Effects of pulsed electric field on selected properties of L‐tryptophan

Abstract

Summary The effects of pulsed electric fields (PEF) treatment on the solubility, surface tension and fluorescence spectra of L‐tryptophan were systematically investigated using a range of PEF intensities (0–50 kV cm−1) and a number of pulses (0–216). PEF frequency and pulse width used in this experiment were 1000 Hz and 40 μs, respectively. Under these conditions, the solubility, pH value and maximum relative fluorescence value (RFV) of L‐tryptophan were generally increased and then decreased with both increasing the PEF intensity and pulse number. Conductivity of the solution was insensitive to changes but still increased slightly with increasing the PEF intensity. In addition, surface tension was decreased at higher PEF intensity and pulse number. Results from the mass spectrum analysis confirmed that after the PEF treatment, the basic structure of L‐tryptophan remained unchanged. These results suggested that PEF treatment induced some function alteration to the isolated L‐tryptophan without changing the basic structure.

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