Utilization of Red Dragon Fruit Skin (Hylocereus Costaricensis) as an Indicator of Formalin and Borax in Food



The development of the times produces new ideas and innovations. This situation brings people to the bebagai advancement in the field of economy, health, biotechnology and so forth. One of the advancements that have a positive and negative impact is progress in the field of food processing, namely in the form of cans and bottles. This food processing technology usually uses preservatives, both natural and synthetic. The preservatives are mixed in the food to prolong the endurance of a food.

Formalin belongs to a group of powerful disinfectant compounds that can eradicate various bacterial decomposers and is usually used as a corpse preservative. The use of formalin in foodstuffs is very dangerous because it can cause direct symptoms, such as heartburn, esophagus, isophagus and stomach. In addition, other symptoms are caused by severe pain, sudden fainting, diarrhea, liver damage, even death. (Yuliarti N. Awas, 2007).

Sodium Tetraborate (Na2B4O7.10H2O) is a mixture of mineral salts of high concentration, which is an impure form of borax. Borax comes from the Arabic language, Bouraq. It is a soft crystal that contains boron elements, is colorless and readily soluble in water. Borax powder is white crystalline, odorless, insoluble in alcohol. Borax is a compound that can improve the texture of food to produce a good appearance, such as meatballs, crackers and even wet noodles in the market. Crackers containing borax when fried will be fluffy and soft, good texture and crunchy. A well-known pyrex glass can have such a performance as it is made with a mixture of borax. Most likely the borax preservative power is caused by the active compound boric

Dangers lead to a ban on the use of formalin and borax on foodstuffs. But in fact, the market is still found a variety of foods that still contain formalin and borax. Therefore, numerous testing efforts have been made to reduce the distribution of formalin and borax food in the community. Formal tests were performed, among others, by visible spectrophotometer analysis, or by using reagents such as Fuchsin, Tollens Reagents, Fehling, KMnO4 0.1 N + NaHSO3 0.1 N and KMnO4 0.1 N. The tests were still limited to laboratory scale, difficult to test independently.

Red dragon fruit that lately attracted a lot of public, 30-35% of their skin is often just thrown away as a waste. As an effort to utilize the red dragon fruit skin waste that has not been optimal, and in order to increase the economic value of the red dragon fruit skin and its usefulness for the community it needs to be utilized in order to increase the economic value and benefit the community

Based on this, the need for simple testing of formalin that can be done by the general public, in a way that is easy and low cost. One of them is by using red dragon fruit skin extract that has potential as a simple indicator of formalin test and borax in food. The dragon fruit skin contains anthocyanins that can be used in acid-base testing. So hopefully the innovation can make it easier for people to distinguish between formalin and non formalin food, borax and does not contain borax

The purpose of writing
1. Show how to utilize red dragon fruit skin as an indicator of formalin and borax in food.
2. Show how to know foods containing formalin with anthocyanin from red dragon fruit skin
3. Show how to find foods and beverages containing borax with anthocyanin from red dragon fruit skin


1. Test of Antosianin Extract of Dragon Fruit On Buffer Solution
The anthocyanin extract used in this study was an anthocyanin extract from red dragon fruit skin. Anthocyanin extracts were made using 100 grams of red dragon fruit skin and 150 ml of aquades or crushed tap water using mortar and pestle. Furthermore, the mixture is filtered to form an anthocyanin extract from the skin of red dragon fruit. After the formation of anthocyanin extract, the anthocyanin extract was tested on buffer solution. Then it is determined some buffer solution at certain pH to be used as sample. In order to show the changes generated from the various pHs, the pH buffer solution 3 represents the acidic atmosphere, the pH 7 buffer solution represents a neutral atmosphere, and a pH 13 solution represents an alkaline atmosphere. Next, the three samples are mixed into the test tube.
The process of extraction of anthocyanin dragon fruit skin

There is a difference to the color change that occurs between the three samples. In the acid sample there is a change of color from colorless to pink. In the neutral sample there is a change of color from colorless to purple. While on the base sample changes color from colorless to purple.

