18B-10 |
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M. HENDRICKX, P. Verlinde, I. Indrawati, and A. Van Loey. Laboratory of Food Technology, Katholieke Univ. Leuven, Dept. of Food and Microbial Technology, 22 Kasteelpark Arenberg, Heverlee, B-3001, Belgium An adequate folate intake is recommended because it promotes health. Since folates are sensitive to temperature, pressure, oxygen and others, these vitamins can be affected during food processing. To avoid further oxidation of folates during extraction and purification prior to the quantification of residual folate concentrations after processing, antioxidants must be used. However, antioxidants can also reduce the oxidized folate degradation products because of their reducing capacity. Hereto, the aim of our research was to investigate the effect of antioxidant (i.e. 2-mercaptoethanol) addition on the estimation of folate stability and the determination of folate degradation kinetics.[6S]-5-Methyltetrahydrofolate (0.2µg/ml) in phosphate buffer (0.1M, pH 7, 8.11ppm O2) was used. The effect of addition of 2-mercaptoethanol (0 to 2%) to the folate samples before and after thermal (25 to 90°C) and combined pressure temperature treatments (100 to 600 MPa/40°C/15min) was investigated. The residual folate concentrations were estimated using RP-HPLC methods. Addition of 2-mercaptoethanol before thermal and combined pressure temperature treatments increased the folate stability. Folate stability was enhanced by increasing the 2-mercaptoethanol concentration. Based on the chromatograms, adding 2-mercaptoethanol to the samples after the treatments resulted in a partial or total reduction of oxidized folate degradation products, depending on the severity of the treatment. The use of 2-mercaptoethanol addition (2%) after thermal treatments caused a 'lag' phase in the beginning of the folate degradation kinetics. It led to an overestimation of folate stability and it also influenced the obtained kinetic data. Our results suggested that the use of antioxidants before treatment enhanced the folate stability, however adding antioxidants after treatment can cause a significant overestimation of folate stability and mislead the determination of folate degradation kinetics.
Session 18B, Food Chemistry: Antioxidant and bioactive agents
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |