The purpose of this study was to investigate the effect of non-thermal technology, a high power ultrasound (HPU) in continuous flow treatment on the reduction in number of Brettanomyces yeasts and lactic acid bacteria (LAB) in wine samples. Yeast cells and lactic acid bacteria were screened for their sensitivity to a high power ultrasound treatment using an ultrasonic processor (400 W, 24 kHz, 100 μm amplitude) at two different wine temperatures (30 and 40 °C). High power ultrasound treatment in continuous flow showed satisfactory reduction of Brettanomyces yeasts (89.1–99.7%) and lactic acid bacteria (71.8–99.3%). Sensory properties of wine were impaired. The results indicate a great potential for the application of HPU in continuous flow system for wine processing in terms of lower usage of SO2 and preservatives. More attention is needed to preserve sensorial properties of wine. 相似文献
In order to quantify the effects of exposure parameters under therapeutic conditions such as sonodynamic therapy, it is necessary initially to evaluate the inertial cavitation activity in vitro. In this study, the dependence of cavitation activity induced by the low-level dual-frequency ultrasound irradiation on exposure parameters has been studied. Experiments were performed in the near 150 kHz and 1 MHz fields in the progressive wave mode. It has been shown that at constant ultrasound energy the fluorescence intensity for continuous sonication is higher than for pulsed mode. With increasing the duty cycle of pulsed field, the inertial cavitation activity is increased. The activity of cavitation produced by simultaneous combined sonication by two ultrasound fields is remarkably higher than the algebraic sum of effects produced by fields separately (p-value < 0.05). This study shows that simultaneous combined dual-frequency ultrasound sonication in continuous mode is more effective in producing inertial cavitation activity at low-level intensity. Therefore, it is concluded that investigations in this combined ultrasound sonication can be useful in sonodynamic therapy for superficial tumors. 相似文献
The effect of high-power ultrasound on olive paste, on laboratory thermo-mixing operations for virgin olive oil extraction, has been studied. Direct sonication by an ultrasound probe horn (105 W cm−2 and 24 kHz) and indirect sonication with an ultrasound-cleaning bath (150 W and 25 kHz) were applied and their effects compared with the conventional thermal treatment.
A quick-heating of olive paste, from ambient (12–20 °C) to optimal temperature conditions (28–30 °C), and an oil extractability improvement were observed when applying sonication. Better extractability was obtained by direct sonication for high moisture olives (>50%) whereas indirect sonication gave greater extractability for low moisture olive fruits (<50%).
Optimal application of ultrasound was achieved with direct sonication for 4 min at the beginning of paste malaxation and with indirect sonication during the malaxation time.
Effect of high-power ultrasound on oil quality parameters and nutritional and sensory characteristics were studied. Changes in quality parameters (free acidity value, peroxide value, K270 and K232) were not found, however significant effects on the levels of bitterness, polyphenols, tocopherols (vitamin E), chlorophyll and carotenoids were observed. Oils from sonicated pastes showed lower bitterness and higher content of tocopherols, chlorophylls and carotenoids. Related to sensory characteristics, off-flavour volatiles were not detected in oils from sonication treatments. Total peak areas of volatiles and the ratio hexanal/E-2-hexenal, as determined by SPME analysis, were lower than non-sonicated reference oils; sensory evaluation by panel test showed higher intensity of positive attributes and lesser of negative characteristics than those untreated. 相似文献
A novel optical arrangement to generate a laser array line source of laser-generated ultrasound based on two-beam interference is proposed. The arrangement simplifies the adjustment of the laser array source period by changing the intersection angle of two interference beams. The performance of the arrangement is illustrated through measurements of the surface acoustic wave generated by the nanosecond laser array line source in aluminum metal. The surface acoustic wave generated by the laser line array source has stronger directivity parallel to the direction of the line source. The intensity of the measured surface acoustic wave is higher than that generated by a laser spot source with the same incident energy. The optical arrangement generating the laser array line source will be particularly advantageous in laser-generated ultrasound systems used for chemical corrosion detection. 相似文献