Bulletin UASVM Agriculture, 68(2)/2011 Print ISSN 1843-5246; Electronic ISSN 1843-5386
Measurement of Malondialdehyde in Fermented Dairy Cristina Anamaria SEMENIUC, Carmen Rodica LAZAR, Ancuţa Mihaela ROTAR, Ramona SUHAROSCHI, Sevastiţa MUSTE University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, Calea Mănăştur 3-5, 400372, Cluj-Napoca, Cluj, România, e-mail:
[email protected] Key words: MDA, fermented dairy, Sana.
SUMMARY A modified method of Tarladgis et al. (1962) and Witte et al. (1970) has been developed for quantitative determination of malondialdehyde (MDA) in fermented dairy. MDA was reacted with 2thiobarbituric acid (TBA) in the presence of tricloracetic acid (TCA). The TBA-MDA adduct was quantitated spectrophotometric (Shimadzu UV/Vis double beam spectrophotometer, model 1700). The UV/Vis detector was set at 532 nm. Beer's law is obeyed in the concentration range of 0.186-3.724 nM/mL. The five different levels of calibration standards were prepared using 1,1,3,3tetraethoxypropane (TEP), the precursor of malondialdehyde. Results showed linearity with a good correlation coefficient of 0.9824. The calibration curve is shown in Figure 1.
Fig. 1. MDA calibration curve
Samples of fermented dairy (Sana - with 3.5% fat) were taken in study. An average of 0.279 ±0.008 mg MDA/Kg sample was found in Sana. The method shows good precision with relative standard deviation (RSD) of less than 3%.Using this method, ppm quantities of MDA can be easily detected in fermented dairy with good repeatability. This study was conducted as part of postdoctoral training received through the project “ŞCOALA POSTDOCTORALĂ ÎN DOMENIUL AGRICULTURII ŞI MEDICINEI VETERINARE (POSTDRU 62371)”
REFERENCES 1. Tarladgis, B.G., A.M. Pearson, L.R.JR. Dugan (1962). The chemistry of the 2-thiobarbituric acid test for the determination of oxidative rancidity in foods. I. Some important side reactions. The Journal of the American Oil Chemists' Society 39, 34-39. 2. Witte, V.C., G.F. Krause, M.E. Bailey (1970). A new extraction method for determining 2thiobarbituric acid values of pork and beef during storage. Journal of Food Science 35, 582–585.
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