10 DAQ was used for determining the differential measurement (electrical potential) to attain more accurate measurement with less noise. The two electrodes (inputs) dipped in solutions were connected to the DAQ. The specifications were: NI-9234 with 4 channels, 5, 24 bit, SW selectable IEPE and AC/DC, 2 V. The advantage of USB-DAQ device was that it alone can build a low cost system. LabVIEW is called as virtual instruments (VI). It contains a set of tools for acquiring, analyzing, displaying, BMN673 and sorting data as well as tools that help in trouble shooting. LabVIEW can be used to build an user interface or front panel, with controls and indicators. The LabVIEW supports the data acquisition

of the analog values. In LabVIEW, FFT is a powerful tool for analyzing and measuring signals (from plug-in DAQ). From the time domain signals, the frequency content was measured. The amplitude of the FFT was related to the number of points on the time domain scale. FFT gave a single waveform with average amplitude against GSK1120212 frequency. A Data Assistant (block

diagram) was used to display the time-voltage spectrum on the front panel. The signals received from the DAQ were displayed. Further, FFT tool (block diagram) was installed in the program. The package was developed user friendly with save options of the waveforms. The program was validated using the frequency generator (Hewlett Placard, USA). The experimental setup was self-explanatory (Fig. 1).9 The aqueous solution of the taste stimulant was filled into the inner tube B through the side tube, C. When the inner tube was filled, the side tube was sealed off with a stretched rubber membrane. Outer vessel was filled with water. The inner tube was hung into the outer vessel A, in such a way that the levels of the liquids in the inner tube and in the outer

vessel remained the same. The electrodes were immersed one into the inner vessel and the other into the outer vessel. The leads were connected to DAQ and further through USB port to the computer. The rubber seal over the side Calpain tube C was ruptured. The electrical potential differences across the electrodes were recorded with time. The data were obtained in the time domain and frequency domain. In the present work, capillary diameter was 0.103 × 10−3 m and length of the capillary was 7.7 × 10−2 m. An isolated environment was maintained and all electrical fixtures were switched off. The experiment was conducted with AC mode. GraphPad prism was used for evaluating the statistical parameters, regression analysis and graphs. The hydrodynamic oscillations were known as density oscillations. The density of the sour taste stimulant in the capillary was responsible for the initiation of oscillations. Hence, densities of different concentrations of the sour taste stimulants (citric acid, hydrochloric acid, lactic acid, and tartaric acid) were determined, using a specific gravity bottle.