Effect of photodynamic treatments on quality and antioxidant properties of fresh-cut potatoes.

This study evaluated the feasibility of curcumin based photodynamic sterilization technology (PDT) applied to fresh-cut potato slices. Potato samples with 30 µmol L-1 curcumin solution were exposed to 420 nm light emitting diodes (LED) at a total dose of 0.7 kJ cm-2. Results showed that PDT inactivated 2.43 log CFU mL-1 of Escherichia coli (BL 21) and 3.18 log CFU mL-1 of Staphylococcus aureus and maintained the color, texture, weight as well as total solid content of treated potatoes. Additionally, loss of phenols and flavonoids was significantly prevented, increasing the total antioxidant capacity. This was attributed to changes in enzyme activity that PDT decreased the activity of polyphenol oxidase (PPO) and peroxidase (POD) by 59.7% and 47.8% and increased the activity of phenylalanine ammonia-lyase (PAL). Therefore, curcumin-based PDT has the potential to maintain the commercial quality of producing and achieving microbiological safety.

Noninvasive thermometer for HIFU and its scaling.

Acoustic-inversion method for a noninvasive temperature measurement in tissue is presented. A set of B-scan operating in M-mode was used as a signal-equipment. The echoes reflected from an assigned surface in tissue were acquired before and after heating, and the corresponding spectra were then obtained by FFT. In order to conduct the acoustic-inversion method, a theoretical formula given by authors in another paper was invoked. The optimization algorithm was implemented to fit the spectra to the measured data and calculate changes in temperature.