Effect of Surfactant on Extraction of Caffeine from Coffee Powder

 

B. Venkata Phani Deepthi1*, P. Muthuprasanna2

1SIMS College of Pharmacy, Mangaldas Nagar, Guntur, Andhra Pradesh, India.

2Hindu college of Pharmacy, Amaravathi Road, Guntur, Andhra Pradesh, India

 

ABSTRACT:

The main objective of the present work was to study the effect of surfactant on extraction of caffeine from coffee powder using surfactant sodium lauryl sulfate. The extraction was carried out at various conditions such as time of extraction, temperature, sonication. The time period employed is at intervals of 30min, 60min, 120min and the temperature exposure was at various degrees like 0o c, 40oc, 80oc .The final sonication step was at various sonication times of 2min, 5min, 0min and 15min. The evaluation of the resulting product was done by measuring various parameters like density, specific gravity, viscosity, surface tension, colorimetric estimation, pH.  Among all these conditions, sonication process along with sodium lauryl sulfate can be considered as favourable method for extraction of active constituents from the crude drug powder and this technique can be extended for study of other extraction of crude drug powders.

 

KEY WORDS: Caffeine, sodium lauryl sulfate, density, specific gravity, pH, viscosity.

 

INTRODUCTION:

The purine alkaloid caffeine is obtained from Coffea Arabica  by germination under aseptic conditions on agar at 26°C, either in the dark or in the light 1.Caffeine as a psychomotor stimulant 2 probably the habit forming 3  stimulates central nervous system 4 cause pleasant effects with improved attention and concentration at lower doses. The caffeine abuse results in caffeinism which include symptoms like  agitation, disorientation and a syndrome which may be mistaken for anxiety neurosis 5. There may be losing sleep over the caffeination of prematurity 6. The adverse effects seen in acute caffeine ingestion including hypokalemia, elevated blood glucose, tachycardia, bigeminy and agitation, respiratory alkalosis and chest pain 7. Massive caffeine ingestion resulting in death 8.The structure of caffeine is shown in figure-1 9. There are several methods for extraction of caffeine from coffee powder. They are traditional extraction process includes water extraction, supercritical carbon dioxide extraction, extraction by organic solvents. Apart from that sonication extraction process, ultra sound extraction process etc are widely used. Now a days a new extraction methods were also developed. Among these, ultrasound extraction is  efficient and  more convenient process for the recovery and purification of the active ingredients of plant materials. In this present discussion we employ traditional extraction process and the effect of surfactant namely sodium lauryl sulfate on extraction was established 10.

 

 

MATERIALS AND METHODS

Coffea arabica was obtained from green label company. Sodium lauryl sulfate(SLS) was obtained from high pure fine chem. Industries, and distilled water. All glass ware were made up of Borosil Company. The sonicator bath used is from  Lobalife company model no:1.5L50.The electronic balance used is obtained from Schimazel model no: ELB300. The photo electric colorimeter was obtained from Systronics model no:113 and pH meter was obtained from Systronics.

 

METHODS:

EXTRACTION OF CAFFEINE FROM COFFEE:

Isolation of caffeine from coffee is done by two ways

1. By using surfactants namely sodium lauryl sulfate

2. Without using surfactant

 

In the first case for one gram of coffee powder, 0.1 gram of sodium lauryl sulfate (SLS) is taken and then 100ml of distilled water is added and further extraction is carried out at  different physical environmental conditions like different time periods, different temperatures and different sonication times and finally filtration is carried out.

 

In the second case to one gram of coffee powder, 100ml of distilled water is added. Here no surfactant is used. Then further extraction is carried out at different physical environmental conditions like different time periods, different temperatures and different sonication times and finally filtration is carried out.

 

Time;

In this case, filtration of samples obtained from above two methods is carried out at different time periods like 30min, 60min, 120min.

 

Temperature;

In this case, filteration of samples obtained from above two methods is carried at different temperature conditions like 0o c, 40oc, 80oc.

 

Sonication;

In this case, filtration of samples obtained from above two methods is carried out  at different sonication times of 2min, 5min, 0min and 15min.

 

Sonication is the act of applying sound (usually ultrasound) energy to agitate particles in a sample for various purposes. In laboratory, it is usually applied using an ultrasonic bath.

Sonication can be used to speed dissolution by breaking intermolecular interactions and to speed up the process of extraction.

