54F-18 |
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M. HENDRICKX, Laboratory for Food Technology, Katholieke Univ. Leuven, Dept. of Food and Microbial Technology, 22 Kasteelpark Arenberg, Heverlee, B-3001, Belgium, I. Indrawati, Laboratory for Food Technology, Katholieke Univ. Leuven, Dept. of Food and Microbial Technology, 22 Kasteelpark Arenberg, Heverlee, B-3001, Belgium, P. Verlinde, Laboratory of Food Technology, Katholieke Univ. Leuven, Dept. of Food and Microbial Technology, 22 Kasteelpark Arenberg, Heverlee, B-3001, Belgium, A. Van Loey, Laboratory of Food Technology, Katholieke Univ. Leuven, Dept. of Food and Microbial Technology, 22 Kasteelpark Arenberg, Heverlee, B-3001, Belgium, and M. T. Nguyen, Laboratory Food Technology, Katholieke Univ. Leuven, Kasteelpark Arenberg 22, Leuven, 3001, Belgium. High Pressure (HP) technology is being used as an alternative for Thermal (T) processing. This technique has been promoted to have advantages in maintaining the natural food properties such as odor, flavor and vitamin because it has no/limited effect on covalent bonds. Up to now, little attention has been paid to study in detail in which extend HP technique can be used to maintain those natural properties. In this study, folates were chosen as a case study because of their health promoting effects, e.g. prevention of spina bifida, heart diseases, colon cancer etc. However, folates are sensitive to oxidation and temperature. The objective of this investigation was to compare the effect of HP and T on the stability of natural folates, i.e. 5-methyltetrahydrofolate and 5 formyltetrahydrofolate. 5-methyltetrahydrofolate and 5 formyltetrahydrofolate diluted in different buffer solutions were used. Thermal treatment was conducted in thermostated water bath (until 90° C, 0.1MPa) and pressure treatment was carried out in multivessel pressure apparatus (6 vessels @ 40 ml) in different pressure (100-700 MPa) and temperature (10-60°C) combinations. The residual folate concentration after treatments was estimated using RP-HPLC method combined with UV (5 formyltetrahydrofolate) and fluorescence (5-methyltetrahydrofolate) detectors. Phosphate buffer (20mM, pH 2.1) was used as elution buffer and the folates were separated using a linear acetonitrile gradient (5-60%). The results showed that folate was degraded during HP treatment as ound during T treatment. In the presence of oxygen, the degradation during T and HP treatment can be described by first order reaction kinetics. At constant pressure and temperature, the degradation was enhanced by increasing temperature and pressure, respectively. These results suggested that covalent bonds of vitamin can be maintained by HP technique but during treatment, HP can also enhance the oxidation reaction of vitamin (referred to the negative activation volume).
Session 54F, Nonthermal Processing: General I
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |