Development of Beverages' Ingredients Distinguishing System by using Shear Horizontal-Surface Acoustic Wave (SH-SAW) Sensor

1998 Fiscal Year Final Research Report Summary

• Project/Area Number: 09660275
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 農業機械学
• Research Institution: Kagoshima University
• Principal Investigator: TANAKA Shun-ichiro Kagoshima University Faculty of Agriculture Professor, 農学部, 教授 (80041664)
• Co-Investigator(Kenkyū-buntansha): TANAKA Fumihiko Kagoshima University Faculty of Agriculture Research Associate, 農学部, 助手 (30284912)
• Project Period (FY): 1997 – 1998
• Keywords: Shear horizontal surface acoustic wave / Beverage / Solution / Ethanol / Concentration / Conductivity / Dielectric constant

Research Abstract

Research objective and experimental equipment
1. The objective was to construct a prototype shear horizontal - surface acoustic wave (SN-SAW) sensor for determination and differentiation of beverages' tastes, establishment of concentration measurement principals and consequently construction of beverages' ingredients management sensor in the manufacturing process.
2. The equipment is composed of signal generator, vector voltmeter, SH-SAW sensor and PC.The signal phase difference and amplitude are measured by vector voltmeter, fractional velocity shift and attenuation change are determined and then calculation of conductivity and dielectric constant follows.
Research results
1. The prototype SN-SAW sensor was designed with resonance frequencies of 30, 50, and 100 MHz, close measured and calculated resonance frequencies was observed.
2. Beverages' conductivity and dielectric constant values could be measured and distinguished by SH-SAW sensor.
3. The idea targeted shochu actual manufacturing p rocess. Glucose and ethanol solutions are poor electrolytes, there was no correlation between concentration and conductivity, but there was inverse proportional relationship with dielectric constant. Furthermore citric acid solution is a weak electrolyte and therefore conductivity and concentration increased while dielectric constant decreased.
4. Mixed solutions of ethanol and citric acid or glucose and citric acid have multiplication effect and therefore concentration measurements are difficult, thus, redesigning is necessary.
5. A standard malt (moromi) model made of a mixture of glucose, ethanol and citric acid was prepared, with ethanol concentration measurement correlation at 0.99. Actual malt's ethanol concentration was measured with R^2 = 0.88, which shows a high possibility of shochu manufacturing process management sensor.
6. Ethylene glycol type brine concentration measured by refraction concentration tester had high correlation with expected concentration by SN-SAW sensor. Furthermore brine concentration with 1 - 5% impurities had high correlation with conductivity and dielectric constant. The observations show a possibility of using SN - SAW sensor as brine management sensor.