Asian Journal of Agriculture and Food Science (ISSN: 2321 – 1571)
Volume 02 – Issue 04, August 2014
Asian Online Journals (www.ajouronline.com) 350
2. MATERIALS AND METHODS
2.1 Preparation of crude extract
The fruits of these almonds were collected, dried at room temperature, and exposed to the sun. For extraction of the
antioxidant compounds, a fine dried powder of the sample (0.5 g) was extracted using 50 ml of methanol by sonication at
room temperature for 20 min. The extracts were filtered through whatman filter paper No. 1 paper.
2.2 Antioxidant activity (Radical scavenging activity)
DPPH was used to evaluate the free radical scavenging activity of plant extracts as described by Hatano and others
1989. Briefly methanolic extract of almonds were diluted to get final concentration 1mg/ml. From 1mg/ml stock
serial dilutions were performed to get final concentrations 1000, 500, 250, 125, 62.5,31.25, 15.62 and 7.81μg/ml. Diluted
samples (1ml each) were mixed with 1ml of methanolic solution of DPPH (1mg/ml). DPPH was filtered through
Whatman filter paper no.1 after preparation. After 30 min incubation in darkness at room temperature (25⁰C), the
absorbance was recorded at 517nm.Control sample contained all the reagents except the plant extract. Percentage
inhibition was calculated using equation given below:
Inhibition (%) = Abs 517 (control) - Abs 517 (extract) *100
Abs 517 (control)
The IC50 values were determined from plots of percent inhibition versus log inhibitor concentration and were
calculated by non linear regression analysis from the mean inhibitory values. Ascorbic acid was used as the reference. All
tests were performed in triplicate.
2.3 Determination of Total Phenolic Content
Total phenolic constituents of plant extracts were performed employing the literature methods involving Folin-
Ciocalteu reagent and Gallic acid as standard . About 1.0 ml of plant extract (5μg/ml) was taken in a test tube. Then 5
ml of Folin-ciocalteu (diluted 10 fold) reagent solution and 4 ml of sodium carbonate solution (7.5%) was added into the
test tube. The test tube was incubated for 30 minutes at 20˚C to complete the reaction. Then the absorbance of the
solution was measured at 765 nm using spectrophotometer against blank. The total content of phenolic compounds in
plant ethanol extracts in Gallic acid equivalents (GAE) was calculated.
2.4 Statistical analysis
All experiments were performed with at least 3 replicates. One-way ANOVA was applied to determine the
significance of results between different treatments. All the statistical analyses were done using SPSS v.11.5 for
3. RESULTS AND DISCUSSION
Phytochemicals especially polyphenols constitute a major group of compounds that act as most active antioxidants
.They are known to act as antioxidants not only because of their ability to donate hydrogen or electrons but also
because of they are stable radical intermediates . Generally, the outer layers of plants such as the peel, shell, and hull
contain large amount of polyphenolic compounds to protect the inner materials. A number of phenolic acids are linked to
various cell wall components such as arabinoxylans and proteins .
Relative oxygen species and associated free radicals have been implicated in the etiology of various human diseases
including inflammation, metabolic disorders, cellular aging and atherosclerosis, heart disease, diabetes mellitus, cancer,
malaria, rheumatoid arthiritis and HIV/AIDS [16, 17,18].
Plants are known to possess diverse substances possessing antioxidant properties having ability to protect the human
body against cellular oxidation. Anti-oxidants possess the ability to protect the body from damage caused by free radicals
inducing oxidative stress [19,20]. Antioxidant compounds like phenolic acids, polyphenols and flavonoids scavenge free
radicals such as peroxide, hydroperoxide of lipid hydroxyl and thus inhibit the oxidative mechanisms that lead to
degenerative diseases .
In the present investigation the antioxidant properties and phenolic content of dried and soaked sprouted almonds was
studied. As far as we are aware this is the first study to investigate the antioxidant properties and phenolic content of
dried and sprouted almonds. Both dried and sprouted (soaked) almonds are considered beneficial for health as it is a rich
source of Vitamin E, protein, magnesium, calcium, phosphorus and niacin, omega-3 as well as omega-6 fatty acids etc.
Besides this soaked almonds are also beneficial as a cosmetic product. It has been observed that worldwide after soaking
the almond peel or skin is discarded. The reducing power of almond hull and shell in different species increases
significantly with phenol content.