Anthocyanin extract on acid, neutral and base buffers

Based on the results of this experiment, it is concluded that the anthocyanin extract can cause the color change to be pink at acidic, purplish red in neutral atmosphere, and purple fade on alkaline atmosphere which can be seen in the table below

Buffer SolutionThe Colour of BufferThe Change Colour
pH 3ColorlessPink
pH 7ColorlessFaded Red
pH 13ColorlessFaded Purple

Anthocyanin extract can be said to be effective as an indicator of formalin and borax can be seen with the color changes inflicted. The clearer the color difference between the various pH the more effective the anthocyanin extract is. In order to know the qualification of anthocyanin extract which is effective to be used as indicator of formalin and borax in food, it is done by research with several different treatment to know the comparison between anthocyanin extract and test solution

In this experiment, three different treatments were performed:
a. T1 = The ratio between the test solution and the anthocyanin extract is 1: 2 (buffer: extract)
b. T2 = The ratio between the test solution and the anthocyanin extract is 2: 1 (buffer: extract)
c. T3 = The ratio between the test solution and the anthocyanin extract is 1: 1 (buffer: extract)
The experimental results of three different treatments are in table below:

Solution Comparison (Buffer: extract)Color quality
1 : 2Good
1 : 1Enough
2 : 1Poor

Based on the result of three experiments it is concluded that the comparison of anthocyanin extract and the most suitable test solution is 1: 2.

2. Testing of Formalin in Foods
In the picture below is a series of research results, tissue paper that has been wet with dragon fruit skin extract which given orange juice will give easy red color (Picture below)

Tissue paper that has been soaked with dragon fruit skin extract

In the next picture below is a tissue paper that has been placed on in each place, tofu A is a non-formalin tofu with tissue paper without dragon fruit skin extract, tofu B is tofu without formaldehyde with tissue paper that has been moistened dragon fruit skin extract, and tofu C is a tofu containing formalin which is given tissue paper with dragon fruit skin extract on it.

Tofu A without formaldehyde, Tofu B without formalin, Tofu C with formalin

Based on observations during the study, obtained data as follows table below

Treatment 1ColorlessRed fadedPink
Treatment 2ColorlessRed fadedPink
Treatment 3ColorlessPurple fadedPink

Based on the results of the above experiment can be discussed that the white tissue paper is a color control, tissue containing dragon fruit skin extract on the tofu that does not contain formalin will be reddish red color when compared with the tofu containing formalin (Picture below) In the study shows that after 10 minutes the tissue paper in the tofu that does not contain formalin color fades faster, from pink to red faded and

Tissue paper that has been silenced for 10 minutes

In the next 10 minutes (total 20 minutes) the color fades and becomes white while the paper on the tofu containing formalin remains red, this is caused by the acidic nature of formalin can stabilize the anthocyanin color of the dragon fruit skin, in addition the function of formalin as a preservative can stabilize the anthocyanin color from the skin of dragon fruit

Tissue paper that has been silenced for 20 minutes
3. Test of Food and Drinking Containing Borax
Foods containing borax can be detected with dragon fruit skin extract by dissolve with water, in this study used food that has been mixed with borax and food that is not mixed with borax, meatball  which has been mixed borax in puree with sliced and softened by using pestel and added water then taken the water.
Meatball Saple A Containing Borax and B without Borax
The same treatment is also done for the meatballs that do not contain borax, in this study as much as 2 ml of extraction solution mixed with 4 ml dragon fruit skin extract. In the figure below shows that a solution containing no borax (Label A) provides an purple color while the borax-containing solution (Label B) dissolves into a faded purple color.
The change color after addition of extract Saple A Containing Borax and B without Borax

The addition of borax tea drink to preserve tea can also be detected in this way, as much as 5 ml of tea not given additional borax (label A) and 5 ml of tea which has been given additional borax

Sample A Without borax, Sample B Using Borax

The two solutions are then added by the extract of the skin of the fruit dragon as much as 10 ml, from the experimental results showed that tea containing borax color becomes faded and medium brown which does not contain borax remains pink.

Result test (Label A without Borax, Label B using Borax)

From the results of this demonstration showed that the anthocyanin dragon fruit extract can detect borax in food and beverages because borax is alkaline, while the tea is acidic. so the anthocyanin will change color to pale purple when in an alkaline atmosphere, whereas in purple tea look brown as it mixes with the brown color of the tea. In tea that does not contain anthocyanin color borax remains pink, because the tea is acidic.

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