International Journal of Nutrition, Pharmacology, Neurological Diseases

: 2012  |  Volume : 2  |  Issue : 2  |  Page : 147--150

Analysis of various brands of tea powder marketed in Oman

Nirmala Halligudi, AR Mullaicharam, Mohanned Abdueghafour El-Khider 
 Pharmacy Department, Oman Medical College, Muscat, Oman

Correspondence Address:
A R Mullaicharam
Pharmacy Department, Oman Medical College, Azaiba, Muscat


Aim: This research paper attempts an analysis of the content and the various properties of different brands of tea marketed in Oman. Materials and Method: The properties of caffeine content , color intensity, angle of repose , bulk density and pH were estimated from six different brands of tea in Oman. Results: Tea is composed of many compounds besides caffeine. These components have various effects depending upon the amount of tea ingested and the quality of the tea. Among the six brands of tea Kannan Devan Tea has the highest caffeine content. Twinning«SQ»s Tea has the lowest caffeine content. Conclusion: Kannan Devan Tea has the highest caffeine content. Twinning«SQ»s Tea has the lowest caffeine contentTwinning«SQ»s Tea and Tata Tea have the highest pH and Red Label Tea hasthe lowest pH. Kannan Devan Tea and Twinning«SQ»s Tea have the high Bulk density.

How to cite this article:
Halligudi N, Mullaicharam A R, El-Khider MA. Analysis of various brands of tea powder marketed in Oman.Int J Nutr Pharmacol Neurol Dis 2012;2:147-150

How to cite this URL:
Halligudi N, Mullaicharam A R, El-Khider MA. Analysis of various brands of tea powder marketed in Oman. Int J Nutr Pharmacol Neurol Dis [serial online] 2012 [cited 2022 Dec 3 ];2:147-150
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The presence of caffeine in tea was first discovered in 1827 and the compound was initially named theine. [1] Soon, it became clear that theine was the same as the caffeine found in coffee and the term theine fell into disuse.Chemically, caffeine is 3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione. It is also known as theine, methyl theobromine, and 1,3,7-trimethylxanthine. Its molecular formula is C 8 H 10 N 4 O 2• H 2 O, and it consists of bicyclic molecules derived from the purine ring system. [2]

Caffeine is a member of the alkaloid family, a group of compounds obtained from plants and whose molecules consist of nitrogen-containing rings. In general, alkaloids tend to have identifiable physiological effects on the human body although these effects vary greatly from compound to compound. [3]

Almost all of the experienced effects of caffeine are mediated through its competitive inhibitory action on adenosine receptors. Adenosine produced in our body is responsible for the sleepy feeling that we experience and the accompanying yawning. When given in sufficient concentrations caffeine can compete with adenosine and occupy most of the available receptors, thereby Counteracting the effects of the adenosine produced by our body. For this concept to be easily understood imagine that the receptor is adenosine's chair in the office and that caffeine occupies it and prevents adenosine from performing its duties. [4]

People who regularly take tea and coffee do not generally worry about their intake of caffeine since research done over many decades has shown that it is not a matter for serious concern as long as the individual has a reasonably good diet and is moderate in alcohol consumption. [5]

The best known effect of consumption of large amounts of caffeine is caffeinism. This syndrome is composed of anxiety, restlessness, and sleep disorders. Chronic caffeine intake in low doses is known to lead to depression and aggravation of the premenstrual syndrome in women.

Other side effects of caffeine intake are diarrhoea, copious urination, and facial blushing. Panic attacks occurs after excessive consumption of caffeine since caffeine acts by triggering the fight-or-flight feedback in our body and a feeling of impending disaster. Caffeine also causes physical and emotional fatigue since it does not allow the body to realize that it must simply rest when it is exhausted.

Another issue is that of caffeine addiction. Once an individual gets used to consuming a certain amount of caffeine daily the body starts craving for it and if the craving is not satisfied the person could become irritable and experience withdrawal symptoms. [6]

Previous findings support an important role of adenosine and adenosine receptors in the homeostatic regulation of sleep. It has also been hypothesized that caffeine, an adenosine-receptor antagonist, reduces the increase of sleep propensity during waking. [7]

Herbal 'tea' is a natural tea that is caffeine free; for example, chamomile, peppermint, lemon, and blossom teas. [8] The objective of this research was to evaluate the physiochemical properties of the various brands of tea marketed in Oman.

 Materials and Methods

The following equipment and material were used: universal indicator, samples of tea leaves of different brands, milk, sugar, Bunsen burner, spectrophotometer, analytical balance, separating funnel, distillation flask, condenser, conical flask, chloroform, 10% lead acetate.

The samples of tea powder were collected from different supermarkets in Oman. We ensured that the expiry date of all the samples were 2 years from the date of purchase.