 

IDENTIFICATION TESTS FOR CAFFEINE:

Murexide test;

Caffeine when heated with HCl and potassium chlorate gives a residue which on exposure to ammonia vapours gives purple colour

 

Observation: Pink or purple colour was observed

Inference: This indicates the presence of caffeine

Estimation of various physical parameters like density, specific gravity, viscosity, surface tension, colorimeter and pH has to be done for caffeine samples obtained by various above extraction procedures.

 

Figure:1  Caffeine 

 

IUPAC name ;3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione 11

 

Control:

Now, control is carried out by using only surfactant (SLS). Here 0.1gm SLS is mixed with 100ml of distilled water and subjected to various time periods, temperatures and sonication periods same as before. Finally influence of surfactant on various physical parameters was estimated.

 

DETERMINATION OF VARIOUS PARAMETERS:

Determination of density;

It is defined as the mass per unit volume of a material at constant temperature and pressure 12.

 

A specific gravity bottle having a capacity of 25ml was selected at 20oc.  The SG bottle with distilled water was cleaned.  The bottle was rinsed with a little (5ml) acetone.  A hot air dryer was used to dry the specific gravity bottle. The empty specific gravity bottle was weighed. Let the weight be w1.

 

The specific gravity bottle was filled with sample solution whose density has to be measured. The lid was placed and wiped the outer surface of the bottle with blotting paper. The specific gravity bottle with sample was weighed, let the weight be w2 . Now this sample was carefully transferred into a measuring cylinder and measured the volume of sample. Let the volume be V. Now the density of sample is determined as follows.

 

w2-w1

E  =

V

 

Where,  E = density of sample

W1= weight of empty specific gravity bottle

W2= weight of SG bottle with sample

V= volume occupied by sample

 

Determination of specific gravity;

It is the ratio of its density to the density of some standard material, such as water at standard conditions of temperature and pressure12.

 

A specific gravity bottle having a capacity of 25 ml at 20oc was selected. The SG bottle was cleaned with distilled water. The bottle was rinsed with a little (5ml) acetone.  A hot air dryer was used to dry the specific gravity bottle.  The empty specific gravity bottle was weighed, let the weight be w1.

 

The SG bottle was filled with distilled water (DW) to its brim, placed the lid and wiped the outer surface of the bottle with blotting paper. Distilled water that has been recently boiled and cooled at 25oc was used.  The SG bottle was weighed with water, let the weight be w2. Distilled water was removed from the bottle.  The empty bottle was rinsed with little acetone. Hot air dryer was used to dry the SG bottle. Carefully transferred a liquid into the SG bottle upto its brim.  The outer surface of the bottle was dried with blotting paper.  The SG bottle was weighed with the sample.

 

  Wt of sample ×  density of water

Density of sample = --------------------------------------

                                    Wt of equal amount of water

 

               w3-w1

E =  -------------------× 1

               w2-w1

 

w3-w1 = wt of liquid in SG bottle

 w2-w1 = wt of water in SG bottle

 

Determination of viscosity;

It is the expression of the resistance to the flow of liquid under an applied stress 13.Viscosity was determined by using Ostwald viscometer.

 

Determined the density of sample solution by specific gravity bottle.  The lower bulb ‘a’ of the viscometer was filled with water and sucked the water into upper bulb ‘b’ above the upper bulb mark-1 level, then allowed the water to flow down and noted the time of flow of water between mark-1 and 2 (just below the upper bulb).  The same procedure was repeated at least for three times and considered either mean flow time or any two matching times. Replaced the viscometer with sample solution and this entire procedure was repeated for the determination of the sample liquid viscosity using the poiseuilies equation.

 

Determination of surface tension;

It is defined as the force in dynes acting at right angles to the surface of a liquid along one centimeter length of the surface 14. It was determined by stalagmometer.

 

A clean stalagmometer was taken and  it was dried  for some time after rinsing it with alcohol, then attached a rubber tube with a pinch clip at the upper end of the stalagmometer to regulate the flow of liquid.

·        The flattened end of the stalagmometer was dipped  in the reference liquid  and sucked the liquid through the rubber tube, until the liquid level reaches above the mark ‘a’

·        The stalagmometer was fixed  to the burette stand and slowly released the pinch clip to allow the liquid run down slowly at the rate of 15-20 drops per minute.

·        The number of drops were counted from the volume of liquid between ‘a’ and ‘b’ and repeated the same procedure at least for 3 minutes and noted the average of the readings.

