I did estimation of TBARS by following below method-
Minced meat sample (5 g) was blended for 3 min with 25 ml of 20 % TCA. Slurry was kept for 10 min. It was filtered through Whatman No. 42 filter paper. 5 ml TBA (1 mg/ml) reagent was added to 5 ml of sample aliquot (filtrate). After mixing the contents, tubes were kept in a boiling water bath for 35 min. Optical density was measured by spectrophotometer at 532 nm. Blank was run simultaneously. For standard curve 1, 2, 3, 4 and 5 ml of TEP (3 mg/ml) standard solution were used.
Calculation for mg MDA / Kg of meat =
(OD of sample*concentration of standard*Volume of extraction*1000) / (OD of standard*weigh of sample*volume of aliquot*1000)
Simplify the formula as
(OD of sample*concentration of standard*25*1000) / (OD of standard*5*5*1000)
Is this calculation is correct…?
The procedure may be needed to be improved. Reading my published paper.
I agree with Dr. Wangang Zhang. The procedure could be improved. We use the Beuge and Aust (1978) method. You can read it in our paper.
Hi.
There are several papers describing TBARs methods. I recommend you to search in the journal you are looking to publish for similar TBARs methods, therefore you will know how deep the method should be decribed.
Dr Aristide
I read your paper
The TBARS were calculated compared with a standard curve constructed with 1,1,3,3-tetramethoxypropane.
Now question is- How to convert TBA value obtained from standard curve into mg MDA / Kg of meat or which formula is used for calculation for mg MDA / Kg of meat
Dear Dr Pathera,
From standard curve you will get equation and with the help of curve you can calculate the mg MDA / Kg of meat e.g. Y=22.371X-0.289, so here if you are putting OD reading as X you can calculate it.
Dr. Panthera,
In order to transform OD reading to mg/kg meat, besides the equation cited in Mr. Gadekar anwer, usually you will need to use an equation, e.g Tarladgis (1964) that correlates the dillutions, standard points used, volume of the aliquots and etc.
Dr. pathera
To convert the absorbance in mg MDA/kg we do in this way. First of all you have to know the absorbance and so the concentration of 1,1,3,3-tetramethoxypropane that you put in your calibration curve. For each calibration point of the curve you have to calculate the ε (absorbance value/1,1,3,3-tetramethoxypropane concentration) and then the mean value of the ε for the curve you obtained. Obviously the ε for each point of the calibration curve must be very similar or equal.
We use this formula:
(ΔO of the sample × final volume in the vial)/ (ε × g of meat)
Where:
ΔO = sample absorbance
g of meat = how many sample you put in the vial
Dr Gedekar
From standard curve, TBA value obtained and this value was of that aliquot which was measured for absorbance.
But question is- How to convert TBA value of that aliquot obtained from standard curve into mg MDA / Kg of meat or which formula is used for calculation for mg MDA / Kg of meat
How to consider or use sample wt, volume of TCA for extraction, aliquot in calculation ?
Dear Fellow researcher,
Just wondering, did anybody face 'bubble problem' when you pour your reaction mixture into the cuvettes for spectrophotometric reading in TBARS method?. I tried couple of methods and at the end I got too much small air bubbles in the cuvette which gave me unstable absorbance all the time.
Please share your experience.
Thanks in advance,
Gaurav Rajauria @ sir, even i experienced bubbles after washing the cuvette with double distilled water ( its expected as we are using organic solvent to extract the pink chromogen).
Hi, you can calculate TBARS values by referring to the formula below.
TBA # (ppm) = Sample A535 x (1M MDA chromogen / 1.56 x 10^5) x [(1 mole / L) / M] x (0.003 L / 0.5 g meat) x (72.07 g / mole) x (1000 mg / g) x (1000 g / kg)
Dear Gaurav Rajauria ,
If you fill the cuvette 3/4 with the reaction mixture and you see bubbles, tap the cuvette until bubbles disappear.
Note: Make sure there is no difference between the cuvette temperature and the reaction mixture temperature to avoid bubbles.
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