Procedure for analysis of tea acidity and taste

Twenty-five grams of each sample was taken in a clean beaker, and 100 ml of water was added to it. The solution was heated till it boiled, after which the beaker was kept covered and allowed to stand for 5 minutes. A drop was taken from each beaker to spot on a pH paper; the pH of the solution was ascertained by matching the color. After recording the pH of the different tea samples we also tasted a sample of the tea from each beaker. [9]

Procedure for analysis of color

The 20grams of the sample was taken in a test tube and 200 ml of distilled water was added. The color intensity was measured using a spectrophotometer at 450 nm.

Procedure for analysis of bulk density

Bulk density of powder is defined as the ratio of the mass of the powder to its bulk volume.

Bulk density = mass of the powder / bulk volume

For determination of the bulk density, a weighed quantity of tea powder was introduced into a graduated measuring cylinder. The measuring cylinder was tapped manually till a constant volume was obtained. This volume is known as the bulk volume of the tea powder. The same procedure was followed for each brand of tea powder. [10]


Procedure for analysis of caffeine content

Twenty grams of tea was taken from the tea bags and placed in a 400-ml beaker to which 200 ml of water was then added. The whole was boiled for about 30 minutes and then filtered into another clean beaker. To the filtrate, 10% aqueous solution of lead acetate was added with constant stirring until no precipitate was seen. The resulting mixture was thoroughly stirred and then filtered by suction filtration. The filtrate was transferred to another clean beaker and concentrated by boiling to a volume of about 25 ml. This was cooled to room temperature. Twenty-five milliliters of chloroform was added to the cold filtrate which was stirred thoroughly with a glass rod. The resulting mixture was transferred into a clean separation funnel. When the mixture separated into two distinct layers, the lower chloroform layer was separated into a clean distillation flask. [11]

To the aqueous layer, 20 ml of chloroform was added and the mixture was shaken well. After some time the two phases separated and the lower chloroform layer was once again collected into the distillation flask. The aqueous layer was once again extracted with another lot of 20 ml of chloroform. The chloroform was distilled from the chloroform extract on a water bath using a water condenser. The dry residue was scraped off the bottom of the flask with a spatula and weighed using an analytical balance. This crude caffeine was purified by dissolving it in a small quantity of boiling water and then allowing it to cool undisturbed. The needle-shaped crystals of caffeine were filtered out and dried between folds of filter paper. Finally, the melting point was determined.


Tea acidity and taste


Tea acidity and taste

The results [Figure 1] and [Table 1] showed that Red Label Tea had the lowest pH among the products tested, with a pH of 4.5. Twinning's Tea and Tata Tea showed a pH of 5.5, which ranks both products as having the highest pH. The rest of the products fall in between, with pH of 5.0.{Figure 1}{Table 1}

With regard to the taste of the products, the results show correlation between the pH and the taste. Red Label Tea, with a pH of 4.5, had a very bitter taste that lingered on the tongue. On the other hand, Twinning's Tea and Tata Tea tasted only mildly bitter, which could be explained by their higher pH of 5.5.

Intensity of color

In this experiment the absorbency of each product was tested to determine the concentration of color. [Figure 2] shows that Tata Tea and Twinning's Tea had the lowest absorbency level at a wavelength of 450 nm of 0.31 and 0.245, respectively. Kanan Devan Tea had the highest absorbency level at the same wavelength (0.55). From these results we concluded that Kanan Devan Tea has the highest concentration of caffeine. {Figure 2}

Bulk density

The results showed that with the exception of Kannan Devan Tea and Twinning's Tea, all brands had relatively low bulk density [Table 2]. That could be seen since the other three products were having less void volume i.e the space occupied for air is more that the particles. {Table 2}

Caffeine content

We also measured the caffeine content of each product. The results [Table 3] and [Figure 3] show that Kannan Devan Tea has the highest caffeine content of 0.51 g/10 grams of tea.The lowest caffeine content was seen in Twinning's Tea, which had only 0.22 g. The other products fall in between, with Lipton Tea having 0.47 g, Mumtaz Tea 0.41 g, Red Label Tea 0.39 g, and Tata Tea 0.34 g. {Figure 3}{Table 3}


Twinning's Tea and Tata Tea have the highest pH and they possess a mildly bitter taste. Red Label Tea has the lowest pH, with a very bitter taste.

Kannan Devan Tea has the highest color concentration due to the high concentration of caffeine. Twinning's Tea has the lowest color concentration due to the low concentration of caffeine.

Kannan Devan Tea and Twinning's Tea have the high bulk density. That means more void volume, which indicates slightly difference particle size distribution when compared to other brands

Kannan Devan Tea has the highest caffeine content. Twinning's Tea has the lowest caffeine content


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