·        Again  the stalagmometer was cleaned  thoroughly and repeated the same with experimental liquid.

 

Colorimeter:

The amounts of caffeine present in the extracted sample are determined by using colorimeter 15 and by using filter of 430nm wave length.

 

For colorimetric estimation of extracted samples standard dilutions were prepared, from which one ml of caffeine solution was pipetted into these test tubes and made up the volume upto 10ml with DW. Now the filter of colorimeter was set at 430nm wavelength. Now the colorimeter reading was adjusted to zero by using distilled water as reference solution in cuvette. Emptied the cuvette and washed  it with sample whose reading has to be recorded and  the cuvette was filled with the sample, wiped off  the outer surface of cuvette with blotting paper and recorded the colorimetric reading of sample. Repeated the same process for all the samples and their readings were recorded.

 

Determination of pH;

pH is defined as a measure of acidity or alkalinity of a solution. It is the negative logarithm to the base 10 of hydrogen ion concentration16.

 

The pH of caffeine solution after extraction by different methods is measured using pH meter. At first pH meter reading is adjusted to zero by using standard buffer of pH- 4, now the bulb of pH  was washed with DW now  the bulb of pH meter was dipped in extracted sample such that the bulb is completely immersed in solution now recorded the reading from pH meter, until that value remaining constant for 30sec. Now bulb was removed from caffeine solution, washed it with DW and dipped  in other sample whose pH has to be recorded. The same procedure was repeated for all the sample and noted their pH values.

 

Sodium lauryl sulfate (SLS);

It is an anionic surfactant used in many cleaning and hygiene products. The molecule has a tail of 12 carbon atoms, attached to a sulfate group, giving the molecule the amphiphilic prosperities required of a detergent.  SLS is the only surface active agent having HLB value of 40 it is mainly used as solubilizing agent.

 

RESULTS AND DISCUSSION:

 In our study of caffeine extraction from Coffea arabica using surfactant sodium lauryl sulfate (SLS) under various conditions such as time of extraction, temperature, sonication we found various results. In estimating the SG of extract under various time duration of extraction we got more specific gravity for the sample having surfactant –SLS than the other. As the time of soaking increased there was rise in specific gravity. In the case of rise in temperature the same was found in the case of sonication also there was rise in SG on using surfactants. On comparing among time, sonication and temperature, extraction by time and sonication gave more specific gravity value than by temperature. In the case of density, as the time of soaking increased density of the extract also increased. This was also same for temperature and sonication. But comparing time,  temperature, sonication, samples having surfactant  has extracted more on subjected to time and temperature than sonication. In the case of surface tension, all the parameters showed decreasing effect of surface tension for the sample with surfactant on comparing with control. But in the case of sonication surface tension was pronouncedly reduced than time and temperature. In the case of colorimetric estimation using blue filter-400nm, the colour intensity was more in the samples containing surfactants. Sonication showed maximum intensity of colour than the other time and temperature parameters. In the case of pH determination the samples containing surfactants reduced, the pH from neutral to acid (7-4). Time of soaking reduced the pH than the case with sonication and temperature.

In the case of viscosity, the viscosity of the sample with surfactant is more particularly for the sample under time, viscosity is more than temperature and sonication. Other extraneous materials such as tannins, gums, resinous materials etc; under time and temperature. Therefore sonication process helped in effective surface tension reduction by surfactant thus extracting maximum quantity of caffeine.

 

TABLES

Effect of time on extraction of caffeine:

 

1.Density

Time

Without

surfactant

(gm/cc)

With

Surfactant

 (gm/cc)

Control

(gm/cc)

30min

1.0019

1.011

1.001

60min

1.0027

1.012

1.001

120min

1.003

1.013

1.001

 

2.Specific gravity

Time

Without surfactant

With surfactant

Control

30min

1.00359

1.00428

0.9651

60min

1.00438

1.00545

0.9651

120min

1.00558

1.00659

0.9651

 

3.Viscosity

Time

Without surfactant

(poise)

With s

urfactant

(poise)

Control

(poise)

30min

0.848

0.8754

0.8245

60min

0.859

1.0165

0.82453

120min

0.887

1.3112

0.82456

 

4. Surface tension

Time

Without

surfactant

(dynes/cm)

With

surfactant

(dynes/cm)

Control

(dynes/cm)

