wolfson and Shearer (11) investigated variations in the amino acid composition in grain protein of maize grown with or without pesticides and standard commercial fertilizers. Ciszewska et. al. (12) tested six wheat varieties for effects of different herbicides, and found that results of protein and lysine varied depending on the year and the cultivars. Not much work has been reported about the effects of pesticides on amino acids in cotton seeds and wheat grains during storage. Effects of certain organochlorine (OC), organophosphorus (OP), and synthetic pyrethroid (SP) pesticides, namely, p,p'-DDT, monocrotophos and cyhalothrin respectively on cotton seeds and OP compounds (chlorpyriphos-methyl and pirimiphos-methyl) and SP one compound namely permethrin on wheat grains

have been studied, evaluated and their results are presented in this paper. The results were assessed using analytical data from trial application of studied pesticides directly to the aforesaid food commodities, stored for one month in sealed glass jars. Each sample was analyzed for amino acids in triplicate along with control sample by employing amino acid analyzer. MATERIALS AND METHODS

The analytical method of Osborne and Voogt (13) was

adapted for the determination of proteins in cotton seeds and

wheat grains. The sample of cotton seeds was taken in three

replicates for each pesticide treatment and transferred to

glass jars. Calculated amounts of monocrotophos (2 ppm),

p,p'-DDT (2 ppm) and cyhalothrin (2 ppm) separately added to

the glass jars and shaken for 3 hours. samples of wheat grain

were also treated with three grain protectants namely chlorpyriphos-

methyl, pirimiphos methyl and permethrin at recommended

dosages i.e., 10, 4 and 2 ppm respectively. The

fortified samples of both the food commodities were allowed to

stand in the sealed glass wars for one month at room temperature

(30 ± 3°C). Each fortified sample was analyzed along

with the control sample. Cotton seeds and wheat grain samples

containing 10-12 mg protein were accurately weighed

and transferred to glass culture tubes and 10 ml 6N HCI was

added. The tubes were evacuated, and sealed. The samples

were hydrolyzed at 110°C for 24 hours and filtered. Filtrates

were evaporated to near dryness by a rotary vacuum evaporator

to remove HCI and the residues in each case were dissolved

in deionized water.

The Chromatographic glass column (10 mm i. d. x 200 mm

long) was prepared with a slurry of ion exchange resin Dowex

50 W-XB (100-200 mesh) in deionized water. A mixture of

studied amino acids which are commonly fond in cotton seeds

and wheat grains, was prepared in deionized water and quantitatively

transferred to the prepared column and allowed to

settle in the column bed. The column was eluted with deionized

water and then with 3.5% ammonia in deionized water.

For complete elution, fractions of 2 ml each were collected

and checked for the presence of amino acid with ninhydrin

reagent till violet color ceased to appear. All 2 ml fractions

were then combined and evaporated nearly to dryness by a

rotary vacuum evaporator to remove ammonia and taken up in

deionized water for amino acid analyzer. A suitable aliquot of

each concentrated volume was subjected to the system of

amino acid analyzed and quantitative recovery of each studied

amino acid was determined.

The concentrated extracts of pesticide cotton seeds and