- Volume 27 Issue 1
The objectives of the study were to analyze the acoustic characteristics related to the internal quality factors of watermelon(Citrulus Vulgaris Schrad). Among the various internal quality factors, only four factors such as ripeness, inside cavity, yellow belt and blood flesh were considered in this study. Relationships between the internal quality factors, the day after fruit set and the day after harvest were also investigated. Test apparatus was the same as the apparatus described in the previous study(Choi et at., 2000). The selected sample was divided into four groups; 69 samples used for ripeness tests 56 samples for ripeness test along the day after fruit set and for yellow belt detection, 60 samples for ripeness along the day after harvest 44 samples fur blood flesh detection. It was shown that the first peak frequencies shifted to the lower range and the energy ratios of the bandwidths between 0∼550 Hz to the bandwidths between 850∼2500 Hz increased as the day after fruit set elapsed. Since the acoustic responses of the watermelon such as frequency and magnitude began to change from 10 days after harvest, the storage period of watermelon in a normal temperature condition seemed to be approximately 10 days after harvest. The ratios of the first peak amplitude to the maximum peak amplitude fur the sound watermelon showed the higher value than that fur watermelon with cavity inside, and the separation between the sound and cavity inside could be accomplished by the ratio value of 0.25. The energy ratios (0∼550 Hz/850∼2,500 Hz) for the watermelon with cavity inside showed the higher value than 2.3. The frequency characteristics of the yellow belt watermelon appeared mostly in the range of 600∼900 Hz frequencies. The yellow belt watermelon showing the energy spectral density function at this frequency range to be over 70 seemed to be not a marketable commodity, The energy ratios(0∼550 Hz/850∼2,500 Hz) for the blood flesh watermelon showed the higher value than 3.5.
- Chen, J. Y., M. Miyazato and E. Ishiguro. 1993a. Discrimination of internal quality of agricultural products using response properties for vibration (I). JSAM 55(3):65-72.
- Chen, J. Y., M. Miyazato and E. Ishiguro. 1993b. Discrimination of internal quality of agricultural products using response properties for vibration (II). JSAM 56(6):43-48.
- Choi, D. S., K. H. Choi, K. J. Lee, W. K. Park, M. S. Kim, D. C. Choi and Y. Hwang. 2000. Acoustic Characteristics of the Watermelon using Neural Network(II)-Yellow belt and Blood flesh. Proceedings of the KSAM 2000 Winter Conference 5(1):422-429. (In Korean)
- Jhang, K. Y., M. S. Kim and H. K. Cho. 1998. An Experimental Study on the Propagation Characteristics of Ultrasonic Wave in Watermelon. The Korean Society for Agricultural Machinery 23(6):615-620. (In Korean)
- Kawamura, T. and I. Nishimura. 1988. Studies on the physical property of watermelon (I). JSAM 50(2):85-92.
- Kim, C. S. and B. S. Myung. 1997. Development of Measuring Sensor for Discriminating Maturity of Watermelon on Repulsion Characteristics. The Korean Society for Agricultural Machinery 22(1):49-58. (In Korean)
- Kim, M. S., D. S. Choi, Y. H. Lee and Y. K. Cho. 1998. Study on Acoustic Characteristics of the Watermelon. The Korean Society for Agricultural Machinery 23(1):57-66. (In Korean)
- Kouno Y., T. Mizuno, H. Maeda, T. Akinaga and Y. Kohda. 1993. The Development of A Device to Measure The Ripeness and Internal Quality of Watermelons. Proceedings of the International Conference for Agricultural Machinary Engineering October 19-22, 1993, Seoul, Korea.
- Yamamoto, H., M. Iwamoto and S. Haginuma. 1980. Acoustic impulse response method for natural frequency of intacts fruits and preliminary applications to internal quality evaluation of apples and watermelons. J. of Texture studies 11:117-136. https://doi.org/10.1111/j.1745-4603.1980.tb00312.x
- Yamamoto, H., M. Iwamoto and S. Haginuma. 1981. Nondestructive acoustic impulse response method for measuring internal quality of apples and watermelons. J. of Japanese Society of Horticultural Science 50(2):247-261. https://doi.org/10.2503/jjshs.50.247
- 정범윤. 1990. 수박의 생육진단과 재배기술. 한국원예정보기술센터.