30min

59.134

37.207

30.4

60min

61.935

35.276

30.4

120min

63.001

35.011

30.4

 

5.Colorimetry

Time

Without surfactant

With surfactant

Control

30min

0.19

0.22

-0.01

60min

0.2

0.23

-0.01

120min

0.21

0.24

-0.01

 

6.pH

Time

Without surfactant

With surfactant

Control

30min

2.4

3.51

7.4

60min

2.26

3.26

7.4

120min

2.23

3

7.4

 

Effect of temperature on extraction of caffeine:

 

1. Density

Temp

Without surfactant

(gm/cc)

With surfactant

(gm/cc)

Control

(gm/cc)

Ooc

0.945

1.001

0.85

40oc

0.951

1.006

0.852

80oc

0.961

1.009

0.853

2.Specific gravity

 

Temp

Without surfactant

With surfactant

Control

Ooc

1.0003

1.0021

0.9884

40oc

1.0008

1.0024

0.9885

80oc

1.0012

1.0031

0.9886

 

3.Viscosity

Temp

Without surfactant(poise)

With surfactant(poise)

Control

(poise)

Ooc

0.8099

0.9468

0.832

40oc

0.8998

1.0357

0.831

80oc

0.913

1.064

0.83

 

4.Surface tension

Temp

Without surfactant

(dynes/cm)

With surfactant

(dynes/cm)

Control

(dynes/cm)

Ooc

50.06

36.9

32.01

40oc

52.03

34.6

32.03

80oc

60.03

33.41

32.05

 

5.Colorimetry

Temp

Without surfactant

With surfactant

Control

Ooc

0.19

0.22

0.01

40oc

0.2

0.23

0.01

80oc

0.21

0.25

0.01

 

6.pH

Temp

Without surfactant

With surfactant

Control

Ooc

4.58

4.57

7.03

40oc

4.45

4.44

7.039

80oc

4.2

4.41

7.45

 

Effect of sonication on extraction of caffeine:

 

1.Density

Sonication time

Without surfactant

(gm/cc)

With surfactant

(gm/cc)

Control

(gm/cc)

2min

0.9514

0.9518

0.9503

5min

0.9522

0.9525

0.9507

10min

0.9511

0.9529

0.9496

15min

0.9533

0.9537

0.9492

 

2.Specific gravity

Sonication time

Without surfactant

With surfactant

Control

2min

1.0007

1.0007

1.000389

5min

1.0011

1.0015

1.000779

10min

1.0019

1.002

0.9996

15min

1.0023

1.0027

0.9992

 

3.Viscosity

Sonication time

Without surfactant(poise)

With surfactant

(poise)

Control

(poise)

2min

0.8999

0.9449

0.9805

5min

0.9363

0.9907

1.206

10min

1.0812

1.12664

1.1596

15min

1.0366

0.9468

1.1232

 

4.Surface tension

Sonication time

without surfactant

(dynes/cm)

with surfactant

(dynes/cm)

Control

(dynes/cm)

2min

87.1044

63.7271

50.019

5min

89.0756

57.24

51.0707

10min

83.5751

56.5071

48.5139

15min

80.2641

46.6279

37.1912

 

5.Colorimetry

Sonication time

Without surfactant

With surfactant

Control

2min

0.79

0.85

0.04

5min

0.81

0.72

0.03

10min

0.89

0.74

0.04

15min

0.87

0.9

0.04

 

6.pH

Sonication time

Without surfactant

With surfactant

Control

2min

4.86

4.84

7.1

5min

4.78

4.83

6.88

10min

4.8

4.99

7.15

15min

4.95

4.91

6.27

 

GRAPHS

Effect of sonication on extraction of caffeine

Sonication time vs Density

 

Sonication time vs Specific gravity

 

Sonication time vs  surface tension

 

Sonication time vs colorimetry

 

Sonication time vs pH

 

CONCLUSION:

Therefore sonication process along with sodium lauryl sulfate can be considered as favourable method for extraction of active constituents from the crude drug powder and this technique can be extended for study of other extraction of crude drug powders.

 

ACKNOWLEDGEMENTS:

The authors are thankful to management of Hindu College of Pharmacy, Guntur for providing necessary facility for the work.

 

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Received on 30.07.2012

Modified on 04.09.2012

Accepted on 27.09.2012

© A&V Publication all right reserved

Research Journal of Pharmacognosy and Phytochemistry. 4(5): September – October 2012, 271-276